[1000mp] Different SWR at SSB and CW

Mike Schatzberg cherokeehillfarm at earthlink.net
Mon Jun 7 18:13:38 EDT 2004 

Hello Sergey:

Okay, interesting data.  So, what is the SWR at the coax connector that is
plugged into the SO 259 on the back of the Mark V?

Are you measuring the SWR externally after a linear amplifier?

If you are feeding your amplifier from your Mark V, you should have a very
low SWR at the input to the amplifier.  In fact, you should not need to even
use the tuner at all, in this case.  An interconnecting cable between the
two units may be a problem.

Reset your memories one more time, and use the CW method to force the tuner
to achieve as close to 1:1 as possible.

Clearly your Mark V thinks the SWR is high on SSB, and is reducing the power
output accordingly, but will not reduce it on CW at all, when the match is
1:1.2 or less....

If one more forced tuning does not solve the problem, lower the overall SWR
of the antenna system as much as possible.  Go to 15 meters, and measure the
SWR of your antenna system, at the desired frequency, and then carefully
start pruning back the coax, perhaps 6 inches at a time, and re-evaluate the
SWR.  While pruning, you can hold the coax braid to the SO 259 connector
with a clothespin, to make contact.

Reducing the overall SWR, prior to making the tuner tune the system, should
help the overall situation.

Finally, prior to doing any of this, check all your jumper cables, and even
your antenna cable, into a dummy load, and make sure they all read as close
to 1:1 as possible.  You may have a bad cable in your antenna system causing
you problems.  A dummy load is a good investment for trouble shooting, and
the Mark V should show 200 watts on all bands, CW and SSB into the dummy
load with a good piece of coax, or a double male connector.

When you are sure that the rig is working into the dummy load, begin the
pruning operation.

Good luck and happy DXing,

Mike
WB2AJI


----- Original Message ----- 
From: "Sergey" <a1sy at yahoo.com>
To: "All about Yaesu 1000mp" <1000mp at mailman.qth.net>
Sent: Sunday, June 06, 2004 11:38 PM
Subject: Re: [1000mp] Different SWR at SSB and CW


> Thanks Mike
> Here is another test i run today:
> Freq   Mode  Internal SWR     Extenal SWR    Internal P meter  External P
meter(PEP)
> 7100   CW      1              1.1               200                 200
> 7100   SSB     1.7            1                 200                 100
> 14160  CW      1.2            1.2               200                 200
> 14160  SSB     1.6            1.1               200                 120
> 21207  CW      1.3            1.2               200                 160
> 21207  SSB     1.7            1                 200                 85
>
> It looks like a Power has a different reading as well.Not sure TRCVR read
PEP or AVG.In AVG it
> would read actually less.
> I made this test on 50 Ohm load and confused with results.
> Not sure it's normal.I talked to my friend that has a 1000MP Field and he
has a difference in
> about 0.1 between SWR and CW.
> Even that's OK,it's a little bit bother me when I use SSB.Not sure I saw
it before.
> Thanks,Sergey
> KO5D
>
> --- Mike Schatzberg <cherokeehillfarm at earthlink.net> wrote:
> > Hello Sergey:
> >
> > I do not pay any attention to the SSB SWR really.  When I find the
frequency
> > I wish to adjust the tuner on, I do it in CW mode.  I like to send a
series
> > of DITS at about 30 wpm, and then push and hold the tuner button, to
force
> > the tuner to retune, and to memorize the setting.  This can be done at
> > relatively lower power, say about 30 watts.
> >
> > I find that even with s 1:1 SWR in CW mode, the SWR meter while in SSB
still
> > reads upscale somewhat, for whatever reason.  The SWR reading in CW
agrees
> > with my Autek Research WM-1, and therefore appears to be accurate.
> >
> > I just ignore the SSB reading.  Of course, if your Mark V decreases your
> > power output, after getting a perfect match in CW, while transmitting on
> > SSB, you would have another issue.  But I never have seen this situation
> > occur, the radio always transmits with full power capability after
adjusting
> > the tuner in this manner.
> >
> > Good luck and happy DXing,
> >
> > Mike
> > WB2AJI
> > ----- Original Message ----- 
> > From: <Sergey_Abrikosov at amat.com>
> > To: <1000mp at mailman.qth.net>
> > Sent: Sunday, June 06, 2004 5:38 PM
> > Subject: [1000mp] Different SWR at SSB and CW
> >
> >
> > > Last week I found a higher than usual SWR on 14MHZ during some
pile-up.
> > > The SWR was around 1.6 with some peaks to 1.8.
> > > I use a dipole and thought that something happened to my antena,but
after
> > > several experiments I found that I have 1.2 SWR on the same frequency
in
> > CW
> > > mode.
> > > So,I tried 7,14,28 MHZ and had the same issue: 1.1.-1.2 on CW and
1.6-1.7
> > > on SSB on the same frequency.
> > > I tried to retune again my tuner but no change in SWR so far.
> > > I did reset all memories and it didn't help either.
> > > Did anybody had the same issue?
> > > Thanks,Sergey
> > > KO5D
> > >
> > > The content of this message is Applied Materials Confidential.  If you
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> > >
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