[Elecraft] Re: RF Coupleing

[Don Wilhelm]

As an alternative to coax, try using twisted pair - pull a couple pairs 
out of a short length of CAT-5 cable.  One of the pair would be grounded 
at each end (will require adding a solder lug at the SO-239 jack).

73,
Don W3FPR

Stewart Baker wrote:
> David,
> A very good point. Although the space is rather restricted for 
> RG58/U it should be possible to fit some of the smaller diameter 
> cable such as that used to connect between VHF/UHF PCB's.
> I have some silver braided coax that would be suitable. 
>
> It would have little adverse effect over such a small length, but 
> might provide additional isolation.
>
> Food for thought...
>
> 73
> Stewart G3RXQ
> On Wed, 16 Jul 2008 12:14:03 -0400, David Robertson wrote:
>   
>> Stewart,
>> Your posting is good information however one of the factors of 
>>     
> isolation between ANT 1
>   
>> and 2 can be how the pigtail leads from the 2
>> SO239 connectors and the antenna coupler board are dressed.  It 
>>     
> would seem easy to have
>   
>> these nonshielded wires crossing or near each other. The space 
>>     
> seems too tight to use
>   
>> rg58/U cable. this could mean that depending how those wires 
>>     
> were dressed the coupling
>   
>> would be different between all K3's.
>>
>> 73
>>
>> Dave KD1NA
>>
>>
>> From: Stewart Baker <stewart at baker.nildram.co.uk>
>> Subject: Re: [Elecraft] Re: KAT3 ATU and SPE Expert 1K-FA 
>>     
> Amplifier
>   
>> To: Dave G4AON <elecraft at astromag.co.uk>, 
>>     
> <elecraft at mailman.qth.net>
>   
>> Message-ID: <2008715195354.766566 at shack>
>> Content-Type: text/plain; charset="ISO-8859-1"
>>
>> I made some measurements of the isolation between ANT 1 & ANT 2 
>>     
> on
>   
>> my K3.
>>
>> There is little difference between ATU & BYPASS. Unable to do
>> 50MHz.
>>
>> 1.9MHz 58.1dB
>> 3.7MHz 51.9dB
>> 5.1MHz 49.2dB
>> 7.0MHz 47.1dB
>> 10MHz 44.7dB
>> 14MHz 42.5dB
>> 18MHz 40.8dB
>> 21MHz 39.2dB
>> 24MHz 37.1dB
>> 28MHz 35.7dB
>>
>> So on 60m for 100W from ANT 1 there will be 1mW from ANT 2.
>>
>> 73
>> Stewart G3RXQ
>>     
>
>
> _______________________________________________
> Elecraft mailing list
> Post to: Elecraft at mailman.qth.net
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
>  http://mailman.qth.net/mailman/listinfo/elecraft    
>
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com
>
> No virus found in this incoming message.
> Checked by AVG - http://www.avg.com 
> Version: 8.0.138 / Virus Database: 270.5.0/1555 - Release Date: 7/16/2008 6:43 AM
>
>
>
>