EFHW/RW - Attaching wire to balun
Re: EFHW/RW - Attaching wire to balun
More great ideas - thanks!
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Re: EFHW/RW - Attaching wire to balun
Just to try explaining it better, see the image below (ugly but hopefully "readable")
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Re: EFHW/RW - Attaching wire to balun
How does this look? The scale is 1cm for major lines.
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- efrw_v2.png (134.11 KiB) Viewed 17670 times
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Re: EFHW/RW - Attaching wire to balun
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
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
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Re: EFHW/RW - Attaching wire to balun
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)
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)
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Re: EFHW/RW - Attaching wire to balun
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
Re: EFHW/RW - Attaching wire to balun
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.
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Re: EFHW/RW - Attaching wire to balun
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