Dave,
Put it this way... I see a weak carrier at 20kHz that has varying day/night
strength, but fairly constant phase. I've no way of verifying for sure where
it's from, or whether it is keyed, as I can detect it with no other method!
The Clicklock technique does work well with pulsed signals (e.g. 40kHz), but
I've not yet had any success on the Russian Alpha ststions, presumably
because the phase of each one I receive on the frequency is different. It
works with LORAN lines because each one has different sideband frequencies.
As Scott says, the efffective bandwidth of the receiver is related to the
reciprocal of the integration period, so if integration time = 1000, then
bandwidth is something around 1mHz! The receiver needs to be very stable,
preferably but not necessarily accurate to within 1Hz. The signal to be
monitored needs to stay within say 10� over the integration period, so for
10 sec integration, for example, needs to be within 1�/sec. At 181.4kHz for
example, that's around 1.5e-8.
I have successfully tracked my own OCXO reference and Rb reference, but the
TCXO in the Exciter isn't good enough without the GPS lock option, when it
becomes virtually perfect, with perhaps a little short-term (< 1 sec) phase
ripple.
Does this help? What did you have in mind?
73,
Murray ZL1BPU
|
