Don't forget the Ameritron ALS-600 FET no-tune solid-state amp, which I
have used for about 2 years now. This comes with a power supply. I
couldn't be happier with it. I see around 900W out on peaks at full power
on 75/160M, and maybe 800W on the other bands. Key down carrier at
700W. I has performed flawlessly in daily use, including all the major
RTTY contests. However, I do reduce the voltage to the finals during
digital contests to keep the heat down. This does reduce the power
output. I do run it on 240v, which may have something to do with the
efficiency.
Jim W4LC
>>> David B. Ritchie <dbr@alumni.caltech.edu> 03/28/97 06:45pm >>>
Icom makes a very nice amp, albeit incredibly expensive and not quite
1500W
Japan Radio makes a nice MOSFET amp at the 1000W level -- also very
expensive.
The big problem with solid state is that you trade volts for amps and
volts are, at least for now, easier to deal with and cheaper than amps.
You should see the power supply for the 18Kw LARCAN they use at
KCBS-TV in Los Angeles -- if you dropped a monkey wrench across its
terminals, you'd wind up breathing the monkey wrench. The power
supply is huge -- much larger than the HV power supply it replaced.
BUT, the MOSFETS appear to be more reliable -- they fail, but only one or
two at a time, and because the entire installation is modularized into 1kw
plug-in modules, the techs just solder in new transistors when they feel
like it without bringing the transmitter down. Its very nice, but its not
cheap. Tubes are cheap. What is the most you could possibly pay for a
1500 W tube? $1200 - max -- less if you are willing to use surplus, used
or pulls (which we are all willing to do or this news group wouldn't
exist). You are not going to find $200 50W Mosfets available cheap,
used and surplus (which aren't fried like the one sitting in front of me
right now) for some time to come. And its harder to build -- a lot of stuff
all running in parallel on stripline or circuit boards rather than a nice
socket and some HV wire and a couple of vacuum caps.
Oh -- Ameritron has a couple of 500+W class amps for DC -- you have to
supply your own power supply -- probably best to just use a car battery
and a charger.
So to conclude -- current technology doesn't permit cheap desktop
1.5KW amps -- you can do it, but the desktop has to be pretty sturdy
and you pockets will need to be deep.
Dave N7UE
On Fri, 28 Mar 1997, Lee Buller wrote:
> I was listen to some guys on 75 meters the other night (Nothing was
good on
> TV) and they were talking about FET amplifiers. They seemed to be
quite
> informed about the subject. > > My questions is this...where is the
technology today to have a big old harry
> 1.5 KW amp with enough headroom that uses solid state devices?
> > I know that is broadcasting (AM and FM) a lot of rigs are being
produced use
> solid state devices. I know Harris, BE, Continental, Elcom/Baur and a
> others are doing this...on FM and AM. Why hasn't the designs made it
to ham
> radio?
> > Thanks for the comments....or flames.
> > Lee
> k0wa@southwind.net
> > > --
> FAQ on WWW: http://www.contesting.com/ampfaq.html
> Submissions: amps@contesting.com
> Administrative requests: amps-REQUEST@contesting.com
> Problems: owner-amps@contesting.com
>
David B. Ritchie, Esq.
D'Alessandro & Ritchie, P.C. -- Intellectual Property Lawyers
3521 E. Yorkshire Road, Pasadena, CA 91107-5432
818-683-8800 (TEL) 818-683-8900 (FAX) dbr@alumni.caltech.edu
--
FAQ on WWW: http://www.contesting.com/ampfaq.html
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
--
FAQ on WWW: http://www.contesting.com/ampfaq.html
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
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