The QRPer Board

I saw a Youtube video yesterday from vendor night at this year's FDIM. IN it, Adam showed an antenna that has a 15 foot radiator and a 7.5 foot radial connected to a 4:1 unun that he said is perfect for the KH-1. Searching online shows that this is similar to the Rybakov 806 antenna but I couldn't find it on his website or Youtube videos.

Has anyone tried this type of antenna? My current "ultaportable" EFRW uses a 29 foot radiator and a 17 foot radial - this Rybakov-like design would work even better with my 7.2m collapsible mast (fishing pole).

Mike, KL7MJ

I built an antenna this weekend with a 4:1 unun connected to a common-mode choke, with a 20 foot radiator and a 7.5 foot radial. I couldn't get it to tune up on 40, but could on 30, 20 and 17. I tried calling CQ using a TR-35 and checking for results on RBN. I was picked up by one station on 20m - nothing on 30 or 17.

As far as tuning on 40m, my ZM-2 seems to have a problem in the 6.5MHz to 7.5MHz region. I can get an antenna (or just the tuner) to load on 80m but it is difficult to tune on 40m.

I'm going to use the unun/cmc combination to build a rybakov antenna and see how that goes.

try using a 9:1 followed by a choke, for the radiator size, use this

https://k7mem.com/Ant_End_Fed.html#Not_Random_Multi

as for the "counterpoise" a 1/16 wave wire at the lowest frequency will be a good starting point, willing to "go vertical" install the radiator as an inverted L

Adam talks about this antenna design at the 13:46 mark in this video:
https://www.youtube.com/watch?v=zlv6JYFxN9g
Other than the rybakov, I haven't seen a 4:1 for an EFRW design before.

That website looks great - lots of good information. Thanks.

73,
Mike, KL7MJ

just in case

https://wb3gck.com/2018/12/09/revisitin ... -vertical/



not a "great antenna" but it works decently and is quite easy to carry/deploy