Ernie, this discussion of carrier null problems with the Omni 6+ brought
back memories of a similar problem with my own 6+.
You might find some insight in these archive posts:
http://lists.contesting.com/archives//html/TenTec/2005-01/msg00236.html
<http://lists.contesting.com/archives/html/TenTec/2005-01/msg00236.html>
http://lists.contesting.com/archives//html/TenTec/2005-02/msg00489.html
<http://lists.contesting.com/archives/html/TenTec/2005-02/msg00489.html>
http://lists.contesting.com/archives//html/TenTec/2005-03/msg00076.html
<http://lists.contesting.com/archives/html/TenTec/2005-03/msg00076.html>
http://lists.contesting.com/archives//html/TenTec/2003-11/msg00579.html
<http://lists.contesting.com/archives/html/TenTec/2003-11/msg00579.html>In
my case, the problem was induced by the installation of INRAD 2.8 KHz
SSB filters, but what struck home was your description of nulling the
carrier and then finding the problem coming back. That kept happening
to me as well. The problem, I believe, can be attributed (at least in
part) to R3 and R4 on the TX Audio Board. Both are 1 turn pots, and
tiny adjustments tend to have a big impact. I'd set things j-u-s-t
r-i-g-h-t and things would be fine for a couple of days, but then I'd
get a report of a carrier, the cover came off, the screwdriver came out,
and the process would be repeated.
A recommendation had been made to replace the 1 turn pots with 25 turn
pots, but I never got around to it. I pulled the 2.8 INRADS (which
eliminated the problem) and sold the rig and bought an Orion. That was
3 years ago. Makes me wonder if the age of the components (R3 and R4)
might be contributing to instability?
Not sure if this is of any help...
73, de Mike, K9UW
Amherst, WI
Ernie Popp wrote:
Carrier present on LSB
Many thanks to all who responded to my problem. Here is some more details on
my LSB carrier problem. My first indication was from my watt meter. While on
40 meters, I notice a significant reading when I hit my ptt switch. I
disconnected the mic and measured about 10 watts of carrier. This was with
just under 100 watts of power. 10% seemed very high. With the help of N1JP,
we checked it on his service monitor. John works as a service tech for
communications shop and has access to top of the line equipment. After
verifying the problem, we used the service monitor to adjust the balanced
modulator. It seemed to adjust easily to a very low carrier level. About a
week later, I noticed problem had returned. This time I used my watt meter an
another rig (TS440) to adjust it again. When I checked it about a week later,
I find about 8 watts of carrier. There is no measurable carrier on USB. I
have sent an email to Paul at TT for the proper procedure for adjusting the mo
dulator as recommended by one of the responses. Tnx again to all who have
responded to my problem.
73, Ernie K2EP
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