[Boatanchors] Electronic T/R Switch vs Coaxial Type

[rbethman]

I, like Pete have been running a Johnson TR Switch on the output of a 
BC-610.  NO TVI!  I monitor the output of the BC-610 with an SM-220 
w/BP-8.  I also feed my receiver's IF into the SM-220.  I observe NO TVI.

I believe that those getting TVI are mistakenly relating the source as 
the TR Switch.  I only see TVI when over modulating an Apache.

Bob - N0DGN

Peter Markavage wrote:
> I've run a Johnson T-R switch on the Johnson Thunderbolt for years and
> not experienced any TVI related issues. I also have a Dow-Key relay on
> the back of my Apache that's been there and working since around 1960/61.
> The Dow-Key on the back of my Viking II has been there and running since
> 1955. These relays were some of my better investments.
>
> Pete, wa2cwa
>
>
> On Tue, 4 Nov 2008 10:36:39 -0800 "BLIMPY" <blimpboy at sonic.net> writes:
>   
>> Biased vac tube T/R switches have bad reputation as TVI generators.  
>> Many
>> in-line filters are not tolerant of impedence mis-matches expecially 
>> those
>> with  reactive components.
>>
>> Run of the Mill Dow Key are second rate relays.. compared to Advance 
>> Coaxial
>> Relays.. which are available for less money and will give no grief 
>> due to
>> unscheduled liberation of smoke.  Some BNC commerical application  
>> surplus
>> relays  with dc  may be contradict this generality.
>>
>> a vox type t/r switch might be a workable compromise, but not true 
>> break-in
>>
>> good luck
>>
>>
>> _______________________________________________
>>
>>
>>     
> _______________________________________________
>
>   

-- 
Bob - NØDGN