Date: Tue, 06 Jun 2006 13:00:24 +0300
To: "Linrad mailinglist" <linrad@xxxxxxxxxxxxxxxxxxxxx>
From: 'Zaba' OH1ZAA <zaba@xxxxxx>
Subject: Homebrew I/Q-chains ; KNOPPIX 5.0.1
Sir Roger & all!
Though I have the complete WSE-line here, I am still missing
the proper power supply (-15V/+15V) amperage to fire them up.
On the other side it is fun to build something small from time
to time, so I constructed the low noise I/Q-amplifier according
to SM5BSZ/Leif's Figure 2 in "Linux PC-radio. Optimised direct
conversion receiver for 144 MHz using standard Schottky diode
mixers" [http://www.sm5bsz.com/linuxdsp/hware/optiq.htm].
As it turned out the 2N2222A is an excellent choice for the
input-transistor. I had some 1980's stock, but ON Semiconductor
[http://www.onsemi.com/PowerSolutions/product.do?id=P2N2222A] is
listing this P2N2222A model with plots of noise figures below 1 dB
over a wide range of impedances and bias. I used the RC4136 for
the op-amps, but if you need to steer a Delta 44 to full range
with the 96 kHz setting, then it may be better to take a NE5532
or a similar type for the output stages, with a higher slew-rate
than the RC4136.
Knoppix 5.0.1 was released June 2d and I installed it to the HD
(after CDR-boot, issue in console: 'knoppix-installer'), as my
previous linux distro had been broken due to a forgotten cause.
With all the wlr2-xx versions of Linrad I had completely lost
contact with the linux versions, and it would be nice to see
a lir2-xx run under X. After 'apt-get update' I got access to
'apt-get install wajig' / 'wajig recommended xlibs-static-dev' /
'wajig recommended automake1.9' command series. However, I still
have problems with make xlinrad and make linrad after ./configure.
There are hundreds of errors at the end for both lir2-14 and lir1-37:
/usr/bin/ld.: symbol 'no symbol' missing from main hash table
Also when trying to run ./xlinrad >>>
Xlib: connection to "0.0" refused by server
Xlib: No protocol specified
can't open display (null)
Ran into similar hash table errors and the helper-module problem
with svgalib 1.9.24 and lir01-37 .... due to the linux break I
have to study again the helper module bypass in libvga.config if
that was the latest trick to avoid the issue (my memory fails).
73, "Zaba" OH1ZAA/2
At 14:09 1.6.2006, W3SZ wrote:
Hello, All,
This is just a followup note to let you know that the problem I am having
with the Presonus Firebox [it is not able to show more than a 48 kHz swath
of spectrum even with sampling at 96 kHz and quadrature detection] is a
'recognized issue'.
It is apparently due to a firmware bug. Presonus' first attempt at a bug
fix apparently caused more serious problems with the unit.
I am told they are working on another fix.
I will let the groups know if/when a satisfactory resolution appears.
Until then, the Presonus Firebox is NOT a suitable device if you want to
sample a swath of spectrum wider than 48 kHz, as it simply won't do it.
73,
Roger Rehr
W3SZ
--
Roger Rehr
W3SZ
http://www.nitehawk.com/w3sz/