[TenTec] OT 75 Ohm twin feeder

[CSM(r) Gary Huber]

Thanks, this hint was provided as a inexpensive solution. As such it is 
truly "cheap and dirty" and should be considered a short term solution to 
getting on the air. (If you saw sausage made, or read a detailed description 
of ingredients and processes, you'd probably not be able to eat it....)

73,

Gary -AB9M
www.csm-gh.com

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From: "Dr. Gerald N. Johnson" <geraldj at storm.weather.net>
Sent: Wednesday, June 11, 2008 12:23 PM
To: <tentec at contesting.com>
Subject: Re: [TenTec] OT 75 Ohm twin feeder

> On Wed, 2008-06-11 at 07:12 -0500, CSM(r) Gary Huber wrote:
>> Try common "lamp cord"... the two conductor parallel kind. depending upon
>> gage of the conductors, you will find them very close to 75 Ohm.
>> Obviously not a high power solution.
>>
>> 73,
>> Gary - AB9M
>> www.csm-gh.com
>>
> The loss probably depends on the insulation and its color. Probably PVC
> insulation will be less loss than rubber, and I'd think white might be
> less loss than black (thinking a white oxide as the insulator rather
> than carbon black). Published reports in QST of loss of lamp or zip cord
> have not been complimentary.
>
> Another RF problem with zip cord comes from lack of control of the
> conductor location in the insulation. For 50/60 Hz applications, that's
> not critical unless the conductors break through the surface or make
> contact or get the insulation so thin between them that it won't stand
> 250 volts.
>
>
> Same thing applies to speaker wires, light or heavy duty, and worse many
> use a clear insulation that is unlikely to stand up to sunlight.
>
> But while probably not optimum, the losses in these products are not
> terribly bad, just not superbly great. Their use is much preferable to
> not transmitting at all.
>
> 73, Jerry, K0CQ
>
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