VS: [EladSDR] Shift in center frequency


Otso Ylönen
 

I have not been able to repeat your sequence, or verify it as I do not have any MW antenna nor local MW stations here. I will throw some kind of wire out of the window once it gets dark…

 

However, what I have found out is that:

The files that play 2 kHz off have a difference in headers:

The ELAD ”Chunk/Unused1” row has a frequency that is 2 kHz off from th CF. Example:

 

 

These are from two different files recorded with the same equipment a few hours apart. The generic parts of the header are same, e.g. CF 1100000. I am pretty sure the 1098000 figure indicates something is wrong.

 

Now, playing back files that I had not played back with my laptop do not get changed like this. But the few files I listened to with the laptop play similarly off-frequency with my desktop PC.

 

Now I am looking at a hex editor in order to see if I can hack the Unused1 thing in the header…

 

BR, Otso

 

Lähettäjä: Bill Nollman
Lähetetty: torstai 21. lokakuuta 2021 11.10
Vastaanottaja: EladSDR@groups.io
Aihe: Re: [EladSDR] Shift in center frequency

 

I agree, I have not previously seen it be off frequency on the first time opening the file.

I have seen bandwidth revert to 384,000 kHz (which I would never set it to) on first open. That is easy to fix by manually setting 192,000.

I am still using v3.50.

Bill

 

From: EladSDR@groups.io <EladSDR@groups.io> On Behalf Of Otso Ylönen
Sent: Thursday, October 21, 2021 3:54 AM
To: EladSDR@groups.io
Subject: Re: [EladSDR] Shift in center frequency

 

 

Hello Bill,

 

Yes, that issue has existed for many years.  The latest, i.e. a file bahaving only on first run, I have not seen before.

 

I will try your sequence during the weekend, when back to home.

 

 

BR, Otso

 

Gesendet: Donnerstag, 21. Oktober 2021 um 01:49 Uhr
Von: "Bill Nollman" <billct97@...>
An: EladSDR@groups.io
Betreff: Re: [EladSDR] Shift in center frequency

Otso;

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.

Bill


-----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


> 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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