PSN-L Email List Message

Subject: Re: WinSDR Wireless Interference?
From: Christopher Chapman chrisatupw@.......
Date: Tue, 13 Sep 2011 18:52:03 -0400 (EDT)






Subject: Re: WinSDR Wireless Interference?


No, there is not a totally blank screen.  The WinSDR screen stays there but=
 there are no seismometer wiggles (hope we're not losing our layman audienc=
e here)  on it.  There are no lines at all, no straight lines and no seismo=
 wiggly lines.  I have to reboot WinXP to get it up and running again and w=
hen it comes back, there are the straight green lines for the time period t=
hat WinSDR was having it's problem.   But again, when the problem happens t=
here are no lines at all, just the blank WinSDR system window as if I'd ope=
ned the program without a seismometer connected.

I have checked the cable connections and all other connections literally do=
zens of times and I also don't get the same symptoms of a blank WinSDR scre=
en when I disconnect a cable.

When WinSDR goes into its problem mode, I can't just close it and re-open i=
t to get it running again.  It will open but not connect to the seismo.  I =
have to reboot WinXP to get WinSDR running again. =20

I agree that it seems unlikely that it's a frequency/antenna problem but I'=
ve convinced myself that it only happens when the router or wireless comput=
er starts transmitting data.






From: Robert Thomasson=20

=20



I have had some trouble keeping my WinSDR up and running.  It frequently sh=
ows just a blank screen, with all helicord traces gone.  Just as if I'd jus=
t opened the software without a seismometer connected to the computer.  The=
 computer is an older Dell with a 2 GHz processor and 512 Mb RAM, running W=
inXP with I think service pack 3.

What is interesting about this phenomenon is that there is a wireless route=
r in the house (the seismo server has no wireless capability and is not con=
nected to the network) and WinSDR will work fine until someone sits down at=
 another computer and the wireless network starts exchanging traffic.  Then=
 the WinSDR screen loses the displayed data and goes blank.

Is it possible that somehow the USB cable from the seismometer to the seism=
o server computer  is acting as an antenna and picking up enough interferen=
ce from the 2++GHz wireless LAN system to crash WinSDR?  WinSDR does not ac=
tually crash, it just loses the data traces, which disappear.  My next step=
 is to dig out some old books and see if I can figure out what length the s=
eismo cable would have to be to resonate at the wireless LAN frequency.   B=
ut I think it would have to be very short?

Hi Bob,=20
    Can you tell us what electronics are connected to the various computers=
, including modems, please?
    Are all the computers properly earthed, please? =20
    The velocity of light is about 300 million metres / sec, so the wavelen=
gth is likely to be 12.5 cm. Put a ferrite ring on the SDR data cable and s=
ee if this has any effect?
    Can you physically check that the seismometer computer does NOT have a =
radio module fitted, please?
    The effects you describe might be explained if WinSDR and a higher prio=
rity program were on the same port / channel and the reception of the radio=
 signal, or one from a modem, just switched the data source.=20
    Regards,
    Chris Chapman=20


=20









= Subject: Re: WinSDR Wireless Interference?

No, there is not a totally blank screen.  The WinSDR screen stays ther= e but there are no seismometer wiggles (hope we're not losing our layman au= dience here)  on it.  There are no lines at all, no straight line= s and no seismo wiggly lines.  I have to reboot WinXP to get it up and= running again and when it comes back, there are the straight green lines f= or the time period that WinSDR was having it's problem.   But aga= in, when the problem happens there are no lines at all, just the blank WinS= DR system window as if I'd opened the program without a seismometer connect= ed.

I have checked the cable connections and all other connections literally do= zens of times and I also don't get the same symptoms of a blank WinSDR scre= en when I disconnect a cable.

When WinSDR goes into its problem mode, I can't just close it and re-open i= t to get it running again.  It will open but not connect to the seismo= ..  I have to reboot WinXP to get WinSDR running again. 

I agree that it seems unlikely that it's a frequency/antenna problem but I'= ve convinced myself that it only happens when the router or wireless comput= er starts transmitting data.

 
I have had some trouble keeping my = WinSDR up and running.  It frequently shows just a blank screen, with = all helicord traces gone.  Just as if I'd just opened the software wit= hout a seismometer connected to the computer.  The computer is an olde= r Dell with a 2 GHz processor and 512 Mb RAM, running WinXP with I think se= rvice pack 3.

What is interesting about this phenomenon is that there is a wireless route= r in the house (the seismo server has no wireless capability and is not con= nected to the network) and WinSDR will work fine until someone sits down at= another computer and the wireless network starts exchanging traffic. = Then the WinSDR screen loses the displayed data and goes blank.

Is it possible that somehow the USB cable from the seismometer to the seism= o server computer  is acting as an antenna and picking up enough inter= ference from the 2++GHz wireless LAN system to crash WinSDR?  WinSDR d= oes not actually crash, it just loses the data traces, which disappear.&nbs= p; My next step is to dig out some old books and see if I can figure out wh= at length the seismo cable would have to be to resonate at the wireless LAN= frequency.   But I think it would have to be very short?

Hi Bob,
    Can you tell us what electronic= s are connected to the various computers, including modems, please?
    Are all the computers properly = earthed, please?  
    The velocity of light is about = 300 million metres / sec, so the wavelength is likely to be 12.5 cm. Put a = ferrite ring on the SDR data cable and see if this has any effect?
    Can you physically check that t= he seismometer computer does NOT have a radio module fitted, please?
    The effects you describe might be explained if WinSDR an= d a higher priority program were on the same port / channel and the recepti= on of the radio signal, or one from a modem, just switched the data so= urce.
    Regards,
    Chris Chapman 

 


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