Issue with ptt

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Issue with ptt

pascal
Hi,
Often, after depressing the ptt key, TX stays ON, and I have to press and depress again to get back to RX. I first think about a bad SWR which could give troubles in the usb wire going from the computer to the USB/I2C module of the Softrock, but even without power output, I get this problem. Why not to double the order given to go back to RX from TX state ? ....
73/Pascal
Pascal, F6EHP,  visit  www.f6ehp.fr
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Re: Issue with ptt

magun
Hi Pascal

I do not have this problem with my FA-SDR. Both the hardware and the button PTT work as exspected (version 3.6.13).

Only when some time ago I was operating the FA-SDR with an endfed half wave antenna (Fuchs antenna) with its high voltage end close to the SDR the PTT operation was irregular and it looked as if the 5 W PA Amplifier was  oscillating and the HF leaked into the usb CABLE.
I noticed, when trying to tune the variable capacitor of the filter for maximum output power, that oscillations started when coming close to the tuning knob. The problem was solved by moving the front panel of the SDR away from the capacitor and extend its metallic axis by a plastic cylinder ( 6 mm diameter). Another solution could have been to operate the SDR away from the antenna. "PTT troubles" stopped also when connecting a dummy load to the PA instead of the antenna.

73, Andreas
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Re: Issue with ptt

pascal
Hi,
The issue seems solved, moving the power supply of the SI570 from usb line coming from the ODROID card to internal supply of the FA-SDR....That also reduces some interferences....
73/Pascal
Pascal, F6EHP,  visit  www.f6ehp.fr
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Re: Issue with ptt

pascal
...issue now solved after change of relay Rl2 in the FA-SDR that stayed stuck sometimes...a classic mechanical failure...but with SDR, it is easy to look for complicated solution where it is simple !
Pascal, F6EHP,  visit  www.f6ehp.fr