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THE AM BULLETIN BOARD => Technical Forum => Topic started by: W0BTU on August 27, 2011, 07:28:58 PM



Title: Beverage receiving antennas
Post by: W0BTU on August 27, 2011, 07:28:58 PM

I've been enjoying the amfone.net forums for some time now. However, I have yet to see anyone mention a single thing about using a separate low-noise receiving antenna, such as a Beverage.

Here's what I use at my QTH: http://www.w0btu.com/Beverage_antennas.html

Perhaps not the best on the planet, but they certainly work for me.

How many AM ops use Beverages or other types of separate low-noise receiving antennas?


Title: Re: Beverage receiving antennas
Post by: K1JJ on August 27, 2011, 07:40:27 PM
Hi Mike,


Very nice beverage website you have! Should be added to the antenna archives here. 

Yes, it's a FB receiving antenna for sure. There's lots of guys using them here.
I had a pair for 75M side by side phased for Europe -  with three others in other directions.

http://amfone.net/Amforum/index.php?topic=6862.0


Go to "Home" here and type "Beverage" into the search box. You will see pages of threads.

Tom, K1JJ     (Still calm with light rain at 7:45 PM)


Title: Re: Beverage receiving antennas
Post by: W0BTU on August 27, 2011, 08:11:05 PM
Thanks, Tom. Looks like it's been awhile since there was any discussion about Beverages.

I might try a phased pair someday like that.


Title: Re: Beverage receiving antennas
Post by: Steve - K4HX on August 27, 2011, 09:21:29 PM
Lots of discussion on receiving antennas. Here are just a few:

http://amfone.net/Amforum/index.php?topic=21784.0

http://amfone.net/Amforum/index.php?topic=10231.0

http://amfone.net/Amforum/index.php?topic=26477.0

http://amfone.net/Amforum/index.php?topic=18760.0


Title: Re: Beverage receiving antennas
Post by: k4kyv on August 27, 2011, 09:52:34 PM
Quote
There's a rumor that there is somehow a benefit to sloping the ends down to the earth gradually in, say, the last 60 feet at each end. (The reasoning was that the vertical drop at each end might pick up unwanted signals off the side). Don't do it. That adversely affects the antenna's impedance and could actually hurt performance. And besides, it's a safety hazard.

I think that old wives tale was started by W1WCR (of Liberty Net fame) with his beverage antenna handbook.

One possible advantage to the idea would be to let the ends of the beverage serve as a guy wire for the pole at each end, and allow a slightly longer antenna to fit into a specific limited space. Probably not worth any difference the additional few feet of antenna would make, except that one pole might be eliminated at each end. The vertical slope over 60' would pick up just as much off-to-the-side signal as a straight vertical wire at the very end of the antenna. That's exactly how the Pennant antenna works versus the Flag.

Exactly how did you mount the two-wire line on top of the poles? Looks like you used water pipe or conduit for the supports, but I couldn't tell from the photo how the wire is suspended from the top of the poles. I just finished building a 140' open wire transmission line from shack to tower.  Found heavy duty rigid conduit and water pipe far too expensive, so used 10' galvanised tee-posts with home-made metal cross arms with embedded ceramic stand-off insulators fabricated by cutting 3/4" dia. 6" long open wire line spreaders into two equal pieces using a diamond cutting saw intended for trimming ceramic bathroom tiles.

My single wire beverage uses four poles made from 1 1/2"water pipe I had on hand. The rest of the supports are trees, but I was able to suspend the wire from the lower branches in such a manner as to make the entire length of the wire run in a perfectly straight line. In winter it runs out to 800-900', but in summer I have to reel it in to 400' to get it out of the way of the farmer I lease crop land to. I use #8 copperweld wire stretched tightly enough to get by with a support every 150' or so. Like yours, I run mine at 10' high to keep it out of the way of surface traffic.

Nice site.  I bookmarked it for further reading.

PS: what is the component in the bi-directional schematic shown as circles with the letters "GO" inside, leading from each side of the OWL to ground?


Title: Re: Beverage receiving antennas
Post by: W0BTU on August 28, 2011, 03:33:43 AM
Quote
There's a rumor that there is somehow a benefit to sloping the ends down ... That adversely affects the antenna's impedance and could actually hurt performance.

I think that old wives tale was started by W1WCR ... with his beverage antenna handbook.

I think you're exactly right. :-)

Quote
Exactly how did you mount the two-wire line on top of the poles? Looks like you used water pipe or conduit for the supports, but I couldn't tell from the photo how the wire is suspended from the top of the poles.

I sawed four slots in pieces of 1/4" Lucite. Not the best way, but I used what I had at the time. Here's a closeup shot:

https://picasaweb.google.com/100482463989537482519/BeverageAntennas?gsessionid=umUSL5yutWWk7Kkk29aomg#5430777844556191714

The poles are 10' steel Rohn masts. I have some other supports made from treated 10' 2x2s to replace them.

Quote
I just finished building a 140' open wire transmission line ...

I think I saw your photos. Nice workmanship!

Quote
Nice site.  I bookmarked it for further reading.
PS: what is the component in the bi-directional schematic shown as circles with the letters "GO" inside, leading from each side of the OWL to ground?

Thanks, Don. That's "GD". Those are 90 volt Bourns GDTs. They are the blue components in the control box photos on my Beverage page. Sorry about the lousy schematics; I drew those as a preliminary step to an AutoCAD drawing, but never got that far.


Title: Re: Beverage receiving antennas
Post by: Bill, KD0HG on August 28, 2011, 11:41:50 AM
Mike, fantastic web site you have there.

I have an ~800 footer pointed about 60 degrees. It works terrific on AM BCB and 160, seems almost too long for 80 meters, best for only a limited area of the NE CONUS. W1, W2, it really drops off into Virginia and further south.I need to figure out how to remotely sectionalize it some day. In the direction it points it works remarkably well on 75.

It's made from standard 10' fencing steel T-posts and clip-on electric fence insulators holding the #18 copperweld wire. Has to be that high so ag equipment in the field can drive under it. Not every place stocks 10-footer steel posts, but they are available. It only takes a few minutes to beat the posts in with a fencing tool and the snap-on insulators take a few seconds to snap onto the posts. A two-wire Bev can be done by using two snap-on insulators spaced a foot or two apart.. The wires don't need to be horizontally separated.

My coax feed is about 200' long and only grounded at the receiver end, not at the feedpoint transformer. Have to replace and/or fix it every so often as critters like to chew into it.

Ground conductivity? We don't have any.

Thanks for the posting.

Bill


Title: Re: Beverage receiving antennas
Post by: k4kyv on August 28, 2011, 02:52:22 PM
I assume GDT means gas discharge tube. Sometimes this alphabet soup business drives me crazy. Where did you get yours, and what is the breakdown voltage? After my meter disaster, I could use all the protection I can get.

For the open wire transmission line, I couldn't find any 10' tee posts locally, so I had to have them do a special order. I could have got them a lot cheaper if I had ordered them on line directly from the company, but I would have had to be home to receive them the moment when they arrived (and unloaded them from the truck myself), or else they would have been re-shipped back to the sender at my expense. So I opted for the special order. I got galvanised posts, well worth the added expense. When they arrived, every post was warped into an arc (probably something heavy piled on top of the bundle during transit), like the bow on a bow and arrow.  I didn't notice that when I picked them up, otherwise I would have refused the order. But I managed to bend them all back straight. I never had much luck even with with a fencing tool, driving tee posts in perfectly vertical in a straight line, so I fabricated a tripod jig out of 2 X 3s to serve as a guide to hold them perfectly vertical while I drove them with the tool. Once driven, they still seemed kind of flimsy, swinging to and fro like an old style 8' chicken-band whip, so I poured about 3" of concrete in a shallow excavation round the base of each pole.  That made them much more rigid.

