The AM Forum

  Good spot on here about verticals, I should say...Ok..thinking about running a receiving wire ant. Likely 600ft., not truly a beverage..I cant have this thing 3ft above the ground, due to animals, deer, dogs, stampeding rhinos, etc.
..I was thinking about 10ft above ground is safe..So, do i terminate the far end, as a beverage, use a 9:1 balun on the feed side, or whatever?..
..Your thoughts are appreciated..
..Tim..

..sk..

I've never had the luxury of room for one so I'm jealous  ;D

But, I'll still weigh in--3 ft. high from what I have read, would make it not work well.  I've always read that they should be 10 feet, maybe 15 feet high.

8-10 feet high is supposed to be a rough optimum height.  Any higher and you do start losing gain.

ON4UN's Low Band DXing book has a full treatise on Beverages, though one edition (5th?) has an error on the diagram with an unnecessary ground.  The ARRL Antenna book also covers Beverages.

http://www.w8ji.com/beverages.htm

http://www.w0btu.com/Beverage_antennas.html

http://n1eu.com/topband/BeverageTips.htm

..Rob..you have hair dont you?...Then I'm jealous...


..sk..

Optimum height above ground will depend somewhat on your ground conductivity and the optimized band you want it for.

If the Bev is too high above a poor Earth ground, then it starts acting like a random length wire with high angle signals creating poorer performance.

I have experimented with various heights between 2' and 15' high.  Using forest soil and rocks for ground, my best height has always been as low as possible. The problem is the deer run into it.  I have compromised and use about 5' high, though I would run it lower at 3' for the cleanest pattern, if I could. My beverages are 580' long, (optimized for 75M)  and terminated with 500 ohm non-inductive Glo Bar resistors.   I use about eight, 12' long copper radials at both ends and a 9:1 toroidal transformer for matching.

Gain is not a factor - S/N is what counts, so shoot for the best pattern with least high angle and lowest side lobes.  Too long a Bev for a given frequency can also produce poor lobe formation.

They perform ALMOST as well as my 2el quad at 190' into Europe for receiving. That's saying a lot, caw mawn.  I use the two systems in dual diversity.  You can't go wrong putting up a good performing Bev for RX use.

T

There is no optimum height without further defining the design criteria. In general, lower height yields less output or gain but often better directivity or at least a lower take-off angle. So, it depends on how much gain you need and what amount of directivity you desire. 8-10 feet is often used just to avoid people and animals. There is most certainly nothing magic about those heights.

Yes, terminate the far end (the one pointing or heading in the direction you wish to have the best reception) and feed with a 9:1 transformer. You can probably just go with a 450-600 Ohm termination and it will work pretty well. If you are going for the best performance, you'll need to determine the surge impedance of the system and select the termination impedance based on this measurement. I'd say this is overkill if you just want to try out a Beverage quickly to see how well one can work for you.

Speaking of terminating resistor values, I once tired to determine the optimum value for the best front to back ratio on my Bev.


I set up a variable resistor at the termination and used an HT to listen to the home RX audio hooked to the Bev (with AGC off) - and a little 3.790 mhz 100mw radio beacon directly behind the Beverage 1/4 mile away.  I adjusted the pot until I nulled the signal down as far as possible. With my given conditions, I found that about 300 ohms worked best.  It was not a sharp dip, but still showed a dip of an additional -12db from say, 600 ohms.

Later I changed the Bev length and location and just put in the 500 ohm resistor without tuning.  But I did prove to myself that there IS some optimum termination resistor value that shows the best f-b using a zero horizon reference signal off the back.

T

Shasha's buddy:
http://now.msn.com/now/0430-dog-stalks-wolf.aspx

Yep, you matched the surge impedance of the system. This reduces the amount of signal from the back side that is reflected to the receive end.

Sasha would have just run up and attacked. No stealth, just speed. She's zapped 3-4 ground hogs and two squirrels this way.

According to my friend Tumtum, put up the best can on the space you have with what ever you can get for materials.  Any beverage is better than no beverage.  Just aim them to the pacific northwest.  Specially if you live in Tenn.

