Re: [IRCA] The "mystery" of 1710khz

[Rick Kunath <k9ao@xxxxxxxxxxx>]

Barry McLarnon wrote:
> I use a program called baudline under Linux... 

Baudline is a great audio application.

Under Linux though, I usually use gLFER. There are a number of transform 
algorithms available to switch to, and using these is really helpful. 
You need to increase the default sampling settings to get the 
high-resolution needed for carrier-offset measurements. Once set, you 
have a full screen of a really narrow slice of audio spectrum to work 
with, and can measure the screen values by moving the cursor and looking 
at the values. I'm at work now so I don't have access to my notes on the 
settings, but I can dig them up later if anyone needs them.

http://www.qsl.net/in3otd/glfer.html

The app works nicely under ALSA.

> I think most Windows users 
> use one called Spectrum Lab.  

I like Spectran under Windows a lot.

http://www.weaksignals.com/

There is a lot of info on the web site about using it for various 
purposes. The app has lots of potential, and I especially like it's 
profiles for saving various setups according to what you're doing at the 
time. There was a profile and palette out there somewhere set up 
especially for MW offsets, though I can't remember where I ran across 
it. Setup of the app is really easy though. You can get a full-screen of 
a narrow slice of audio spectrum with this app, too.

One handy use for the on-screen carrier-offset display is when nulling. 
I have dual preamplified outputs on my home brew loops and the Kiwa 
loop, and I almost always have a second receiver set to see the 
on-channel carriers I'm hearing on the main audio receiver. If the audio 
spectrum analyzer scroll time is set fairly fast (opposite to what you 
normally use for offsets), the effects of nulling become really apparent 
when rotating the loop. I don't have anything suitable for phasing yet, 
but this might also be useful there too. I'd be interested in hearing 
what folks thought about that use for the apps. It does work nicely when 
I use the ANC4 for nulling noise using my short noise-sense antenna.

And speaking of other helpful radio-related Linux apps, LinRad has a lot 
of potential. I ran across a discussion about computer-based DSP on one 
of the lists a few days ago that mentioned using Dream, but LinRad is 
lots more powerful. It's a bear to get running and really needs a 
dedicated machine running Linux, but one of these days I am going to get 
serious about building the new version and giving it another go. It's 
got some amazing capabilities. It needs fairly junk hardware (except for 
a good sound card) and I have a few old machines that might do the job. 
The TimeWave 599zx has been doing a decent DSP job so far, but I need to 
take another look at getting LinRad going one of these days.

http://www.nitehawk.com/sm5bsz/linuxdsp/linrad.htm

Rick Kunath
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