Re: [Discuss-gnuradio] *much* faster filtering --- plus vhf mountaintopping

[James Cooley]

All,

I've got a Targus 150W APV07US Slimline inverter and a Buslink external 
usb enclosure... works great. Only things are that the Targus lets out 
this ear-splitting beep for some unknown reason when it starts up.... 
Also, my car's a bit flaky in that it shuts off the cigarette lighter 
power at inconvenient times!!

Another tip for all of you: Use a more ROBUST file system on the 
external drive. I lost a day's worth of data because I used FAT32 on the 
external drive and had the power shut off as stuff was being written. 
The FAT filesystems are notoriously lousy. I now use ext3. Do mount and 
umount it cleanly, but if you should lose power accidentally, you are 
more likely to be ok. The drawback is that you can't really use it under 
windows.

Try out the compression before you go all the way to a mountain top, 
though. :) I can't swear that my laptop isn't dropping data... I don't 
*think* it is (I'm packing extra header data ahead of each sample block 
and things really wouldn't work if the number of complex samples were 
messed up), but you never know. If gzip can't read from the fifo quick 
enough, data will just be dropped.

Any improvements, better compression schemes would be welcome! I'm sure 
there's a way to come up with a compression scheme that's tailored to 
the sort of sample data we see...

-j



cswiger wrote:

> Daniel & James (et al) - Firewire or USB drive looks the way to go,
> with compression in the stream (Tks James). I've found a world of
> 12vdc input ATX power supplies are available, like:
>
> http://www.orbitmicro.com/products/power%20supplies/dc-dc/ps2/KPDX250H.htm
>
> might run a small server mobo with big SCSI disk.
>
> --Chuck
>
> On Wed, 11 May 2005, Daniel O'Connor wrote:
>
>  
>
> > If you can power a mains appliance (car inverter?) you could use an external
> > firewire drive.
> >
> > I doubt you could run a USB enclosure and the USRP without running out of USB
> > bandwidth but firewire should be OK.
> >
> > The enclosures I've used (Mapower) can keep up with WDxxxxJB drives which do
> > around 30-50Mbyte/sec.
> >
> > --
> >    
>
>
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