I enclosed my beverage feedpoint transformer in an old rural mail box.  The only critters I have to deal with are ants, which I take care of with bug spray.

Beverages are supposed to be their best with low or non-existent ground conductivity.

Another W1WCR old-wives-tale is that HF beverages work better with a single ground wire, shallowly buried like a ground radial, running directly under the full length of the beverage wire. I tried that, using the braid on a run of crapped out coax, lying on top of the ground under the beverage wire. About all I could hear with the antenna was power line noise. Removing the ground wire improved performance.

The beverage is predominately a vertically-polarised receiving antenna, so it is prone to pick up local electrical noise just like a vertical antenna. Its low-noise reputation is due to its horizontal directivity. Chances are good that the noise source will not be in line with the direction of the wire but in another slice of the pie, so the s/n ratio is improved. But if you are unfortunate enough to have a local noise source in the bore-sight of the antenna, all you will  hear is noise, and the antenna will be useless.


Title: Re: Beverage receiving antennas
Post by: W0BTU on August 28, 2011, 05:48:43 PM
Lots of discussion on receiving antennas. Here are just a few: ...

Those look interesting, and I will browse them later. Thanks!

Question: what is the policy in the AMfone forums of replying to an old post? Some forum managers really frown on that. I was thinking I might run across something in those older threads that I might want to comment on. Would that be alright?


Title: Re: Beverage receiving antennas
Post by: W0BTU on August 28, 2011, 06:18:14 PM
Thanks, Bill! Glad you like the Beverage page. :-)

... I need to figure out how to remotely sectionalize it some day. In the direction it points it works remarkably well on 75.

Great idea! With a two-wire Beverage, that's very easy. I have often thought about doing the same thing to mine.

With a single-wire Beverage, I've seen people do that with 24 or 48 volt relays. But it sounds like your ground conductivity is so poor that that it may not work. You may have to walk out there and manually switch the extra length in or out when you want to switch bands, or better yet, come up with a radio-controlled switch powered by batteries.


Quote
It's made from standard 10' fencing steel T-posts and clip-on electric fence insulators holding the #18 copperweld wire. ... A two-wire Bev can be done by using two snap-on insulators spaced a foot or two apart.. The wires don't need to be horizontally separated.

Not to pick on you, but I see a real problem with a two wire-Beverage done that way. Here's why I say that.

When we are receiving signals off the feed end of a Beverage, those two wires act as a transmission line that carry the signal from the reflection transformer back to the feed end. The degree of balance of each wire to ground (or each wire to nearby objects) is very critical indeed.

If the balance on that open-wire line is upset just a little tiny bit, we will really kill our F/B ratio. Even small imbalances in the transformers affect this, but a two-wire Beverage with one wire 10' high and the other 9' high is certainly going to make the difference between either hearing some signals and not hearing them at all.

Even if the supports were non-conductive, this would be true. But in the case outlined here, the top wire has less capacitance to the support than the lower wire does. This would further fill in the nulls and degrade the F/B ratio.

Mechanically, your idea is ingenious. But when we think about what it does electrically, that's an entirely different matter.

Having said that, we might be able to get away with that if the spacing was small, especially if we put a slow twist in the open-wire line.

Quote
My coax feed is about 200' long and only grounded at the receiver end, not at the feedpoint transformer.

Exactly the way it should be done.


Title: Re: Beverage receiving antennas
Post by: W0BTU on August 28, 2011, 06:47:30 PM
I assume GDT means gas discharge tube. Sometimes this alphabet soup business drives me crazy. Where did you get yours, and what is the breakdown voltage? After my meter disaster, I could use all the protection I can get.

Yes, they are Bourns 90 volt ceramic gas discharge tubes. I just looked on mouser.com. I don't have access to the exact part# right now, but think the ones I used are either # 652-2027-09-BLF or 652-2027-09-B.

The data sheets are on mouser.com;  you should look at the specs, they are pretty impressive, given their small size. I opened one up, and they have a very large and close-spaced gap between the electrodes. That would explain their large current-carrying ability.

Some Beverage antenna transformers that are being peddled to hams that purport to have gas discharge protection actually use NE-2 neon lamps. That is little better than no protection at all. NE-2's are $0.15 and GDTs are $1.03 in the same quantities. Of course, neither the NE-2 nor the much heavier duty GDT will protect against a direct hit; but given the price, I think it's deceptive to sell a unit with NE-2s without telling the buyer.

Quote
Beverages are supposed to be their best with low or non-existent ground conductivity.

They don't work over saltwater, that's for sure!

Generally speaking, the higher the ground conductivity, the longer the Beverage must be.

Quote
Another W1WCR old-wives-tale is that HF beverages work better with a single ground wire, shallowly buried like a ground radial, running directly under the full length of the beverage wire. I tried that, using the braid on a run of crapped out coax, lying on top of the ground under the beverage wire. About all I could hear with the antenna was power line noise. Removing the ground wire improved performance.

I don't know where he got that idea. Since his books don't say how long his Beverage actually is, I thought maybe his antenna was so short that it actually was closer to a loop than an Beverage. Maybe in that case, a wire under the antenna would make some sense. But a ham who lives near him told me that wasn't the case at all.

I was really tempted to say what I really think about W1WCR's design on my Beverage page, but I didn't.



Title: Re: Beverage receiving antennas
Post by: Bill, KD0HG on August 28, 2011, 10:34:16 PM
Tnx for comments, Mike and Don.

I'm almost read to fire up for the season, but the CBS Volumax died. Need to fix it.  Mike, are you ever on AM?


Title: Re: Beverage receiving antennas
Post by: k4kyv on August 29, 2011, 02:47:01 AM
I have a spool of several thousand feet of 3/16" diameter shielded cable. Not coax, but it looks like similar dielectric material. I have entertained the idea of testing a 1000' piece for rf loss, and if it is satisfactory for rf up to 7 mc/s, to use it in similar fashion to the two wire balanced version for bi-directionality.  I haven't sat down to figure out exactly how to do it that way, but it should work with the proper transformer configuration. Wonder if you ever heard of anyone successfully doing it that way, using the exterior braid as the beverage wire, while using the coax in normal fashion to pipe the signal back to the other end.


Title: Re: Beverage receiving antennas
Post by: W0BTU on August 29, 2011, 07:23:29 AM
Mike, are you ever on AM?

I wish, but not presently. All I have right now are a couple of slopbucket Icom transceivers, and I'd almost be ashamed to get on AM with them. :-)

I built an AM transmitter many years ago, but I no longer have it. I do have some 833C's and components that I've been thinking would make a nice legal-limit AM transmitter for 160 through 40.

And after listening to K4KYV in conversation with a couple of others recently, I see that I really need a good receiver and a synchronous detector. I was pointing out some nice vintage receivers to the XYL at the Joplin Hamfest this Friday, but that'll have to wait for another time.


Title: Re: Beverage receiving antennas
Post by: W0BTU on August 29, 2011, 07:28:27 AM
I have a spool of several thousand feet of 3/16" diameter shielded cable. ... Wonder if you ever heard of anyone successfully doing it that way, using the exterior braid as the beverage wire, while using the coax in normal fashion to pipe the signal back to the other end.

Oh yes, that's certainly been done. This photo is from the 5th edition of ON4UN's Low Band DXing, page 7-89.

Of course, you would need to have the supports closer together than if you were to use steel-cored wire, since coax can't take a lot of tension. (Or could a non-conductive "messenger" rope be used to support it every 100' or so?)


Title: Re: Beverage receiving antennas
Post by: KZ5A on August 29, 2011, 11:36:14 AM
Not having the room or the inclination to string up several hundred feet of wire for Beverage antennas I'm building a rotatable, orthogonally tuned K9AY loop for low band receiving.   I don't expect it to be quite as good as a Beverage but it should be considerably more versatile and a whole lot easier to build.

