OHR Sprint tuning mod

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From: Lee Stanford (lstanford@sj.aishd.com)
Date: Fri Oct 13 1995 - 17:27:02 EDT


On Oct 12 Preston responded to question about OHR Sprint usability
>You will tire of the DC receivers and will grow to find them
>annoying, even though they have a distinctive clean sound. The two
>sideband signals for each actual signal is a pain because you must
>always get your transmitter on the correct side to call a station.

I have found a simple modification to help with that problem. You need
to add another small switch to the front panel and use it to switch in
a 1N4148 to ground. I put the switch between the power switch and the
tuning dial. Solder the anode (no band) end of the diode to the
switch, and the cathode (banded) end to a spot on the front edge of
the circuit board on the ground trace (where you have scraped off a
spot of the solder mask). Solder one end of a piece of wire to the
other switch contact and the other end of the wire to the
anode (no band) end of D9 (I think the top end of R34 will also
work). On the schematic the point you want is the junction of D9 and
R34. When the switch is closed, the receiver offset is removed and
you can "zero beat" the signal. Opening the switch places you on the
right sideband. Probably best to use a momentary switch to make sure
you do not leave the switch closed.

Author takes no responsibility for use or misuse of this modification.
Anyone who sees an error, or a better way, is encouraged to post a
reply.

73, Lee KM6LA


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