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Date: Sat, 19 Sep 2009 12:06:22 +0100
Message-ID: <fc7eccec0909190406r6b596274h8e84feed93216356@mail.gmail.com>
From: Andy Talbot <andy.g4jnt@googlemail.com>
To: rsgb_lf_group@blacksheep.org
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Subject: LF: 'JNT Dual purpose beacons
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I'm in the last stages of modifying my beacon to include a WSPR transmission
that will run pseudo-simultaneously with the 15 minute regular one at
503.7kHz

It has turned out to be posible to fit all the code into one controller PIC
which simplifies the hardware considerably - the only downside is that the
PSK31 message length has had to be shortened by a few characters to be able
to get the additional WSPR symbol and frequency information into the EEPROM
area of the PIC.

I've included to option to be able to transmit the WSPR signal at a lower
amplitude than the 15 minute beacon, and the pseudo random timing is
anything but - it has been chosen to fit round the 15 minute intervals, and
preferably not adjacent to them.

Before I programme-up the actual beacon Tx, can I have some suggestion on
the frequency that would be best to avoid existing users, and what sort of
power to adopt, bearing in mind the main Tx runs at about 100 Watts of RF
giving somewhere in the region of 24dBm ERP.  Also some idea of a duty cycle
to use - 50% is the maximum I've allowed for.

Andy
www.g4jnt.com

this email has been scanned for political correctness by the nanny state

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<div>I&#39;m in the=A0last stages of modifying=A0my beacon=A0to include a=
 WSPR transmission that will run=A0pseudo-simultaneously=A0with the 15 min=
ute regular one at 503.7kHz</div>
<div>=A0</div>
<div>It has turned out to=A0be posible to fit all the code into one contro=
ller PIC which simplifies the hardware considerably - the only downside is=
 that the PSK31 message length has had to be shortened by a few characters=
 to be able to get the additional WSPR symbol and frequency information in=
to the EEPROM area of the PIC.</div>

<div>=A0</div>
<div>I&#39;ve included to option to be able to transmit the WSPR signal at=
 a lower amplitude than the 15 minute beacon, and the pseudo random timing=
 is anything but - it has=A0been chosen to fit round the 15 minute interva=
ls, and preferably not=A0adjacent to them.=A0=A0</div>

<div>=A0</div>
<div>Before I programme-up the actual beacon Tx, can I have some suggestio=
n on the frequency that would be best to avoid existing users, and what so=
rt of power to adopt,=A0bearing in mind the main Tx=A0runs at=A0about 100=
 Watts of RF giving somewhere in the region of 24dBm ERP.=A0 Also=A0some=
 idea of a duty cycle to use - 50% is the maximum I&#39;ve allowed for.</d=
iv>

<div><br clear=3D"all">Andy<br><a href=3D"http://www.g4jnt.com">www.g4jnt.=
com</a><br><br>this email has been scanned for political correctness by th=
e nanny state<br></div>

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