[Hammarlund] SP-600 Electronic Dial

[rbethman]

I have my own thoughts, but I have a nagging question in MY mind.

Why in the world would you want a digital readout on such a fine piece 
of workmanship?  If it is properly aligned, the dials provide great 
accuracy, and since you are receiving ONLY, how accurate do you need to be?

[Befuddled]

Bob - N0DGN

On 2/24/2011 2:07 PM, k2cby wrote:
> Has anybody tried to couple a digital counter to an SP-600 to make a digital
> dial?
>
> I've tried a couple of methods and none seems to work very well.
>
> I have had passable results on the lower three bands (below 7 MHz) by
> tapping off the feed
> from the HFO to the crystal oscillator switch through a 50 pF capacitor,
> although the
> HFO signal is full of harmonics.
>
> If I try this on the bands above 7MHz the HFO gets pulled to far off
> frequency (even with the
> coupling reduced to 10 pF) I can't even align the receiver. (The trimmer is
> too small.) The only
> solution I've found is to wind a multi-turn coil around the 6C4 HFO tube.
> The signal is strong
> and the waveform looks real good, but it's quite a kluge.
>
>
>
> Miles B. Anderson, K2CBY