I used to manage operations for the military that used R-390s in vast
quantities. It was not uncommon to have over a hundred of them at a
facility and thousands in our overall inventory. For what they were
designed to do they did a great job. As is mentioned they did not have
a product detector. I once saw a prototype sideband adapter, but
before it was adopted in any number, we went to newer solid state
receivers (none in the ham price category... 10K each and up.]

There were a couple problems we had with R-390's. The main one was
maintenance. The tuning scheme was so complicated you practically had
to be a mechanical engineer to fix one. The gear trains to control the
permeability tuning are a wonder to behold. They were cumbersome to
tune and military intercept operators who used them all day long
complained of "R-390" wrist because it took so much arm torque to
change the megahertz dial. It was time consuming to get from one end
of the spectrum to a different end. Some guys, particularly HF search
operators got carpal tunnel from tuning them day in and day out. They
consumed a lot of energy, particularly if you had a bunch of them
operating at the same time. We usually had air handlers to cool the
rooms they were in. The only reason they didn't drift is because ours
were on all the time.

I was the program manager for programs which used a bunch of these,
and as such I didn't use them day in and day out (I did use them some,
but not as a day-to-day operator.) I also didn't have to fix them
myself, but I oversaw the programs that made sure there was someone
there to fix them. The criticisms I heard were from the military ops
and the maintenance guys. We reduced our maintenance overhead in
personnel and spare parts considerably when we finally got rid of
them. We could afford to buy 10K receivers because we didn't a ten man
maintenance shop on site to keep the R-390s (among other gear) going.
Of course in the end, we had to get rid of them because there just
weren't parts available in the quantities we needed. They were used
for long after government contracts for manufacture and for spare
parts production ran out. I've been retired now seven years and the
last 15 or so years of my career we didn't have any R-390's on my
projects (there probably are some still in the government through, if
only in depots.) I saw my last operational SP-600 series in the early
70's. The search operators loved it because you could scan a large
chunk of spectrum (before automated systems) in far less them than
with an R-390 or 51J receiver. The 51Js were all gone by the time I
started in 1964. I don't think I ever saw one operational.

Of course a ham restorer dealing with unit quantities doesn't have the
maintenance management problems we had because a ham trying to fix up
one or two can probably scrounge up the parts or cannibalize another
like units, but we had to look at the R-390 and almost any other piece
of gear the military used in terms of life cycle support, personnel
costs, training tails, depot stockpiling and a host of other issues.
It was a good receiver that just wasn't supportable anymore. The same
could be said for the SP-600 series which was actually obsolete when I
entered the profession 43 years ago, but that hasn't stopped dedicated
hams from making them work in unit quantities.

Jon W3JT



On Sat, 24 Mar 2007 21:01:37 -0400, Rick wrote:


Well, I am beginning to have some doubts about the likelihood of finding
an excellent-quality Hammarlund HQ-180 at a price I can afford.

Certainly I am going to keep looking, but meanwhile I guess I need to come
up with a few alternatives that I can "settle" for if, as seems likely,
the HQ-180's have priced themselves out of my reach.

I need something that is all tubes, and works well on SSB. I plan to use
it mostly on CW but I need decent SSB performance. AM is relatively less
important (it should work on AM but doesn't need to be a spectacular
performer).

It does need to be general coverage 500 KHz to 30 MHz.

R390's and 51J4's would be good (but of course, more expensive than the
HQ-180) but none comes with a product detector and so performance on SSB
is likely to be marginal at best, right?

I have looked at a few Hallicrafters SX-100's (that is to say, looked at
their pictures on eBay... haven't actually seen one up close in at least
30 years). How does that model and other comparable models from
Hallicrafters and National stack up?

Did Heathkit ever make a general-coverage communications receiver that was
worthy of the name "communications receiver"? I know they had one, I
think the model was AR-3. I had one when I was a kid and it wasn't much.
Everything else I've seen from them seems to be ham bands only, and mostly
80-10 (no 160).

Any suggestions, places where I should start looking?