The antenna consists of a roughly equilateral triangle, 20 ft on the base and about 20 ft high, with the base about 2 ft off of the ground.  The base is two 10 ft sections of 1/2 inch rigid copper tubing, the sides are copperweld.  It is supported on 5 sections of the common fiberglass military masting and uses an old AR-40 rotator.   The elevation tuning for the null is accomplished with a modified MFJ -956 tuner at the operation position.   The general design is from a QST article a few years back.

IF this antenna works near as well as it models on EZNEC it will allow me to put a 20 to 30db null in any direction and any elevation and should work well from BCB to 20M.

73 Jack KZ5A



Title: Re: Beverage receiving antennas
Post by: W0BTU on August 29, 2011, 12:11:52 PM
... I'm building a rotatable, orthogonally tuned K9AY loop for low band receiving.  ... IF this antenna works near as well as it models on EZNEC it will allow me to put a 20 to 30db null in any direction and any elevation and should work well from BCB to 20M.

Jack,

The K9AY is a good antenna. But if you can get a 20-30 db null in any direction and at any elevation from any antenna, you're a better man than me. :-)

I'm not arguing with you, since I'm not real familiar with the K9AY. I've never built one nor have I ever even modeled one before today.

Just glancing at the single K9AY model on http://www.k7tjr.com/rx1comparison.htm, it doesn't look that good. But it was the only K9AY .ez file I could find. I think maybe it's flawed. I would love to see your file.

Take a look at the four square array of K9AYs on that page. May be better than the performance of a one-wavelength Beverage in a lot less space.

Have you ever seen Dallas Lankford's work with small phased loops? Looks pretty interesting to me. http://groups.yahoo.com/group/thedallasfiles/ He claims a 50 dB F/B ratio and a very clean pattern with his best loop array.


Title: Re: Beverage receiving antennas
Post by: KZ5A on August 30, 2011, 11:09:29 AM
Mike,

I attached the .ez file.  To get this performance from the model you have to use a complex termination, rather than the simple resistive termination used in most published K9AY plans.

The new idea in the QST plan was remoting the termination to the shack  so it can be better manipulated.  So the antenna is connected to the shack via 4 to 1 transformers and RG-6. At the shack I plan to use a MFJ-956 tuner which is a simple L and C in  series, modified with the addition of a variable R to provide the necessary variable complex termination.

No telling if the real world antenna will match the model until I get it built.

This was done in an older version of EZNEC, as I haven't coughed up the $$ for a new version in several years.

I had to rename the file extension ".txt" because the web site would allow uploading a ".ez" file so it will have to be changed back to ".ez".

73 Jack KZ5A


Title: Re: Beverage receiving antennas
Post by: Steve - K4HX on August 30, 2011, 11:54:44 AM
If the post contains good info, no problem.


Lots of discussion on receiving antennas. Here are just a few: ...

Those look interesting, and I will browse them later. Thanks!

Question: what is the policy in the AMfone forums of replying to an old post? Some forum managers really frown on that. I was thinking I might run across something in those older threads that I might want to comment on. Would that be alright?


Title: Re: Beverage receiving antennas
Post by: WA1GFZ on August 30, 2011, 12:18:48 PM
Dallas has a phasing configuration that only works over a small frequency range since he is only interested in MF. Last night I found a phasing configuration that works 160 through 40M with 1 delay line length. I will be testing it soon. The loaded delta loops work quite well. I had a phased pair facing East last winter but phasing wasn't right for more than one band. I put up a pair broadside yesterday. I was playing with HPSDR beam steering but this antenna configuration in broadside mode is not the way to go. Simulation and tests agree it doesn't work that well. Steering the beam only gives a couple dB of gain.  I'll put up the end fire next to verify simulation.
I will be comparing it to simulation of W8JI dxengineering 4 square performance.


Title: Re: Beverage receiving antennas
Post by: Steve - K4HX on August 30, 2011, 12:42:33 PM
Quote
Quote
Beverages are supposed to be their best with low or non-existent ground conductivity.

They don't work over saltwater, that's for sure!

Generally speaking, the higher the ground conductivity, the longer the Beverage must be.

Mostly irrelevant at HF. The incoming wave is not at zero degrees elevation angle, so the lossy earth is not required to induce phase delay. Differences in ground conductivity just mean the termination resistance will need to be different and/or the height can be different for a given amount of gain.

Nulls (on the K9AY or any other directional antenna) are mostly a sideshow. Big numbers sound good but mean little in the real world (assuming they even exist in the real world). For amateur radio work at HF, the amount of the rejection off the entire backside of the antenna is what counts, especially if you have noise on a broad front from that direction (e.g.  An east coast station wishing to work Europe can do well with good broad rejection to the Southwest. This reduces all the electrical noise from a large population of the country, QRM from those directions and T-storm static too). Another important factor is how narrow the front lobe is. The more narrow, the less noise is picked up. The front side and back side performance can be compared across antennas using RDF (Relative Directivity Factor) and DMF (Directivity Merit Figure).

The K9AY is a terminated loop. It's in the same family as the EWE, Flag, and Pennant. All of these terminated loops produce a cardioid pattern with a broad forward lobe and fairly deep but narrow null off the back. The position of the null off the back can be varied by changing the shape of the loop and to some extent the termination resistance. The RDF and DMF are about the same for all of them: an RDF of about 7 and a DMF of about 11. A vertical has an RDF of 4.  A properly terminated one-wavelength Beverage has an RDF of about 10 and a DMF of 19.

There are times when a deep but narrow null is important or useful.  One is when you are trying to null out local noise. A phasing box and two antennas (one optimized to pick up the noise) is a better way to go than a K9AY. Another is when you are doing BC band DX. Here you want to null out other stations on the same frequency and/or adjacent frequencies to pull out a rare one in a different direction. For both of these applications, the null should be maximum at or very near zero degrees elevation. The null on a K9AY is maximum in 20-30 degree range. These angles are not optimum of local noise rejection or BC DXing but better for amateur radio work where incoming noise and QRM is likely be at higher angles.
 

K9AY. Info at the link below.

http://amfone.net/Amforum/index.php?topic=26477.0


I also have up a pair of offset, end-fire phased Beverages. The Bevs of course are superior. But they only work in one direction. The K9AY is very simple and easy to put up  and covers four directions. More info on comparing my Bevs and K9AY at the link below.

http://www.amwindow.org/misc/huzantennas/antennas.htm


One other thing to consider are dimensions of the K9AY loops. As designed by Gary Breed, K9AY, the loops are too large be effective on 40 meters and for sure on 20 meters. He actually optimized the system for 160 meters. It works reasonably well on 80 meters too. If you aren't going to operate on 160 meters and want directivity on 40 meters, make the loops smaller - something around 50 feet total wire instead of the 80-85 feet used in the original design.


Title: Re: Beverage receiving antennas
Post by: Steve - K4HX on August 30, 2011, 12:50:39 PM
Some audio clips showing how the K9AY works for AM amateur radio purposes.


The first is Ken-K8TV on 3875 kHz at 2PM ET. Reception is rather noisy on the dipole (you'll hear it first) but much less so on the K9AY. Ken is about 390 miles northwest of my location.

The second is Tron/WA1HLR on 160 meters, 26 February at about 10PM ET. The band is quite noisy and his signal isn't all that good on the dipole. Switching to the K9AY cleans it right up. On the clip, it's hard to hear when I switch the antennas (there is no audible click). Instead you will hear what sounds like Timmy fading and the static coming up. He wasn't fading. That was me switching to the dipole. Tron is 600 miles from my location, but I've seen similar results on stations as close as 250 miles, depending on band conditions and/or time of day.





Title: Re: Beverage receiving antennas
Post by: W0BTU on August 30, 2011, 01:02:49 PM
I attached the .ez file.  ... I had to rename the file extension ".txt" ... so it will have to be changed back to ".ez".

