Transmission of NBTV is limited by the transceiver used. There for the frame rate and resolution is some what limited. Most if not all users have standard SSB HF transceiver and a sound card. At this point I will explain the problems that apply to NBTV.
Modulation system used Orthogonal Frequency Division Multiplex (OFDM). The FM carries is dependent on the number of lines in the picture, one line per carrier. There two formats that I like there both 96 x 72 line. One is the RGB 3 pilot carrier; this mode takes 9 seconds per frame. The other is 96 x 72 line, colour difference 2 pilot carrier; it takes 4.5 sounders per frame. Under good conditions both modes work very well, when the signal is week the RGB mode butter of the two. On 20 meters under stable conditions colour different mode is faster one. Problems to look out for when setting up Con (ZL2AFP) software, I have listed below.
1 Linearity of the sound card that is used, not all cards are the same. By experimenting with different type of PCI cards I found that the Creative labs sound Blaster is best to use. Next the linearity of the HF amplifier, more power is always the answer. ALC auto gain controls can a problem as well.
2 Frequency stability is very important the modulated carriers are only a few hertz apart. Older VCO transceivers are a problem for this mode. For receive you need to within one hertz of the transmitted frequency. With both modes there is a turning window and a find turn slider to centre up on.
This TV mode can only get better over time. The plan is increases the transmission bandwidth up 10 kHz. Sound has been work on in time this will be added. One frame per/sec at 96 x 72 colour is a good possibly over wider bandwidth. By using software defined radio I & Q transceiver or Soft-rock kit will give freedom in this area
These software require .rar decompression software ie. WinRAR
RGB 3 Pilot Carrier 9 Second Mode: download here CLICK HERE
Color Differance 2 Pilot Carrier 4.5 Second Mode: download here CLICK HERE
Some more NBTV are listed on the Software page.
-Low quality compared to regular TV
Probalby best on local VHF but can be accomplished on HF as well.
Mode Audio Sample
FFT Window Screenshot