|
Marcus
Jose has reduced the decoder pass band
to 50 Hz , this reduces the over heads on the
'decision' process , it seems to be a harsh
environment , compared with say 136 . there
where some AFC improvements in recent issues
, if you check the psk-map for 2
meters , there are a group of EA
stations running diffraction/scatter , over some
considerable ranges , system is tacking the Doppler
shifts
The decoder assembles the recovered blocks , after
the final symbol , so there is short time
lag , depending on the pc speed as to when
the decode is stamped , but as there is no link
to 'real time' its not too important , web-data
also passes via the server , where added
information , range etc is added
From the recent results , decode
levels seem to be satisfactory , just
need a night at the Opera , this side
to see if Bob can get the TA decode ! ,
73-G,
Sent: Saturday, March 08, 2014 6:36 PM
Subject: Re: LF: 27.925 is correct dial
Hi Graham,
well opds "dBOp" has been calibrated
to display SNR on the same "average power" scale as Opera, ie carrier
power in 2.5 kHz minus 4 dB. However
I concede that opds SNR measurements are not always
accurate. Especially with either strong signals, or unstable /
incoherent transmissions, the estimate of the carrier power or noise can go
wrong by several dB.
You mentioned improvements to the decoding
algorithm in the latest Opera version - can you give details?
73, Markus
Sent: Saturday, March 08, 2014 7:19 PM
Subject: Re: LF: 27.925 is correct dial
...
OP32 min as used on 136 KHz ,
gives ~ -41 dB min , so OP2H
should
run - 47 , I note Dex reached -48 , which is
-54/55 on
Marcus's scale
Tnx ,
G,
|