EZNEC+ 5.0 choked on it. It displayed a run-time division by zero error and quit. Thanks anyway, though.


Title: Re: Beverage receiving antennas
Post by: Steve - K4HX on August 30, 2011, 01:44:16 PM
Some audio clips showing how a Beverage antenna can improve receiving conditions even relatively local AM signals on 75-meters.

The first is of Kerri - KC2UFU on 3872 kHz in the fall of 2009. She is located 211 miles from me. The static is not terrible but you can hear the noise drop when I switch from the dipole to the Beverage. The clip starts out on the dipole, then switches to the Beverage at about 12 seconds, then back to the dipole at 27 seconds and then back to the Beverage at 32 seconds. She was running about 30 Watts.

The second clip has Kerri and Bob - K1KBW. Bob is located 352 miles from me. Here you can hear the reduction of some SSB QRM. Both Kerri and Bob are located Northeast of me, right in the main lobe of my Beverage. The SSB stations were all to the South of me. Some were in Florida. Notice the drop off in the SSB when switching from the dipole to the Beverage at 8 seconds. Then the SSB comes back up at 22 seconds when I switch back to the dipole and drops again at 30 seconds when I switch to the Beverage. Then it's back to the dipole at 44 seconds and back to the Beverage at 52 seconds. The drop off in the SSB is completely due to the back and side rejection of the Beverage. I'm not changing IF bandwidths at all.


Title: Re: Beverage receiving antennas
Post by: Todd, KA1KAQ on August 30, 2011, 02:47:54 PM
I'm still not sure which is more impressive - the overall performance or actually seeing the two systems you use, Steve. The K9AY is at least discernible in the trees and brush, but the beverage has to be hunted for. Hard to believe you can get such results from something so....simple? I'd think you were yanking our collective chain if I hadn't seen it myself. I remember thinking it would somehow make the signal hugely louder, which it doesn't; it just takes away all that noise and makes it appear louder as a result.

A beverage is next on the antenna project list here. Trenching the feedline will be the worst part here. It's always interesting to read of others' experiences and learn new tricks.


Title: Re: Beverage receiving antennas
Post by: KZ5A on August 30, 2011, 04:24:50 PM
I should spring for a new copy of EZNEC, mine is EZNEC 3 and is umpteen years old, and doesn't model ground systems very well.

The article is in Oct 2010 QST by Tony Preedy G3LNP.  My copy seems to have escaped me so I need to hunt for another.

A schematic is at....

http://www.flickr.com/photos/79358868@N00/5212370224/

I didn't try to model the transformers, feed lines, and remote termination.  Just modeled with local feedpoint and termination.

Beverages, I'm sure, are great if you have the acreage.

73 Jack KZ5A





Title: Re: Beverage receiving antennas
Post by: Steve - K4HX on August 30, 2011, 07:02:25 PM
I've talked to Tony many times on 80 meters and once or twice on 160 metet phone. His article cover his version of phasing two loops to move the back side null. Pretty neat stuff. I've thought of trying his design. Could be very powerful for getting rid of some QRM. Let me know if you need the article. I think I still have the hardcopy here.

How much space do you have? Depending on your requirements, you may have the space you need for a Beverage.


Title: Re: Beverage receiving antennas
Post by: Bill, KD0HG on August 30, 2011, 07:32:22 PM
If no space, I'll add my pro comments sbout shielded (or not) loops.
A tuned 4-footer in the yard is steerable and has terrific directionality.


Title: Re: Beverage receiving antennas
Post by: WA1GFZ on August 31, 2011, 10:20:23 AM
http://www.hizantennas.com/ check this out


Title: Re: Beverage receiving antennas
Post by: KZ5A on August 31, 2011, 12:05:35 PM
About as close as I could get to a Beverage would be about 175 to 200 ft oriented E-W.   The angle for Europe is not there on this lot.

Small tuned loops look like an interesting option and I will probably get around to trying one.   My impression from various articles is that the K9AY may be better from a SNR perspective.  

Although I've been a ham for almost 50 years this winter will be my first serious venture into low band operating so it's all one big learning curve and I'm enjoying it.   The antenna "farm" will be a 50 ft roof mounted vertical that is remotely switchable for 160/80/40, a sloping 160/80/40 trap dipole running SSW-NNE, and the rotatable K9AY.   I expect the vertical to be primarily a TX antenna, its up now but is noisy as Hades on RX.   The dipole is on the ground waiting for me to get a support rope up 70 ft in a pine tree.   All the parts for the K9AY are on hand and I'll start on it as soon as the dipole is up.

The orientation for the dipole is "non-optimal" and I'm hoping the slope will give it adequate utility to the NE.  It may get converted to an inverted-V later.

The K9AY is not the "best" low noise RX antenna around but it looks like the champ from a cost/benefit consideration.

73 Jack KZ5A


Title: Re: Beverage receiving antennas
Post by: k4kyv on August 31, 2011, 12:18:28 PM
If no space, I'll add my pro comments sbout shielded (or not) loops.
A tuned 4-footer in the yard is steerable and has terrific directionality.

I have a 5' square shielded loop  built per the 1970s ARRL antenna book. The null is so sharp that it could be considered omni-directional, but if it can be rotated some noises can be nulled out very effectively. It often is less noisy than the vertical on 160m. It also works on 80m with the trimmer cap run all the way out. It is now on a rotatable frame inside the shack, but with all the other metal and wiring in close vicinity it is of limited use. When the "shack" was in the main house, I hung it on the wall like a map, and it still usually pulled in signals better than did the quarter-wave vertical.

A couple of times I took the rotatable version outdoors, well away from the shack, and using my R-1000 with a long extension cord, was able to get excellent result nulling out a lot of (but not all) local noise, but it seemed virtually omnidirectional to sky-wave signals (totally ineffective in nulling out QRMers).  I have an old TV antenna rotator, so maybe I should try to get it working and move the loop outside. Problem is, the tuning is very sharp, so it would require another remote tuning device with reversible motor to make it work in more than one segment of the band.

From what I have read, the K9AY loop, Flag, Pennant, EWE, etc. are basically two-element phased verticals, with a  cardoid pattern rather than figure-8, and the nulls are not razor-sharp like the shielded loop, allowing them to better null out the noise. I picked up a bunch of 4-ft fibreglass  rods at Dayton one year with the idea of using them to support a K9AY or similar antenna, but have had greater priorities and never started  the project. It appears feasible to build a rotatable K9AY loop if you have the uncluttered space to rotate it and anchor it down in the chosen direction.

I built up a K6STI Loop (http://www.angelfire.com/md/k3ky/page45.html) from the original Sep 1995 QST article, but it turned out to be a big disappointment. No more 'low noise' than a random piece of wire tossed out the window. About the only use it ever was to me was to provide the motivation to build the beverage, which has given good to excellent results. The thing is a PITA to mow around, but I haven't taken it down, thinking maybe some day I'll play with it some more and see if I can make it work better.


Title: Re: Beverage receiving antennas
Post by: W0BTU on August 31, 2011, 01:05:47 PM
A couple of times I took the rotatable version outdoors, well away from the shack, and ... was able to get excellent result nulling out a lot of (but not all) local noise, but it seemed virtually omnidirectional to sky-wave signals (totally ineffective in nulling out QRMers).

Yes. Small loops at certain low heights only have the deep null at very low angles. I just discovered that this week while playing with them in EZNEC+.

This is shown on Fig. 2 on http://www.w0btu.com/magnetic_loops.html (the first 3D plot as you scroll down a little). Note that the deep nulls along the X axis decrease dramatically as the elevation increases.


Title: Re: Beverage receiving antennas
Post by: Steve - K4HX on August 31, 2011, 03:55:29 PM
Quote
About as close as I could get to a Beverage would be about 175 to 200 ft oriented E-W.   The angle for Europe is not there on this lot.

