Pressing MOX zeroes spectrum - why?

Kari Gustafsson SM0HRP

I run SO2R with a 6700. 40 m yagi till ANT1 and 20 m yagi to ANT2 on different towers. When I press MOX with TX2 active (red) and 0 W, spectrum for radio 1 at ANT1 disappears and flattens out as ANT1 being short circuited. The effect can be avoided if I disable TX1 keying Line. Is there a possibility that RFI can be routed over THE TX1 keyline and null the ANT1 spectrum?

Mike NN9DD

Do you have Full Duplex enabled. FDX on lower left corner Mike NN9DD

Kari Gustafsson SM0HRP

Yes. And spectrum is there if I do disable TX1 key line or dettach the cable to the TX1 input key line on the rear panel. 

Tim - W4TME

As per the SmartSDR Software User's Guide, Section 26.4 TRANSMITTING ON A TRANSVERTER 

"...when transmitting on a split IF transverter configuration, because the transverter RF output is low power it will not be dramatically visible on the transverter Panadapter like it is shown when transmitting on HF at high power. 

Both conditions during transmit can be quite confusing as they do not accurately represent the transmitting state of the radio properly.  For this reason, the Panadapter will pause when using IF transverters while transmitting."

Steve Gw0gei

Am I missing something - there was no mention of a transverter being in use Tim? Maybe fdx not enabled , as suggested above? Am following this thread as I want to use a 6600 or second hand 6700 for hf so2r.

Kari Gustafsson SM0HRP

Yes, no transverter. Just "regular SO2R" - two radios each with an independent amplifier with 6700 in full duplex mode. I am starting to think that there could be a potential difference between the TX1 and TX2 keylines (that connects each amplifier to the 6700 rear panel)  that triggers this behavior. Despite the fact that both 6700 and both amplifiers are bonded to the same grounding post.
In other words, if you press MOX while radio 2 active (and with 0 W power level) you engage the TX2 key line and in parallell alters the TX1 keying line potential so that radio 1 appears as active (and  disengage radio1 ) in a transmit like stage?  
Any comments on this? 

k3Tim

I think Tim got a hold of some bad White-Lightning.  :-)

Is the "show spectrum on transmit" option set in the Radio Setip submenus?

k3Tim

Kari Gustafsson SM0HRP

Yes and I see the spectrum with TX1 disengaged....