----- Original Message -----

From: craxd

To: ham_amplifiers@...

Sent: Tuesday, January 09, 2007 8:09 AM

Subject: [ham_amplifiers] Re: hi power mobile

--- In ham_amplifiers@yahoogroups.com, "pentalab" ...>
wrote:
>
> One would think the logical way to go, would be a 24-26 v
system..
> instead of 12 v ?
>
> You could use something like 2 x cat batteries in series.... with
a
> 28 V... 3 phase alternator.

We made some tube mobiles this way back in the late 70's to early
80's. You took the 14V 3 phase AC and powered a HV transformer with
it. The large tube amps they use on those 11 meter shoot outs are set
up this way. Galaxy Transformer up in New Jersey makes the
transformers for several amp builders.

> You could still run the vehicle on the
> 12v from one battery. .... or run half the car's 12 v stuff on
one
> battery... and the other half of the vehicle's 12 v stuff.... on
the
> other battery.
>
> Even a 50 v system.. with 4 x batteries in series would work.

Yup, and you have way less current draw meaning you don't have to
handle all that large battery cable to hook a 12 volt amp up.

I also made what was called a motor maul which is really a voltage
regulator that ties to 2 banks of 12 V batteries in series. It works
from RF keying. During Idle, the batteries are in parallel and are
being charged by the alternator. When it's keyed by the RF sensing
circuit, it places the batteries in series making 24 V then runs that
through a variable series regulator. When using 2SC2879 transistors,
you can run them at around 18-19 Vdc and get Mo-Power from them and
they run just fine. At 12 Vdc, it cuts the power by about 1/4.
Heavier heatsink is recommended though when running one class AB at
18 Vdc.

>
>
> Later... Jim VE7RF
>

Best,

Will