The IF amplifier also needs to be checked for the correct IF frequency,
because your tunnig L and C was designed to track at the IF frequency and
it will not track correctly at another frequency. Those IF trannys are very
tempting for inexperienced people to tweak.

With any of the LC tuned receivers, the inductance of the RF coil (which is
probably the loopstick), and the inductance of the oscillator coil is set
while the tunning capacitor is fully meshed. This is at the lowest RF
frequency. The RF and Osc trimmer caps are set at the high end of the dial
or when the tunning cap is fully unmeshed. Repeat the steps as neccessary to
get your best results at the extreme ends of the tunning range. If the
tracking goes bad in the midband, some tunning caps have slotted plates so
that the plates can be bent to improve the tracking, but this method is not
to common for low frequency cheap receivers.


wrote in message
.com...
I have an old 6 transistor radio (Spiket 2 Band, MW and LW) made in
Okenawa Japan. Complete with leather case, looks to be a late 1950s or
early 60s model.

The radio works well toward the lower end of the AM band and also upper
end, but reception drops off in the middle of the band around 800KHz,
but the reception is good if I touch the antenna loopstick.

I have tried to peak the antenna trimmer capacitor with no effect
around 800KHz, but the trimmer does peak the stations near the high
end.

I have also tried to adjust the main tuning capacitor along with the
oscillator coil to try and get a peak around 800Khz without success.

I have connected a generator to a couple turns of wire around the
antenna loopstick and monitored the signal on a scope. It tunes very
well and there is a sharp peak wherever I set the generator and tune
the cap. The local oscillator signal on the tuning capacitor also
looks good with fairly constant amplitude across the band.

It's a perplexing problem. Everything works well, but reception
is poor in the middle of the band.

Any ideas?

-Bill