Thursday, January 10, 2019

Fence beverage drawback

It has been raining a lot today and immidiatly I noticed a drawback of a non isolated fence beverage. Since the water is terminating the wire to the ground it doesn't work anymore. I have to wait till dry weather. That can take a few days according to the weather forecast. But anyway it was a nice experiment and from the comments I read that others find it interesting as well. OK1RP Petr asked for a drawing and info. Well all the info is on this blog in the previous posts. Here is a drawing of the setup:

I measured the fence with the help of google maps. One side is 450m long but I don't know if it is interupted bij a gate at the other side. My neighbour did cut out a piece so it is not a square anymore.


On this photo on google maps you can see the exact position. The fence is fed at the corner just below the trees.

So far it was a nice experiment. There is two experiments left actually. Measuring the noise difference between the inverted-V and the beverage on 160m which is especially important for our PA6AA contest group. Second is a receive comparisation on 80m. But I have to wait till I can do further experiments. When I finish those I will not continue since the antenna is not reliable. But at least I know the transformer and balun works well. So I can use them whenever I want to do a RX experiment.

7 comments:

  1. Yes, I see that effect with the electric fences now installed here. Mind you, without the connection to a radio, your ground connection and fence system is a good way to reduce spark noise from an electric fence!

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    1. Oh yes, it is the ultimate solution John. Just ground the electric fence and it will not be electric anymore. "Shocking" for the owner and good for us HAMs. 73, Bas

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  2. We don't connect a Beverage's far end directly to a ground rod. A ~450 ohm termination resistor must be in series with the end of the antenna, or we can also leave it unterminated (not connected).
    You would be *much* better off with a straight wire, which would make it a genuine Beverage antenna.

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    1. Hello Mike, I wanted to use the fence since that was what PE9DX did. That was part of the experiment. I agree it is not terminated like a directional beverage should. I agree that a single wire would be a lot better. I will test with that though I have only space for about 50m (the end of the trees at the photos). Another experiment I want to do is that earth electrode antenna G3XBM uses. 73, Bas

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  3. Ah yes. Experiments like this are always good. :-)

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  4. Hoi Bas, zo'n afsluitweerstand aan het uiteinde van de draad lijkt mij niet zo'n slecht idee. Beverage antennes werden veel in begin 2000 toegepast met een weerstand van 400 tot 600 Ohm. Tegenwoordig een stuk minder. Ik denk dat het ligt aan de nodige grondoppervlakte die men daar voor nodig heeft. Ik ben benieuwd naar de aardelectrode antenne van Roger,G3XBM. Leuke experimenten! 73 Hans, PE1BVQ

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    1. Hallo Hans, ik heb begrepen dat de weerstand er voor zorgt dat de antenne een bepaalde richting uit ontvangt. 450 Ohm word het meest toegepast en het mag geen inductieve weerstand zijn. Als ik mijn buurman tegenkom zal ik hem eens vragen of ik de beverage over de sloot op de rand van zijn land mag maken in de winter, dan kan ik ongeveer 1000m kwijt. 73, Bas

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Thanks for your comment. Bedankt voor je reactie. 73, Bas