[Elecraft] EARC End Fed 6-40 question (Was Re: cobweb antenna)

[Jeff Ellis]

I got the kit John talks about and made the antenna. Its was quick and fun to make.  I have a question about it though. I had a 70' wire that I had been using just for RX to test a IC-718 and I hooked it up to the UNUN box instead of the 30' wire that came with the kit. Its below 2:1 on 6m, 12m, 17m, 40m and less then 4:1 on 10, 20m, 80m and about 6:1 on 30m, 160m. The only really high one is 60m.  So really all but 60m are tunable by the KX3 tuner board. I am using what I remember to be about 15' of RG-58/U. My Shack area is on the second floor of the house and the wire goes out my window and down to the back fence.

My problem is I am getting RF coming back into the shack (on just 5W) where it will reset my USB hub a few feet away from the radio. Not fun when trying to work digital modes. This only happens on some bands but I know happens on 20m where I try and work the most. I expect its just the ones less resonate that its doing it on but I need to check again.

Will adding a number of ferrite on the feed line help choke the RF? Will winding the feed line around a tube to make an air choke work? I guess that one is cheep enough I should just try it. Buying 10 or more ferrite to clamp to the line costs more ;)

What about using a longer feed line? I really don't want to add a counterpoise and the instructions said it does not need one. I could use the 30' antenna wire it came with if that is going to help. I would not think so since its resonate on so many bands and tunable on the others.

Thanks for the help!

Jeff, K7GDE

On May 31, 2013, at 10:56 AM, John Saxon <johnbsaxon at yahoo.com> wrote:

> The "Emergency Amateur Radio Club" in Hawaii sells an antenna that has worked for my needs.  They sell a 30' length of wire and an UNUN fitted with a SO-259.  I got a 33' telescoping fiberglass pole from MFJ.  I attached the pole to my back fence (6' wooden).  It only takes a couple of minutes to attach the wire and host up the pole.  Collapsing the pole also a couple of minutes.
> 
> The antenna is here...
> http://earchi.org/92011endfedfiles/Endfed6_40.pdf
> John
> K5ENQ