[hpsdr] Star-10 Transceiver article in QEX

[John Miles]

Forwarded to the list earlier this morning, at your request.

One final question, though -- I know I said I'd step aside from the matter
and wait for the next QEX issue, but I'm curious, after reviewing your
photos.  How are you getting < -137 dBc/Hz at ~2 kHz out of the HP 8640B you
use as the heterodyne source in your measurement?  Obviously it must be
cleaner than your own PLL to yield a nice, flat PN trace like that from 500
Hz to 20 kHz.

My own 8640B is only good for about -125 dBc/Hz at 2 kHz in the 64-128 MHz
band, and it is the quietest one out of several that I've measured.
Ordinarily, you would need an HP 8662A or better reference to make a
close-in measurement like that, and even then, the 8662A's specs are about
the same as your reported results.

It appears from the HP 3585A display that you were downconverting to
baseband (0 Hz IF), correct?  I assume you were quadrature-locking the 8640B
to your PLL, as is required for baseband downconversion?

By the way, I'd be more than happy to run a test on the 8662A/11729C
phase-noise rig here, if you have any examples of this synthesizer you'd
like to have independently evaluated.  I am always looking for new and
interesting things to measure, as there is always something for one or both
parties to learn. :)

(That goes for anyone else on the list as well.)

-- john, KE5FX


> -----Original Message-----
> From: constantin popescu [mailto:res1fz2o at verizon.net]
> Sent: Monday, December 17, 2007 12:15 AM
> To: John Miles
> Subject: Fw: [hpsdr] Star-10 Transceiver article in QEX
>
>
>  Hello John,
>  Can you please  post it for me in your forum until I became member?
> Bob already posted his comments.
> Thank you
>
>  73 de Constantin KG6NK


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