[Lowfer] Lowfer transmissions ?

[John Andrews]

The catch in all of this is trying to stay within the regulations for 
the transmitters and still have a usable signal at a distance. You are 
limited to 1 watt DC input, and the transmitter PA needs to be at the 
antenna tuning network, lest the transmission line be counted as part of 
the antenna length.

The 1 watt DC input thing argues mightily for Class D or Class E PA 
configurations, which can easily be over 90% efficient. But they are 
non-linear, which is nasty to SSB signals and other non-constant 
envelopes. Of course, Class D or E is great for AM high-level 
modulation, but with AM, you are paying a substantial SNR penalty for 
the carrier and other sideband. Use of a linear PA for SSB or varying 
envelope signals is fine, but with efficiencies of 50-60%, you've lost 
SNR, again.

Regular speed CW was standard up until the mid 1990's, and was most 
successful in under 100 mile situations with low noise levels at the 
receiving end. But as homes and businesses got more electronically 
active, noise levels went up, and "copy by ear" got more difficult in 
many residential areas. Like mine.

Slow speed CW (QRSS), and SOME of the various digital modes can be very 
effective in low SNR situations, which is why they became "standard" for 
Lowfer use. Distances of hundreds of miles have been common, and some 
have obtained usable copy at 1500 miles or more.

But, if you've got some ham folks in town who would like to have a local 
net, an intercom, musical entertainment, or whatever, voice modes like 
AM or SSB are entirely practical, and you would be free from normal 
Amateur regulations.

John, W1TAG