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Antenna Query


#1

I was looking through some old PW “Antennas to Go” suppliments and noticed the W3EDP antenna. This looks promising for SOTA use and I am thinking of trying it. To save time (I’ve got to knock up a tuner by Wednesday as I’m heading for the Gower on Thursday if the WX is OK) has anybody tried this and if so what is the best length for the counterpoise on 5 megs?

73

Brian G8ADD


#2

In reply to G8ADD:

Hi Brian

Not used a W3EDP “in the field”, but it’s what I’ve used for my home HF aerial for a good many years and it seems to do very well on 5 megs. I use the “standard” 84’ top with 17’ counterpoise draped round the shack. Make up a tuner using the original arrangement of a parallel tuned circuit and link coil - seems to work much better than trying to use a T-match or similar ATU, as some do. For 5 megs I use a 26 turn coil about 75mm long on a 50mm dia. former, tuned by a 250pF variable and with a 5 turn link over the cold end - you might want to scale that down for portable use! (Don’t know what the PW article says, so if this is gibberish let me know and I’ll try and send you more detail!)

73 de Paul G4MD


#3

In reply to G4MD:
Thanks, Paul, it will be useful not having to switch counterpoises for 5 megs. The PW article emphasises that a small value of capacitance gives the best result, which will help keep the size down. I already have a suitable coil - it’s even silver plated courtesy of the WD! - so construction should be fairly painless.

73

Brian G8ADD


#4

In reply to G8ADD:

Hi, A couple of suggestions for if it doesn’t tune.

  1. Try shortening or removing the counterpoise.

  2. Make the main element 35m long with 5m counterpoise. i.e. Add another 10m of wire for 60m operation. This should then work on 60m, 30m, 20m, 15m, 10m.

I am interested to know how you get on.

Regards,
Nigel. G6SFP.


#5

In reply to G8ADD:

It’s always worth consulting the Cebik antenna site. Since Cebik died a few months back the site has changed and you now have to register. However, registration is free. http://www.cebik.com

Andy
MM0FMF


#6

In reply to MM0FMF:

Also some antenna description from SOTA-DL on:

http://www.sota-dl-alpen.de/articles/uKWA_DD1LD.pdf

and

http://www.sota-dl-alpen.de/articles/Bergfunk_Antenne_DL2DVE.pdf

text is german but the drawings are international :slight_smile:

for 5MHz the center-coil would need an increased inductance.

73 andy DL2DVE