Carrier

[Rolf G]

    Hi,

    Yesterday someone sad he could hear my carrier and that I had to do
    something about it. What can I do to suppress the carrier in a K2?

    73 de Rolf   SMØYQC
    K2 #4979
    Stockholm
    Sweden

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[Don Wilhelm-3]

Rolf,

Unless there is something wrong with your KSB2, adjusting the carrier
balance pot on the SSB board will yield good carrier suppression.

If you have a 'scope, connect a dummy load to the K2 and connect a 'scope
10X probe across it - do not connect a mic, but use the DOT paddle line to
activate PTT in LSB, then adjust the carrier balance for the minimum RF
output - switch to USB and check the RF level with PTT operated (dot paddle
closure again) - if the USB RF is greater than that for LSB, adjust the
carrier balance pot again to reduce the USB output slightly - you may have
to compromise a little to get the same carrier suppression with both LSB and
USB.

You will have to use a sensitive scale on the 'scope because the amount of
RF will be small.
If you do not have a 'scope, an RF Probe and DMM may be used, but you will
have to adjust slowly to determine the minimum because the response time of
the DMM will be slower than the 'scope voltage indication.

73,
Don W3FPR

> -----Original Message-----
>
>     Yesterday someone sad he could hear my carrier and that I had to do
>     something about it. What can I do to suppress the carrier in a K2?
>
>     73 de Rolf   SMØYQC
>     K2 #4979
>     Stockholm
>     Sweden
>

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[Tom Hammond-3]

Hello Rolf:

>Yesterday someone sad he could hear my carrier and that I had to do
>something about it. What can I do to suppress the carrier in a K2?

While monitoring your transmitted signal on a separate receiver (use
a VERY SHORT RX antenna), tune off-freq. just a bit, so you can hear
the beat note of the carrier, then adjust R1 on the KSB2 board for
minimum received signal in the monitor RX.

73,

Tom Hammond    N0SS

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[Nick Waterman]

Don Wilhelm wrote:
> Unless there is something wrong with your KSB2, adjusting the carrier
> balance pot on the SSB board will yield good carrier suppression.
[...]
> If you do not have a 'scope, an RF Probe and DMM may be used, but you will
> have to adjust slowly to determine the minimum because the response time of
> the DMM will be slower than the 'scope voltage indication.

This is what I did, but I found the null to be VERY VERY tight, the pot
had to be in exactly the right place otherwise I had quite a strong
carrier. I wouldn't be surprised if I've since knocked it and have too
strong a carrier myself.

Is the carrier balance pot supposed to be quite so sensitive, or have me
and perhaps SM0YQC built something wrong that makes it so tricky to set?

--
"Nosey" Nick Waterman, G7RZQ, K2 #5209.
use Std::Disclaimer;    [hidden email]
IBM: Intriguingly Blue Motif
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