VK3NHis number62member，register2016-12-08 00:12
Radiocommunications Consultant - semi retired - working for my company Analyse Solve & Test Pty Ltd.
KC901 serial VNA • 144 days ago • No reply
Since there have recently been responses to a number of "old" posts, can you please provide one for this.
I am not the only one who has noticed the difficulty of working out if the signal generator or audio source is working or not when you change the frequency or level. It is noted in the reviews and it only involves a software change.
If the level indication flashed when it was in stop mode then that would be perfect.
Thanks - Noel 06:59 17Asia/Chongqing3230Asia/ChongqingSat, 18 Nov 2017 06:59:32 +080018am17
I have found that mine is a long way off the height above sea level.
How can I do the altimeter calibration to fix this?
If its purpose is relative height then you can use the difference as you suggest. 06:46 17Asia/Chongqing5030Asia/ChongqingSat, 18 Nov 2017 06:46:50 +080018am17
I am not an expert in the software capability of the KC901V but I will offer the following comments based on my understanding of the process and use of the KC901V.
1/ Corrections as part of the SOL calibration occur at a number of points dictated by the selected start and stop frequencies. (User calibration is voided if either of these is changed)
2/ You are correct in your observation that phase of the leakage should be constant but that is only at a set frequency.
3/ As the S21 function is a frequency swept process, compensating for the leakage based on phase I don't believe is possible.
4/ If the software for the field strength function at a set frequency with its associated loss calculation option was modified to be applied to the calculation then that might work in achieving a greater dynamic range.
I happy for you to challenge the reasoning of any of the points above.
regards Noel 5 days ago
I agree poor isolation in the upper range is an issue.
Whilst I suggested the use of the extra fixed attenuation as indicated above you are right about the loss of dynamic range. But doing what you suggest will not compensate for the phase change that happens when you are measuring say a HP stepped attenuator set (0 to 110dB) as I have done by first calibrating the unit at 10dB step because the steps in switching in and out attenuation actually change the signal path length.
However if you just use the KC901V as a signal source for substitution transfer comparisons with a reference attenuator set or for tuning a filter notch with any suitable spectrum analyzer or measurement receiver, then the isolation problems go away.
regards Noel 9 days ago