PGXL intermittently fails to key up when transmitting on 6400m. Suggestions?

K7KKR

I have a 6400M connected to a PGXL amplifier via ethernet. Both are connected to a TP-Link TL-SG105 powered network switch. All equipment is in close proximity in my radio room. I read in the forums it might be RFI entering the switch through the power cable. I installed a ferrite on the power supply cable with no success. The amp will key up normally dozens or hundreds of times then suddenly won't key. When it occurs, I release the transmit, then immediately re-key and the amplifier engages properly. Any suggestions?

K7KKR

Thanks for your comments. I tried Cat 8 Ethernet cables (double shielding and shielded plugs) with no success. I updated the 6400M to firmware to version 3.3.33 which seemed to solve the problem. Previous version was 3.3.29. I’ve run three radio nets (3+ hours each) with no instances of the PGXL failing to key.

KD0RC

It can be RF getting into any number of cables, including the ethernet cables themselves. Other cabling can contribute as well. Things like mic cables, key cables, an unrelated 2 meter antenna, etc etc. It can find sneaky paths that don't seem radio related, so it can be very difficult to track down.

I usually have to start disconnecting things one at a time until I find the culprit. I have recently taken a brute force approach and put ferrites everywhere. I still have a minor problem on 20 Meters where I never had a problem before, but 40, where I had a bad problem is now totally clean. You just never know with RF...

Because like you, my problem is intermittent, it is really hard to track down. I recently got a clamp-on RF ammeter, so I will go through all my cabling to see if I can sniff out some 20 Meter RF and concentrate my efforts there.

Best of luck tracking this down.

Mike Steventon

You could try some of these:

https://www.dxengineering.com/parts/dxe-iso-plus-2

I swear by them!!

73 Mike

KD0RC

Excellent! I am glad that you got it working.