Have you got a sluggish crystal that
doesn't key too well?
This can happen and does not mean the
crystal is faulty. Some crystals just will not key quickly. If you improve
the feedback in the PA then you should be able to get even the most reluctant
crystal to key fairly well. There are two Paraset pa circuits around so read
below carefully and select the best method for your type of Paraset.
If your Paraset has an r.f. choke in
the cathode then do this:
Connect a low value capacitor between
the grid 1 (pin 5) and the cathode (pin 8) of the pa. Somewhere between 5
and 15pf should do nicely. You could use a gimmick insulated wire twist capacitor
about 1" to 2" long. Or a square of double sided pcb about 5/8" square as
the capacitor plates. Don't use a low voltage rating capacitor here as there
are quite a few volts flying about, you could use a silver mica capacitor
here as that would survive.
If your Paraset has a resistor in the
cathode then do this:
Connect a low value capacitor between
the anode (pin 3) and the grid (pin 5) of the pa. Somewhere around 2 to 5pf
should do nicely. The best and most simplest way is to use a gimmick insulated
wire twist capacitor about 1" long. One could use a square of double sided
pcb about 3/8" square as the capacitor plates. Don't use a low voltage rating
capacitor here as there are quite a few volts flying about, you could use
a silver mica capacitor here as that would survive.
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