The 70 cm band has become impractical to be used for ATV. The lowest band left is the 50 cm (UHF TV Channel 39 - 615.25MHz). As it is only 8 MHz wide, VSB TV transmitters need to be used.

With Digital switch over coming up in the next few years or so, we may not have access to this band for much longer. Another way to look at this is new mode new possibilities that digital television could provide. DVB-T is very good transmission mode and it would work in well for ATV. There is three levels of modulation with in the DVB-T standard QPSK, 16QAM and 64QAM. At QPSK level we would get very good improvement over the older analog AM for signal to noise performance.

Bands above 1 GHz

FMTV is used on all bands above 1GHz this done because of the improved signal to noise performance you get over the older AM. The sound subcarriers used are 6.0 MHz and 6.5 MHz. Where by the left sound channel is on the 6MHz and the right uses the 6.5MHz sub-carrier. RF bandwidth’s of 18 MHz is used on the 23 cm band to work into New Zealand TV repeaters.

Bands and their bandwidth are dependent on which band is being used. There are two bands that have more then 200 MHz of bandwidth. The 23 cm band falls within the IF pass band for satellite receivers. This is why I am using the same IF for my TV modulator designs.

The satellite bands S, C and KU are nearby in frequency to our ham bands. S band and C band LNBs are both have high side LO (local oscillator), S band is 3.65 GHz and C band has 5.150 GHz. Changing or moving the DRO inside its cavity causes the LO frequency to move. KU band LNBs with a 9.75 or 10 GHz L.O. are the best type to use for this conversion. This is a simple way to get started on the 3 cm band.