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Friday, 14 June 2013

QRSSing Again

Well,

You may remember way back when I did some mucking about with QRSS (that's really low power slow morse):

http://g0mgx.blogspot.co.uk/2010/12/qrss-beacon.html

I've found another kit from Hans Summers:

www.hanssummers.com

This time it's an Arduino shield - so I can write and fiddle with the software to drive this myself.

Here's the kit as delivered:


it's very simple to make:




and here is the finished thing sat on top of it's Arduino host:


So, a bit of simple software to get the board to send my callsign in FSK QRSS mode, and we now need to align the beacon to be somewhere between 10.140.000 and 10.140.100 - that's quite a narrow band to aim at.

The easiest way seems to be to use the Argo software - it's a kind of spectrum monitoring thingamabob where you can set the offsets associated with the radio connected. So I tuned by FT5000 to 10.139.000 USB (because the carrier offset in USB is 1000Hz) and then entered that as the offset in the Argo software. I then adjusted the beacon to be at what looks like 10.140.060:


I dont really understand why I can see more faded images of the beacon in other parts of the spectrum, but the main beacon seems to be around 10.140.060/065. You can see the end of an "X" and then the start of my call again with a "G" then a "0".

Looking at the output of the beacon on my new Spectrum Analyser thingy, we see this:


The Analyser cant go to an accurate enough frequency, but it confirms that the RF peak is at 10.140 - so I am certainly in the right ballpark and my maths isn't out of bonk.

It looks good and clean on the 'scope too:


Might just take this back with me to A71 land and see what we can see. In the meantime I'll connect this to an antenna and see if anyone can spot me!

Fun, egh?

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