My design. It's quite preliminary since I've been working on it for maybe half an hour so a few new stuff might be included in the future. Anyway this version has a low pass filter at the output so the harmonics problem should be eliminated plus i tried to use as clear signals as i could so not much harmonic distortion should come from the first stages.
Anyway some of the specs are:
- Output power - 4W
- Power draw - 10W
- Modulation depth variable from 0-100%
- Efficiency - considerably good at 40%
- Range - depends of terrain but could go as far as 50km at the right conditions and if using a DX antenna you could get a few hundred if not even thousands of km (again with the right conditions)
- Antenna - either dipole antenna with 2x40m long wires or loop antenna. There's a trick you can try and apply, by using a loop antenna with inductive reactance matching 50ohm at the given frequency, to somewhat fool the transmitter into believing that you have the right kind of antenna. Must warn you though, the efficiency will be extremely low, and a lot of standing waves will form at the output.