PGXL SWR Observations and Responses

Ray - K6LJ

WX7Y

Ray - K6LJ

Appreciate the comment

bahillen

Ray Bret’s input is right on. I have had a number of insulators arc over on my wire antennas. They are multi band antennas so that resonant elements can be isolated by insulators. Long before my PGXL arrived there was a thread here that suggested getting ready by changing old coax and connectors. We have a tendency to feel coax last forever. In reality, it is an inexpensive component to a high power station. Changing to a double shielded coax is worth the extra cost. I just changed much of my coax and my RFI was greatly reduced and noise pick up was reduced. That includes even short jumpers. Much of my insulator problem surfaces when there is rain or snow. Antenna resonate frequencies shift and SWR increases. That increases the voltages across the insulators. Moisture in the connectors increase an moisture creates a path that only gets worse with time. Big stations use large air line and Heliax, great ground systems ant other things they learned over time. Specifically, when it rains and snows or wind **** the wires around that is the time that rare station comes on I want to work. I throw caution to the wind. The good news is that the PGXL has not failed. It shuts down. When I see a problem if I back down to 500 watts the arcing stops, if not I go to the 6600. Eventually even 100 watts is too much. The insulator is burned and an obvious black track is melted and burned. I operate FT8 a lot so heat build up is an issue with non ceramic insulators. The better you antenna and the better your grounds grounds the higher your Q in the antenna. Thus SWR goes up quickly as you move frequency. The voltages and currents go up quickly too. This week my SWR was high. The snow shifted the antenna resonance 50 khz on 80 m. Over 3:1 SWR. PGXL shut down. This is like working with a puzzle, we know the pieces but the picture improves as you get the pieces put together. This Text may be too long but I have been intrigued with solving these problems during the journey. 73 Bill W9JJB

Ray - K6LJ

Thank you. Very good comments.

N2WQ

SS amps are rather sensitive to poor antennas, SWR close or above 2, and fluctuating SWR. I love my SS Acom 1200S for DXpeditions, but never run anything but tube amps at home, even though all antennas are resonant with SWR of 1.5 or less. IMHO, it will be quite a while before SS amps reach the reliability and ruggedness of tubes.