G2 power supply - TAKE CARE!
Posted: Sat Apr 06, 2024 8:39 pm
Somewhere I thought I'd noted that the specification for DC power supply for the G2 was for 13.8v plus or minus 5 (five!) %, not the more usual 15%. Well, while transmitting a couple of days ago there was a power fault at my QTH that briefly dropped the DC voltage indicated on the shack power supply to 12.9v (I completely shut down the station within a few seconds, as soon as I noticed this).
This is a drop in the DC supply voltage of about 9.5%, for a few seconds while transmitting on 28 mHz. The result now seems to be that something in the transmit chain has been fried - the G2 is producing 28 mHz output regardless of what transmit VFO frequency is selected.
I haven't been able yet to access a suitable test rig to get hard data on this, but the external solid-state linear (that has automatic band switching) switches to 28 mHz regardless of the G2 VFO setting, and using another radio I have verified that the external linear is working perfectly.
Actual power output from the G2 is unaffected (monitored either side of the external linear with Wavenode sensors). A two-tone signal with the PureSignal AmpView window open produces a plot like I have never seen before - on any band other than 28 mHz there are now two separate, and slightly diverging amp output lines in the plot.
Receive is completely normal following a cold boot, BUT after transmitting even momentarily, on returning to RX the receive noise levels go 20-30 dBm higher.
Obviously a scope will reveal all, but in the mean time - BE VERY CAREFUL about your power supply. It appears the G2 is completely intolerant of a 10% supply voltage drop during transmit. Hopefully I'm not now the owner of a very expensive black doorstop...
UPDATE: I connected the G2 to a dummy load via a power meter, similarly connected my Xiegu X6100 to a dummy load, then put these two dummy loads right beside each other. With this setup I now know that the G2 transmit frequency is locked on 28.379 mHz. The TX frequency does not respond to any change whatsoever in the Thetis VFO setting, not even within the 10 meter band itself. Conclusion: at the very least, whatever G2 hardware is involved in setting the TX frequency is not functioning. Tx'ing a voice SSB signal on 28.379 produces output, but readability = zero.
Any constructive comments/info would be much appreciated, I'm not looking forward to the prospect of shipping a 3-month-old G2 back to India.
Tony, ZL3ES
This is a drop in the DC supply voltage of about 9.5%, for a few seconds while transmitting on 28 mHz. The result now seems to be that something in the transmit chain has been fried - the G2 is producing 28 mHz output regardless of what transmit VFO frequency is selected.
I haven't been able yet to access a suitable test rig to get hard data on this, but the external solid-state linear (that has automatic band switching) switches to 28 mHz regardless of the G2 VFO setting, and using another radio I have verified that the external linear is working perfectly.
Actual power output from the G2 is unaffected (monitored either side of the external linear with Wavenode sensors). A two-tone signal with the PureSignal AmpView window open produces a plot like I have never seen before - on any band other than 28 mHz there are now two separate, and slightly diverging amp output lines in the plot.
Receive is completely normal following a cold boot, BUT after transmitting even momentarily, on returning to RX the receive noise levels go 20-30 dBm higher.
Obviously a scope will reveal all, but in the mean time - BE VERY CAREFUL about your power supply. It appears the G2 is completely intolerant of a 10% supply voltage drop during transmit. Hopefully I'm not now the owner of a very expensive black doorstop...
UPDATE: I connected the G2 to a dummy load via a power meter, similarly connected my Xiegu X6100 to a dummy load, then put these two dummy loads right beside each other. With this setup I now know that the G2 transmit frequency is locked on 28.379 mHz. The TX frequency does not respond to any change whatsoever in the Thetis VFO setting, not even within the 10 meter band itself. Conclusion: at the very least, whatever G2 hardware is involved in setting the TX frequency is not functioning. Tx'ing a voice SSB signal on 28.379 produces output, but readability = zero.
Any constructive comments/info would be much appreciated, I'm not looking forward to the prospect of shipping a 3-month-old G2 back to India.
Tony, ZL3ES