Cross Band Interference with Flex 6600M and Elecraft KPA500

Al Dewey

K3SF

Al Dewey

Kari Gustafsson

Hi, I had a similar experince with 2 x OM2500A in SO2R. When one in Operate mode I got rf feedback to other slice and also detected rf on power meter of the amp. De-taching PTT send cable to the amp avoided the phenomena. But no good solution in a real live contest .Unfortunately I forgot how I solved the problem.

Al Dewey

Ken - NM9P

How are you getting PTT sent to the amp on ANT A? Is it accidentally keying the amp when transmittingnon ant B?

Al Dewey

bobby

Unfortunately if you look at the profiles the slice, rcv, xmt antenna are in the global profile and the tx1,tx2, and tx3 are in the transmit profile. I see no way you can get the rig to change transmit profile based on which antenna you have or slice selected without changing global profiles everytime you want to use the other antenna and that would be a total pita for an operator.

The option I see would be a manual switch which would disconnect the rca plug from either the flex or the kpa when you wanted to use the other slice, once again a pita and not operator friendly.

The real solution is to have flex change the profile operation and allow an antenna to be assigned to each tx input independently, but you know what the chances of that happening would be, zilch.

Maybe you could use an mfj1708 to detect the xmt on ant b to close a ckt to cause a relay to open disconnecting the rca cable from the kpa as soon as you transmit on b.

Al Dewey

bobby

Al I found this under transmit profiles look at the bottom paragraph highlighted in yellow which indicates you should be able to set the transmit profile to make it work for you, see photo.

Rich - N5ZC

bobby

Transmit profiles are linked to the tx antenna setting in the transmit slice, that should do it.

Rich - N5ZC

Kari Gustafsson

Hi, yes the way you and Rich discuss is the way I solved it. Good luck. Doing SO2R is a blast ....

Al Dewey

Rich;

Thanks for the great instructions.  I followed them last night and it solved my problem !  I was getting all ready to hook up a complex relay system that would disconnect the Slice A / Antenna 1 PTT relay when transmitting on Slice B / Antenna 2.  That is no longer necessary.  

Again thanks for the great tip.  Now I am all ready for SO2R in the  ARRL RTTY Roundup this weekend.


73,

Al, K0AD

Rich - N5ZC

Glad I was able to help. 

See you in the Roundup this weekend. 

I'm not very good at SO2R, but RTTY is easier to manage since the computer is doing most of the work. 

73,

Rich - N5ZC