WSPR-beacon V3 / 1W @ 160-6m / based on Arduino™ & AD9851
From version 3.5.4 on the following new features are implemented:
- improved frequency stability due to temperature drift correction during transmission
- more precise transmission timing
- beacon can operate in day- or nightmode, automatically turning on/off about 1h after sunrise/-set
- a calibration mode can be activated to facilitate frequency calibration
What's new about WSPR-beacon V3 compared to V2:
- special attention was paid to using off-the-shelf components
- wide range of input voltage (9...24V) for portable/mobile use
- supports AD9850 modules (160-10m) as well as AD9851 (up to 6m)
- compensation of frequency drifts due to changes in DDS quartz temperature
I bought the cheap MMIC-based PA shown in the picture at eBay for a first test. It's specified for 1...960MHz but the MMICs used have a lower spec. of 50MHz!? I was surprised to find that after replacing the 5µH coils by 50µH ones it actually does work down to 1MHz, although distortions are significantly increased below 20m and definitely unacceptably high at 2W. If you limit the output to about 1W it's perfectly ok. But there are no doubt better alternatives.
» All details on the GPS beacon (you'll have to build this one first) » The beacon schematics & software (incl. all libraries) » Project "Astro-Clock" (for those who'd like to use the broadcast of the GPS beacon) » A digital clock synchronized by the remote GPS unit displaying time, date, in- and outdoor temp.
