[Milsurplus] Command Set antenna relays

[WA5CAB at cs.com]

Hue,

The antenna connect relay in the Command Set transmitters is part of the 
transmitter select circuit or system.  When you select transmitter #1 with the 
transmitter control box, the antenna connect relay K54 and the HV connect relay 
K53 close.  What happens when you key the transmitter depends on whether the 
selected mode is AM, CW or MCW but these two relays stay closed as long is 28 
VDC power is on and the transmitter is selected.  When you select another 
transmitter (assuming two or more are installed), the two relays in transmitter #1 
open, taking it off the antenna and off the HV, and the two in the now selected 
transmitter close.  Speaking of MF/HF installations only.

In a message dated 2/20/2005 12:56:24 AM Central Standard Time, 
kargo_cult at msn.com writes: 
> Sometimes you find a transmitter without this part stripped out to "improve 
> it".
> Pat Person W7YIR ( i think that his call) has plenty of these new stock 
> SCR-274
> spare relays. I saw them at hamfest today. I am sure he does not want to 
> deal in
> mail-order at all, but if you really need one or some, i might be convinced 
> that
> i should help transfer them to you. 
> Also, how do these work? It kinda looks like the antenna contacts close
> AFTER the B+ contacts close, which doesn't seem right.

Robert Downs - Houston
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