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Date: Tue, 2 May 2000 23:48:32 +0200
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Data: Tue, 02 May 2000 22:26:12 +0100
To: rsgb_lf_group@blacksheep.org
From: "M. Bruno" <spin@inrete.it>
Subject: Re: LF: IK1ODO beacon signal
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In 14.02 02/05/00 , hai scritto:
>Friday (28 april) arround 22UT I had a good copy of Marco's 10mW signal,
>both with Spectran and Spectogram.
>Some screenshots can be found at my webpage :
>
>http://www.qsl.net/on7yd/IK1ODO/ik1odo.htm
>
>Although, based on the difference in bandwidth, Spectran was supposed to be
>7.5dB better I had the impression that the difference in SNR between
>Spectran and Spectogram was less.
>Further I noticed that launching another application while running Spectran
>caused a kind of 'frequency shift' (see screenshot at my webpage).
>
Alberto found this same problem, but he says that debugging will be difficult,
and will probably take some time. Incidentally, he is releasing a new "beta"
version (beta3).

>Finaly I want to thank Marco for the beacon signal, it gave many hams the
>opportunity to do some testing and proved what can be achieved with 10mW ERP.
>At the risk of being 'greedy' I would suggest following to Marco : would it
>be possible to have a series a characters at reduced power after the call ?
>eg. : 'IK1ODO X Y Z' where IK1ODO is tranmitted at 10mW ERP, X at 5mW ERP,
>Y at 2.5mW ERP and Z at 1.25mW ERP (of course any other 3 characters can be
>used).
>
>73, Rik  ON7YD
>
Rik, I will take this seriously. What about writing a modified version of QRS
to command an attenuator and step power levels?
I may build a linear amplifier, of some 10W output, and reduce the power
in four steps of 5 dB (3W, 1W, 300 mW, 100 mW for instance).

The big problem is to have an automatic tuning. I started the beacon
on Thursday evening, then left home Friday, and it was raining; so I had to
raise the power, since the aerial current was down from the nominal.
The rain stopped on Saturday, and the antenna current rose to (probably)
+5 dB respect to Friday evening. I was not able to transmit a fixed power
level;
my station currently can't run unattended (in effect, my wife was attending
and checking for smoke, HI).

I returned home by Tuesday, and found the tuning of the variometer 
completely different from Friday.

Thanks to all for the reports. I think we have to go on.

Well, Rik, what signal may we use to change the power levels ? go to
the parallel port, or use an UART on the serial ?

73 - Marco IK1ODO