The discussion about antenna cable delays made me think of the issue of the antenna delay. An antenna typically has a bandpass filter and amplifier so there clearly is some non-negligible delay associated with this.
The issue is usually sidestepped by calibrating the delay of receiver+antenna (against what? A calibrated receiver + antenna from the BIPM of course...) But sometimes, after calibration, an antenna in the field has to be replaced with a different antenna and the original calibration is invalidated. It then becomes necessary to expand the uncertainty of the delay. I did read a NIST paper where they described measuring the delay by physically disassembling the antenna so that they could feed signals directly to the electronics. Delays like 30 ns were measured, I think. Myself, when changing antennas I have seen steps like 10 ns. Does anyone have any data points to add to this ? Cheers Michael _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
