LF: 'JNT Dual purpose beacons

[Andy Talbot <andy.g4jnt@googlemail.com>]

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

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