[hpsdr] Excalibur checkout

[jkelly]

Graham,

Can I use standard broadcast stations to achieve the same test?
I guess I would have to confirm that they are on freq first.
I just did a quick test with a local sports station:

http://mysite.verizon.net/jkelly/hpsdr/phase/hpsdr.swf.html

Does this look right to you?

Jeff
KT2K

----- Original Message ----- 
From: "Graham / KE9H" <KE9H at austin.rr.com>
To: <aa8k73 at gmail.com>
Cc: "HPSDR (open)" <hpsdr at openhpsdr.org>
Sent: Sunday, January 10, 2010 11:51 AM
Subject: Re: [hpsdr] Excalibur checkout


> ***** High Performance Software Defined Radio Discussion List *****
>
> AA8K wrote:
> > My Excalibur oscillator was 10.5 Hz off at 10 MHz
> > against WWV and my Trimble Thunderbolt, after a 10
> > hour warm up.  I waited another day and zeroed it.
> > I'll check it again after a month or two.  I like
> > the beat LEDs.  I'll be using the Thunderbolt anyway.
> >
> > Mike - AA8K
>
>
> Geoff wrote:
> > Powered up without smoke :-). 5Hz off against WWV on
> > 15MHz using the TCXO. I'm very happy, it's well
> > within spec. Time to get my LPRO101 integrated.
> >
> > 73 de Geoff vk2tfg.
>
>
> All:
>
> My personal experience, having built three of the
> Excalibur modules, is that three out of three TCXO were
> within 1 Hz., out of the box.
>
> With Mike, AA8K's report I now have two reports of
> errors out of the box on the order of ten Hz, but
> within adjustment range such that they can be adjusted
> to zero error.  I don't know if this is a problem, or
> just a factory set error, with multiple hundreds of
> kits shipped.
>
> --
>
> I had reports from several users that the "Phase
> Display" built into PowerSDR could be used to
> set/check the frequency of the TCXO in the absence of
> a local 10 MHz standard or GPSDO.
>
> Playing with the "Phase" display (not Phase 2), you
> can see the phase error relative to the station you
> are listening to.  You get a rotating "RADAR screen"
> plot where distance from the center of the circle is
> amplitude, and angle is phase.
>
> So, tune to WWV, or your local frequency standard
> station. Once a second rotation means one Hz error.
> Two seconds to rotate once, means one half Hz error.
> Ten seconds to rotate once means one-tenth Hz error.
>
> Narrow the AM bandwidth to less than 100 Hz to wipe
> the modulation off the carrier, so you are only
> looking at the carrier, to stabilize the dot some.
>
> Multiple dots at once, on opposite sides of the circle
> means you are multiple Hz off frequency. Adjust until
> you see only a single dot/plot spinning around.
>
> Once again, don't bother trying to get the error below
> one-half to one-quarter Hz, since the oscillator walks
> around about one Hz over the course of a day.
>
> There is also a granularity in the DDS/CORDIC built
> into Mercury, in that its resolution is not infinite,
> and it actually steps frequency in step sizes of about
> 0.03 Hz.
>
> So realize that when you tune to a particular
> frequency with Mercury, it means that the receiver is
> on that frequency plus/minus 0.03 Hz.  So even when
> locked to a GPSDO with an error in the milli-Hertz,
> you can only use the phase display to measure your
> friend's carrier frequency to about 0.1 Hz.
>
> ;-)
>
> --- Graham / KE9H
>
> ==
>
>
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