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w3sz | 1 Jun 13:09
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Presonus Firebox

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/

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'Zaba' OH1ZAA | 6 Jun 12:00
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Homebrew I/Q-chains ; KNOPPIX 5.0.1 --- Re: [linrad] Presonus Firebox

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
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'Zaba' OH1ZAA | 6 Jun 13:40
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Xlinrad progess (su#); Fwd: Homebrew I/Q-chains ; KNOPPIX 5.0.1 --


Hello All!

Thanks to my godson Lasse/OH5XP I got 2-14 X_linrad a little
further and became aware of the fact how ignorant I still am
with the most basic features of Linux. Supposedly I can not
start X under Linux as a superuser if have logged in as a
normal user initially. Thus I could not run #./xlinrad  !!

However, with $ xlinrad I got to the setup screens and the
Linrad start screen. After pressing A (for CW) I got some
setad.c warning and comments on attributes of a par_file.
At least it gives the feeling of being close (closer).

[If I go to superuser mode # and then back to $ ... then I am
not able to start $xlinrad any more (can't open display); but
if I close the console window and open a new one then xlinrad
works again under normal user control].

Now after executing 'make svgalib' I may have more luck in
bypassing (or fluent use) the helper_module with lir01-37 at
next reboot, but I don't count on it (ref. former experience).

                         73, "Zaba" OH1ZAA/2

>Date: Tue, 06 Jun 2006 13:00:24 +0300
>To: "Linrad mailinglist" <linrad@...>
>From: 'Zaba' OH1ZAA <zaba@...>
>Subject: Homebrew I/Q-chains ; KNOPPIX 5.0.1
>
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Leif Asbrink | 6 Jun 14:06

Re: Xlinrad progess (su#); Fwd: Homebrew I/Q-chains ; KNOPPIX 5.0.1 --

Hi Zaba,

To run xlinrad you must be logged in as root to
have the permission to use parallel ports. If you
select not to use any, then it should be ok to go
as a normal user.

(Personally I am always root, I can not comment
to normal user problems because of ignorance...)

> Now after executing 'make svgalib' I may have more luck in
> bypassing (or fluent use) the helper_module with lir01-37 at
> next reboot, but I don't count on it (ref. former experience).

To run xlinrad you do not need svgalib. Just ignore it
and leave it as is in a non-working state.

The only thing needed:

make xlinrad
(lots of error messages about hash tables if latest Linux) 

Then just type ./xlinrad in the console window from where
you typed make xlinrad.

> >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.
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w3sz | 6 Jun 15:05
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Homebrew I/Q chains and Op-amps, compiling Linrad

Hi, Zaba, and all,

I am glad to see that you are making progress!  Building small receivers  
is fun!

I wish I could help you with the hash table stuff, but I have no idea what  
the problem is.  I have only the most basic idea of what a hash table is  
or does.  For those like me who have only a vague idea of what a hash  
table is, here is an interesting reference.  It won't help your problem  
though, as its way to basic and general.

http://en.wikipedia.org/wiki/Hash_table

Since you mentioned possible op amps to use for the final stage of your  
receiver I have a question for you and the group.

Around 2000 or so when I built my simple EME receiver to use with Linrad,  
it looked like the AD797s had the best noise specs and so this is what I  
used.

Now it seems that some of the cognoscenti tout the LT1128A and don't even  
mention the AD797.

The typical noise at 1 kHz for the AD797 is 0.9 nV/sqrt[Hz] and that for  
the LT1128 is 0.85, and max figures are 1.2 for the AD797 and 1.1 for the  
LT1128, so the LT1128 is ever so slightly better in this respect.

The gain bandwidth of the AD797 is 110 MHz and that of the LT1128 is 20 I  
think;  I guess that doesn't matter for our baseband amps.
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'Zaba' OH1ZAA | 6 Jun 16:56
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Linrad & slew-rates; Re: [linrad] Homebrew I/Q-chains and Op-amps, compiling Linrad


Hi Roger!

