[amsat-bb] Re: ARISSat-1 over West Malaysia

[Luc Leblanc]

On 5 Aug 2011 at 10:28, Phil Karn wrote:

Date sent:      	Fri, 05 Aug 2011 10:28:23 -0700
From:           	Phil Karn <karn at philkarn.net>
Subject:        	[amsat-bb] Re: ARISSat-1 over West Malaysia
To:             	"Sion Chow Q. C. (9W2QC)" <9w2qc at 9w2qc.net>
Copies to:      	sangatsingh at gmail.com, amsat-bb at amsat.org

> On 8/4/11 8:04 PM, Sion Chow Q. C. (9W2QC) wrote:
> >
> > 2. Does the CW beacon needs to be really +/- 100 Hz of the yellow  
> > line?  The reason for this is that I would like to see how much offset  
> > should I apply to doppler control, for possible automated reception.
> 
> Tuning the CW beacon to 500 Hz automatically centers the BPSK1000 signal
> at 1500 Hz. I didn't put in a whole lot of frequency tolerance in the
> BPSK-1000 demodulator because the signal is 2 kHz wide from null to null
> and it would begin to be chopped off by the edges of the receiver's SSB
> filter. So while you should ideally tune to +/- 100 Hz you might go to
> +/- 200 or even 300 Hz and it will *probably* still work, but I wouldn't
> go too much wider.
> 
> Go ahead and experiment; I'd be interested in any reports on how well my
> demodulator (which is incorporated into both the Windows and Mac
> telemetry programs) tolerates tuning errors. Frequency acquisition and
> data synchronization are the hardest parts of any digital demodulator,
> and I'd like to know where there's room for improvement.
> 
> 73, Phil
> 
> 
> 
I try to decoded the last 30deg pass this morning but no luck even if the blue marker remain steady on the CW bump nothing "lock" as far i 
can tell any QRM or QRN seems to hold the lock process and on VHF here i have some intermod... living about half a mile from a cell/paget 
tower?

"-"


Luc Leblanc VE2DWE
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