[1000mp] Different SWR at SSB and CW
Sergey
a1sy at yahoo.com
Mon Jun 7 20:05:37 EDT 2004
Mike
In experiment I did yesterday I connect my TRCVR to the dummy load.
I measure my SWR with TRCVR meter and in the output of TRCVR I have a Daiwa SWR meter.
Daiwa was connected to the 50 Ohm 200 Watts dummy load.
I undestand that some people saing go ahead and just enjoy to be in the air.
I think I have some problem with My SWR reading.
The facts:
1.Doesn't metter if Tuner is ON or OFF - results are the same.SSB SWR higher than CW for 0.5-0.7.
2.Test done on 50 Ohm dummy load,so I exclude any influance of antenna.
3.I think it doesn't make sence to have different SWR on the same Frequency.
So,I seriously thinking to send it to Yaesu.
I don't think it a good idea to work on SSB and to see SWR around 2 and to verify every time that
"I still have an antenna" by swithching to CW.
I wrote this message to the forum to ask if anybody else had the same issue and what was the
solution.And bisides I wanted to hear more opinions on that issue from others.
Thanks,Sergey
KO5D
--- Mike Schatzberg <cherokeehillfarm at earthlink.net> wrote:
> 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
> > > >
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