[R-390] Post to List (Antenna Relay)

[rbethman at comcast.net]

KEEP THE ANTENNA RELAY PACKAGE!

I use a Johnson T/T SW, the R-390A is sensitive enough to pick up what is neing transmitted.

Lord, I've had it on the bench with the antenna disconected, and had a HAM a half mile away key up and come booming through the audio output!  You WILL get reception on the RCVR IF you don't use the break-in!

Bob - N0DGN


> I think it best to keep this relay, so terminals are grounded
> during break times when transmitting.  Am I wrong, and
> is the relay really needed for ham use?   jsullivan
> 
> Most fellows using R390 or R390/A for Ham use are also running a transmitter.
> The relay gets used for break-in operation. 
> 
> Some fellows have TR switches, but these can bleed RF through, so having the 
> antenna get grounded is good. Some of the TR switches just swap the antenna 
> via relay between trans and receive. Some just cut the receiver signal off by 
> driving a tube or transistor into cut off. Some TR switches actually ground the 
> break-in circuit on the R390's and use the antenna relay to ground the 
> receiver input. Of course in these circuits you cannot also feed the whole 
> transmitter output into the R390 input, some other switching action has to 
> occur. 
> 
> The receivers offer a single ended coax for input. The better balance input 
> is just a Twinax IBM network type cable. The connectors and coax are very 
> available. The Receivers also were operated with an adapter from twinax to 
> grounded 
> one side and single center conductor coax feed. Any of these work real good.
> 
> Just Chuck Ripple's R390 Page.
> 
> http://www.r390a.com/html/history.htm 
> 
> As Les keeps it going.
> 
> Chuck did a how to hook any wire to the input of an R390. Its been working 
> for fellows for a long time.
> 
> No need to hack the antenna input on any receiver.
> 
> Roger KC6TRU
>     
> 
> 
> 
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