[Scan-DC] 137-138 MHz satellites?

[Andrew Clegg]

I just added a Mini-Circuits pre-amp and the signals are much stronger. They 
definitely have the Doppler signature to them, so I have confirmed they are 
satellites. (Mini-Circuits makes great stuff!)

Andy


----- Original Message ----- 
From: "David I. Emery" <die at dieconsulting.com>
To: "Andrew Clegg" <w4jecom at w4je.com>
Cc: <Scan-DC at mailman.qth.net>
Sent: Saturday, June 13, 2009 1:43 AM
Subject: Re: [Scan-DC] 137-138 MHz satellites?


> On Thu, Jun 11, 2009 at 08:40:33PM -0400, Andrew Clegg wrote:
>> I've been recording some waterfall plots of the 137 - 138 MHz satellite
>> downlink band with my HP spectrum analyzer today. I looked back through 
>> the
>> data recorded while I was at work, and it appears I caught several
>> narrowband signals throughout the band, and one relatively strong 
>> broadband
>> signal near the top of the band. This is just with a discone, and without
>> any pre-amp, so the signals must be fairly strong (for satellites) to 
>> show
>> up directly on the specan, given the lousy noise figure. The signals come
>> and go consistent with the ~few minute pass of a LEO satellite, so I 
>> believe
>> they are real, although I can't yet be certain. They should be easily 
>> heard
>> on my receiver, or even a regular scanner with a decent antenna.
>
> You should also see doppler on any satellite based signals.
> On a waterfall this will result in a tilt rather than straight line
> plot.
>
>
> -- 
>  Dave Emery N1PRE/AE, die at dieconsulting.com  DIE Consulting, Weston, Mass 
> 02493
> "An empty zombie mind with a forlorn barely readable weatherbeaten
> 'For Rent' sign still vainly flapping outside on the weed encrusted pole - 
> in
> celebration of what could have been, but wasn't and is not to be now 
> either."
>
>