[linrad] Re: Linrad and the microwaves

[w3sz <w3sz@xxxxxxxxxxx>]

My use of Linrad on microwave has been most satisfactory but I am less 
experienced with microwave work than Arie, and probably less demanding.

As you know, the main problems with microwave activity are not noise, as 
they are on the lower bands, but rather:

(1) most often the station I am trying to find is quite a ways off 
frequency (e.g. in the last contest, 10 KHz or more)

(2) he is also often very weak and

(3) chances are he drifts a lot.


The combination of (1) and (2) makes it hard to find him initially, with 
a regular receiver.  If he is 10 KHz off a soundcard waterfall hooked up 
to the audio output of a conventional receiver just doesn't cut it, and 
trying to initially detect him without a waterfall is very difficult. 
With Linrad I can see 90 KHz and I always find him quickly.  I think 
this is a tremendous advantage on microwaves, and only Linrad has it so 
nicely.

The combination of (2) and (3) means that I want to use a narrow filter 
to improve S/N, but his drifting makes that difficult as he doesn't want 
to stay in the filter.  With Linrad and its nice AFC the problem is solved.

I used Linrad in parallel with my FT1000 receiver for the last contest 
(last weekend), as I had posted, and found that I could hear things just 
as well on the FT1000MP with its 60 or 120 Hz DSP filter as with Linrad, 
but I would have never found the way-off signals with the FT1000 were it 
not for Linrad detecting them and allowing me to put the FT1000 right on 
the frequency as displayed on the Linrad waterfall.  My parameters for 
Linrad may not have been optimal, but that had no practical 
significance, as everyone who could hear me I worked, and I found 
everyone's frequency very easily with Linrad.

I prefered this setup of Linrad in parallel to my previous setups of:

transverters and FT1000
transverters and Elecraft K2
transverters and DSP-10, and to
and I think to Linrad alone for this purpose.

Why the last statement?  Well the great noise reduction capabilities of 
Linrad are less important for this purpose because in my experience 
noise isn't a problem as it is on the lower bands, and I am more 'used 
to'  the sound of the signal in the 1000MP DSP window than in a narrow 
Linrad filter window, and find copying it 'easier'  on the 1000MP as a 
result.  Would this be the case if I had grown up with Linrad?  Probably 
not, but that's a difficult psychoacoustic question ;)

On two meters the noise reduction of Linrad is so important that it wins 
hands down in spite of this fact.

I apologize for not making any microwave "S" files during the contest. 
Too bad this thread didn't occur 1 week ago. Then I would have ;)

73,
Roger
W3SZ



>  

--
Roger Rehr
W3SZ
2 Merrymount Road
Reading, PA 19609
http://www.qsl.net/w3sz





LINRADDARNIL