Having just finished building
my new power supply I decided to try it on this RF24 unit.
I wired the rear Jones plug
to 6.3VAC and HT1 which I adjusted to 300 volts and connected
the spectrum analyser. I had a little difficulty with the band
switch because it was heavily tarnished, but got the picture
below. The peak on the right (29.8MHz) is the local oscillator
appearing at the IF output and the peak on the left (21.733MHz)
the tuning characteristic of Channel 5 to which the RF24 is set.
The difference between these
is the IF of about 8MHz. Because of component aging the correct
IF of 7.5MHz is not quite right.