[Johnson] Electronic TR Switches

[Bill Cromwell]

Hi David,

I have used and will use again the electronic switching for full breakin 
CW. I have Johnson electronic T-R switch and two homebrewed units. 
Overcoming the problems you named are not so very difficult. But - if 
you are not going to use full breaking QSK you'll find the relay much 
simpler and useable with just about any combination of TX/RX without any 
mods to any of them.

73,

Bill  KU8H


On 07/25/2014 08:34 AM, David C. Hallam wrote:
> I am revising the antenna feed line of my Invader 2000 to be able to 
> switch between low and high power as desired with a B&W two position 
> coax switch.  I was thinking about replacing the Dow Key relay with a 
> B&W 381-C electronic switch.  After reading back through comments on 
> various reflectors concerning electronic TR switches, this might not a 
> good idea.  Things like harmonic generation in the switch and 
> increased receiver noise floor are cited.  I do have a couple of low 
> pass filters.  I get the impression that unless you work full break-in 
> CW (which I don't), it might be a better idea to stick with the Dow 
> Key relay.
>
> What might be comments on this.
>
> David
> KW4DH
>