Too bad about the angle/orientation. You definitely want NE for Europe. A pair of 180 footers phased would be superior to the K9AY. But go with what you got and have fun. Hope to hear you on the bands.


Title: Re: Beverage receiving antennas
Post by: KM1H on August 31, 2011, 04:52:35 PM
Use 5 of the larger metal Slinkys stretched out over 150', soldered end to end, and you have almost the equivalent of a full wave on 160. Termination here in very poor soil is 1200 Ohms found by aiming directly at a groundwave BC station at 1590 and using a carbon pot to null. Use a binocular core transformer to match the feedline.

Steel rusts so give it a good coat of your favorite rust preventer paint or spend the extra bucks for the brass version.

Ive found them to be quieter than a copper wire one a few hundred feet away possibly due to the RF resistance loss but very seldom was a preamp needed on 160/80. It worked fine to 30M and even on 20 when the snow static took out the yagi.

Carl


Title: Re: Beverage receiving antennas
Post by: W0BTU on September 01, 2011, 12:25:48 AM
Quote
Beverages are supposed to be their best with low or non-existent ground conductivity.

They don't work over saltwater, that's for sure!

Generally speaking, the higher the ground conductivity, the longer the Beverage must be.

Mostly irrelevant at HF. The incoming wave is not at zero degrees elevation angle, so the lossy earth is not required to induce phase delay. Differences in ground conductivity just mean the termination resistance will need to be different and/or the height can be different for a given amount of gain.

Whether lossy earth is required for phase delay or not, I don't know. But one thing is for sure: A Beverage HAS to be erected over earth that has a certain degree of losses. A Beverage will absolutely NOT work over highly conductive earth, such as a salt marsh near the ocean.

(And either will a Beverage work if we run wires under it. Numerous reports from people who tried to follow W1WCR's advice testify to that.)

There have been countless experiences of hams who put up a Beverage over the ocean (or over areas with salty, highly conductive ground), and nobody --not one single person or group on a DXpedition-- has ever had a Beverage work over that type of earth. Without exception, when you read the many experiences of people who have tried that, the result is utter disappointment. In each and every case, those Beverages were absolutely worthless, period.


Now, I made the statement here that "Generally speaking, the higher the ground conductivity, the longer the Beverage must be." I based that mainly on the experience of one person, and perhaps I'm wrong there. Most people who have tried longer and longer Beverages reach a point of diminishing returns. But K5RX, the one guy with the 10 to 15-ohms-per-ground-rod earth (that's much better earth conductivity than average), reported an observation consistent with the long-held idea that Beverages work better over poorly conductive earth. That's why I said that. (See http://www.w0btu.com/Beverage_antennas.html#How_Long)

One thing is for sure, there is disagreement over exactly how Beverages work on HF. Some highly respected people say there is no such thing as wave tilting. N5IA (near the end of my Beverage page) gives the interesting analogy of the Beverage being a transmission line that works because one of the conductors is more lossy than the other; but other respected people say that's nonsense. I can't say for sure, because I don't know. I try and keep an open mind about all this. But one thing is for sure: As long as Beverages aren't installed over salty earth, they work very well indeed, and that's all that really matters! :-)

Quote
The K9AY is a terminated loop. It's in the same family as the EWE, Flag, and Pennant.

Interesting page about those antennas at http://www.w8ji.com/k9ay_flag_pennant_ewe.htm


Title: Re: Beverage receiving antennas
Post by: Steve - K4HX on September 01, 2011, 09:15:41 AM
Quote
Whether lossy earth is required for phase delay or not, I don't know. But one thing is for sure: A Beverage HAS to be erected over earth that has a certain degree of losses. A Beverage will absolutely NOT work over highly conductive earth, such as a salt marsh near the ocean.

I'm not discounting past experiences, but why is this so? Why is lossy earth needed at HF (and if you think about it, all earth is lossy)? Did these people try extensive tests at the higher HF frequencies? Did they do the proper tests to determine the termination ressistance? Or did thay just run out a set length of wire and use a set termination resistance and then decide that it didn't work.

Since most of use don't live on or near a salt marsh, this is a rather moot point anyway.  :)


Title: Re: Beverage receiving antennas
Post by: KM1H on September 01, 2011, 11:06:29 AM
Its very simple. A Beverage is vertically polarized.

The loss is there to force the incoming wave to tilt which then imparts a voltage on the horizontal wire. The more the tilt the shorter it can be which is why a 150' Slinky works so well. A Beverage is also called a slow wave antenna and for good reason.

Over saltwater there is no tilt and all you have is a horizontal longwire with frequency sensitivity. A Beverage is non resonant altho over some grounds they do show some SWR variation. On my rock pile its minimal.


Title: Re: Beverage receiving antennas
Post by: WA1GFZ on September 01, 2011, 12:08:19 PM
I tried phasing a couple loaded delta loops and got some great nulls in front but back null side I had very little control so it will take 4 antennas, two for East and two for West. I have variable phasing with the K5SO HPSDR diversity program


Title: Re: Beverage receiving antennas
Post by: WD8BIL on September 01, 2011, 01:06:51 PM
Ground stability, as in losses, is a parameter that's really important in beverage function. A stable ground impedence will perform more predictable than one that varies greatly with changes in weather.


Title: Re: Beverage receiving antennas
Post by: Steve - K4HX on September 01, 2011, 01:35:02 PM
That makes sense at LF. It does not make sense at HF. The wave is already tilted, so why would lossy ground be needed?

Its very simple. A Beverage is vertically polarized.

The loss is there to force the incoming wave to tilt which then imparts a voltage on the horizontal wire. The more the tilt the shorter it can be which is why a 150' Slinky works so well. A Beverage is also called a slow wave antenna and for good reason.

Over saltwater there is no tilt and all you have is a horizontal longwire with frequency sensitivity. A Beverage is non resonant altho over some grounds they do show some SWR variation. On my rock pile its minimal.



Title: Re: Beverage receiving antennas
Post by: k4kyv on September 01, 2011, 01:52:42 PM
Ive found them to be quieter than a copper wire one a few hundred feet away possibly due to the RF resistance loss but very seldom was a preamp needed on 160/80.

I have never needed a pre-amp with any of my  receiving antennas.  The beverage is only about 20 dB down from the full size dipole or vertical, and I often use a 20 dB attenuator pad with the vertical to prevent broadcast station intermod.  Even the 5' square shielded  loop works without a pre-amp as  long as it is tuned to  resonance.

I have a nuvistor pre-amp, but I took it off-line.  It amplified the signal, but also amplified the noise by an equal degree, plus the noise and intermod that it contributed.  I found I had a better s/n ratio without it.

Maybe the 75A-4 was built with too much rf gain at the front end, and would have been cleaner with less. That was a common problem with receivers built in the mid 60s and earlier; back then a lot of people believed the more gain the better, but couldn't figure out why they had cross-modulation.


Title: Re: Beverage receiving antennas
Post by: KM1H on September 01, 2011, 03:44:45 PM
Quote
That makes sense at LF. It does not make sense at HF. The wave is already tilted, so why would lossy ground be needed?

Where is the magic dividing line? How much is a vertical wave tilted over salt water?

If its only a LF antenna we all might as well tear down our Beverages. The tilt imparts the directivity and if you make a Beverage too long it will reverse direction

Just because it was developed at LF doesnt mean it can only be used there.

With that sort of thinking yagis would never have progressed above low VHF and it took hams about 50 years to try Beverages at HF/MF since the "experts" said it couldnt be done.


Title: Re: Beverage receiving antennas
Post by: W0BTU on September 01, 2011, 06:08:23 PM
I have some thoughts about how the Beverage works at HF, but they haven't yet congealed in my head to the point where I can explain them as I would like to. Regardless, here are some observations of mine, and I'd like to hear what you think of them, good or bad.

