[AMRadio] AM and power

[Todd, KA1KAQ]

On Thu, Jan 26, 2012 at 4:44 AM, Bernie Doran
<qedconsultants at embarqmail.com> wrote:

> 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.

And this applies to the nights that are relatively quiet enough to
listen in the wide positions. Unless I have a blowtorch signal nearby
on a noisy night like K4HX, the improved fidelity is lost in the
static crashes or adjacent frequency interference.

> 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.

Interesting. Collins built the early 30Ks with 75TLs for modulators
but changed to the TH. I've seen the TH used over the TL in other
places too, can't recall where. BC-610 maybe? Perhaps done
intentionally to throttle the modulation a bit at the gate?

~ Todd,  KA1KAQ/4