The lower the antenna the higher the elevation angle as the ground coupling supresses the low stuff. Over a very poor ground such as my hilltop rock patch even a 500' BOG works well but one parallel to it and 6' high is better on the real long haul DX such as over EU into Asia. I can switch between them for EU and AS on 160/80. Often the BOG has a better SNR.

Carl

Short or long high or low, they really do the job. They were doing watershed forestry out back this year and I had to pull mine in and boy do I miss it!

It's amazing what an antenna laid right on the ground will do. When I was putting up my 75 meter dipole, I had it stretched out flat on the ground getting it ready to hoist up in the tree. Just to see what would happen, I went in the house and grabbed a 2 meter HT and plugged it into the short piece of coax that came out of the feedpoint of the dipole. To my surprise, I was able to key up a repeater 50 miles away with that dipole, while it was laying on flat ground. The signal coming back was not reading that high on the meter, but it had little noise on it. so scale that up to 75 or even 160 meters. I should also mention it seemed directional, since the repeater was to the south (in line with the wire) and I had problems with the stuff to the east (broadside to the wire).

Sounds like a plan. My Beverages are only 580' long. Why not make it a true Beverage? Just feed and terminate it properly, point it in a useful direction, and you'll be glad you built it. Complete instructions are on my web site.


I am aware of two different grounding errors in two different versions of ON4UN's excellent book. I think the CD-ROM that came with the book corrected at least one of them. There were five editions of that book; my favorite was the fourth. All the editions I saw had an error or two (in the Beverage info anyway), but the book is still worth buying.

One had to do with the reflection transformer wiring, and the other incorrectly showed the coax shields grounded at the antenna. The only thing that should be connected to the feedpoint ground is the secondary of the matching transformer.  It is clearly pointed out on my web page; I copied the schematic from his book and drew a red X through the ground that's not supposed to be there.

Having said that, ON4UN's book is probably the best source for Beverage antenna info that I have seen. But I have never seen all the info that is necessary to build a bi-directional Beverage in one place (either a book or web page), and when I created http://www.w0btu.com/Beverage_antennas.html it was my main goal to do just that.

It has been well said that "Beverages want to work". Although it's certainly possible to make a mistake and seriously degrade the antenna's performance, almost any Beverage is better than no Beverage (as explained at some length there).

If you want to have that joyous feeling like a boy who just got his ham ticket and made his first DX contact, stop thinking about it and go build something. Yes, Beverages are that good. :-)

..i guess i'd like it longer, and it may be, come the winter...ok..i will terminate the far end, and do the 9:1 balun...one question though ..why a carbon resistor?...400-600 ohms is no problem, but why not any good 2 watt resistor?...btw, the far end will be grounded with a nice ground rod, into my river...

..tim..
..sk..

Almost any resistor will work. Carbon or metal composition resistors are just less likely to fail from nearby lightning strikes than a carbon film.

You can make a Beverage too long. It's a long story, but consider just this:
A one-wavelength Beverage has a 3 dB beamwidth of ~90 degrees. On 160, our 1-wavelength Beverages can cover the entire 360 degrees of the compass with only four directions.

If we made them longer, we might hear better in some directions, yes. But if the stations you want to hear are spread way out (angularly), then making it too long might make the beamwidth too narrow and you might not hear some of them.

A little thought and planning is in order before you string up the wire. What bands and areas are you mainly interested in?

..well mike, 75/80 and would be nice to have 160 as well..i have the room, to run abt 800ft right now...the fall/winter could be longer, when the farmer takes his crops off...likely up to 2000ft..
..tim..
..sk..

I have had many beverages....BOG types on the lake ice in Alaska, BOG types in the grass, 1 and 2 wavelength terminated types 7 ft above ground....Bevs over poor ground, bevs over fallow ground, bevs over meadow grass, bevs in the woods...Terminated and unterminated, They all work and are worth the time and trouble of putting them up (or down)....Sure there are the perfect parameters and configurations and if you have the room and the materials that is the way to go....K1JJ's tests are very interesting.....I bet that tuned Bev was great...!I have 2 Bevs at the present in Tum Tum  and I wish I had my barn Bev (#3) up...Tim , I wonder if 2000 ft is toooo Long....????