About the only significant difference between a Beverage and a high longwire of the same length is the height. The patterns are the same, at least at HF. Since we can't terminate a high long wire (the vertical feed and ground leads would pick up more signal) and compare the pattern to a Beverage, let's compare an unterminated Beverage to a high wire of the same length.

I just modeled a ~100' high unterminated 580' wire @ 1.8 MHz in EZNEC. It was a single wire with one source right at one end, over 'real' earth. Its lobe shapes and F/S ratio was not unlike that of my terminated 580' Beverage 10' high (image attached).

It's the pattern --those narrow lobes and nulls-- which give a Beverage (or an array of phased verticals, for that matter) its greater S/N ratio, and therefore an edge over a dipole or vertical at HF, isn't it?


Most Beverages are terminated, and have only a single lobe (and therefore a F/B ratio) because of that termination. I left the feedline and termination off in the longwire model because when we raise a Beverage up to the height that a typical long wire might be, we have much greater --and undesired-- pickup on the vertical portions on each end. It wouldn't have been a good comparison.

However, this doesn't explain why so many different people --many of whom never knew one another-- have found that they work so poorly over salt water.

What do you think of the analogy of a Beverage to an open-wire transmission line with one lossy conductor? This is what N5IA said:

"In the most simple explanation of the theory of operation of the  Beverage antenna you must understand that the single wire above (or on) the ground is 1/2 of an unbalanced transmission line.  The earth conductivity is the other "wire" in the transmission line.

"When the earth 1/2 of the "transmission line" becomes very conductive, the whole array approaches being an actual 2-wire transmission line (perfectly balanced).  When that happens there is near ZERO signal received.

"The more unbalanced the line is, the more signal level is impressed on the wire which can be detected by proper impedance matching to a coaxial feedline going to your receiver.  That is why the Beverage works well over poor earth."


Title: Re: Beverage receiving antennas
Post by: Steve - K4HX on September 01, 2011, 07:19:21 PM
So, what you are saying is that the incoming wave angle is zero? I've never heard of such a thing at HF, saltwater or otherwise. The point is that tilt does not need to be induced. It already exists because of the non-zero wave angle. The fact that Beverages were originally developed for LF/MF has nothing to do with this fact.


Quote
That makes sense at LF. It does not make sense at HF. The wave is already tilted, so why would lossy ground be needed?

Where is the magic dividing line? How much is a vertical wave tilted over salt water?

If its only a LF antenna we all might as well tear down our Beverages. The tilt imparts the directivity and if you make a Beverage too long it will reverse direction

Just because it was developed at LF doesnt mean it can only be used there.

With that sort of thinking yagis would never have progressed above low VHF and it took hams about 50 years to try Beverages at HF/MF since the "experts" said it couldnt be done.



Title: Re: Beverage receiving antennas
Post by: Steve - K4HX on September 01, 2011, 07:32:31 PM
Quote
However, this doesn't explain why so many different people --many of whom never knew one another-- have found that they work so poorly over salt water.

Who are these people and how did they erect a Beverage of salt water? Did they experiment with heights, lengths and terminations?

The lossy earth two conductor explanation sounds very similar, if not exactly what Harold Beverage wrote 80 years ago. He was working at LF/MF.

Even over salt water, the conductivity of the two conductors of the balanced (unbalanced) feedline model will not be equal. The conductivity of copper is  59 x 10^6 siemens per meter. The conductivity of salt water is around 5 siemens per meter. Granted, the salt water conductor could be quite a bit larger or have greater surface area but I'm not sure it would be a million times larger.


Title: Re: Beverage receiving antennas
Post by: W4AMV on September 01, 2011, 09:17:46 PM
This is my understanding:

The performance of the Beverage is dependent on the imperfection of the earth conductivity. If the earth were a perfect conductor, there would be no horizontal (tangential) electric field due to a vertically polarized electric field. I looked in the text Antennas, by Kraus, and the statement from his text is “However, if the surface is an imperfect conductor, such as the earth’s surface or ground, the electric-field lines have a forward tilt near the surface as in Fig 14-22 b”.

I think this idea of tilt is really a play on words and is with regard to the figure in the text. If the earth surface were a perfect conductor, there would be only the vertical component of the electric field. There is no bending or tilting of this vertical electric member. In the presence of an imperfect conductor, the original electric field now has both a vertical and horizontal component.  It would appear as though the vertical component is dragged across a lossy surface and this bending creates a horizontal component that the Beverage antenna takes advantage. In the absence of the Beverage, this component would be still present, however dissipated as heat. All of this is simply paraphrasing Kraus.


Title: Re: Beverage receiving antennas
Post by: W0BTU on September 02, 2011, 07:23:11 AM
Quote
However, this doesn't explain why so many different people --many of whom never knew one another-- have found that they work so poorly over salt water.

Who are these people and how did they erect a Beverage of salt water? Did they experiment with heights, lengths and terminations?

I don't know the answers to either of those questions. A few years ago, I spent countless hours scouring the web for any Beverage antenna info I could get my hands on, and ran across the experiences of more than a few hams who had tried this. I just remember reading them, and I wasn't interested enough at the time to pay attention to exactly what they did or who they were. I think I read some of them in the Topband reflector archive. If you're interested, I can try and find some of that info, but like you stated, it's really a moot point.

I just looked in the 19th edition of the ARRL Handbook. They say "Beverages operated over saltwater do not work as well as they do over poor ground". (p. 13-17).

The 5th edition of ON4UN's Low Band DXing (p. 7-60) says "The Beverage does not work at all over saltwater. ...this does not mean they do not work near saltwater!. ... another condition is that the ground under the Beverage is not soaked with saltwater."

You make a very good point that the conductivities of copper and saltwater are so far apart. I just don't know the answer.


Title: Re: Beverage receiving antennas
Post by: k4kyv on September 02, 2011, 11:13:17 AM
The lossy earth two conductor explanation sounds very similar, if not exactly what Harold Beverage wrote 80 years ago. He was working at LF/MF.

Which includes 160m.


Title: Re: Beverage receiving antennas
Post by: KM1H on September 03, 2011, 12:53:44 PM
Quote
So, what you are saying is that the incoming wave angle is zero? I've never heard of such a thing at HF, saltwater or otherwise.

Thats not what I said so stop skewing things.

Quote
The point is that tilt does not need to be induced. It already exists because of the non-zero wave angle. The fact that Beverages were originally developed for LF/MF has nothing to do with this fact.

The point is that the degree of tilt determines the voltage imposed on the wire and also the maximum useable length. A perfectly vertical wave will not impose any voltage on a horizontal wire over perfect ground....theoretically. The length of the antenna determines the lowest wave angle and since this is with lossy ground its impossible to be zero, more like 20* for most of us.

Id suggest investing in ON4UN's book which covers all the bases and would minimize a lot of the chatter and guessing here.

Quote
Who are these people and how did they erect a Beverage of salt water? Did they experiment with heights, lengths and terminations?

Several contesters and DXers many of which were multi-multi stations with an educated group trying everything. W1KM is one who is in a salt marsh on Cape Cod. Its not so much as they didnt work but a well tuned 4 square was better for SNR.

Quote
The lossy earth two conductor explanation sounds very similar, if not exactly what Harold Beverage wrote 80 years ago. He was working at LF/MF.

Thats where it all started but there was no such thing as LF and MF back then, using todays arbitrary terms it was all LF operating.
When 1500W became "legal" on 160 the Beverage was brought back to life and studied extensively; eventually by software.





