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[linrad] UKSMG / 50 MHz and low-VHF Linrad ; Re: [linrad] Linrad-02.14

Sir Leif & others!

As Linrad/Winrad is a very effective tool in my opinion especially in the lower
VHF-range (due to the existing amplitude-ratio of signals and noise-levels), I
have generally posted the newest developments of these software packages on the http://www.uksmg.org/announce_cs.php UKSMG pages. As radio DX-peditions to rare
spots very often hit environments with a poor electricity network and a lot of
interference sources, it would be nice to have some ready dedicated hardware
packages to allow these expeditions to enjoy optimum reception during difficult periods of the expedition. Possibly this would be an eye-opener for some hardened experienced operators and thus an inspiration for effective future VHF-operations.

Given the old times with "just" Linux and Linrad, I noticed that with the given time and energy I was generally spending all my attention on the software. Then with time the knowledge base (personal memory) is decaying and there is just so
much that one remembers from the past "lessons" and documentation. Generally I
have seen about 1 second delay when starting Linrad with default parameters and 48000 kHz sampling. Can you tell us, Leif, what we give up in reception features
if delays are reduced to the values you mention in your May 27th comparison?

                                               73, "Zaba"  OH1ZAA/2

P.S. At the moment I am assembling an oscillator for a Finnish 70 MHz beacon.
     It would only be a small step to make a few 50 MHz oscillators and make
     the I/Q-chains ready for 50 MHz.... generally some priorities take over!

OH1ZAA-posts to UKSMG  >>>>>>

Linrad 2.14 --- As a follow up to my previous (May 22d) message I am forwarding Leif/SM5BSZ's announcement of his latest Linrad version. The files are available through http://www.sm5bsz.com/linuxdsp/linrad.htm ----- For years the only option was to use it through Linux, but now the Windows version wlr2-14.zip will permit to have it up and running in a minute.... However, it still takes a good deal of time to understand where all the functionality of the whole package is located and how to optimize it for optimum use (there are "hundreds" of pages on his site to study that) .... Leif has a new page http://www.sm5bsz.com/linuxdsp/usage/ldfw/ldfw.htm describing the use of Linrad with various fast and also very slow computers --- For Windows users it may be a good and easy start to begin with Alberto/I2PHD's Winrad 1.0 (build 22) http://weaksignals.com/ ..... If you would like to know what Winrad/Linrad can do for you in a city environment or under other circumstances with man-made noise, then you should download and compare the two MP3-files at the bottom of the Winrad-page --- If Winrad works well for you with simple hardware, then you can switch over to Linrad for even more robust noise removal.... You will need very little hardware (a preamplifier, a couple of crystal oscillators, a direct conversion I/Q-mixer, and a 96 kHz soundcard) to beat the performance of very expensive commercial receivers on 50 MHz with these noise-canceling features .... Hopefully someone will publish a homebrew design soon (focused on 50 MHz) ... Some people have had good success with newer versions of the SoftRock-40 kit serving as a transverter-IF ----- 73, "Zaba" OH1ZAA/OHoMZA ----

 - Saturday, May 27 2006 at 20:06 (GMT)

Winrad/Linrad-updates: The Summer_Es_season has definitely started on the VHF-bands. Many operators would like to improve on their noise suppression, and the tools for that are now near and easy to implement..... Alberto/I2PHD just released the new
build 22 for Winrad 1.0 and Leif/SM5BSZ's Linrad has already progressed to the
multi-threaded version 2.13, which fully works with Windows as well.... Both
software packages are very small and installed within a minute ---- I do not
want to take space and repeat my February/March_2006 postings on this subject
[but you can easily find those by filling in the Announcements-search on the
right: Show Postings in Last 111 Days by Callsign OH1ZAA ... contains download
information and important information for optimal functionality]... The most
important aspect for man-made noise canceling is to take in as much bandwidth
as your sound card can accept (narrow pre-filtering would take away the
software's superb properties) ---- Good DX to all! 73, "Zaba" OH1ZAA/OH5ZA ---

 - Monday, May 22 2006 at 09:22 (GMT)

At 20:22 27.5.2006, SM5BSZ wrote:

Hi All,

Linrad-02.14 is now available at the usual locations:

The g7rau site does not work with Firefox but it
is ok for Internet Explorer.

Linrad-02.14 contains various fixes for new places
where OSS may store header files, for different screen
sizes under X11 and Windows and for better real-time
performance on slow computers.

I have tested Linrad-02.14 under Linux 2.4 and 2.6
with svgalib and X11 as well as under Windows 98
and Windows 2000 under extreme graphics load (fast
waterfall) as well as demanding timing (short
processing delay from antenna to loudspeaker)
These tests show what can be expected on Pentium IV,
Pentium III and Pentium II at 2700, 650 and 350 MHz
respectively. For details, look here:


This page is completely rewritten. The poor result
for Microsoft Windows on the previous version of
this page was due to the needless buffer usage bars
that were displayed when "T" was pressed to get timing
info. (These bars are now a compile time option in

Please download Linrad-02.14 and check whether it works
on your system(s). Save all parameter files first because
Linrad-02.14 may force you to change them. It may be
a good idea to use a text editor to restore parameter
values in the new parameter files.


Leif / SM5BSZ

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