[CQ-Contest] 1st legal limit amplifier

Radio K0HB kzerohb at gmail.com
Fri Dec 17 13:52:19 PST 2010


I'd second the motion on the Ameritron AL-1200.  It provides full legal 
output with 100W input and is much more forgiving than the AL-1500.  Tunes 
up quick and easily, and after about 15 years of contesting, mine is "good 
as new" and the tube is not showing any age at all.

73, de Hans, K0HB
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-----Original Message----- 
From: w7vo at comcast.net
Sent: Friday, December 17, 2010 6:33 PM
To: CQ Contest
Subject: Re: [CQ-Contest] 1st legal limit amplifier

Tim;

I guess the begging question is; "What is your budget, and how serious do 
you want to be?"

I am currently using an Ameritron AL-1500, which is one of the most robust 
amps out there for the price . It has a lot of gain, (45W in for 1500W full 
legal limit) output. At such low drive levels the exciter stays nice and 
cool, and the Ameritron barely gets warm at that level even during long 
runs. I have also an old Amp Supply amp which used to really heat up the 
shack during big contests. Those 3-500Zs put out 150W of heat just in grid 
current.....

The AL-1500 is a very efficient amplifier, but very easy to mis-tune and get 
a grid current spike, especially with a guest op or late in a contest when 
your eyes are not open fully. Using the overlays made by Idiom Press that 
give you numbers (0-100 graduations for the Load and Plate controls) instead 
of "band segments" does make band changes much quicker. (I keep a chart of 
all SSB and CW settings for each band and at hand). No, I do not work for 
Ameritron or Idiom Press....

That said, I think the AL-1200 would be my pick if I had to buy another amp 
in this class. It is less finicky about input power, (can take 100W) and 
with the 3CX1200A7 tube with much greater grid current capacity is probably 
easier to tune quickly. Others may comment on this, I have no experience 
with it other than what I have read.

Of course, you cannot beat a "two tube" Alpha 77, but for the money ....

I would not recommend the SB-2xx (Especially the SB-200) for any serious 
contesting, although others may argue the point. The power supplies are just 
not up to task in stock form. I had a good run of JAs going in the 1982 IARU 
contest with my newly built SB-220 and after a while you could smell the 
transformer baking. As any good contester would do, I turned the room's AC 
down as low as it would go (about 50 degrees) and kept going....

"Ah, I love the smell of melting varnish in the morning....." You knew you 
had a good run going.

73;

Mike, W7VO



----- Original Message ----- 
From: "Maarten van Rossum" <pd2r.maarten at gmail.com>
To: "Timothy Coker" <n6win73 at gmail.com>
Cc: "CQ Contest" <cq-contest at contesting.com>, "SCCC" <sccc at contesting.com>
Sent: Friday, December 17, 2010 2:39:41 AM
Subject: Re: [CQ-Contest] 1st legal limit amplifier

My vote goes to the Acom 2000a. Great, reliable amplifier that will tune
automatic and easily deliver US legal power limit.
It also has a very effective protection circuitry, you would have to try
very hard to damage this piece of equipment.

Acom website: http://www.hfpower.com/
Eham reviews: http://www.eham.net/reviews/detail/39

73, Maarten
PD2R


2010/12/16 Timothy Coker <n6win73 at gmail.com>

> Is anyone willing to share with me their experiences with their
> amplifier that they are using for contesting? My main HP contest
> interest is the California QSO Party, CQ WW WPX, and ARRL DX. I have a
> lesser interest in working DX through the week for all time new ones
> or new band/entities. During contests that I am not serious about I
> will S&P Assisted using point and click on packet/skimmer spots to
> hand out the points.
>
> My station setup is as follows:
>
> FT-2000, SB-220 (usually 800-400w output), Top Ten Automatic band
> decoder, Array Solutions Sixpack
>
> Antennas:
>
> F12 C31XR w/separate feed lines, Cushcraft A3WS w/30m, Cushcraft
> XM240, 80m dipole on top of 54' tower.
>
> I imagine having something that is easy to tune for quick band changes
> will be helpful while contesting. My current SB-220 is easy, but it's
> narrow and needs retuning as I go throughout the band if I want to be
> anywhere near my max output.
>
> Thanks,
>
> Tim, N6WIN.
> _______________________________________________
> CQ-Contest mailing list
> CQ-Contest at contesting.com
> http://lists.contesting.com/mailman/listinfo/cq-contest
>
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