Anomalous S meter reading on 6m band only
Posted: Fri Mar 24, 2023 4:43 am
Firstly - this post has nothing to do with Ritch's meter enhancements. Ritchies improvement has only facilitated me gathering the data. The issue predates all this.
The S meter reading on 6m looks anomolous cf other bands for comparable uV/Dbm readings (see table).
Comparison of readings across all bands was done using same bandwidth/mode (3Khz/USB) and all antennas disconnected with exception of small dummy load on acitve antenna port.
My expectation was that with no antenna/limited external noise the Smeter would be in the 0-1 range on all bands. Which it is, except on 6 meters. Switching the 6m LNA in/out made no significant difference.
I assumed the Smeter reading was calculated/interpolated from the actual voltage reading on the ADC - so that relationship shouldnt change with frequency/band.
Looking through the Thetis Manual and the 8000 manuals I couldnt find anything band specific on S meter calibration.
Note - The physical readings look fine (dbm/uV) Im not quibling about the physical calibration of the rig - just the S meter calcs on 6 mters.
I dont have a decent signal generator so the best I could do for a comparison across the bands was just active antenna socket terminated in a dummy load for equivalence.
Welcome any comments whether this is normal or why the relationship appears to breakdown on 6m. Is there anywhere in software to adjust this ?
I have had the Anan 8000 since 2019 used mostly on 6m and WARC bands (limited antennas living in an inner city suburb).
I upgraded from FT991 and initially noticed background noise level was >>7 S units where as FT991 was usually around 3-4.
Didnt pay much attention to it and just assumed for last 3 years I have a very noisey 6m environment.
On unplugging the antennas noted that S meter reading was still S4 on 6m.
Operate mostly digital modes and not really been interested in S meter readings. But with increased TEP activity on 6m , I have started using SSB again.
I noted that my signal reports were significantly and consitantly higher than others nearby (10Km) were giving (ie I was reporting S9 +20 and they S7) with better antenna systems and Flex 6000s.
Which made me question the calibration of the S meter on 6m. If its displaying high on no noise then I assume its reading high on moderate/strong signals too.
The S meter reading on 6m looks anomolous cf other bands for comparable uV/Dbm readings (see table).
Comparison of readings across all bands was done using same bandwidth/mode (3Khz/USB) and all antennas disconnected with exception of small dummy load on acitve antenna port.
My expectation was that with no antenna/limited external noise the Smeter would be in the 0-1 range on all bands. Which it is, except on 6 meters. Switching the 6m LNA in/out made no significant difference.
I assumed the Smeter reading was calculated/interpolated from the actual voltage reading on the ADC - so that relationship shouldnt change with frequency/band.
Looking through the Thetis Manual and the 8000 manuals I couldnt find anything band specific on S meter calibration.
Note - The physical readings look fine (dbm/uV) Im not quibling about the physical calibration of the rig - just the S meter calcs on 6 mters.
I dont have a decent signal generator so the best I could do for a comparison across the bands was just active antenna socket terminated in a dummy load for equivalence.
Welcome any comments whether this is normal or why the relationship appears to breakdown on 6m. Is there anywhere in software to adjust this ?
I have had the Anan 8000 since 2019 used mostly on 6m and WARC bands (limited antennas living in an inner city suburb).
I upgraded from FT991 and initially noticed background noise level was >>7 S units where as FT991 was usually around 3-4.
Didnt pay much attention to it and just assumed for last 3 years I have a very noisey 6m environment.
On unplugging the antennas noted that S meter reading was still S4 on 6m.
Operate mostly digital modes and not really been interested in S meter readings. But with increased TEP activity on 6m , I have started using SSB again.
I noted that my signal reports were significantly and consitantly higher than others nearby (10Km) were giving (ie I was reporting S9 +20 and they S7) with better antenna systems and Flex 6000s.
Which made me question the calibration of the S meter on 6m. If its displaying high on no noise then I assume its reading high on moderate/strong signals too.