Below are two antenna patterns. Both are for a 600 foot long Beverage on 3.8 MHz. The dotted line is for a height of 10 feet. The red line is for a height of one foot. The takeoff angle for the 10 foot high Beverage is 30 degrees. The takeoff angle for the one foot high Beverage is 25 degrees. I've done similar modeling in the past with Nec 4 and the results are the same, at least for the pattern shapes and the take-off angles. Gain is usually not predicted as accurately with Nec 2, but this is of little consequence in most cases for Beverages. Other have had similar results.

The most noticeable difference I see is higher overall attenuation with the lower wire. However, the lower height appears to attenuate the high angle lobes a few dB more than it attenuates the main lobe, something I would consider more significant than the slightly lower average angle of the main lobe, but even that difference is not astounding.  Makes me wonder whether or not the improvement in performance with the lower wire would be worth the physical inconvenience (obstacle to mowing, foot traffic, etc.)

The main lobe is down about 1.5 dB. The high angle lobes are down about 4 dB. The plots are merely to point out that there is no magic height and to also consider low or on-the-ground Beverages as a viable option. The low or on-the-ground approach is even more valuable when using shorter lengths.

how short is short?  what if you modeled one for a regular guy who only has 100 or 200 feet of room? (like me hi hi).

Short is relative to the wavelength of course, but the "performance" drops off gradually. So, you can get away with Beverages shorter than you may think.

The two I am using are only 200 feet long. Are they as good as one 600 feet long? No. But they beat the heck out of nothing and they are better than my K9AY. I use two in end-fire phase to help make up for the shorter length. Two phased this way give about the same performance as a single wire twice the length. I've also placed mine very close to the ground which improves the back lobe response and lowers the take-off angle. So, I wind up with something that is roughly the equivalent of a 500 foot Beverage.

Some claim a Beverage-on-the-ground (BOG) gives performance nearly equal to one twice as long a heights of 10 feet. So, you may want to try one on the ground if you don't want to mess with the phasing arrangement I've used. It's all about velocity of propagation. The closer the the ground the wire is place, the slower the wave propagation down the wire, the more directional the pattern. Beverage and his cohorts has all this figured out in the 1930s.

All that said, if you are looking for some directional receive capability, I'd start with the K9AY. It takes up very little space and gives you four directions (vice one or two with a Beverage). If you want to go to the next level, phased short verticals will be better than the K9AY and can begin to compete with a Beverage.

Info on the K9AY here.

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

Good point Steve on the K9AY antenna. I also put in Gary's antenna and it works OK. The directivity is more like diversity! Switching the remote relay on any given signal can give no change to a significant change dependent on the arrival angle and the rate of QSB. I have seen over 20 dB shift in signal level received to no change whatsoever. I installed a remote PIN diode to alter the termination of the antenna. I can vary it from 50 ohms to over 1k ohm. In the end... ineffective. However for a small compact "BOG" its not a bad substitute. Running the predicted radiation pattern using EZNEC or 4NEC2 is useful.

Alan

Since no program available to consumers can model an antenna that close to ground its a nice exercise...period.

The proof is when the high Beverage can discriminate between a distant and local station on the same frequency on the BCB during the day. The BOG hears only the louder local.

On 160/80 the high beverage is superior on long haul low angle DX but more prone to T storm static when comparing similar strength signals. I also compare between the inverted vee and verticals as to which angles are better. Over the past few weeks Ive added 2 more 500' 2 wire reversible BOG's parallel to the existing Beverages.

For those with a short memory my RF ground is about as poor as it can get. Others may have quite different reaults.

Carl

For 500 kHz I've had good results with a 1000' (1/2 wave) coaxial cable/reflection xfmr BOG setup. F/B is on the order of ~20 dB indicating it performs like a longer antenna - maybe 2X. Also have a large (3X normal size) K9AY and the BOG consistently outperforms it ... to the tune of 4 dB s/n on signals from EU (as measured using WSPR and OPERA digital modes). 'Band noise' from the BOG is sufficient to override receiver noise at 500 kHz without a preamplifier. This may not be the case higher in frequency. Termination resistance is significantly lower than for an elevated beverage.

Would like to try a BOG on 137 kHz ... but that would require a 3600' antenna.