I am monitoring 502kHz ROS MF1
-----Original
Message-----
From: [email protected]
[mailto:[email protected]] On
Behalf Of Graham
Sent: 02 July 2010 13:33
To: [email protected]
Subject: Re: LF: 137.500 kHz ROS
MF-1 beacon
MF1 ROS is 0.837053 symbols/second. If
you can decode at -33dB (presumably in the reference bandwidth of 2.5kHz)
that's +1.7 dB S/N in a symbol bandwidth, that in the case of 16FSK with Viterbi Decoder is
possible.
ROS calculate S/N for
100Hz, after tx , show's S/N for an equivalent system of
2500Hz >> CANCEL> -36 dB <<
(end of rx text string)
Sent: Friday, July 02, 2010 8:01 AM
Subject: Re: LF: 137.500 kHz ROS MF-1
beacon
MF1 ROS is one symbol per
second isn't it. If you can decode at -33dB (presumably in the reference
bandwidth of 2.5kHz) that's -1dB S/N in a symbol bandwidth.
Which I'm not sure I can believe. FSK with good Feed Solomon, or
whatever, FEC needs 2 - 3dB S/N.
Is the S/N calculation
being a bit optimistic? The calculation in WSJT / WSPR gives an
artificially high S/N value if the input bandwidth is restricted below a
complete 2.5kHz's worth, and if impulsive noise is present. So could ROS
be suffering some similar effect?
On 1 July 2010 23:47,
Graham <[email protected]>
wrote:
Just a couple of
db's short of a decode via the web , -36 is
going some though
RX1:
21:55 @ 13.8 Hz: *[:]V-KFY:32DM5#("")EM3H#/F[_
<CANCEL> -36 dB
G ..
Sent: Thursday, July 01, 2010 6:35 PM
Subject: LF: 137.500 kHz ROS MF-1 beacon
Hi LF,
My ROS MF-1 beacon is
transmitting now with 3 minute timer.
Frequency is 137.500 kHz
(dial 136.500 kHz USB), reports & QSO attempts very welcome.
