OK agn, Scott/Murray
I had another look at the phasescope pdf file and with an integration
time of 300 or so seconds its obvious the effective b/w is waaay down.
I guess I was just interested to see if there was any phase or
amplitude tracking capability-obviously not!
I'm nearly finished writing up a long and somewhat boring (well it is
now, after about 100 pages!) report for work, so have only had half an
eye on LF goings on in recent days, today being no exception. So much
for being inattentive!
If I get a chance today/tomorrow I'll get phasescope fired up and see
what it can do.
Cheers
Dave, ZL3FJ
----- Original Message -----
From: "Murray ZL1BPU" <[email protected]>
To: <[email protected]>
Sent: Monday, April 24, 2006 1:29 PM
Subject: Re: LF: Re: PhaseScope beta 1.0 release...
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
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