R-1051B Reciever help needed

[ke7trp]

I just picked up a very clean 1051B at the swap and swindle. 

THe manual was included but it only contains repair information and no operating procedures or pinouts.

I am confused on few things:
 
The Audio output is two connectors.  One for LSB and one for USB.  I am mainly an AMer.  Will I need two amplified speakers running?  Or in AM mode does it use only one of the outputs for both Sidebands?
 
What do you use as an audio amplifier?  I see that its 600 ohms with only 60MW output. Thats not going to be enough to power my Hallicrafters and collins speakers in the shack.  Should I run RCAs to an amplifier and then to a speaker?  Should I get a power speaker?
 
How wide is the AM filter?  I read he included manual and did not find any mention of the filter spacings.  I dont see a way to increase the width on the front panel.
 
My Yellow light blinks all the time. Is this normal?
 
The manual I have is about 3 inches thick and does not contain hookups/pinouts or operating procedures. Is this located in any of your manuals?

Does the 1051B have a MUTE line?

 
My goal is to use this receiver instead of my R390A.  There is a broadcast station (disney kids program) running 50KW 8 miles from the house. THe R390A plays this on nearly all freqs. My hallicrafters do not. I am hoping to have better then hallicrafters performance with no Disney music blasting in.

I did power it up and heard WWV clearly through headphones.  I used a short piece of wire strung up the door. Did not have a chance to LUG this 70lb beast onto the table for further testing. 

Finally.. Can someone give me a break down of the performance of this machine?  Is this something an AMer wants? Mainly going to use it on 75 meters.
 
As always.. Thanks for the help!

Clark

[w3jn]

That thing is great if you're going to listen to a few stations of known frequency.  For band scanning it's an impossibliity.

The IF for AM is 7 KHz as I recall.  And yes, you'll need to run the audio to an external amp.  Believe the AM audio comes out of the USB channel.  If you want to listen to LSB you have to switch channels, as I recall, but this is all done for you at the headphone jack but not true of the outputs in the back.  A stereo amp (goodwill special!) or powered computer speaker will work fine here.

Yes it does have a mute, it's one of the pins in that amphenol connector in the back.  Manual should tell you which one.

The yellow light indicates you have the vernier tuning on (the knob in the upper right, that tunes between the 1 KC steps).

A better solution than the R-1051 would be to figure out why you're getting BC interference in the R-390.  Are you usingthe balanced ant inputs, or the whip input?  You could very easily build a high pass filter to get rid of the BCI, but it almost sounds like there's something else going on there as the 390 has a very stout front end as opposed to the Hallicrafters.

I'm not a real fan of these, they're mechanically very complex and they make that irritating whirring every time you change frequencies - which is hard enough as it is!  The performance is pretty good, though.

[ke7trp]

Thanks for the tips.  I searched through the manual and still could not find the mute pin.  Its almost 300 pages long. I will have to find a powered speaker to try it out. 

I would use it on 55,70,80 and 85 on the 75 meter band so it wont matter about scanning.

THe R390A and the other one I tested here gets the 50KW disney channel.  It just cant reject it. I have tried using the bal and the Whip connections.  I can tune the Disney ch in all the way out to the 3rd harmonic and listen to it clearly.   So I have two of them and both of them have this trouble.

THe Collins 75s, SP600, Halli 100,110,96 ect  dont have this issue.  My 1000D does not have this issue either. Something in the R390A does not like 60DB plus of 1860 going into its throught!

7KC is not really wide enough. I will have to listen with it tonight to see how it sounds. 

Clark

[WA1GFZ]

Do you have all the shields installed on the R390? I bet BC crud is getting into the detector around all the RF stages.  Check all the coax shields between RF sections. Also make sure the tubes have shields on them if required. The coax feeding the R390A wind a common mode choke ahead of the radio. Do the same thing with the power cord. A bunch of snap on beads is also usable if you have enough of them. Bypass the audio output leads and use shielded wire twisted pair shielded.

