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SSB Delay

Recon

NY 881
Jul 28, 2019
1,045
1,240
173
Up-State NY
My question to the gang.
My RCI-2980 has USB and LSB capabilities, but my two-pill driver amp and ten-pill main amp do not have sideband delays. Can I use the amps on sideband?
I don't dare try it without asking. Thanks!
 

I would not, because of hot-switching. Risk of frying the amp is high.
Delay is simple to make, it is just electrolytic capacitor holding tx keying in amp.
Typical RF-sense TX circuit in amp:
C.PNG

C3 hold PTT for a while.
Mike
 
Last edited:
I would not, because of hot-switching. Risk of frying the amp is high.
Delay is simple to make, it is just electrolytic capacitor holding tx keying in amp.
View attachment 58038
C3 hold PTT for a while.
Mike
Thanks for the quick reply Mike! I don't have a clue (or knowledge) of radio tech "stuff". The 2980 does OK as-is and maybe I should have purchased the sideband delay option when I ordered the amps.
 
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The Amps will probably not have the correct biasing for SSB use, all you will get is a large splatter box, which will not go down well with your fellow SSB operators.
Just saying ;-)
I agree and that is why I asked the question. I'm only asking just in case we have a Member Call-in Channel on sideband.
 
If the amp has no auto or switched SSB delay it's probably a class C box. If you were to test it you would have to talk fast with no break between words so the amp would stay keyed. Even then you will be able to tell because the amp will make a click click click sound the whole time.
 
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If the amp has no auto or switched SSB delay it's probably a class C box. If you were to test it you would have to talk fast with no break between words so the amp would stay keyed. Even then you will be able to tell because the amp will make a click click click sound the whole time.
Thanks for the little "trick of the trade", but I have a considerable amount of money invested in the two amps and I'm not ready for a trial and error test. I'll let the sleeping dog sleep.
 
How does one go about removeing this automatic ssb delay in a super star 200 amplifier ?.
Thats right i want to disable the delay now can anyone provide any input on this ?
 
As a rule there will be a large electrolytic cap alongside the keying transistor. Might be 220uf, maybe larger.

Maybe. Keying circuits are not all created equal. But if you can identify a cap over 220uf that is wired to the "cold" side of the relay coil, unhooking it should do the trick.

Just one problem. You may still need a small cap, 4.7 or 10uf wired where the larger one had been to prevent the relay from chattering with modulation. An amplifier with a SSB switch will generally have a diode in parallel with the relay's coil. This is to catch the reverse-polarity "spike" of voltage coming out of the coil when you unkey. A keying circuit built with that big capacitor in the circuit all the time doesn't need it. Remove the cap, and now you need one of two things. A smaller capacitor to reduce chatter, or a diode.

And if there is no large cap like that connected to one side of the relay coil this means the keying circuit is different from the one expected.

73
 

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