Re: RCA AR88D Comms Receiver.
Putting the osc aside for a while, as the RF section uses the same coil former material, looks like perspex, I decided to go through the alingment proceedure as per the manual.
It took a day, winding back and forth about 10 to 15 times on each band, it aligned perfectly, nice sharp peaks on coils and trimmers. I found that I had to use my adaption of the mixer to a cathode follower as the scope probe on the mixer grid affected the tuning of the final RF stage, although the waveform is a little distorted using this method.
Now, the crunch, the output of bands 4, 5, & 6 is obout 18 dB down on the bands 1, 2, & 3.
This is again pointing me towards the coil former material causing low Q.
My next step is to buy a Q meter.
If there is anyone in Essex or Suffolk that can loan me one for a few weeks please pm me.
It could be a few weeks before one appears on ebay.
John.
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