[CQ-Contest] 500 Watt Amp or 1500 Watt Amp

Timothy Coker n6win73 at gmail.com
Sun Jul 15 17:31:36 PDT 2012

I asked this same question about two years a go to my local contest club
and also this reflector... I say that because I went through the same
thought process. Tune up time, budget, tracking, reliability, repairs, etc.

In the end I bought a used Acom 2000A for Radio A after using an SB220. My
friend has also loaned me an Alpha 78 semi-autotune amplifier for Radio B
that puts out 1200-1500 watts. I am happy now and will one day replace the
Alpha 78 with another Acom 2000A for reasons of similarity of parts /

I like SO2R and also enjoy hosting MS or M2 at my QTH. The auto-tune full
power amplifier is a great treat. No more tune up time thoughts and cheap
replacement tubes with service available in Texas. The older Alpha has
tubes that I hope to never have to replace for my buddy because of the
availability and excessive cost.

500w vs 1500w is something like 4-5dB increase of power. I absolutely want
that for my run radio. The mental idea of would 4-5dB help me while calling
CQ on a "dead" frequency would haunt me in every HP contest. Would it
always make a difference? Absolutely not... but when I feel loud I am

Also remember that you level the playing field. Most other serious HP
competitors stateside are running at least a KW. Being -3dB for quick tune
up is not a good trade off in my mind. You will save minutes of tuning in
each contest for a noticeable decrease in signal strength when conditions
are marginable or your defending your run frequency. Even when you change
bands quickly during S&P with your marked manual tune presets you will have
800-1000w output (with say an AL-1200) versus never more than 500w with the
solid state.

Then there is SWR issues. I have used my tubed amplifiers (including the
Acom 2000a) into swr's of 6:1 so long as I kept the reflected power down
below the manufacturers stated limits. You won't do that very well with
solid state amplifiers. If you do want that flexibility then you need a
tuner in front of the amplifier... more expense and things to fail during
the contest.

Where I am left with now in my understanding is that if I wanted to keep
the budget down I would buy a used AL1200. If I had the bucks I would buy
an Acom 2000A or possibly an Alpha 9500 (I love Alpha, just not that well
versed in this model). This way you will never wonder about what if in
regards to power. The autotune is great, but honestly if you have good
antennas you tend to run for a while with band changes well timed and
prepared for in advance. When you move a guy from band to band you can use
your hand made quicksets if needed, but then again he is already listening
for you and 100w often works fine.

I am writing this from my phone in my truck at the car wash so please
forgive me on the format of the message.


Tim /N6WIN

On Jul 15, 2012 4:38 PM, "Richard Thorne" <rmthorne at att.net> wrote:

> Hello Group,
> I'm finally building my first serious contest station after hamming for
> over 30 years.  My wife and I moved out to the country last August to a
> lot with no restrictions.  My first tower is up and I'm planning a 2nd
> soon.
> I'm looking at amp possibilities.  My rig is an Elecraft K3 so the
> KPA500 looks intriguing in that it will follow the rig and I won't have
> to tune it, i.e., quick band changes.
> Is 1500 watts really worth looking at?  I could go the Acom 2000a or
> Alpha route, but that's not quite in the budget now.  So I'm looking at
> the Ameritron AL-1200, 1500 or other comparable amp. The disadvantage is
> tune up time, but I'm not sure that's really a big deal.  I've operated
> at K5NA for years and it doesn't take much to tune to a different band
> using pre-marked settings.
> So the question, does the extra 1000 watts make a difference? as
> compared to the ability to make quick band changes using a solid state amp?
> Thanks
> Rich - N5ZC
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