|
New to Ham Radio?
My Profile
Community
Articles
Forums
News
Reviews
Friends Remembered
Speak Out
Strays
Survey Question
Operating
Contesting
DX Cluster Spots
Propagation
Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers
Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net
|
| Reviews Summary for Collins R-390 (non A) |
|
Reviews: 4
|
Average rating: 4.8/5
|
MSRP: $1421
|
|
Description: Military Receiver covering .540 to 30 MHz
|
|
More info: http://
|
|
Email Subscription
You are not subscribed to this review.
Subscribe!
My Subscriptions
Subscriptions Help
|
You can
write your own review of the Collins R-390 (non A).
|
KB1OKL
|
Rating: 5/5
|
Apr 11, 2009 14:06
|
Send this review to a friend
|
|
everyone should have one
|
Time owned: more than 12 months
|
It is one of the best period, I'll take one of those over any modern rice box any day, it is a real radio, great on splits for BCB DXing and the audio is great. Everyone should own an R390, they are the cream of the crop. There are many other boatanchors which are right up there though including R-390A's, National HRO's, and Hammarlund SP-600's are the others that spring to mind quickly, but when you really have to dig it out of the dirt quickly, fire up the old R-390. I have two and use many receivers but the R-390 is one of my favorites, another being the R-390A. They are complex and I'll usually send them out to an expert such as Don Heywood, WC4G who can be reached on Chuck Ripple's site, he does a great job
|
|
K6DPZ
|
Rating: 5/5
|
Dec 26, 2007 11:32
|
Send this review to a friend
|
|
Higher quality than the 390A
|
Time owned: more than 12 months
|
|
This radio is better for the short wave listner mainly it has inductive band pass I.F amplifiers and has the more softer band pass response with not as sharp of skirt sharpness as a mechanical filter gives you.And as far as construction it is much better even through the power supply may be more questionable We speak with some authority my company over many years have repaired both receivers.And sold them all over the world.
|
|
W9LBB
|
Rating: 5/5
|
Nov 8, 2003 16:02
|
Send this review to a friend
|
|
The King of the Tube Receivers
|
Time owned: months
|
Without a doubt, the R-390 is the finest and most revolutionary vaccuum tube receiver design ever conceived. It's the ultimate, cost is no object exercise of the tube era. The engineering is so solid that an R-390, if it's in good alignment and has a set of good tubes, can hold it's own in a side by side comparison with most current HF receivers. The noise figure, frequency stability, and selectivity of a well maintained R-390 is well within the ballpart of current performance standards. It's a design that pushed the envelope of tube technology to the limits.
In the beginning, the R-390 was so advanced a design that it was a military secret; into the 1960s the rig was classified, and normally issued only to organizations that specialized in HF signal intercept and surveillence work... it was THE Spook Radio of the Cold War; the rig of choice where only the best would do.
The R-390 was also produced (in small numbers) in an LF / VLF version, the R-389. Also, there was a remote controlled, motor tuned version, the R-391/
These were expensive receivers to build; try $4000 - $6000 a copy in 1950's dollars. The rigs only began to show up in less security sensitive units in large numbers after a cost cutting analysis program resulted in the development of the less expensive R-390A.
As near as I've been able to determine, the R-390 was ONLY produced by Collins and Motorola. On the other hand, the R-390A was farmed out to a multitude of manufacturers and subcontractors, including, rather amazingly, Helena Rubenstien, the lady's cosmetics maker!
The most revolutionary design feature in the R-390 family of receivers is the use of permeability tuning; moving ferrite slugs in and out of coils instead of using large, multisection "bread slicer" type variable capacitors (which were state of the art technology then) to adjust the resonant frequency of LC circuits. The result was a receiver that has RF circuitry that is not only more mechanically rugged, but much more electrically stable than variable capacitor tuned designs.
In order to make this radical departure from current conventions work at all, the R-390 was also a miracle (or nightmare, if you were the poor dude who had to design it) of mechanical design. All of those coil slugs sliding in and out at once have to be accurately tracked, and the assortment of gears, cams, and other mechanical gizmos needed to accomplish the task is simply wonderous to behold!
The dial mechanism is HORRIBLY complex, and it will be heavy and stiff unless it's regularly serviced. As a result, 99% of the R-390s out there now ARE heavy and stiff; dealing with those beautiful cast bronze gears in the Geneva drive is a job that tries men's souls. I've heard it claimed that a properly serviced R-390 dial mecahnism (torn down, cleaned, lubricated, properly adjusted) can be easily turned with one finger. On the other hand tho, I've never actually SEEN one in that condition! The average R-390, when used to scan large segments of frequency, is a definite carpal tunnel syndrome risk.
One of the significant differences between the R-390 and the R-390A is the last IF strip. The 390 derives it's selectivity curve on the basis of a LONG chain of amplifiers using complex LC circuits, while the 390A is somewhat simpler, getting it's selectivity from the inclusion of Collins mechanical filters.
There's an ongoing debate among boatanchor fans about which IF strip is better.
The 390's skirt selectivity isn't as good as that of the 390A, but the 390A has a tendency toward "ringing" of the mechanical filters (especially in CW). I personally prefer the R-390, but ya pays yer money and ya takes yer choice.
Another difference between 390 and 390A is the power supply. The R-390 supply was also a revolutionary design aspect of the rig.
The 390A uses a high voltage DC supply with a conventional LC filter. On the other hand, the 390 uses a supply whose filtering is derived from the use of two series regulator tubes. The obvious intent in the R-390 supply was to reduce supply weight by eliminating the smoothing choke and filter capacitors by substituting a dynamic electronic regulator to remove rectifier ripple.
IMHO the R-390A has the superior power supply design. The R-390 supply is a MAJOR heat generator that was the wrong way to go.
Those supplies are a problem these days because the the series pass tube (6082) is becoming more and more difficult to obtain... and obtain them you must, because the high operating temperatures involved result in relatively short tube life.
A lesser problem, but problem nonetheless, is the high voltage rectifier tube. It too is becoming almost impossible to obtain, but can be replaced by solid state rectifiers. The only problem with that is the B+ supply voltage rises (due to the lower internal voltage drop thru a solid state device as compared to a tube), and a lot of R-390 fanciers have gone into the supply to modify it to bring the B+ rail back into spec.
BTW, the rectifier problem is shared by the R-390A.
All in all, the R-390 is STILL a great hunk of receiving equipment, but it takes a good electronics tech to make it perform at it's best, and keep it there.
73's,
Tom, W9LBB
|
|
G8JFJ
|
Rating: 4/5
|
Jun 6, 2003 05:06
|
Send this review to a friend
|
|
Complex, competent.
|
Time owned: more than 12 months
|
|
Complex HF Rx with no mechanical filtering and an extra RF stage compared with the later R-390A. Designed by Collins. Most production was made by Motorola for Collins. This receiver has fully regulated HT and the heat from the two 6082s causes many overheating problems. In operation, this receiver is smoother than the R-390A due to reduction in IF ringing. Excellent radio but with the usual poor Collins AGC, audio, calibrator and noise limiter.
|
|
If you have any questions, problems, or suggestions about Reviews,
please email your Reviews Manager.
|
|
|
|
|
