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[linrad] Re: multiple instances of Linrad
- Subject: [linrad] Re: multiple instances of Linrad
- From: Roger Rehr <comcast.net; w3sz@xxxxxxxxxxxxxxxx>
- Date: Thu, 13 Sep 2007 20:15:54 -0400
Hi Bodo et al,
I guess this email is a long-delayed-echo, internet style? ;)
I assume this was re-posted because there is some interest, so I will
provide a brief update of where all of this ended up for me.
The original email was from April 2006 as you see. By June of 2006 I
was routinely running 4 instances of Linrad simultaneously on one
computer. This is possible using either Linux or Windows; I generally
use Windows for this purpose for non-Linrad-related reasons.
My purpose for this was/is to monitor constantly the 50/144/222/432 MHz
bands during a contest. This arrangement has worked great for that.
My initial configuration, in use for a bit more than a year, used 2
Delta-44's hooked to various combinations of the 28 MHz SoftRocks,
TimeMachines setup for 28 MHz, and homebrew 28 MHz front ends. Each 28
MHz receiver was connected to a different transverter, covering the
50,144,222,and 432 MHz bands.
I found that the Softrocks didn't handle well the large number of very
strong signals on 50 and 144 MHz that are present during a contest.
So for the past few months my configuration has been:
SDR-14 for 50 MHz
SDR-IQ for 144 MHz
Softrocks for 222 and 432 MHz
and this has worked well.
I had to reduce the bandwidth a bit on the SDR-14 and SDR-IQ to keep
them from locking up when run simultaneously, but I still have more
than 90 kHz bandwidth. The SDR-IQ needs to be started before the
SDR-14 or the SDR-IQ won't be recognized by Linrad.
I used this setup for the ARRL September VHF contest just ended, and it
worked very well.
I have it setup so that if I see a potentially interesting signal on
any of the 4 Linrad bandscopes, I just click on it and the audio of
course goes to my headphones. If the signal is one I want to work, I
type 'q' and the 28 MHz frequency corresponding to that station is sent
by Linrad over my network to my FT1000MP which is on another computer
so I can quickly work the station, and then go back to doing what I was
doing on whatever band I was on before I noticed the potentially
interesting signal on the Linrad bandscope.
I have another instance of Linrad running using the WSE hardware on
another computer that is used for the main band/receiver bandscope. It
uses a homebrew transverter to convert the 28 MHz signal from my
transverters for 50 MHz thru 10 GHz to 144 MHz so I can feed the signal
into the WSE hardware. That instance of Linrad uses another SDR-IQ as
The Softrock 28 MHz
was out of production very quickly, but there is talk of bringing back
a 28 MHz version, possibly now Tx/Rx!
In addition to less than ideal strong-signal-handling capability, the
original 28 MHz softrock was insensitive; see for example:
and I have to run a 28 MHz preamp before mine.
I will be mentioning all of this in the talk I will be giving at
Microwave Update on "A VHF and Up Operator's Discussion of Useful DSP
Software and Hardware".
Hope that helps, and hope to see some of you at Microwave Update!
There will be a lot of other people giving excellent talks:
Quoting Bodo Heyl <bodoheyl@xxxxxx>:
----- Original Message -----
From: "w3sz" <w3sz@xxxxxxxxxxx>
To: "Linrad mailinglist" <linrad@xxxxxxxxxxxxxxxxxxxxx>
Sent: Saturday, April 22, 2006 2:45 AM
Subject: [linrad] multiple instances of Linrad
The SoftRock v7s are so cheap I am starting to come up with all
sorts of uses for them in conjunction with Linrad.
One thing I had mentioned to Leif in the past was running multiple
instances of Linrad so that one could watch simultaneously the
'bandscopes' of each of the lower VHF bands at all times during a
contest. Now that X Windows and MSWindows versions of Linrad are
available, it is easy to display two or more Linrad windows on the
screen at the same time.
With a Soft Rock dedicated to each of 50, 144, 222, and 432 MHz one
would have things covered pretty well in terms of constant
monitoring of the lower bands during a contest [or just looking for
openings on each of the bands simultaneously at other non-contest
My thought is to have one computer and monitor dedictated to being
this 'full time monitor' using 2 delta44's as inputs [each Delta44
could handle 2 SoftRock cards and therefore 2 bands], and the
onboard sound for output, and constant simultaneous displays of the
Linrad bandscopes for each of these 4 bands on the screen.
With the appropriate selection of parameters [and the fact that for
MONITORING you don't even need to be clicked on a signal most of the
time] one should be able to run 4 instances of Linrad and not
overtax the cpu.
As I type this I am running two instances of Linrad with the Delta44
sending a different [I/Q] input to each and thus I am monitoring two
different receive chains displayed in two different
Linrad-for-Windows-Windows. Even when listening to both signals
with 96000 Hz sampling the CPU is happy and I am not getting
glitches [Windows XP, P4, 3.2 GHz, Linrad-02.6a].
So running 4 instances of Linrad at once with parameters chosen to
minimize cpu overhead should be no problem.
I put a screen grab of the two copies of Linrad running at the same
time, much as they would be displayed in this application, for your
The only glitch that I forsee would be if two Delta44 cards
installed at the same time are not handled properly by the OS. But
mAudio's site says you can have up to 4 installed at the same time.
If that is true, and if you had the cpu power...I will leave the
math to you ;)
I can't wait to get those SoftRocks! Its almost like free radio ;)
Maybe I had too much caffeine today at work. Have a great weekend all, and
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