[Elecraft] 80m KPA1500 High reflected power problems **SOLVED!**

[john at kk9a.com]

I am not sure how a second antenna effects the amplifier, I believe that 
the K3(S) has a safeguard from some overload conditions. If your RX 
antenna is close to your TX and you run HP, I would protect your 
transceiver from overload by either shorting the RX feedline during TX 
or with a protector such as this one:  
https://www.dxengineering.com/parts/dxe-rg-5000

John KK9A




PETER DOUGHERTY W2IRT wrote:

-------------------------

Hi folks,
FOUND THE PROBLEM....Maybe??

I have a 30 foot vertical ground-plane style antenna that I use for 
diversity RX on 40 and 80, which was connected to the AUX antenna port. 
This was being overloaded by the QRO power from the TX antenna 
feedpoints just a few feet laterally and 40-50' higher vertically. As 
soon as I disconnected this antenna the problem went away.

NOTE that the problem only occurred on the lower CW portions of both 80 
*and 40*, as I found out tonight. In the SSB sections, even on CW 
transmit, there were no problems. But as I said, disconnecting the 
diversity AUX antenna solved the High SWR amp fault.

So now, the big question, is there some form of filtering within the K3s 
to disable receive on the AUX line during transmit, or do I have to look 
into a second "front end protector" device as I have on my K9AY loop 
connected to the RX IN port. Or perhaps some other valid solution?

At least I'm glad I finally have full operation back on 40 and 80!