[Moon-Net] SDR-IQ and Linrad

Serge Szpilfogel ve1kg at eastlink.ca
Tue Aug 14 21:36:12 CEST 2012


Ian you apparently live in noisy place. No Rf front end like noise whether
it is Hardware front end or your FT736 which by the way has a good noise
blanker so I am told. What I would do first is to use your FT736 with the
mast mounted preamp & try to identify your noise sources. Is it in the
house? Or is it outside the house? Drive around the neighborhood with an AM
radio or walk around. Make sure you have a good ground. I mean a GOOD ground
using 4X6 foot rod tied together with HEAVY copper wire. Also make sure you
have no ground loops. I also would ground the computer as well. Every pieces
of equipment should be connected to a common ground. Once you identify the
noise sources then you look for a solutions. It could be leaking transformer
on a pole. It could be a high voltage line not far from your home. Then deal
with it if you can.

No SDRIQ or IQ+ or any hardware software front end will solved the problem.
Now Linrad is apparently very helpful l& has a great noise blanker so I am
told etc..etc.. But it appears that even that is not enough in your case. So
if I was in your situation I would simply deal with the noise sources FIRST
before you deal with hardware/software front end. It compounds the problem.
Another question what are your Smeters readings with preamp ON & OFF?? As to
the IQ+ I am very happy with it & the combination of the IQ+ & MAP65 is
truly great. Again the IQ+ like any other software front end do not like
noise. The noise blanker on MAP 65 works well for me but my noise level is
almost nonexistent unless I turn my antennas towards the house Since the
house is south of my antennas I am always elevated at that point.GL & stay
in touch.

Serge/VE1KG

 

PS:" I have done so much with so little for so long that I believe I can do
anything with nothing in no time" VICTOR HUGO

-bounces at mailman.pe1itr.com] On Behalf Of Ian McCloy
Sent: Tuesday, August 14, 2012 16:19
To: moon-net at nlsa.com
Subject: [Moon-Net] SDR-IQ and Linrad

 

Just an observation in regards to using an SDR-IQ and Map65 2.0

 

I have been running Map65  and Map65-IQ  for the past few months as many
have seen by my posts in regards to the RX

 

Over the past few months I have been running Linrad 3.38 and Map65 2,0  and
this was all setup for me by Russ  K2TXB

 

I live in a noisy environment as tested by Lionel VE7BQH   as I use a
pre-amp built by Lionel using 1802 gasfet  .25nf/19db

 

I have had little success in decoding anything when running Linrad 3.38 with
Map65 2.0.  Russ reset everything up for me after I messed up a few setting
and 

 

still minimal success in getting decodes.

 

I switched back to Map65-IQ and Linrad 3.05 and I am starting to see decodes
again even though 1 KHZ above the actual TX frequency

 

It seems that Linrad 3.38 and above with Map65 2.0 doesn't like my noisy
environment while Map65-IQ and Linrad 3.05 does

 

Not being of a technical or mathematic guru.  Wonder if someone can tell me
why   one version of the software works and the other does not.

 

I am at the point of total frustration like Serge  VE1KG was at a short time
ago.  I can not use any lna that has more than 19db of gain as anything
above causes over load of

 

the front end of my 736R

 

With the money invested in a Khuene transverter and the SDR-IQ   btw  the
transverter is extremely stable(model TV28-144)  circa 1990

 

There must be a way to get this software and equipment to work properly.
If anyone needs to understand my system it would be better to email Lionel
VE7BQH and

 

he can fill anyone in with all the necessary details as some of what is
going on I would have a hard time explaining

 

Running a pair of M2  XP20s with RX line about 12 meters in length using
LMR-400 as a separate RX feeline going into a DCI 145 bandpass filter

 

I just want to get this gear working period  

 

Thanks  Ian VA7SW

 

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