[TenTec] Tx IMD and Purity

[Robert Mcgraw]

Rick, on point #1, why internal?  .....less boxes, less cables, less
connectors, reduced or eliminated ground issues between equipment,
dedicated power supply designed to do the job and not some kludged up
piece of noise generating crap.

Audio amplifier designs that produce significant amounts of power all
have been using bipolar +/-36 volts to +/-56 volts for years.  They for
the most part use switching supplies internal.  No reason ham
transceivers can't follow suit.  Even a +50 volt supply would be
preferable for a transceiver.   Self regulating, auto line voltage
sensing, works between 95VAC and 250VAC with no changes.  Current
limited.ll medium and large box radios should run off of 48v.

In the case of the L4B and external PS, voltage requirements and single
piece weight would be my take.  The current legal limit amps today
typically have internal supplies.

The other stuff, cheap designs {not price} do not typically yield good
overall results.

There is one very popular and current model radio introduced less than 2
years ago that is being sold in the US today.  Regarding that model, in
my testing, as well as tests conducted by others, it does not meet FCC
purity regulations.   It emits a significant amount of broadband noise
from 0.5 MHz to over 30 MHz when it is in transmit.

Issues such as these contribute to band noise and general RF pollution.


73
Bob, K4TAX