If you place different data on either sideband, its ISB which is illegal or if not now, may be in the near future.
However, if detecting either sideband independently does not produce separate data streams, then its not ISB. DSB would only double the information of one sideband so you would want to use the other sideband for more data. The question you have to answer is which is better...doubling, being redundant as with interleaving or sending characters twice or obtaining a greater bit rate or raw throughput. Another consideration is what would the bandwidth be with DSB where two 350 Hz PSK modes were sent? The bandwidth would be 770+ Hz. I think that you would still need a raised cos or filter on the transmit tones as well as a brickwall filter on the received signal. Noticed I said think because I haven't really had time to totally digest the use of DSB but I kinda like the approach. A 100 watt PEP DSB transmitter is sooooo easy to build. Using the FCC-2 oscillator as described in the Feb. QST, and a low level diode balanced modulator and several stages of amplication, you could easily build a 100 watt PEP (50 watts per sideband) transmitter. But the problem is finding an ISB receiver which you would need. Perhaps a direct conversion receiver with a Q/I (?) detector and DSP brickwall filter would work. Walt/K5YFW Paul L Schmidt, K9PS wrote: > For a simple transmitter, how about a sound card mode that uses the > sound card in STEREO mode with I and Q components on L and R channels, > feeding two balanced modulators, and build a phasing-type exciter > to do J2D type emissions? > > Maybe not quite as simple as AM, DSB, or NBFM, but probably pretty > close. > > A companion receiver could use the same scheme to produce a simple > I and Q output to feed to a sound card. > > And no crystal filters on either one... > > - ps > > kd4e wrote: > >>>Interesting. Run PSK on AM and you get two sidebands for diversity >>>reception and a pilot carrier. This could make building small PSK rigs >>>easier... >>>Leigh/WA5ZNU >> >>What about DSB or NBFM, same result? >>
