[TenTec] humm

[Dr. Gerald N. Johnson]

On Thu, 2009-11-26 at 07:38 -0600, Lyle Dunlap wrote:
> I always thought a power supply sitting beside a transceiver analogous to 
> a car battery in the passenger seat.  Only my humble opinion of course

Only a warped opinion. Since many a power supply has included the
speaker (at least since Collins introduced the 516F-2 in about 1959 with
speaker in the power supply cabinet) its been appropriate for power
supplies to be adjacent to the radio. Having the speaker anywhere else
makes less sense.

And as a practical matter whether feeding 15 amps of 6.3 volts to a
gaggle of tubes or 20 amps DC at 13 volts to a solid state PA, keeping
the power supply leads short often makes the radio run better. Voltage
drop in the DC supply causes reduced power output and increased PA
distortion and that can come from tube heaters running cooler than they
were designed for. Many a modern radio has excessive voltage drop with
the factory power cable.

It appears the problem with some Tentecs is only when the power supply
is adjacent to the audio stages of the transceiver or to a poorly
shielded dynamic microphone. I might say the audio stages if sensitive
to the power supply's magnetic field are also poorly shielded. The
magnetic fields from many a CRT are greater than from many a power
supply.
> 
> Happy tks gvng ev1
> W9FCX
> 
73, Jerry, K0CQ