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Beverage receiving antennas




 
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W0BTU
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« Reply #50 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.
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73 Mike 
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« Reply #51 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
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KA3ZLR
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« Reply #52 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.. Smiley


73
Jack
KA3ZLR
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KL7OF
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« Reply #53 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 Huh
I have an acreage that has many different soil types as well as some rocky areas...
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Steve - K4HX
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« Reply #54 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.


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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.


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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.


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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.
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Steve - K4HX
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« Reply #55 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 Huh
I have an acreage that has many different soil types as well as some rocky areas...
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W0BTU
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« Reply #56 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?
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73 Mike 
www.w0btu.com
Steve - K4HX
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« Reply #57 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.   Grin

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

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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.
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« Reply #58 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.

Quote
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
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KL7OF
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« Reply #59 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...
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W0BTU
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« Reply #60 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.
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73 Mike 
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« Reply #61 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.
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KL7OF
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« Reply #62 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
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« Reply #63 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
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