[GreenKeys] Dovetrons

[telegrapher at att.net]

Finally figured out a way to use the one i acquired last year.  No
modifications necessary.

I also have an ST-6 and an IRL FSK1000.  Both could be used as loop
drivers with the Dovetron being the actual Demod. unit.

The IRL unit has a serial in port that will accept the RS-232 voltages.
The DOvetron has an RS-232 out port.  I hooked those two ports together
and it appears to work fine.  Running the RS-232 signal into the "serial
in" port of the IRL unit does nothing but run the loop keyer circuit for
the machine.  When typing on the keyboard the loop is keyed of course
but in the IRL unit it operates the "KOS" circuit and the transmit
portion of the TU which is the AFSK unit thereby sending the AFSK out to
the transmitter.  

The ST-6 could probably also be used in a similar manner.  Locate the
point where +12,-12V drive the loop keyer circuit and tap into that
point using either an RCA or BNC connector on the back of the ST-6.  YOu
then have the versatility of using the variable tuning Dovetron Demod.
and the ST-6 stability of 170-850 shift (standards) without making any
modifications to the Dovetron keeping it's integrity intact.  My
DOvetron came set for 85, 850 and 200 cycle shift.  I'm sure one of
those could be adjusted for 170 cycle shift but haven't done anything
with that.  Also the Dovetron states the AFSK output is 0 dbm.  I'm
measuring anything from +6.5 thru +9 Dbm.  When looking at the AFSK
output on an O'scope things aren't looking right.  Maybe the high level
output is causing some other interaction in the AFSK section. 

Thot i'd share this with some of you who might be wondering how your
going to get some results from your investment.  Maybe the HAL folks
could give a boost for their venerable ST-6 by suggesting a method or
providing interface information between the two units.  I suspect it
would be worked with most TU's as long as the loop keyer circuit is
driven by either the MIL-188 or RS-232 voltages.

Larry
W0OGH