[amsat-bb] LL Grace DSP-12 and AO-40 Telemetry

[John Zaruba Jr <jzaruba@xxxxxxxx>]

Hi Folks,

I've been trying to use an LL Grace DSP-12 for decoding AO-40 telemetry. I
noted a very large spur from the unit, extending from 145.7 MHz to about 146
MHz. Has anyone using this device noted a similar occurrence, or does my
little gray box have a problem? This spur makes the DSP-12 unusable for
decoding AO-40 telemetry.

I tried all the standard RFI cures (grounding the unit, chokes on all the
I/O line) with no decrease in the interference. It looks like the next step
is optically isolating all the I/O signals.

Fortunately, I also have a PacComm PSK-1 (which I got dirt cheap at a
hamfest a few years ago) so I've been able to collect AO-40 telemetry.

73 de John AA2BN


-- 
John Zaruba Jr.
Engineering Technician
Rowan University College of Engineering
Electrical & Computer Engineering Department
201 Mullica Hill Road
Glassboro, NJ  08028-1701

voice: 856 256 5337
fax: 856 256 5241
email: zaruba@rowan.edu
       zaruba@galaxy.eng.rowan.edu
web: http://engineering.rowan.edu

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