[Antennas] RG178 B/U / Choke/Balun?

[Rick Karlquist]

Niel - W0VLZ wrote:
> I have some RG178 B/U I'd like to try as a choke/balun for a light
> weight QRP C-pole (see
> http://w0vlz.blogspot.com/2010/05/c-pole-antenna-for-qrpxpeditions.html
> for my heavy weight model).
>
> I have a 2" diameter coil form. How do I calculate/test for the number
> of turns required to be an effective choke at 14MHz? Right now 15 turns
> of RG8X single layer wound on a 4" plastic coffee can works.
>
> Also, anyone know the attenuation factor of RG178 B/U at HF frequencies?
>
> 73,
> Niel

You're probably better off putting several turns through
a ferrite toroid or sleeve made of 43 or 61 material.

The loss of 178 on 20 meters will be something like 6 dB / 100 ft.
Can you at least move up to RG174?

Rick N6RK