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Hi SWR, sometimes

 

This seems to be a complex problem because I do not understand what is happening. I will try to explain as best as I can.
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QMX mid bands built for 12 volts and Z-11 Pro auto tuner.
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I start on 40 meters and go to hardware then SWR tune and start the tune. The tuner light move and ends when a <1.5 SWR is reached. I then go to iambic and send CW at about 20 wpm. After about 10 dits the tuner jumps up to over 4 and the S protection letter shows on the screen after the last number. I cycle the menu, go to hardware, SWR tune and it shows <1.5 SWR. I go back to normal CW and the same pattern shows up again.
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It happens on multiple bands and is frustrating because I can't complete a POTA contact let alone a ragchew.
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My sBITx is also low power 1 - 4? watts and does not do this action with the tuner.
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Any ideas where to look?
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73, Dean/ N2TNN
 

Does this happen into a dummy load?

73
Roger
8P6RX?

Get
Dean, N2TNN via groups.io wrote:


This seems to be a complex problem because I do not understand what is happening. I will try to explain as best as I can.
?
QMX mid bands built for 12 volts and Z-11 Pro auto tuner.
?
I start on 40 meters and go to hardware then SWR tune and start the tune. The tuner light move and ends when a <1.5 SWR is reached. I then go to iambic and send CW at about 20 wpm. After about 10 dits the tuner jumps up to over 4 and the S protection letter shows on the screen after the last number. I cycle the menu, go to hardware, SWR tune and it shows <1.5 SWR. I go back to normal CW and the same pattern shows up again.
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It happens on multiple bands and is frustrating because I can't complete a POTA contact let alone a ragchew.
?
My sBITx is also low power 1 - 4? watts and does not do this action with the tuner.
?
Any ideas where to look?
?
73, Dean/ N2TNN
 

Roger,
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I just checked and the SWR protection never faulted into a dummy load. Full 4.9 watts on all bands.
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Dean
 

So i would suspect the antenna/tuner to have an intermittent connection of some sort, or to be inadequate in some way.

Roger

Get
Dean, N2TNN via groups.io wrote:


Roger,
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I just checked and the SWR protection never faulted into a dummy load. Full 4.9 watts on all bands.
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Dean
 

Thank you Roger!!
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I was surprised to see the results into a dummy load so I went back to the original configuration and back to the same problem. So just curious to see my wattage I inserted a Barb-A-Watt meter in line. Now no problem with a fault.
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I guess it was a bit of rfi on the coax tripping the SWR protection. Simple solutions to simple problems.
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Thanks again, Dean
 

Dean,
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there is a fault in the SWR tune function (until now). If you start the SWR tune function your last VFO frequency is shown but a per band default frequency is used. Please rotate the frequency encoder to see the real frequency and tune to your wanted f.
As far as I know this problem is on Hans list.
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73 Ludwig
 

On Sat, May 24, 2025 at 10:50 AM, @Ludwig_DH8WN wrote:
there is a fault in the SWR tune function (until now). If you start the SWR tune function your last VFO frequency is shown but a per band default frequency is used. Please rotate the frequency encoder to see the real frequency and tune to your wanted f.
Yes, and the 'default' frequency used is the band 'Frequency center' specified in the Band Configuration.
 

Check the cables.
instead the antenna, connect the dummyload behind all your cables and tuner.
 

Test a rf choke near the antenna side of your coax. This solved same problem with my portable groundplane.
 

Sri my english - not rf choke, coaxial choke, current balun. hi
 

Ludwig,
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That is very interesting. I will check again on the frequency. Maybe that explains this:
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Working POTA around 7.060. I complete the SWR tune function and transmit with 1.5 no problem. I then move up to 7.118 and SWR protection kicks in. I clear the S and retune to get a 1.5 reading again. Try to transmit on 7.118 and protection kicks in. I retry the procedure again and the protection kicks in and no transmit. I gave up and went back down to 7.060 and transmit no problem.
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So what you are suggesting is that in the SWR tune I should turn the encoder to the frequency I want?
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Dean
 

Yes, I just checked and when entering the hardware tests menu, then Tune SWR the frequency shown is not what is used to transmit. You must use the encoder to adjust the frequency you desire to transmit on.
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Very good catch and thank you!
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Dean

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