[Antennas] [Bulk] Re: RG178 B/U / Choke/Balun?

[Brian Cake]

You need to be very careful about the balun used in the C-pole. I strongly 
recommend that you read my original article (QST, April 2004). There are 
many more details in my book "ARRL Antenna Designer's Notebook". The 
following is also a very useful link:

    http://www.qsl.net/hb9mtn/hb9mtn-c-pole.html

    Good Luck!

    73

    Brian KF2YN

----- Original Message ----- 
From: "Rick Karlquist" <richard at karlquist.com>
To: "Niel - W0VLZ" <w0vlz at aggienetwork.com>
Cc: <antennas at mailman.qth.net>
Sent: Wednesday, June 30, 2010 7:47 PM
Subject: [Bulk] Re: [Antennas] RG178 B/U / Choke/Balun?


> 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
>
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