>I am not sure exactly what they use. Some are using military surplus,
>others use alternators designed for emergency vehicles such as
>ambulances.
>
>I would start with those categories. The next time I run into one of
>those guys I will ask for some specific details.
>
> A 3CX3000A7 mobile xfmr is rated at 3500VDC @ 1.5A @ 14VAC input. It
>is not small, and weighs in at 53 lbs. Price is $379 ...so I have heard..
> The 11M boys allow the input volts to vary and are designed with 25KV
>insulation. At alternator frequencies it is an easy task to filter the
>DC. Many simply use K2AW diode blocks and hope for the best and others
>use real diodes of the 3A and 6A variety.
>
>Filament V is derived in many ways. All that I know of use a stock 95A or
>similar alternator along with the big one. Some use an inverter and a
>standard 51A xfmr. Others use a seperate 12V battery, mounted in the rear
>with the amp, with a trickle charger and a resistor to obtain 5V or
>whatever voltage they need.
>I have personally witnessed mobile installations up to a 3CX20000A7. The
>3CX10000A7 is 2nd in popularity behind the 3000 and the 6000 is gaining
>in popularity.
>Others go the tetrode route and anything from the 4CX3000A and up is fair
>game.
>
>I have also seen installations with 3 to 5 big alternators and a racing
>type serpentine belt driving them all. This is not for the small engine
>category. The GM 350 ci engine with a forged crank will snap. They use
>steel racing cranks and/or 454 ci engines.
>Popular vehicles are Chevy/GM Surburbans and vans. Others like Dodge.
>Ford is not very popular and NO ONE would be caught dead in a RiceBox.
>
>These guys are serious and spend big $$$ .
>
>After all it is just a hobby!
>73....Carl KM1H
You see Carl, IMHO moving out of 11m and up the ham ladder seems to have
an inversely proportional effect of losing ones sense of humour!
Yes, I'm aware of most of what you say above. I have a friend in LA who
runs a serpentine belt driving 4 X 200 A Leece Nevilles to power 6 X
8877's at around 24KW DC I/P, around 16KW out through the Bird.
I've been doing some history research on who were the early high power
mobileers on 11m and have come across a chap still up there in the windy
city who is no longer allowed to take part in his local shootouts.
He currently runs 2 X Lexidyne locomotive 450 A generators for the main
output stage, a 250 A for the driver and can keydown around 120KW. At a
recent shoot he ended up racing the official champ in a friendly grudge
afterwards. The official champ, a guy called Dave out of NJ who builds
competition amps was, believe keying around 50-60KW, when our man's
carb backfired and his generators started to slow down. He reckons he
lost around 40KW because of the slowdown but there was still not even a
whisper of Daves audio underneath the 80KW signal.
Kind of brings a smile to your face.
I'm sure the guys family must all be sterile by now!
Phil G4ZOW
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