[AMRadio] AM and power

[Bernie Doran]

It would be pretty difficult to be 25 KC wide without going into severe 
distortion, I have not spoken to Mr. Mouse or Mr. Bat lately.  Most male 
voices fall off at about 5 KC with occasional leaps out to 7 KC or so for 
certain syllables.   last I checked we are not allowed to play music, 
however I have heard some at the infamous upper end of 80/75.  Most of the 
wide signals that I encounter are SSB, probably over driven amps.  The 
broadcast stations that I look at with the SDR-IQ all seem to cut off at 10 
KC frequency response range, most receivers and transmitters  will not go 
that wide or pass audio that high.   It took me some time to find a receiver 
that would pass that bandwidth and audio.  The R390A with modified audio 
seems to meet what I wanted. It is usually set in the 8 KC position ( the 
actual filter passes 11 KC) ,  that sounds very good with a transmitter that 
is flat out to that or more. on very rare occasions The 16 KC position shows 
a slight improvement, usually means a home built or broadcast transmitter. 
I know at least one of our posters has a 75A4 with a bank of external 
filters, synch. detection and a HI FI amplifier, that probably sounds very 
nice. I suspect his IF is stagger tuned.  His transmitter (Triodes)certainly 
sounds excellent.   That brings up Triodes VS Tetrodes. I still believe that 
low or medium mu Triodes  simply have the ability to modulate( plate 
modulate) much better.  Especially the low mu tubes.  Hi mu Triodes and 
Tetrodes do not even come close to the square law plate characters needed. 
Eimac addresses that on the data sheets for the 3-1000, they state that one 
must modulate the driver also. That is when grid driven, of course, that is 
always necessary for a cathode drive config for all tubes.