It seems that the hash table is no show-stopper at present, according
to Leif's recent observations. Lasse/OH5XP advised me to use additional
commands like  xhost +localhost  as Knoppix does not allow direct root
logins like in the old pre-version4 days. In between I ran 'alsaconf'
for running sound. I get some xlinrad starts, but the following few
error messages I get consistently:

When trying to save the parameters (W):

[1029]routine:thread_main  file: menu.c
Failed to open/create the file par_user int

When trying to set sound configuration (U):

[1016]routine:set_analog_io  file:lsetad.c
----------------------------

I get stuck on these two errors; no Linrad operation yet.
I did not mix up the linrad/xlinrad options, but I wanted
to keep the 01-37 version with svgalib as a backup in case
that the 02-14 does not work in X. Well, both are still "0".

Noise and slew-rate (op-amps/W3SZ)

Regarding the selection of low-noise operational amplifiers, your
question is very valid. Even the simplest circuit deals with many
(often independent) parameters, and it is very hard to oversee the
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Leif Asbrink | 6 Jun 17:34

Re: Homebrew I/Q chains and Op-amps, compiling Linrad

Hi Roger and all,

> Around 2000 or so when I built my simple EME receiver to use with Linrad,  
> it looked like the AD797s had the best noise specs and so this is what I  
> used.
> 
> Now it seems that some of the cognoscenti tout the LT1128A and don't even  
> mention the AD797.
> 
> The typical noise at 1 kHz for the AD797 is 0.9 nV/sqrt[Hz] and that for  
> the LT1128 is 0.85, and max figures are 1.2 for the AD797 and 1.1 for the  
> LT1128, so the LT1128 is ever so slightly better in this respect.
> 
> The gain bandwidth of the AD797 is 110 MHz and that of the LT1128 is 20 I  
> think;  I guess that doesn't matter for our baseband amps.
It all depends on where the performance limiting factors are.

The low end is noise, but there is a high end also and 
second order distortion is usually the interference that
limits dynamic range. I think the AD797 has much lower
harmonic distortion than the LT1128. The LT1028 is better,
probably because it is faster.

> The slew rate of the AD797 is 20 V/usec and of the LT1128 is 5V/usec.
> 
> So my question is:
> 
> For use as the 'last stage' of amplification before the soundcard for a  
> system sampling at up to 192 kHz, are these two chips pretty much  
> equivalent given the [to me] tiny differences in noise, or is the LT1128
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Leif Asbrink | 6 Jun 17:43

Re: Linrad & slew-rates; Re: [linrad] Homebrew I/Q-chains and Op-amps, compiling Linrad

Hi Zaba,

> It seems that the hash table is no show-stopper at present, according
> to Leif's recent observations. Lasse/OH5XP advised me to use additional
> commands like  xhost +localhost  as Knoppix does not allow direct root
> logins like in the old pre-version4 days. In between I ran 'alsaconf'
> for running sound. I get some xlinrad starts, but the following few
> error messages I get consistently:
> 
> When trying to save the parameters (W):
> 
> [1029]routine:thread_main  file: menu.c
> Failed to open/create the file par_user int
Seems you try to run as non-root. Surely that
should be no problem at all, but you need permission
to create a file in the currently logged directory.

Typical solution:

grep 1029 *.c

This will point you to a call: lirerr(1029).
(and perhaps a few irrelevant other things)

When looking it up you would find:
    file = fopen(userint_filename, "w");
    if (file == NULL)
      {
      lirerr(1029);
      goto menu_x;
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John Harrison, NI1B | 7 Jun 12:40

Latest Knoppix is 5.0.1


Hi All,

   Just loaded Knoppix 5.0.1. Much smoother than older versions. Haven't
tried linrad yet, but several other "difficult" programs just ran. Like
Microchip compiler student version under Wine, and Xilinx ISE, linux web
version.

   Looks like Klaus has really done it this time.

   There are two versions CD and DVD (4+GB) !! Right now I am running CD
version installed on HD.

   Have fun.

   john

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Jan Wedin | 22 Jun 10:45
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Missing par_xx_fg

Hi list,

I think I found a bug. Since 2-08 up to 2-14 the par_xx_fg file is not created. 

My operating conditions: Windows, Linrad 2-xx with normal audio or VLF input direct to microphone
connector, radio interface1.
Symptoms: Under windows I get reversed frequency axis in respect what is labeled on the scale. I.E. zero
frequency is to the right.
Reason: the file par_xx_fg is absent. xx is the mode, wcw or whatever.
Temporary solution: run 2-07 and create the file. Copy it to the recent version directory.

I guess it will be corrected in coming versions.

/Jan, SM4HFI

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