Title: Re: Beverage receiving antennas
Post by: KL7OF on September 03, 2011, 07:23:16 PM
Great thread...I have recently hooked my two remaining beverages back up for the winter low band season coming up..The "Cal beverge" is 585 +/- ft long copper clad steel over uneven rockpile terrain mostly about 9 ft above ground ....Unterminated.....Oriented south and a little east...Strung as a single span between 2 large pine trees....Fed to the shack thru a 8 to 1 transformer (ungrounded) and 75 ohm CATV (RG 59?).....I hear the west coast , especially California very well on this antenna....I used it terminated with 600 ohm carbons for a while but when I was trying to hear Europe on the low bands I needed it bi sexual...so I took off the termination..The other Bev is about 450 ft long and is unterminated oriented E and W..Bi directional,About 9 ft above ground..Fed to the shack thru a homemade 9 to 1 transformer mounted in a can on the side of the shack..75 ohm triax audio line is the feedline...This antenna is over a black dirt grass meadow and hears out to the east very well ....Attached pictures are of my beverage feedpoints...The transformer in the can got a brush out of the insect debris and the transformer in the Jar got a new Jar , new coax and connections cleaned .....I am interested in real ham reports from users of the K9AY...Haven't got to try one yet...


Title: Re: Beverage receiving antennas
Post by: W0BTU on September 03, 2011, 09:16:04 PM
...I used it terminated with 600 ohm carbons for a while but when I was trying to hear Europe ...

Why don't you try some instantly-switchable bi-directional terminated Beverages? Like these:
http://www.w0btu.com/Beverage_antennas.html
I gar-run-tee you that you will be happier with them than a K9AY.


Title: Re: Beverage receiving antennas
Post by: KM1H on September 06, 2011, 09:29:14 AM
Unless you have the acreage, time and money to install a Circle 8 receiving array the Beverage is the next best and phased Beverages are better.

My current "farm" is 5  2 wire reversibles of roughly 600-900' and I might phase a couple of them.

The measured RF ground resistance on this rock pile is around 250 Ohms so I had to subtract that from the theoretical 500 Ohms and design 250 Ohm transformers for the best match. I also isolated the primary and secondary windings for minimum capacitive coupling and Im very pleased with the front to back on 160-30M. Id suggest that your 600 Ohm termination is a bit high.

Carl


Title: Re: Beverage receiving antennas
Post by: KA3ZLR on September 06, 2011, 09:53:21 AM
Good Day,

I live on a Rise here in Pennsylvania I don't say hill or mountain it's just a rise, and all I use for
listening around is a 40 meter double bazooka up at 40 Ft. mated with an L Coupler I built from
an older Radio Handbook. I have another one up at 30 feet in the front yard for 20 meter PSK31.

I like bazookas.. :)


73
Jack
KA3ZLR


Title: Re: Beverage receiving antennas
Post by: KL7OF on September 06, 2011, 11:17:06 AM
Unless you have the acreage, time and money to install a Circle 8 receiving array the Beverage is the next best and phased Beverages are better.

My current "farm" is 5  2 wire reversibles of roughly 600-900' and I might phase a couple of them.

The measured RF ground resistance on this rock pile is around 250 Ohms so I had to subtract that from the theoretical 500 Ohms and design 250 Ohm transformers for the best match. I also isolated the primary and secondary windings for minimum capacitive coupling and Im very pleased with the front to back on 160-30M. Id suggest that your 600 Ohm termination is a bit high.

Carl
Carl...I would agree that my bev over rocks  may need a lower impedance termination....  what is the best way to determine this...Measure the impedance between two ground rods ???
I have an acreage that has many different soil types as well as some rocky areas...


Title: Re: Beverage receiving antennas
Post by: Steve - K4HX on September 06, 2011, 03:04:57 PM
Quote
So, what you are saying is that the incoming wave angle is zero? I've never heard of such a thing at HF, saltwater or otherwise.

Thats not what I said so stop skewing things.



Good one, skewing. No pun intended. I just asked a question.  Is the angle zero or not? If it's not zero, tilting caused by lossy earth is needed (the field is already tilted), or maybe safer to say, it's less important.


Quote
Quote
The point is that tilt does not need to be induced. It already exists because of the non-zero wave angle. The fact that Beverages were originally developed for LF/MF has nothing to do with this fact.

The point is that the degree of tilt determines the voltage imposed on the wire and also the maximum useable length. A perfectly vertical wave will not impose any voltage on a horizontal wire over perfect ground....theoretically. The length of the antenna determines the lowest wave angle and since this is with lossy ground its impossible to be zero, more like 20* for most of us.



Now your just repeating what I previously said. I guess you agree with me.


Quote

Id suggest investing in ON4UN's book which covers all the bases and would minimize a lot of the chatter and guessing here.



A good suggestion indeed. Even ON4UN has modified and improved his stuff (especially in the directional receive antenna area) over the years. Get his latest book for the best stuff.


Quote

Quote
Who are these people and how did they erect a Beverage of salt water? Did they experiment with heights, lengths and terminations?

Several contesters and DXers many of which were multi-multi stations with an educated group trying everything. W1KM is one who is in a salt marsh on Cape Cod. Its not so much as they didnt work but a well tuned 4 square was better for SNR.



OK. So they do work. That was my point. The idea that they do not work is false. As is the idea that lossy earth is of absolute importance. Scaring people off from trying to use a Beverage near saltwater is not useful. Sure a 4-square might work better. Which is easier to construct? As with any antenna consideration, there are a host of tradeoffs. You can better judge the tradeoffs when you have complete data.


Quote
Quote
The lossy earth two conductor explanation sounds very similar, if not exactly what Harold Beverage wrote 80 years ago. He was working at LF/MF.

Thats where it all started but there was no such thing as LF and MF back then, using todays arbitrary terms it was all LF operating.
When 1500W became "legal" on 160 the Beverage was brought back to life and studied extensively; eventually by software.




True. But much of it could be chalked up to reinventing the wheel. Beverage pretty much had it all down decades previous. Some bogus stuff also came out of the supposed studies, like magic "cone-of-silence" lengths.

This reinvention still goes on. The so-called crossfire phasing now bandied about with respect to directional receive antennas was patented in the 1960s. Same for verticals feeding hi-Z amps and phased - also patented in the 1960's. As usual, hams are largely behind the technology curve. Nothing wrong with that, other than when some believe they're not. Then it's just sad.


Title: Re: Beverage receiving antennas
Post by: Steve - K4HX on September 06, 2011, 04:04:59 PM
Sweep the system over several bands and measure the SWR. It doesn't matter what the SWR is. Not how much it varies. Change the termination and do it again. The termination is optimized when the variation is minimal. Then wind your matching transformer to get the lowest SWR on your 50 or 75 Ohm feedline.




Unless you have the acreage, time and money to install a Circle 8 receiving array the Beverage is the next best and phased Beverages are better.

My current "farm" is 5  2 wire reversibles of roughly 600-900' and I might phase a couple of them.

The measured RF ground resistance on this rock pile is around 250 Ohms so I had to subtract that from the theoretical 500 Ohms and design 250 Ohm transformers for the best match. I also isolated the primary and secondary windings for minimum capacitive coupling and Im very pleased with the front to back on 160-30M. Id suggest that your 600 Ohm termination is a bit high.

Carl
Carl...I would agree that my bev over rocks  may need a lower impedance termination....  what is the best way to determine this...Measure the impedance between two ground rods ???
I have an acreage that has many different soil types as well as some rocky areas...


Title: Re: Beverage receiving antennas
Post by: W0BTU on September 06, 2011, 06:53:34 PM

Quote
Who are these people and how did they erect a Beverage of salt water? Did they experiment with heights, lengths and terminations?

Quote
Several contesters and DXers many of which were multi-multi stations with an educated group trying everything. W1KM is one who is in a salt marsh on Cape Cod. Its not so much as they didnt work but a well tuned 4 square was better for SNR.

OK. So they do work. That was my point. The idea that they do not work is false. As is the idea that lossy earth is of absolute importance. Scaring people off from trying to use a Beverage near saltwater is not useful.

Ok, you convinced me, and your point is well taken. In spite of what ON4UN (5th edition) and others have said, they can indeed work over saltwater.

