VS: [EladSDR] Shift in center frequency

Otso Ylönen


I was not able to reproduce this even though I tried to follow your method below. And my normal way of jumping between MW, OIRT-FM and CCIR-FM bands is to use predefined profiles which change the center frequency and bandwidth, along with other preferences. Profiles were also able to remember rx mode, I think, but that is not the case with the latest SW2 releases. E.g. when having first listened to FM, the WFM mode stays on when selecting an MW Profiile.


You could have a look at the off-freq file with WavHeaderManager to see if it also has different values in the ”CenterFreq”  and ”Unused1” Fields.



BR, Otso


Lähetetty Windowsin Sähköpostiista


Lähettäjä: Bill Nollman
Lähetetty: keskiviikko 20. lokakuuta 2021 22.49
Vastaanottaja: EladSDR@groups.io
Aihe: Re: [EladSDR] Shift in center frequency




I can reproduce your 9kHz/10kHz problem in a similar way.

Open a WBFM capture (88-108MHz) with a 100kHz bandwidth.

Close it and then open a MW capture (1.5MHz capture centered on 1120kHz). The bandwidth will still be 100kHz even though I'd prefer 10kHz.

Change the bandwidth to 1kHz or 10kHz (only so I can tune in finer steps than 100kHz). Every station will be off frequency. For example my local 1080kHz is tuned in on 1065kHz.

Now with the bandwidth set to 10kHz close and re-open the same MW capture and everything is working and on frequency.





-----Original Message-----

From: EladSDR@groups.io <EladSDR@groups.io> On Behalf Of Otso Ylönen

Sent: Wednesday, October 20, 2021 10:37 AM

To: EladSDR@groups.io

Subject: Re: [EladSDR] Shift in center frequency


An additional finding: I made a clip out of a ”badly behaving” IQ file (between A and B markers). When played back, it also was fine only on first load. When loaded again to SW2 it moved all frequencies up with 2 kHz. E.g. stations on 1440 come now at 1442 kHz!





> Otso Ylönen <otso.ylonen@...> kirjoitti 20.10.2021 kello 14.42:


> Hi,

> I have a strange thing going on with the latest beta SW2 (3.51):


> The first time I load a saved (MW) IQ file everything is fine. On consequtive attempts to listen to the captured RF, the center frequency has shifted (e.g. 2 kHz) and all ststions on the band come on ”wrong” frequencies.


> I have sometimes had similar trouble when at times using 9kHz step while recording and then attempting to use 10kHz step when reproducing the IQ file (or vice versa).


> Now, this is with the same laptop I have done the recordings. I will have to see if things change once I am back from my DX expedition and can use my desktop, which has worked fine with 3.51.


> BR, Otso


















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