[R-390] A Christmas Wish

[Craig C. Heaton]

To All,

	Well, after becoming a caretaker of a R-390A for less than a year, I would
like to make a suggestion to this illustrious group, using the phrase "To
make the best, better", the Y2K manual could use a few additions. Also
please accept the fact, I don't know the original intent of those who wrote
this manual.

	With that said, I'll further clarify. Roger, KC6TRU, made a post on
Sept.26,2005 and it included a few sentences. "Once you get to the point
where you have a calibration tone every 100 KC, you have a working R390/A. A
working R390/A and a wonderful receiving R390/A should not be confused with
a good looking R390/A. Each of these are different. Good looking R390/A's
are selling for over $1000.00 on Epay and may not work at all." His next few
pages outlined what it takes to arrive at a wonderful receiving R390/A. Now,
Roger is to blame for my quest of a wonderful receiving R390/A.

	The Y2K manual is great. Without its content, I would not of been able to
arrive at the point where I have a working R390/A. Note, this is the first
receiver I've ever attempted to repair, fix, restore, align, etc. Heck, the
manual is only 300 and some pages, what's a couple more to take us to a
wonderful receiving R390/A.

	So, addition one: How about something like Scott Seickel's illustration of
how to reassemble the gear train. Using his information and good techniques
on disassemble, I laid everything out on a clean bench in order, it still
took over 12 hours to clean, reassemble, and lubricate the tranny. Note, I
did not say copy his work without his permission. Great work Scott!

	At some point the IF section has to be able to pass a 30db Signal + noise
to noise test. Or at least some authors in the past have stated. With that
in mind and not wanting to start a feud, measurement creeps into the
picture. A short dissertation of what happens when a sig-gen, such as a
URM-25() is used without consideration of impedance matching, RF leakage,
etc. Then addition two: A blow by blow account of what to connect, where to
connect, the values are we looking for, and the correct order of tubes to
swap while measuring for the 30db goal. Is that clear?? I believe I know the
answers and pitfalls, but they were spread out at different sites and had to
sift through several hundred pages.

	Addition three: Same thing in the above paragraph to the RF section all the
while hoping for the 20db difference between modulated signal to unmodulated
signal. Of course ignoring impedance matching between the sig-gen/receiver,
RF leakage, plus the antenna to be used with the receiver will vary your
results in real life.

	The three above wishes are made without criticism. Not everyone that
follows this group has a radio background as a living. Bet you a soda few
here have ever sent an instrument to a metrology lab for
calibration/certification.

	Gotta find some tubes..........with that and not trying to be politically
correct, after all more people are trying to get into the U.S. than are
trying to leave.

                                MERRY CHRISTMAS!!!!

wd8kdg
Craig