PGXL

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  • Updated 1 week ago
My PGXL drops off if transmitting into a 40 M antenna with 1.5:1 SWR or greater.  Same type of problem that it used to have on 80/160M before the latest firmware update 3.2.15 fixed it. Flex boasted that it would handle 3.0:1 so I thought that it would give me full 40 M antenna bandwidth but it is more limited than my Alpha 87A.  Can the same fix that was implemented to correct the problem on the lower bands also be used on 40M? 

I have yet to resurrect my 40-10M log periodic antenna that has varied SWR below 2.5:1 on all bands that I suspect might also exhibit the same problem when I get it back up.  Why not use the same fix on all of the bands?

Bill AB7AA
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Bill Hickey

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Posted 1 week ago

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bahillen

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Try turning off Meffa. I don’t understand what it is doing specifically, only on a general basis.

When I turned up PGXL power SWR would go up above 300-400 watts. And would het a HISWR screen on the PGXL utility. I thought I has an antenna problem. I turned off Meffa in the tools as I recall and everything worked fine. No hi SWR and no strange behavior. I was using on WSJT and they indicate Meffa is for CW and SSB. Doing to many other things to investigate.

Thought this may be helpful.
73
Bill W9JJB
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Bill Hickey

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Thanks for the input but it did not help.  PGXL still kicks off.
Bill
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Brian Morgan VK7RR/4

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If you have a proper dummy load, check how things go into it, instead of an antenna. It sounds to me like you have had RF feedback in your system both with the Alpha and the PGXL.
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NX6D Dave

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The fix applied to all bands.  Please open a Help Desk ticket so the hardware guys can have a look and deal with the problem.

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Bill Hickey

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Thanks Brian but both the Alpha and PGXL work fine on the same 40M antenna when tuned to the center of the bandwidth.  It exhibits the same behavior that it used to have on 80/160M antennas when getting out of the heart of their envelope but fixed with the latest firmware.  No doubt that there is some reactive component that presents the problem when tuned more to the edges.  Using a dummy load would not tell much, it needs a real antenna.  No doubt it was designed using dummy loads and it loves purely resistive antennas even if at other than 50 ohms.  It might just present a problem when there is a slightly reactive component value that would only show up with a real antenna.
Bill
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NX6D Dave

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The amp will trip off when it sees reflected power above a calibrated limit.  A limit is stored for each band.  To the extent that the reactive component of the antenna load causes reflected power, you are correct.  Any significant impedance mismatch in the antenna system at any given frequency will cause reflected power, as you know.

When the amp trips off, you should be seeing an error message on the front panel display.  Would you please note that message and post it here?  Also, please mention the output power at the time of the fault.

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Bill Hickey

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Hi Dave,
  The PGXL is in another room and the message is gone by the time I get out there, but the software utility says "High SWR".  Power is about 1.2K but hard to capture because it faults so quickly.   It works sometimes at lower power (800W) but may kick off on peaks.

Bill
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Clay N9IO

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Bill I would open up a help desk ticket and have them help you sort this out. I don't think you're going to find your answer here.
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Jim K4JAF

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Sure glad I did not purchase a PGXL when first offered....  
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bahillen

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Jim, you are missing an outstanding amplifier. There are new things that it does that are easily picked up. Changing bands and power is just where I set it in prior Q on that band. I worked in the digital contest and 50% duty cycle at 1.5 KW. Solid. It is a commercial quality amplifier. I couldn't be happier. Remote operation is a breeze with the amp.
73
Bill W9JJB
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WW1SS - Steve

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My KPA-1500 just hums along and it has a tuner in it.
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Brian Morgan VK7RR/4

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Hi Bill,
My theory behind testing with a dummy load is to see whether the tripping is caused by a reactive component in your antenna feed or through simple RF feedback. The fact that it only happens on 40 metres points more to antenna issues, although as NX6D has pointed out the linear may be set for tripping earlier than you might expect. I like to eliminate possibilities, then the probabilities become more evident. Good luck with resolving your problem.

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DH1RK

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Hi Bill,
could it be arcing (isolation not okay)?
Did you check the SWR with a fast (digital) meter?

73
Rudy, DH1RK
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Burch - K4QXX

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Interesting thread.  My PGXL works great but for some reason it doesn't like 80 meters.  I can't run more than about 200-300 watts on 80 meters before the amp goes into "High SWR" mode.  I thought I might be getting RF into the radio/amp but I put up another 80 meter antenna (first antenna is StepIR vertical and 2nd is 80 half wave dipole) and the same thing happens on both antennas.  I did recently upgrade the firmware on the PGXL but I haven't tried 80 meters yet.  I will try tonight and see if the firmware fixes the issue.
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Bill Hickey

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Thanks Burch Yes, my PGXL had the same issue on 80 M too until I installed FW 3.2.15 that fixed 160/80 but they didn't implement the same fix for the other bands.  Looks to me like they should have included at least 40 M with the fix and maybe all other bands too.

Bill
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Bill -VA3WTB

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The PGXL has been tested extensivly on 80 meters. I have talked to a few people on 80 meters and they do not have any problems. In your case it is hard to know what is causing your problems. I hope the Help Desk can help sort it out.
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Joe Conover

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What is PGXL
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Bill -VA3WTB

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Joe, it is the Flex amp
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Joe Conover

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Ok thanks