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R: [Linrad] Re: Frequency scale in Linrad
- Subject: R: [Linrad] Re: Frequency scale in Linrad
- From: "libero.it; ik7ezn@xxxxxxxxxxxxxxxx>
- Date: Sun, 15 Nov 2009 14:24:30 +0100 (CET)
I did as you suggested and I got what I wanted.
Now the scales
coincide with the frequency of Linrad and frequency in MAP65.
Thank you for
your usual availability.
73 Ermanno / ik7ezn
>Data: 14/11/2009 21.13
>Ogg: [Linrad] Re: Frequency scale in Linrad
Linrad as front-end for MAP65 and WSJT.
>> To view an jt65
>> signal, on the
waterfall of linrad (SSB), shift the BFO to -1270.5 and filter
>> to about 2.4
>> The frequency in Linrad corresponds exactly to the specified
frequency of MAP65 (+/- Doppler).
>> The audio output from Linrad, which uses
>> input for WSJT is perfectly focused (DF = 0) on the desired signal.
>> problem is that the scales of frequency of all windows of Linrad
>> different frequency, that is without compensation of the BFO.
It is difficult
>> to click on the signal desired in high resolution spectrum,
>> there are many JT65 signals in a few kHz.
>> How to get
the right indication on
>> the scales-frequency of Linrad ?
readout gives the frequency of the carrier. In SSB mode
>that is the frequency
of the BFO. In CW mode the carrier is assumed to be
>placed at the center of
the baseband filter. If you use AFC it will
>be forced to the center if locking
>You should run in CW mode. Then a carrier (or a JT65 sync
>is placed at the baseband center would produce a frequency readout
>that is in agreement with the frequency scale in all the graphs
>independently of the BFO setting. By placing the BFO 1270.5 Hz below
passband center you can make the frequency of a signal at the
appear at 1270.5 Hz in the output. In this way the
>true frequency of the sync
tone which would be shown in the frequency
>readout as well as on all scales
will differ from the MAP65 readout
>by 1270.5 Hz. That is because Joe decided
it is easier that way for
>people who use an ordinary radio. (I am NOT in
favour of that, but now
>it is the established "standard" for JT65. )
make all the scales as well as the frequency readout show the true
with a 1270.5 Hz shift you should make a users_hwaredriver.c
>that sets a
frequency that differs from the hardware frequency by 1270.5 Hz.
>If you use
the WSE units, edit users.c and make it contain your own version
c which would differ from the standard version by having
rx2500_fqcorr=1270.5; (Or perhaps minus...)
>That way scales and readout
would no longer show the frequency, they
>would all show the true frequency
plus (or minus) 1270.5 Hz.
>In case you are not satisfied by having Linrad
and MAP65 showing the
>same frequency but want the frequency of both to agree
with the true
>frequency you would have to add a frequency correction to the
>and add the same correction to the frequency that you feed into
>Leif / SM5BSZ
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