EFHW/RW - Attaching wire to balun

[KL7MJ]

More great ideas - thanks!

[Andrew (grayhat)]

Just to try explaining it better, see the image below (ugly but hopefully "readable")

[KL7MJ]

How does this look? The scale is 1cm for major lines.

[Andrew (grayhat)]

looks good !

the carabiner hole is useful both when the antenna is deployed and to hang it to a backpack wnen the antenna is wrapped, the velcro stripes will help keeping the wire/coax wrapped

[Andrew (grayhat)]

as for the radiator length, see here

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

ensure to add a good guanella choke after the 9:1 and use at least one counterpoise wire with a lenght around 1/16 Lambda at the lower frequency (e.g about 5m if the lowest frequency is 3.5MHz, eventually add a 2.5m additional counterpoise to offer a low impedance return path on 10m)

[Andrew (grayhat)]

An example, using a radiator (wire) of 84ft and a counterpoise of 17ft a 9:1 and a wideband choke (Guanella) both wound on FTxxx-43, we'll have a random covering all bands (including WARC) from 80 to 6 meters with the help of an antenna matching unit by the way

[KL7MJ]

I'm going to try a 29/17 EFRW. My home antenna is a 35.5/17, and works well enough for me. For the choke, I'm using N6ARA's choke design - 12 bifiliar turns on a T50-43. I've got it all built, and I hope to get some time to try it out today.

[Andrew (grayhat)]

I'm going to try a 29/17 EFRW. My home antenna is a 35.5/17, and works well enough for me. For the choke, I'm using N6ARA's choke design - 12 bifiliar turns on a T50-43. I've got it all built, and I hope to get some time to try it out today.

it all depends from the bands you're interested to cover and from the efficiency you want to achieve; as I already wrote, to offer good efficiency the "random" should be "near" to 1/4 Lambda at the lowest frequency one plans to use it and must be away from 1/2 Lambda and even multiples at any frequency one wants to use; the idea is to stay far away from low impedance (1/4 Lambda or less) and high impedance (1/2 Lambda or even multiples of it) and have enough radiation efficiency (at least near 1/4 Lambda) to offer decent performance

Regarding the choke, while for portable use it's not so important, when it comes to a "random" it must offer very high impedance to CM currents, then the counterpoise(s) will help by offering a low impedance return path to currents; as I already wrote a 5m and 2.5m counterpoise wires should be fine in most cases for a "random" covering bands from 80 to 10 meters