> when n becomes big, the ratio tends to 1/square(n) 
> For example, for MT63 where you have 64 carriers in parallel, 
> You transmit only 12.5 watts with a 100 watts maximum XCVR.

The same applies to the digi-sstv hamdrm/windrm modes. 30 to 60 
carriers, crest factor (average to peak power) is about 10db.
On a 100w tx im running 10W to 15W average power.

Most hams use PA's with this mode. A 1kw pep amp runs an average 
power of only 60W for best SNR's. Increasing the average power will 
make the signal less readable due to peak-clipping.

It usually takes some time for beginners with those modes to realize 
and believe this.

The advantage of the mode is speed. 2400 bps with +10db snr, 1200 bps 
with +6db snr.

Reply via email to