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Re: [linrad] users_extra

Hi, Bob,

Thanks for the email.  I look forward to hearing of your experiences with  
the Delta 44 under Linux [and with the SDR 1000!]!

I don't think I explained my 'problem' very well.

I can change the card sensitivity, it but not on the fly.

What is going on is a software 'problem' or 'feature'.  Clicking on a  
strong signal seems to modify how Linrad processes it, and it 'blows up'.   
And this is a signal that is not even quite at 50% of the peak signal  
based on the dynamic range of 0-120 dB.  Clicking again so that the signal  
is outside the baseband passband returns things to normal.  This just  
shouldn't be.  It means that as you are tuning across the band you have to  
[for signal strength variations that would be easily handled in a 'normal'  
receiver] constantly be throwing in attenuators or playing with soundcard  
parameters, or whatever.  Its kind of like having to stop the car and get  
out and throw a switch on the front bumper every time you want to go from  
making righthand turns to making lefthand turns.  Somewhat inconvenient.

This didn't used to happen, and I don't know what caused it to start  
occurring.  I suspect that Leif or someone who has recently been playing  
with Linrad has the answer at his fingertips.  If I didn't have the  
contests this weekend to get ready for, I'd spend a few hours playing and  
trying to figure it out.  But I can live with it for the EME contest [no  
60 dB signals there], and time is of the essence, so I am looking for a  
'quick fix'.  If none is available, I'll operate as is as worry about it  
later.  I don't want to do anything drastic that will potentially take  
hours for me to undo if something goes awry [e.g. reinstall / update OSS  
or the kernel].

I have changed computers, Linux installation and updates [still RHL 8.0  
but on a new machine, with new install of course, and different update  
history], Linrad version and parameters, and RF hardware between when  
things worked without this glitch and now, so it is hard for me to  
pinpoint what 'difference' in my situation caused it.  ;)

But I think it is a Linrad parameter issue most likely, second most likely  
something new in the Linrad code, third most likely something in my Linux  
OSS / soundcard environment.

Thanks again, and


Roger W3SZ

On Tue, 7 Sep 2004 13:12:52 -0000, Robert McGwier <rwmcgwier@xxxxxxxxxxx>  

> Roger:
> I have not yet put my Delta 44 on my Linux machine but that is
> "coming soon".
> Can you set the Delta 44 scale as you can on the Windows Driver?
> If so, you might try changing it from +4 dBu scale to the -10dBv
> scale on the input.  I find that it is impossible for me to yse
> the +4dBu scale on output ever.
> If this can be done on the fly, then you would have at least one
> easy setting to change between strong signals (+4dBu) to weak signal
> (-10dBv).

Roger Rehr