Today I completed my first keyed optical beacon transmitter (with 100mm optics) which I'll be
using for tests at greater range than hitherto. The 481THz
(red light) beacon sends my callsign in either 10wpm CW, QRSS30 or
QRSS60 as well as a continuous carrier or a 30sec on/off sequence. The TX uses a sub-carrier of 1.082kHz or 8.659kHz, the frequency being derived from an HF crystal divided down in a 4060. The message comes from a K1EL K-ID2 programmed PIC. Initial tests this afternoon at dusk allowed me to copy the 1.082kHz 10wpm CW sub-carrier signal by reflection off a wall across the street at decent strength.
My next challenges are to find some local paths of a few kilometres to check the beacon and the receiver. I'd also like to try some non line-of-sight paths, possibly including cloud-bounce.
Showing posts with label beacon. Show all posts
Showing posts with label beacon. Show all posts
29 Jan 2012
25 Jan 2012
New beacon chips arrive
Today my new KID2 pre-programmed beacon ICs arrived from www.k1el.com . These are for use in my VLF, 136kHz, 500kHz and 481THz beacons. With 7 pre-programmed messages in 10wpm CW, and various QRSS speeds these are ideal. I have used these before and been very satisfied. See http://k1el.tripod.com/files/kid2man.pdf for more details of the ICs.
6 Jan 2012
OPERA - new weak signal beaconing mode
There is a new very weak signal beaconing mode being trialled currently on 136 and 500kHz called OPERA. The current version is available as a zip download at http://www.mediafire.com/?w74a061m48nv806 but this is a beta version and updates are happening quite fast at the moment, so best check the RSGB's LF reflector for the most recent version from Graham G4WGT.
Initial indications are this is even better than WSPR, which as we all know is an excellent QRP beaconing mode. I managed to decode SM6BHZ (just under 1000km) and PA0A tonight when using just my 20m separated earth electrodes (no antenna in the air here at all) on 136kHz.
Over the weekend I may give this a go with a few mW ERP on 500kHz and, when I get my vertical loop re-erected, on 136kHz too.
Early days yet, but a most interesting mode that does NOT need critical PC timing (unlike WSPR) and that can use the PTT line or VOX control to key the TX i.e. it is simple to interface rig to PC.
Initial indications are this is even better than WSPR, which as we all know is an excellent QRP beaconing mode. I managed to decode SM6BHZ (just under 1000km) and PA0A tonight when using just my 20m separated earth electrodes (no antenna in the air here at all) on 136kHz.
Over the weekend I may give this a go with a few mW ERP on 500kHz and, when I get my vertical loop re-erected, on 136kHz too.
Early days yet, but a most interesting mode that does NOT need critical PC timing (unlike WSPR) and that can use the PTT line or VOX control to key the TX i.e. it is simple to interface rig to PC.
17 Nov 2011
A local 478THz (red light) beacon !
Map showing coverage of the 471 THz optical beacon GB3CAM |
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