From: "Mike Dennison" <mike.dennison@rsgb.org.uk>
To: rsgb_lf_group@blacksheep.org
Date: Tue, 20 Mar 2001 10:24:11 -0000
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Subject: WOLF: Success and failure
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I tried out WOLF for the first time last night with total success.

Jim was sending GY(^%? JGGF, followed by H(*^RCKO KKl, followed by . . . . 

OK, so it wasn't quite as successful as I would have liked.

My first problem was finding the Command Prompt (pseudo DOS) on 
Windows ME. After 20 minutes, I located it under Programs, Accessories!!

I then successfully generated a test signal (WAV file) and 'received' it 100% 
as per the instructions. So WOLF is easy after all.

Now for the big test - real RF. Jim came up with his test transmission and I 
recorded it using Spectrogram but this didn't work. The problem seems to be 
that WOLF needs a sample rate of 8kb, and Spectrogram doesn't do this rate. 
An hour later, I used Cool Edit (a nice program) to generate a usable WAV 
file of Jim's signal. 

Several hours later I gave up, having failed to read anything at all from Jim.

Possible causes: Jim's signal is very strong so possible sound card level 
problem. Also I may have been a long way off frequency (see below). Will test 
further tonight.

Getting the correct audio frequency proved difficult and I only fixed it this 
morning after breakfast. I can use BBC 198kHz to calibrate Argo to measure 
a 136kHz signal to much better than 1Hz, but could not find an easy way of 
measuring 800Hz!! First I believed the Argo readout at 800Hz, but later tests 
showed this to be a long way out (this is not a complaint against Argo). I 
finally listened to DBF38 on AM and beat my DDS against it, then used the 
resultant 800Hz beat note to calibrate Argo. Later I found the offset facility on 
my IC-706. This sets the audio frequency for comfortable CW reception - 
normally about 400Hz. Setting this to 800Hz gave me 800Hz audio to within 
half a Hertz with the RF dial set to the correct frequency. Now why didn't I 
think of that in the first place?

Some thoughts on WOLF:

It looks very useful and I think it may well be the mode for the 2001/2002 DX 
season (though I will still run CW and QRSS).

The command line is hard work and needs a lot of interpretation. I am sure 
there are programmers out there who could provide an easy display with 
'switches' and 'dials', and some automation of the variables to optimise 
reception.

Transmit is a bigger problem if you cannot generate high power SSB at 
136kHz. Jim has cracked the problem with his Decca (Class D), and I look 
forward to him publishing his modulator circuit. His signal is VERY clean with 
me only a few km away.

We will need to devise a protocol for QSOs.

We will also need to find a way of having 'random' QSOs. At present the 
frequency must be known accurately in advance and monitored for a very 
long time. This is not viable if you don't know there is someone transmitting.

I find WOLF fascinating and challenging, whilst - at least on receive - not 
needing huge amounts of work to get going.

I hope Jim will continue his test transmissions to get more people set up.


Mike, G3XDV (IO91VT)
http://www.lf.thersgb.net