[ke7trp]

I am not really into modifications to the R390As.  I dont want to alter them.  Both are open frame.  No covers or cabinets. That could be some of the issue.  I did try Snap on cores. Did nothing. The BC is comming in the antenna.. THe station is beaming 60DB over and its just mixing around in them.   

Why this never happens with the hallicrafters or other RXers is beyond me.. I do know that if you Flip the Exiter or VFO on a transmitter (To zero beat the RXer) you do hear the disney station on the hallicrafters.. But once you turn the exciter or VFO off, you dont hear it anywhere. It does not bug me so its not a problem.

Thanks for the 390 tips though!

Clark

[W7TFO]

It sounds to me like you have a resonant rusty downspout or something else forming a diode joint and re-radiating the carrier from them @ 1580 kHz.  This can manifest as an overwhelming amount of broadband but modulated hash right on top of your shack.

I'd get together with another ham with a directional FI meter and go looking for it.

The 390 is really a bulletproof receiver by contrast to the lessers you have, with exception to the SP-600.  I have used them and lived just outside of Lehi (where that TX is located) and never heard a peep of harmonics from that station, or the other right there @ 1310 kHz.  Something is wrong with those R-390 radios.....or it is  broadband interference.

The Navy loved them as they wouldn't overload even with the ships' radar signal scanning right over the whip antennas they used for HF.  The R1051 was just as good on rejection, but as previously mentioned a pain to operate.

Fair Radio used to have tech lit for the R-1051.

[ke7trp]

Yeah.. Maybe mine and my friends R390A are both broken. I honestly dont know.

On the 1051.. I read the entire manual.  Never once is anything about muting mentioned.  I did read a thread on some forum that yahoo linked me to... THis thread said that the 1051 mute is auto.  It went on to say that the 1051 has a complex system with a relay that will mute once it senses to strong an RF signal. This was to protect the radio on the ships.  Users claim that if you key the transmitter, the 1051 just mutes on its own.

Interesting..  I wonder if this does really work. I will have to try it to find out. 

Now just to find some kind of powered speaker that wont have RFI..  I was thinking of injecting the 1051s audio into another reciever.

Clark

[w3jn]

It was made to work with the T-826 transmitter, and there was a wiring harness that connected the two and the matching linear amp.  You'll just hafta figure it out from the skizmatic and/or circuit descriptions, I guess.

[kc6mcw]

Hey, dont get your hands caught in the chains while tuning that thing! HA

[ke7trp]

Making some progress.  Just so others know..  This unit has two Demodulators.  THe audio outputs are SEPERATE for LSB and for USB.  It has no SPeaker outputs. Only two 600ohm low level audio outputs. You will a stereo amplifier and speakers.

In the AM mode, the audio goes out the LSB audio port.  THe Width is 7KC in the Am mode according to the manual.

I am going to hook it up once I find a powered speaker of some kind. Then use it for a night on 75.

Clark

[KD6VXI]

I am going to hook it up once I find a powered speaker of some kind. Then use it for a night on 75.

Clark

Cheap, quick and easy, Radio Shack.

It's also high impedance, and makes a great signal tracer.

If my memory serves me well enough, it might even be dual powered, ie battery and a DC jack on the side.

--Shane

[Opcom]

What is the nomenclature number on the manual?

The R1051 is a very fine set. It is a cousin of the GRC-106's RT unit and some modules are common. If you are lucky, yours will have an original meter with a radium painted indicator. People pay extra for that. If you find a spare frequency standard module, get it. If that breaks, it is very interesting to repair.

The unit is a work of art and, save for the aforementioned unit, the pinnacle of digitally-controlled analog frequency synthesis combined with a clockmaker's dream. Each dial has its own synthesizer except the MHz dials which share one. They are easy to understand but you must read the service manual theory a few times, and pore over the schematics to gain true elightenment! A box of 18 or 24 colored pencils is sometimes helpful, especially after the madness sets in. I have many fond memories of pleasant hours repairing the more complex GRC-106's for all kinds of very, very strange things. I spent a few hours on one because a gear would only occasionally slip on its shaft and the tuning coils would be in one position and the MHz dial in another! Hmm.. switch or gear or motor or code detector? which could it be? haha that was reall fun there!

