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SSB tuning with a vintage receiver

Discussion in '"Boat Anchor" & Classic Equipment' started by KK4RUT, Nov 24, 2021.

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  1. KK4RUT

    KK4RUT Ham Member QRZ Page

    Hello Everyone,

    I wanted to ask how to tune in SSB with a Vintage AM/CW receiver. I understand it needs to be in CW mode, but from my understanding moving the BFO up or down can help with tuning it in. So on most of the receivers I’ve seen they have +1/-1 markings on the BFO. Should I adjust it to either of those of upper or lower?

    Thank you for any and all advice!

    Zack KK4RUT
  2. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Depends on exactly which vintage receiver.

    If you have one, what is it (model)?
    KI4ZUQ likes this.
  3. W7UUU

    W7UUU Principal Moderator Lifetime Member 133 Administrator Volunteer Moderator Platinum Subscriber Life Member QRZ Page

    Turn the BFO to "+" a bit for bands you expect USB: 20, 25, 10 or "-" a bit for LSB bands: 40. 80, 160

    Tune until you find an SSB station, then turn the RF gain down a tad and tune the dial until the speech is clear.

    That should get you close.... the sweet spot will be the "just right" spot on the BFO, RF gain, and main dial tuning.

    It's just fiddly - not difficult. Your ears will tell you when you're good to go.

    As WB2WIK points out, the specifics will depend on the exact receiver

    KI4ZUQ likes this.
  4. WA9FZB

    WA9FZB XML Subscriber QRZ Page

    Once you begin to get the hang of it, you will also develop techniques to optimize tuning with your particular receiver.

    As long as the receiver has a BFO, you can copy SSB. My elmer was actually on SSB in the 1960's, using a Heathkit AR3 receiver (basically a 5-tube superhet with shortwave coverage) and a DX-60 transmitter with the SB-10 sideband exciter. They told him he couldn't do it. They were only partly correct.
  5. KP4SX

    KP4SX Premium Subscriber QRZ Page

    If the receiver is properly aligned (a big if) you should hear the sound of the noise change on either side of zero as you swish the BFO. Don't depend so much on the markings. Use your ears.
    WA1GXC likes this.
  6. KL7AJ

    KL7AJ Ham Member QRZ Page

    Hi Zack....done this a bazillion times. Turn OFF the AGC, if it exists. Turn the AUDIO gain up full, reduce the RF gain to a suitable volume.
    The reason this works is that most vintage receivers have VERY weak BFOs. For low distortion on SSB, the BFO signal needs to be at least 10x the incoming IF signal. Once you get the feel of this, you'll be amazed at how good SSB can sound like on a boat anchor.
    KA0HCP, W2VW and WA1GXC like this.
  7. WA1GXC

    WA1GXC Ham Member QRZ Page

    For anyone not accustomed to older receivers, they're not used to the V E R Y precise tuning required for SSB --and CW.

    Essentially, you have to develop the feel of a safe-cracker. It's not overwhelmingly difficult--it's just a coordination style you're just not
    called-upon or used to in daily life. And once you get used to it--in short order--it will become second-nature. Don't be discouraged.

    As noted above, one of the technical issues (too deep to go into here) is the BFO injection level in a lot of old equipment is not proper or
    optimum for the signal it is mixed with . So yes, get into the habit of audio gain at full or near-full, and use the RF gain as your stand-in for
    "Volume". You tune with one hand, "ride" the RF gain with the other--two-handed operation. It's a style and skill that will serve you well in
    all aspects and modes of radio communication. As a bonus, it'll keep your ears from getting blasted-out and developing a hearing-loss
    'notch' in your auditory ability.

    N3RYB likes this.
  8. KK4RUT

    KK4RUT Ham Member QRZ Page

    Hey everyone,

    I’ve got 2 rigs I have been using a bunch lately: a Collins 75A-1 and a National HRO-60.

    @W7UUU Thank you! That was a great bit of advice with the gains. I have noticed that I have to turn down the RG gain I order to get it exceptionally clear. Thanks for the reassurance on that one.

    I have definitely enjoyed using these two. I know there are little tricks for optimization with the boat anchors with almost any setting. I WANT TO LEARN THEM ALL !!!!!!!!!!!

    Thank you all!!!
    W7UUU likes this.
  9. KK4NSF

    KK4NSF Ham Member QRZ Page

    I listen to SSB on my R-808 all the time..... and it's not very difficult to tune. I set the BFO to zero until I tune in the station, then slightly tweak it to clarity. It takes longer to talk about than it does to do it.

    As far as precise tuning goes, that depends on the radio. Many old military rigs can be tuned VERY precisely, if they are calibrated correctly. My R-808 has a built in calibrator.... so it's easy. It's not digital of course.... but it is still nicely sharp.
  10. SM0AOM

    SM0AOM Ham Member QRZ Page

    Most BA:s lack sufficient BFO injection to demodulate SSB signals properly when IF strip operates
    at full gain. To make it worse, the AGC very seldom works properly when the BFO is on.

    So, procedure in summary is as follows;
    • Set the receiver for about +/- 2 or 3 kc (kHz) selectivity if it is adjustable
    • Turn on BFO and center it in the IF passband
    • Turn off AGC
    • Turn RF gain to minimum
    • Turn AF gain to maximum
    • Advance the RF gain so much that signals can be heard
    • Tune in an SSB signal using the slowest tuning rate available until it sounds natural
    • Adjust the RF gain for a comfortable listening level
    • You may reduce noise and interference somewhat if the BFO is moved towards the edge of the passband on a "single-signal receiver", and the tuning adjusted for each move

    A complication occurs if there is interference from stations close in frequency or the receiver uses steep-sided selectivity (the Collins 51J-4 comes to my mind).

    Then these additional steps can be taken:
    • Switch to narrower selectivity
    • Adjust the BFO in small steps in one or the other direction to get it towards the edge of the IF passband
    • For each BFO adjustment, retune the receiver so the SSB still sounds natural
    • The direction in which the BFO should be moved depends on if the received SSB is USB or LSB, and on the mixing scheme of the receiver.
    • Some practice rapidly gives you "the knack".
      You will soon make a habit out of where the BFO should be set for USB/LSB for a given selectivity and band.


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