PC's and Linrad

["w3sz" <w3sz@xxxxxxxxxxxxxxx]

Hi, All!
 
This is just a note to indicate what I have used here with
Linrad with success, and more recently what I have used with
the SDR-1000.
 
For a couple of years I have used a
 
Dell Dimension 8100 1.4 GHz Pentium4 with
768 MB RAMBUS Memory
Delta 44 Soundcard as input
Various Creative Labs cards as output [most recently, PCI64]
Radeon Video card [various flavors have worked;  I think I
have a 32MB DDR 4x AGP in now].
 
I have had no speed problems running 96000 Hz sampling rate,
two receive channels [simultaneous horizontal and vertical,
and I/Q sampling.
 
I have been running various versions of RedHat Linux, from
6.x to most recently 8.0.
 
I used the OSS audio drivers and saved myself thousands of
dollars of wasted time and frustration.
 
I have not been bothered by computer noise from this
machine.  My EME array is about 100 feet horizontally from
the shack, and 70 feet in the air.
 
 
 
More recently I put together another [much cheaper] machine
to use with both Linrad and with the SDR-1000.
 
This is an assembled from parts unit.
 
I started using a Soyo 7VBA133U Motherboard with a Pentium
III 1.0 GHz [256K cache, 133 MHz FCPGA], with integrated
sound [VIA AC97] for output and another Delta44 for input,
again with 768 MB PC100 SDRAM memory.  I chose this board
because I need ISA slots for other reasons and it has
several.  I have since found some P4 industrial boards with
plenty of ISA slots.  I am using a Radeon 7000 video card
with this setup.
 
This configuration as noted works FINE with RHL 8.0 for
Linrad.  However, there are major problems in using it with
the SDR-1000.  The onboard sound has only a mic input, and
not a line input.  And the SDR-1000 software does not
recognize the Delta44.  So even though I could get the
combination to 'work' with the above setup, it turned out
that whether I went thru the Delta44 for input to the
SDR-1000 or thru the onboard sound, I effectively had mono
input and thus no I/Q and thus terrible image rejection,
etc.
 
The solution was however simple and cheap.  The bios allowed
me to disable onboard sound, and for good measure I set
aside IRQ5 for 'Legacy Devices' in the bios setup [I don't
know if the latter was necessary, but things work fine so I
didn't go back and change it back].  And I stuck an old
Creative Labs AWE64 [Type 1] into one of the ISA slots to
use for the input instead of the onboard sound.  
 
Now everything works perfectly both for Linux running Linrad
and for Windows running the SDR1000Console hardware.  With
this machine running Linrad I can do 96 KHZ sampling and two
receive channels [horizontal and vertical] and I/Q receiving
with no apparent timing problems.  It has no problems with
the SDRConsole exe file.  When I run SDRConsole under the VB
6.0 IDE the machine will occasionally 'hiccup' briefly.
 
Again, I saved much time and avoided much frustration by
using the OSS audio drivers in Linux.
 
Again, I note no computer noise problems from this setup
here.  I have LOTS of noise here, but these two machines
don't seem to add to it.
 
The cabinet I chose for the second computer was aJust4PC ATX
Midtower case with 350W PS.  From Tiger it was # B452-1018
and cost 34.99 with the 350 watt supply.
 
Hope that helps.  I am not a computer expert, but I can tell
you what has consistently worked here.
 
Questions are welcome.
 
Have a great weekend, all!


73,
Roger Rehr
W3SZ
FN20ah
http://www.qsl.net/w3sz




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