[1000mp] PTT Interface

[Carl Kratzer]

Thanks to everyone who responded to my query regarding the interconnectio=
n of
an optoisolator keying circuit (i.e, Rigblaster) to the rear panel
PTT/Packet/RTTY connectors on the Mark V Field.  There were several excel=
lent
suggestions, but I chose to implement a solution recommended by George, V=
E3YV.
 Simply place a resistor (in my case 150 ohm) between the PTT key line an=
d
ground (in other words, across optoisolator output).  This lowered the 13=
=2E8
volts that was present at the radio when unloaded down to about 2.5 volts=
,
allowing the optoisolator to do the rest of the job, closing the PTT circ=
uit
when triggered.  This solution required no mod to the radio or the Rigbla=
ster
itself.  I just put the 150 ohm resistor across an RCA male plug and inse=
rted
it into the rear panel PTT jack.  The Rigblaster PTT connection via the
"packet" DIN connector now works fine.  Again, many thanks for the variou=
s
recommendations.  Carl, K3RV.    =