[pskmail] IS0GRB-3 PSK250 mode and atomic signals
- From: Roberto IS0GRB <is0grb@xxxxxxxxx>
- To: pskmail@xxxxxxxxxxxxx
- Date: Mon, 29 Oct 2007 22:42:59 +0100
Hi all.
I switched, for tests, my server to *PSK250* mode for some weeks.
My frequency is the same, 10.148.75 Mhz.
Reports will be appreciated.
In fldigi i have configured:
- Search range to "*300*" Hz (about 240Hz is the total bandwidth)
- Allowable Rx Carrier Offset to "*50*" Hz (to garantee connection to
all radio that have up to 50Hz of offset in the pll reference
oscillator, i see that there are many errors in the frequency read in
the display from winter to summer if the HF radio don't have a TCXO
oscillator)
----
A way to see if the radio is in frequency is to go to the HF atomic signals.
In europe the best signal is 9.996MHz in CW (Russian); in America is
10.000MHz in CW (Colorado).
Configuring this mode e frequency you can hear a tone that must
correspond to a 800Hz if your radio switch to 800Hz in CW and 700Hz if
the radio switch to 700Hz in CW (see the manual).
You can see the signal in fldigi, that must correspond to 800Hz.
If no, change the frequency of the VFO to have a 800 Hz signal in
fldigi. The difference is the frequency error of your radio.
For example if to have a 800Hz signal in fldigi is necessary to set the
frequency 9.995.97 your radio has 30Hz of error etc...
You adjust it with the calibration in the pll section of your radio.
This procedure garantee the exactly frequency read and transmitted of
your radio.
In the 9.996MHz, from 1 to 7 and from 30 to 37 minute there is a fixed
signal and you can see a stable trace in fldigi; in the 10.000Mhz the
signal is always fixed.
My radio has about 20-30Hz of error of frequency from winter to summer,
although i have a TCXO oscillator. I verify it about 1-2 time of week.
Very important!! If you would calibrate your radio, wait up to 2 hours
with the radio on, to have a stable temperature in the pll oscillator.
During this 2 hour the temperature will change.
---------
Best 73
Roberto IS0GRB
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