Racal RA 6217 A coaxial connectors

Discussion in 'General Technical Questions and Answers' started by AA7EJ, Feb 16, 2016.

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  1. AA7EJ

    AA7EJ Ham Member QRZ Page

    Could somebody help me to identify these small coaxial connectors used on this RX ?
    T he thread diameter is about 4.5 mm
    One IMG_5540_COnnector.jpg of them is broken and I would like to replace it.
    73 Shirley
  2. WA7DU

    WA7DU Ham Member QRZ Page

  3. AA3EE

    AA3EE Ham Member QRZ Page

  4. AA7EJ

    AA7EJ Ham Member QRZ Page

    Would prefix S denoted surface mount component?
    I have received some info from the Pasternack customer service , however, these connectors are made with two different sizes of mounting hole.
    I'll have to take the broken one out to find out exact dimension of the connector I need.
    I am also finding out that the broken connector is " 1.6 MC out ".
    After more inspection , I MAY be able to superglue the connector back together. Or use the new UV "welding compound" HI HI HI.

    I am planning to hook the Racal to SDR and it looks as the "455 kHz out" is on different connector, so I may not have to monkey around with the this one after all.

    Thanks for your help.
    73 Shirley
  5. WA7PRC

    WA7PRC Ham Member QRZ Page

  6. W4KJG

    W4KJG Subscriber QRZ Page

    I agree that they are probably SMBs.

    I never worked for what became the Grimm/Racal receiver group in Maryland. I knew founder Ralph Grimm, formerly of WJ/CEI. Many of my friends joined him during a down time at other local radio companies. I worked across the highway from the R.E.Grimm/Racal group when they won a contract that attracted a lot of competing friends. After Ralph died of a massive heart attack, the group was bought by Racal.

    I don't have manuals, but I still have some reasonable memories of how the analog portions of the radios were built by WJ/CEI, ACL/AIKEN/Applied Communications/Norlan, HRB-SINGER, Scientific Communications/SCI/California Microwave, TRW, Potomac Instruments, and a few others.

    Many of us moved from company to company based on who won the next big receiver development contract. As a traveling band of developers, we used similar designs and mechanical designs at each company for new developments.

    If you find something analog you can't understand, I may be able to assist. Once we went to digital controls in the late 1970s, the microprocessor controlled software circuits, from synthesizers, spectrum displays, front panel displays, etc., these may be very difficult to make operational if they have had a failure. In the 1980s I got a lot of consulting hours writing drivers to interface with these receivers so the could be controlled through machine languages and UNIX based languages like Pascal, various versions of C, etc.

    Good luck with your radio. The radios from all of these companies were extremely rugged. Few ever came back for repair. They just didn't fail unless hit by something really nasty.
  7. AA7EJ

    AA7EJ Ham Member QRZ Page

    Thanks, it it always interesting to know little about history of the gear.

    I became interested in the Racal concept to convert HF range to 2 - 3 MHz when Czech Amaterske Radio published a small construction (!) article about it somewhere in late fifties. I think I still have the original of it somewhere.
    I bought this one years ago and was little disappointed with the audio output, but I think I used wrong headset - impedance mismatch. Also the volume pot was little scratchy. I have not used it since.
    It came with decent manual and an Osterman's book on receivers. Those were the days when amateur radio community operated on a different level.
    Nice book, but I don't like his comments on "ugly" radio R-392 .
    I am a proud owner of this still working paper weight!
    It keeps my desk balanced!

    Nowadays I cannot give away a manual ( on zed) without posting a picture of it.

    The RX allegedly came from some government listening post HI HI HI.

    73 Shirley
  8. W4KJG

    W4KJG Subscriber QRZ Page

    After looking closer at them, I'm not sure they smb. I can't remember what they are called. Send that photo to Joel at http://www.therfc.com. He will know, plus he should have what you need.
  9. AA3EE

    AA3EE Ham Member QRZ Page

  10. W4KJG

    W4KJG Subscriber QRZ Page

    I apologize for any confusion I might be causing. When I first looked at the photo, and because of previous comments, I just jumped to the conclusion that it was an SMB.

    As I posted above, after looking more closely at the photo, I felt it wasn't an SMB. The connectors in the photo don't have a locking groove.

    In the late 1960s and well into the 1970s a lot of us went to "self centering" connectors to connect to RFI tight plug-in modules. These connectors were very similar to SMBs, but they had centering tolerances that allowed them to mate with other modules or a chassis mainframe without damage. Some were designated as SMCs.

    If they are SMCs, the were rather life-cycle limited. We found that they were rather RF leaky and intermittent after a limited number of insertion cycles. By the 1980s we pretty much abandoned the SMCs and SMBs, and went back to manually connected SMAs for high performance receiver and transmitter modules. SMCs pretty well died out. SMBs were still used inside of RFI tight modules.

    By the 1970s and 1980s there were quite a few similar connectors that were not compatible with each other. That is why I mentioned the link above. Joel is very close to where many of our old radio factories were located -- probably within a mile of the old Racal factory. He bought a lot of our surplus. He knows connectors.

    I wish I could be of more help.
    Last edited: Feb 20, 2016

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