The AM Forum

Hi All,

 Two hollow-state receivers have recently caught my eye. A Hallicrafters SX-122 and a Collins R-388. Both are described as being in very good electrical and cosmetic condition.

 Putting price aside, which radio would be the better choice for casual listening and eventual hamming activities. I confess I know nothing about either one except that the '122 has a product detector while the '388 does not. I really like the looks of both.

 Thanks, Roland.........

 

Collins R-388/URR was basically a 51J built for the military. Usually when I'm looking for information on a particular radio, I check the reviews on eham for what others say about them.

SX-122: http://www.eham.net/reviews/detail/4659/

51J/R-388: http://www.eham.net/reviews/detail/2590

The R-388 is a huge step up in quality from the SX-122, even though it doesn't have a product detector.  The R-388 will be much more stable and has a MUCH better frequency readout than the SX-122.  The 122 isn't a bad receiver at all, but if the price point is the same and the condition is decent, the R-388 would be my choice.

Actually, you can very easily add a product detector to the R-388 with some minor wiring and component changes and changing the BFO tube to a 6BE6.  Don't even have to change the tube socket. See the article by Orr, Ham Radio Magazine, February 1978. I think it's also documented several places on the web. When I picked up my R-388 years ago, it had this mod done and it works well.

I agree with JN about the R-388 build quality and calibration.  A novice friend had one with a 4 to 1 knob which was a really nice setup..

My R-388 has a CE Sideband Slicer attached for SSB use, the 500 Khz. IF in the R-388 is within the Slicer's range and provides good SSB detection along with a useful increase in selectivity.

In the Hallicrafters line a SX-101 (later versions have a product detector) would be better for amateur usage than the SX-122 but it does not provide general coverage.  The SX-101 stability (both mechanical and electrical) is very good and it provides additional selectivity choices beyond that of the 122 along with a much better dial mechanism and readout.  Other ham band only family members include the SX-111 (kind of a cost reduced SX-101), the very nice SX-115, and the SX-117 which mates and transceives with the HT-44.

Earlier general coverage family members are the SX-96 and SX-100.  All of these, unlike the SX-122, provide selectable sideband on AM via switch selected crystals in the 2nd conversion oscillator along with 5 degrees of selectivity  This quick sideband switching on AM provides a very useful interference fighting tool.  I have a SX-96 (paired with a HT-30) and a SX-100 along with a SX-122 and I prefer both of the earlier models to the SX-122.

You don't even need to do that, if you're willing to forgo the IF output.  Using 1/2 of a 12AU7 that's in service as the IF output cathode follower, a few parts and some wiring changes with the AM/CW switch (to switch the audio between the two detectors), it makes a FB product detector.  I did this in my 51J-4.  Easier, and a much better product detector than a 6BE6.

The 6BE6 gets hammered by the high IF gain and easily distorts, a 6BY6 is a little better but neither would be my choice with strong signals. Im using a CE B Slicer which includes a nice Q Multiplier which is not in the A Slicer.

I didnt think the 4:1 Collins knob worked on a 51J Roger.

Also check if the R-388 has had the J4 type mechanical filter adaptor added. This was a depot/tender level change and turned it into a R-388A altho Ive heard of the factory also doing it.

Carl

Carl,

I cannot remember if the receiver had a regular 4 to 1 Collins knob or if it was some other mechanism, I last saw the receiver back in the late 1970s.  The owner was a retired Coast Guard radio op and it was his favorite receiver.   I remember him proudly explaining why the tuning was so much better than a regular R-388.  He had lost his voice due to throat cancer and operated only CW and the slow tuning made operation much more pleasant. 

My parents purchased a Johnson Valiant from him for my Christmas present in 1974 and it was unquestionably the best Christmas present I ever received although the Mattel "Thingmaker" a few years earlier was pretty memorable too :)

Rodger

Thanks for all the great information.

 How does the R-388 stack up against an SP-600?

Thanks, Roland....................

I have both. I like the SP-600 for general short wave listening and quick tuning around the bands. The R-388 is used primarily for just ham band tuning. The audio sounds better listening to short wave stations on the SP-600.

Pete has covered some of it. I'd only add the clear use/performance advantages to each:

R-388/51J-3 - superior stability and accuracy

R-274/SP-600 - superior tuning feel and audio output.

You really can't go wrong with either one, and both are a better choice than the SX-122 in my opinion.

Since both use a single ended 6AQ5 for audio output it isnt much of a chore to improve the audio. The other choice is to take the low level output into an external amp.

I have a R-388 and 51J4 and the only downside to use is the 30 1 MHz bands take a bit of time to navigate thru but I usually stick to a few of the SW bands or non ham voice in the clear, AM or SSB.

Carl

I use my R-388 all the time as my main AM receiver on 75m and 40m.

I prefer it over the R-388s I have used at other folk's shacks.
I like the audio - I run into an old time Altec coax speaker, high efficiency, it fills the room
and is easy to listen to.

You can find the mechanical filter adapter from time to time on ebay and elsewhere.
It is a 500kc IF.

There are all sorts of product detector mods for it. No shortage of methods.

Also you can take the IF out and put that into a Softrock  or equivalent I/Q type board, and use the computer with one of the many SDR programs and suddenly have a rather state of the art radio with a nifty old time front end! :D  I got the Softrock to do that, but have not have had any time to build it up and run it :(

Watch the power transformer and the filter cap (plug in can) the cap can short, and the power transformer can run hot and have shorted turns. I think the potted xfmr is superior to the end bell type - mine is the end bell type and probably has a weakly shorted turn or two in it, and runs too hot, but has run like that for years now. :D

Great radio, imo. Love it.

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