My original measurements of spectrum pollution at JO01JK were slightly off. It turned out the noise floor for the sound card in SpectrumLab was -97dBFS and as such when I took the first measurement with the 50ohm calibrated load connected the generated noise was below the noise floor of the sound card, I've now corrected for this and taken another measurement.
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| Noise against HF calibrated S-Meter |
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| Noise against VHF calibrated S-Meter |
This seems to show the noise here isn't quite as bad as I originally thought though the 6dB rise in noise caused by the apparent outside light coming on is still annoying and will need to be tracked down and fingers crossed replaced.
All the measurements I've taken so far are to the West which is the worse direction for noise and so I'll need to repeat the measurements every 45deg from North at some point just to get a base level at which to compare any apparent increase in noise in the future.
While I was at it I also did a quick calibration of the S-Meter on the IC7300 with the Anglian 3L 2m transverter using a Marconi TF2015 signal generator. I set the output of the TF2015 to -47dBm I then used some SMA attenuators to reduce the level down to the various S-Point values for a HF receiver so in some cases I'm up to 2dB off the required power.
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| All measurements taken in 2.7kHz bandwidth with the AGC set too slow. |
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