[R-390] Alignment R-390A... simple ( ?

[Pete Williams]

​Having a aligned  R-390A (many ) over the  years, I've never had a sig.gen
with  the  ability to  store all the  alignment frequencies  to  minimize
the  knob twirling on a   URM-25 as well the  rx setting to  accommodate
the  desired  frequencies. The  aging process led me to  make  things  a
bit  simpler.. Doing this  assumes the  rx s in some  operating condx.
I recently  made  myself a  marker generator  from a piece in a  copy of
Popular Electronics using a  100khz xtal and a  CD4017 chip... A  2N 2222
is  an  oscillator  and  another for the   amplifier.
The  CMOS divider  produces outputs  at 100,  50, 20 and 10kHz with useful
level output  markers up to  30MHz
Using the manual  setup of  connection to the  diode load and inputting to
the   balanced  antenna , the  output level  from the  marker is well in
excess of the input needed to  get the  -7V or less  and having a HP
switched  attenuator in the line, it was easy to get the  level down to or
even less than  -7V.
Yes  knob twiddling still  needed  but only on the  rx . With the
exception of the  0-1   MHz range. all align  frequencies including the
1st  and 2nd  IF  are  multiples  of  100kHz . Band 1  can be  accommodated
using the 50kHz output.
As a rough alinement it works  well and for more meaningful /sensitivity
tests one  has to  resort  to  a  sig.gen with a   calibrated  attenuator.
 A possible  side benefit is being able to  check the linearity of the  PTO
with the   10  and  20kHz markers'
 Works fine  for me.
Cheers
Pete VK3IZ