The question that remains in my mind is, why have so many people reported than they don't? I mean, Beverages over land are so easy to get working, that 'even a caveman could do it'.

When I  get the time, I'm going to do some research on this. It certainly does seem to me that while they can work over saltwater, perhaps there's a 'trick' to making them work well?


Title: Re: Beverage receiving antennas
Post by: Steve - K4HX on September 06, 2011, 09:07:46 PM
Remember most "data" from most hams is anecdotal at best. Very few undertake rigorous test and measurement efforts to document how well something works. Most don't even define what "works" means.   ;D

Beverage, Rice and Kellog in in their 1923 paper, "The Wave Antenna, A New Type of Highly Directive Antenna":

Quote
The surge impedance for a given type of construction will be slightly less on shortwaves than on long waves. The double wire antenna with reflection transformer has a decided advantage in convenience compared with a single-wire antenna. The equivalent of the reflection transformer- namely, grounding one wire and leaving the other open-circuited, will, as a rule, be prefered for its simplicity. Rear end compensation by means of the reflection balance is desirable and easily applied. This calls for a series- tuned circuit in series with the surge impedance, as shown in Fig. 85. The resistance should be variable and the capacity reactance and inductive reactance should preferably not exceed about 500 ohms each. For output a coil of about 0.1millihenry in the ground lead of a single-wire antenna, or, if the reflection transformer system is followed, a 0.2 millihenry coil connected between the two wires of the antenna is suitable.

I've seen this approach documented in more recent writings on Beverages. But most people I've talked to or read about on the Web have only ever used a resistive termination. I have no idea if the RLC termination will make a Beverage work better over salt water, but if I were to investigate the idea, I would certainly try it.

Beverage, Rice and Kellog also stated:

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For ground of a given resistance the wave front tilt increases as the wavelength decreases, and for short waves (less than 1000 meters) there is a substantial tilt, sufficient for satisfactory operation even over wet ground.

Wet ground and salt water are two different things but the trend is headed in the right direction. Maybe you can take it from this point.


Title: Re: Beverage receiving antennas
Post by: KM1H on September 06, 2011, 09:36:56 PM
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Ok, you convinced me, and your point is well taken. In spite of what ON4UN (5th edition) and others have said, they can indeed work over saltwater.

I believe it is the way it is interpeted. Dont work likely means not well or not as expected which to some means an absolute It Dont Work.
If it provides the same SNR as a single vertical or inverted vee what would you call it?

That a 4 square has a better SNR is saying a lot as they are not known as being particularely quiet for receiving.

The reason for a lossy ground is still alive and well.

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Carl...I would agree that my bev over rocks  may need a lower impedance termination....  what is the best way to determine this...Measure the impedance between two ground rods
I have an acreage that has many different soil types as well as some rocky areas...

I use a MFJ 259B to determine the lowest VSWR variation from 1.8 to 10MHz. Unless a soil condition covers several wavelengths little anomalies dont count. What is needed is a stable ground at both ends and I use 3 4' ground rods at each end driven in at an angle. One is at the antenna and the others at about a 20* total seperation about 10' away. Each rod has 6 20-30' radials fanned out. In antenna mode the procedure is the same for a single wire as a 2 wire Beverage.

I also use BN73-202 binocular cores and wind a true transformer, not an autotransformer. The primary and secondaries are wound thru seperate Teflon (or anything else that works) sleeving to get winding isolation resulting in minimum coupling.....it really makes a difference.

Here is some good winding info, ON4UN's book is a real hard read on the subject and a certain W8's web page has enough errors and half info to make it mostly useless unless you want to buy his "designs" at DX Engineering for ridiculous prices.

http://www.dxzone.com/cgi-bin/dir/jump2.cgi?ID=19733

Carl


Title: Re: Beverage receiving antennas
Post by: KL7OF on September 06, 2011, 10:13:48 PM
I'm using On4un's method of winding a  transformer...I use enameled wire and the twin toroids that he recommends in the book....Does the winding isolation thru teflon sleeves make a difference that you can hear? or a difference you can measure...?  I'm for anything that makes a difference that my old ears can hear...


Title: Re: Beverage receiving antennas
Post by: W0BTU on September 07, 2011, 12:06:35 AM
I'm using On4un's method of winding a  transformer...I use enameled wire and the twin toroids that he recommends in the book....Does the winding isolation thru teflon sleeves make a difference that you can hear? or a difference you can measure...?  I'm for anything that makes a difference that my old ears can hear...

If you are looking at the 5th edition of ON4UN's book, I (along with others) disagree with John's transformer winding data.

The transformer data on my Beverage antenna page (http://www.w0btu.com/Beverage_antennas.html) is based on his earlier books, among other things. He made things so much more complicated in his latest book. The advantages of those new designs --which are supposed to be a LITTLE bit less lossy-- simply aren't worth all the hassle of making them.


Title: Re: Beverage receiving antennas
Post by: KM1H on September 07, 2011, 06:16:32 PM
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I'm using On4un's method of winding a  transformer...I use enameled wire and the twin toroids that he recommends in the book....Does the winding isolation thru teflon sleeves make a difference that you can hear? or a difference you can measure...?  I'm for anything that makes a difference that my old ears can hear...

Isolation results in better F/B so its only measurable if you can instantaneously swith between 2 transformers.
I did tests on the BCB high end with a HP 8536B at the feed and comparing F/B with autotransfomers, quick and dirty binoculars, and isolated ones. There were progressive improvements.

It could also be seen on the bench with test equipment.

I didnt use any version of ON4UN's info as it certainly was nothing but confusing. I just used the standard transformer formulas (and transmission line formulas for the 2 wire) and started winding, no magic.

Im into serious DXing on 160/80 CW and any extra improvement lets me dig deeper into the noise.


Title: Re: Beverage receiving antennas
Post by: KL7OF on September 07, 2011, 07:54:15 PM
W
Quote
I'm using On4un's method of winding a  transformer...I use enameled wire and the twin toroids that he recommends in the book....Does the winding isolation thru teflon sleeves make a difference that you can hear? or a difference you can measure...?  I'm for anything that makes a difference that my old ears can hear...

Isolation results in better F/B so its only measurable if you can instantaneously swith between 2 transformers.
I did tests on the BCB high end with a HP 8536B at the feed and comparing F/B with autotransfomers, quick and dirty binoculars, and isolated ones. There were progressive improvements.

It could also be seen on the bench with test equipment.

I didnt use any version of ON4UN's info as it certainly was nothing but confusing. I just used the standard transformer formulas (and transmission line formulas for the 2 wire) and started winding, no magic.

Im into serious DXing on 160/80 CW and any extra improvement lets me dig deeper into the noise.



Carl....WOW......I applaud your efforts and methods....I haven't been able to tell (by my ear) much  difference between various termination and feed transformer impedances...I know this is very subjective...I am using AM only.....Do you recall the numbers when comparing autotransformers=binocs= and isolationists??  This is interesting stuff?..Steve


Title: Re: Beverage receiving antennas
Post by: KM1H on September 07, 2011, 08:32:44 PM
Id have to go thru the notebook but over a period of weeks of measuring RF ground resistance, building and testing transformers and on the BCB Id say 5-10dB improvement at groundwave was real.
On 160/80 at times if felt like more but that is purely subjective. One thing I did notice is that some local RFI, where a few antennas ( N/S and NE/SW had their ends close to a neighbors house, the F/B was much better when I switched directions. The E/W pair is now eerily quiet to the East and signals just jump out and all of that is 700+' back in the woods. The antennas also play well on 20M which was suprising as past versions needed a preamp. I do use them also on 30 and 40M.

For AM BCB the directivty is amazing and I can often get clear copy of 4 or more stations on the same frequency even at the low end. Directivity is even good at roughly 150-250 kHz for the LW BCB where I wouldnt expect any from such short antennas.

Carl
AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands