Hi Joe and All,
Last couple months I have been seeing multiple occurencies of the 50Hz
amplitude modulation of the JT9
signals, that combined with the intermodulation products causes multiple
decodes of the same JT9 message with 50Hz step.
During resolution of these interference issues I have found that the main
reason for it is 50Hz voltage difference between
desktop's and transceiver's inclosure/case.
Fortunately JT9 does allow to see amplitude modulation issue, while JT65 does
not let it.
For JT65 we getting increased noise inside and outside of the transmitted JT65
signal, that causes two issues on the receiver side:
1. as this noise is not AWGN one, it makes multiple spurious candidates for
decoding if dirty JT65 signal SNR is/better -01, hence increases time of the
interval decoding
2. hiding weak signals on the receiver side under the noise level.
I see this as important update to the User Guide: all (WSJT-X + desktop) users
shall connect desktop and transceiver cases toghether by at least 12 AWG wire.
73 Igor UA3DJY
------------------------------------------------------------------------------
Site24x7 APM Insight: Get Deep Visibility into Application Performance
APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
Monitor end-to-end web transactions and take corrective actions now
Troubleshoot faster and improve end-user experience. Signup Now!
http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
_______________________________________________
wsjt-devel mailing list
wsjt-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/wsjt-devel
