[Elecraft] Coax and the walking VFO

Tue Nov 26 14:35:01 2002

The 9913F7 has a high-density foam core, and it is my understanding that 
center-wire 'creep' is not a problem unless one exceeds the 6" radius 
bending spec.

best wishes,

dave belsley, w1euy

--On Tuesday, November 26, 2002 1:05 PM -0600 "George, W5YR" <[email protected]> 
wrote:

> There is a problem with using any foam-core coax in an applications
> where it is bent, curved or stressed.That is "creep"of the center
> conductor through the relatively soft foam dielectric toward the
> shield. This not only causes a minor impedance bump but also can
> greatly reduce the voltage rating of the coax at the bend. Solid
> dielectric coax is usually preferred in any application where there
> will be movement or mechanical stress that results in curvature of the
> coax.
>
> 73/72, George
> Amateur Radio W5YR -  the Yellow Rose of Texas
> In the 57th year and it just keeps getting better!
> Fairview, TX 30 mi NE of Dallas in Collin county EM13qe
> K2 #489      Icom IC-765 #2349     Icom IC-756 PRO  #2121
>
>
> ----- Original Message -----
> From: "Doug Faunt N6TQS +1-510-655-8604" <[email protected]>
> To: <[email protected]>
> Cc: <[email protected]>; <[email protected]>
> Sent: Monday, November 25, 2002 10:14 PM
> Subject: Re: [Elecraft] Coax and the walking VFO
>
>
>>    From: "David A. Belsley" <[email protected]>
>>    Content-Disposition: inline
>>    Date: Mon, 25 Nov 2002 23:02:51 -0500
>>
>>    Bruce:
>>      Get yourself some 9913F7.  It's about the same size as RG-8U
> but a lot
>>    more flexible. And it is very, very low loss and will easily
> handle 500w.
>>    The 'F' in the name indicates 'flexible' and the 7 is the number
> of
>>    strands.  Be careful not to confuse it with 9913, which is solid
> wire and
>>    quite stiff.
>>
>> For what it's worth, the guys at RF Connection said that they're out
>> of stock on that, and Belden isn't producing it currently.
>> I just ordered some CXP1318FX from Cable Experts.  I'm hoping it
> will
>> turn out to be flexible and rugged, since it's got a high number of
>> small strands for the center conductor, and a foam core instead of
>> air.
>>
>> 73, doug
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----------------------------------
David A. Belsley
Professor of Economics