Honestly if it has been well cared for, they are very good radios.

I use a spotting receiver e.g. KW TS-430 then set up the "real receiver" on frequency and mode. I don't think it has a noise blanker, that could be annoying at times. If you try it and don't like it, let me know.

Please let us know how it performs!

[ke7trp]

Thanks for the info!   SOme guys really really like these old recievers.  I am a bit worried about the low AM sensitivity. Its rated at 4uv.  Maybe that wont be an issue?  7KC should be wide enough.. I use a 6KC wide RXer on AM alot of times.

Its so big and so heavy the table wont support it. Thats my main issue right now.. lack of space to set it, speakers and an audio amp up in the room.  I am going to set it up on a small table in here for testing.. So far so good though.. I can hear WWV on 5, 10 and 20 MHZ clearly with a speaker wire thrown over the door!

Its just fascinating to hear those motors and chain drive move around when you click the knobs!  I hope its a good reciever for my main AM use.. If not, then it will be passed along. Its time again to thin out the collection! The S line, The A line and other collins gear is ready for a new home.

Clark

[WB6NVH]

I am compelled to offer some slight corrections here...

The R-1051 can indeed be used with a speaker, just fine as it is.  Typically you use a dual set of speakers with 600 Ohm transformers.  There is a military speaker for this purpose which is typically being sold as an R-390A speaker, with resulting lofty prices, but you can make one.  The output level is not going to be ear splitting, but unless you are nearly deaf, it should be fine.  That's the way I use mine and the way I used them in military stations.  I have never needed to advance the audio gain more than perhaps 1/3 of full output.

The earphone jacks are not common-connected.  There is an LSB and a USB phone jack, so marked on the panel, just like the audio outputs on the back.  AM audio is output on the USB side and controlled by the USB audio gain control, not the LSB.

There are two meters on the 1051B and I don't think either is radium, and DRMO has no information that they are either.  R-390 and A meters are a different story.

There are indeed two IF modules independent from each other, basically one for USB and the other LSB.  Bandwidth on AM is more like 10 KHz so you won't like it much on a crowded band.

Muting facility is available by the big connector on the rear and was activated by a line from the T-827.  You will need to make sure the toggle switch inside near the front apron is set to allow the correct power input, and that the frequency standard is not set to the external input mode.  The overload mute circuit disconnects the antenna in high RF situations but I would not want to rely on it.

Most of these receivers were used in multiple rack mount configurations and the AGC is set for what might be described as a "military" purpose which is not too pleasant for ham use.  In other words, they typically have a fast attack and very long release characteristic.  The AGC technically requires an extender cable to bring the module out of the set for adjustment.  With the chassis pulled out of the case, you can defeat the interlock by pulling up on the white plastic shoe on the interlock switch.

There is an R-1051 mailing list on QTH which has some useful information in the archives, although there has been no activity of late (thanks to the DRMO destroying these receivers rather than releasing them on the surplus market, I suppose.)

Before powering up a set for the first time, I suggest re-forming the plug-in electrolytics.  Also, many of the axial lead tubular electrolytics may be showing high ESR by now, which can cause some very strange problems.  Intermittent fuse blowing is often caused by insulation failure of the rubber gaskets under the porcelain terminals of the power transformer's high voltage terminals.  If that happens, post back here and I will tell you how to fix the power transformer.

[Opcom]

The inexpensive ($10-20) green colored LS-454 or LS-151 speaker box has a 4" square driver and will work and has the 600 ohm xfmr built in to run the 8 Ohm speaker. Thanks for mentioning the spekers in general. Time to avid lofty prices! If those are the ones being sold for R-390's, somene is getting ripped off.

The 4uV sensitivity is not a real issue, as the rig has a wide dynamic range and will pull in weak stations well, and it shoudl be pretty quiet. It is also not easily overloaded, so you can use a preamp if you have to.