Mini Beverage Problems

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John Faulkner, Skegness
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Mini Beverage Problems

Post by John Faulkner, Skegness » 14 Aug 2019 10:13

I have been experimenting with mini Beverage antennas recently, but with extremely poor results. The question I am asking myself is "Why?" In the past, I have run out much shorter Beverages and with GOOD results. Here's the situation:

The North American Beverage:
This stretches for 400 feet at 320 degrees and will extend to 550 feet at the most.

The North American Beverage runs in a near-straight line and varies in height above the ground between one and three metres. This is necessary as there are stables in the way and it is impossible to get the wire behind the stables so I have to drape the wire over the roof.

This is not terminated as termination made no difference, so the wire is tied to the end of the conifers at the far end.

My laptop is powered in the stables themselves and this is where the Perseus is fed, half way along the Beverage itself. So a length of coax sits awkwardly underneath the Beverage wire for half of its length. I have tried grounding this but it had no effect.

The Asiatic Beverage:
This is slightly shorter at 370 feet and points to 60 degrees. It runs perfectly straight and is consistently one metre above the ground, terminated to straight to ground. On the face of it, it's ideally located and should give good results. The use of a variable resistor made the rear null worse.

Both mini Beverages are connected using a length of 50 ohm coax, via a correctly built transformer, made for the job by a radio ham friend.

I am aware that a true Beverage is a 'tuned' antenna, as are all antennas, but the Beverage is still known to exhibit useful directivity from lengths down to 200 feet, as I have found myself in the past.

I wonder if the problem could be that both Beverages run above wire fences. Naturally, they are isolated from the wire. There is some debate over this. I have heard that the presence of a wire underneath a Beverage will totally destroy its performance, but I I have also heard the contrary. When I used to run out wires in the Derbyshire countryside, the wires sometimes had to sit above existing fences. I wasn't aware that there was a problem then as reception could still be very good.

Having made numerous overnight recordings in these situations this summer, I can conclude that all Beverage experiments have been a waste of time. I have heard recordings of good North American signals on simple domestic setups when this system has barely been able to hear 1520 WWKB. Even the Asiatic beverage struggles to hear China on 1521, let alone pick out any Chinese time pips anywhere else. Back home on my flag, all regular Asiatic signals were present.

Any thoughts?

tvdxrools
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Re: Mini Beverage Problems

Post by tvdxrools » 14 Aug 2019 10:42

this is where the Perseus is fed, half way along the Beverage itself

am i reading this correct , ur feeding the bev half way along it or the coax is underneath it which the latter shouldnt make a diff ,, 9/10 i have found if there is a prob the first thing to check is the balun after all a beverage is just a long wire terminated at the end and if the balun is not ok it wont transform the high imp at the feed down to 50 ish ohms , on my beverage which is a bit longer than yours ( 400m ) i use a simple 33/11 turn balun and a fixed 640 ohm res at the end , one thing to check on the balun are ypu putting the short windings to the coax and long ones to the ant , David

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John Faulkner, Skegness
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Re: Mini Beverage Problems

Post by John Faulkner, Skegness » 14 Aug 2019 12:38

Hi David. Thanks for the feedback.

hat's right. The Beverage is end-fed, in the say Beverages should be. It just happens that the receiving station is half way along its length. So a lot of coax goes to the feed point and sits under half of the antenna run.

I also checked the balun and it's all correct. The right way around and a 3/1 ratio. The ham used the correct toroids etc. I have one for Beverages on the ground, one for a wire resting on tree branches at one metre above the ground, another for higher Beverages, etc. (I have four in total.) He said they won't make a lot of difference between them, but though i should give it a try to compare. True enough, they didn't make obvious difference. I think he said an S point at most. I've got baluns made toe 75 ohms and 50 ohms. The difference they make is so negligible at MW it's not worth worrying about.

I am sure the differences between all these different windings would be more noticeable had I got the Beverage set up correctly.

The other consideration is conditions. But I know that my home setup and other DXers setups are doing much better than the Beverages. I don't get it - and there lies the problem no doubt, i.e. I don't fully get it. I am no technical whizz with antennas but I know it should work better than this. I can only hope that there is a break in a connection somewhere. I think it's time for me to simply bung a wire in the back of the Perseus next and see how that fares.

tvdxrools
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Re: Mini Beverage Problems

Post by tvdxrools » 14 Aug 2019 13:02

one way to be sure if its the balun or coax thats at fault , take balun away and just use coax , ie inner to bev , sheild to ground , and if it works ie u rx TA that will give u a clue

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John Faulkner, Skegness
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Re: Mini Beverage Problems

Post by John Faulkner, Skegness » 14 Aug 2019 13:07

Yes. That's the next plan. Something must be wrong somewhere.

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