[AMPS] My 3CX3000A7 in the mobile.

[philip de cadenet]

>I have a 240 HP turbo-diesel large Ford truck, with 200 amperes 14 
>volt electrical system.
>
>What I am doing is charging a set of four batteries to 50 volts via a 
>switching supply, and running 16 MRF150 FET's at 2400 watts.
>
>My problem, on 160, is arcing across the coil and the coil support 
>as well as corona and RF burns even from touching the truck. I have 
>however, worked Europe and VK on 160 mobile. 
>
>I can not imagine 10 kW, except on ten or twenty meters.
>
>73, Tom W8JI 
Hi Tom,
Yes, even with our little SGC cube or the homebrew 8-pill (2SC2879 unit
we can draw 1/2-1" arcs from the body of the van. 
At the present power level we have just about got a handle on the corona
problem but feel our next jump in power level that we'll be onto the
copper wc systern ball department.
If your coil is arcing, increase the coil spacing and add some more
wire/copper tubing to make up the inductance, what's the problem?
I'd thought about the FET route but my experience with switch mode psu's
is that RF gets into the the ps and the regulation goes to pot. Did you
wind your own transformer and what did you do about filtering all the
noise that must drown your receive (or iss it only ioperating on
keydown?).
The other problem with eight MRF150's, I have'nt got my RF Parts cat
around, is the price. I can replace my 2SC2879's for $129 US, all 8!
I appreciate the improvement in IMD though with your 50v devices.
What config of antenna do you use on 160m?
I was considering a 16 X 2879 unit which I reckon would be good for
around 2-2.5KW out.
You are about running at the max for a real 200 A alternator.
I can pull nearly 150A with my 8-pill at 14.6V measured on keydown.
I have full current measurement via a 300A shunt to a digital LCD.
Beyond 16 pills I really do think tubes are the way to go, there really
is no argument.
The largest solid state amp that I have come across is a 96 X 2SC2879
unit, it took the guy several days to match the devices, 64 pill units
are commonplace.

                                         So many toys,
                                         So little time
                                         and So little money.
73

Phil  G4ZOW.


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