Hi Ken, Martin, and group,
I'd say yes...
8970 Hz * 2e-9 = circa 18 µHz resolution, that's fine.
Even better than most soundcard's short-term oscillator stability, and
the dreadful effects caused by the soundcard driver permits.
Even if Radio 4 may suffer from daytime/nighttime propagation effects
(depending on your distance to the transmitter),
it will be good enough even for "ridiculously long FFTs".
Alternatively, you could go for an el-cheapo GPS receiver with
one-pulse-per-second output. The next version of Spectrum Lab will
support that as reference input, quite similar to what Paul Nicholson is
using. I am using a Garmin GPS 18x VLC, available for a fair price at RS
components. The performance (jitter) is not spectacularly low ...there
are "better" GPS receivers out there..., but it should be fine for our
applications. And the receiver is very sensitice, I have it running
indoors, with a ceiling and the roof above me, still gives perfect lock
(9 to 11 satellites in view).
All the best,
Wolf .
Am 18.03.2011 21:09, schrieb Martin Evans:
To All VLF.
Is the following frequency stability sufficient for Spectrum Lab:
1MHz and 10MHz derived from Radio 4 198 kHz Accuracy 2 parts in10-8
over 1 sec,2 parts in10-9 over 10secs.
73s
Ken
M0KHW IO91TV
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You're after the Quartzlock unit on eBay eh, Ken.
I'm watching that too.
Martin GW3UCJ
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