[R-390] WTD - AN/URM-25

[Kenneth G. Gordon]

The AN/URM-25 is a pretty good OLD unit, but there are better, more 
useable signal generators which do a far better job. I don't like their drift 
at the higher frequencies, and you must use a frequency counter with 
them in order to really know where you are.

If you really want an AN/URM-25, get hold of Ashley (?) in Oregon who 
completely rebuilds them for, IMHO, peanuts. She does a superb job, 
and often times has rebuilt units for sale on "the bay". Do a search for 
URM-25 to see what pops up.

Personally, I would prefer to use practically any of the more modern 
units which cover the required frequency ranges.

The HP-8640B WAS an excellent choice, but since those used nylon 
gears, many of those units are becoming unusuable since the gears are 
gradually "going away" and there are no replacements.

I have an HP-8640B which I use a lot, but I am very apprehensive that 
a gear will fail, and I will be in the market for a replacement.

I also use a pair of BC-221s when I am aligning receivers for band end-
points, one set at the high end and one at the low end. The BC-221 is 
more difficult to set on frequency, but it is very stable and when 
properly calibrated, plenty accurate enough frequency-wise.

They are also cheap, if you buy them properly. One of those I bought 
cost me $10.00 and the other one $5.00. The $10.00 one had an AC 
power supply in it.

Ken Gordon W7EKB