[ARC5] Keying suggestions

[Mike Hanz]

There are *two* ways to employ a spike diode - one *across* the relay 
coil, and the other *in series* with it.  See Steve Williams' 
interesting keying relay experiments on a complete 274N set at 
http://aafradio.org/docs/docs.html , under SCR-274N relay timing notes, 
for a lot of good information.

I'm a little puzzled by the original question, though.  K-53 isn't 
designed well for keying purposes unless you intend to send fairly 
slowly, and keying the MO at the same time isn't conducive to 
stability.  An external relay in the B+ line like the original design is 
actually easier to rig up than the effort needed to modify the 
transmitter wiring, reversible though that might be.  Just a couple of 
data points to think about....

Best 73,
Mike

David Stinson wrote:

>----- Original Message ----- 
>From: "Ian Wilson" <ianmwilson at earthlink.net>
>Subject: [ARC5] Keying suggestions
>
>
>
>>I'd like to key an unmodified ARC-5 TX using the internal relay.
>>
>>    a) I know that originally, the relay in the modulator did this
>>    b) will apply the reversible mod that leaves the antenna relay in 'on'
>>       position
>>
>>What R/C snubber components should I use around the key? Should I use a
>>spike-catching diode?
>>
>
>I would recommend the spike diode, but I've never used
>an R/C snubber.  If you're just keying one relay, I don't think
>it should be a problem.
>