Hi folks,

There is a reason to use a big tube in an amateur amplifier. I have a six meter amplifier that uses a 3CX3000AA7.  It uses the shorted turn tuning method with a copper tube that moves in and out of the PI-L coil. It was used in a multi op station where operators were unfamiliar with the equipment. They also never looked at plate and grid meters! A 3 by 3 is not a huge tube as in the 160 meter amp being discussed, but it is capable of making lots of power. It has 13.0 dB gain at 50 MHz. The loading cap etc is set to run it at 1500 watts and it needs about 65 watts of drive. There is no way an operator can over drive it. There is also no way anyone can get more than 1500 watts out of it without going inside and tweaking the loading cap values etc.  In short, it is a perfect contest amp. It is clean and produces no splatter. I do the same trick with a single band 10 meter amp used on that band. It is designed to produce 1500 watts of very clean RF and is not capable of being over driven with my K3 exciter. At one point in a ten meter contest, I was called by the op at K1RX on ten meters. He said it was the cleanest amplifier that he ever heard. K1RX was seven miles away, all downhill, and there was basically no splatter.  All my old amps with smaller tubes had issues with over driving and more with ops who were great contest ops, but never watched plate and grid meters. 4CX250B, 4-400, 4CX1000 and small triodes etc all had issues.  I am temporarily off 160 now. I am hoping to be QRV again soon.

K1WHS

On 6/24/2026 7:01 AM, Peter Voelpel via Topband wrote:
How should that be possible?
Splatter are not caused by signal strength but by poor signal purity.

73
Peter

-----Original Message-----
From: Topband [mailto:[email protected]] On
Behalf Of Bob Abernethy via Topband
Sent: Dienstag, 23. Juni 2026 02:43
To: [email protected]
Subject: Re: Topband: 5kW amps

Not to mention splattering everything and everyone in a 200 mile radius.

BA

On 6/22/2026 5:28 PM, Mike Smith VE9AA via Topband wrote:
Anyone who claims they don't care if the guy across town or even a
State/Province over is running 5kW or 12kW is not being truthful.

Think of it.  They beat you in every contest you ever enter (maybe denying
you WRTC points or nice plaques if you are into that stuff) or beat you in
every dx pileup you ever enter.  Maybe they're in the same pileup as you
for
Bouvet, Scarborough Reef, Spratley or North Korea, but you never get
through.

This "analogy" of the fast car going 160mph is flawed.  I own a Harley and
ride it at the speed limit. (yes, really)

Two days ago 2 crotch rockets went by the house likely approaching 200km/h
(125mph). Maybe more.

    They were literally a screaming blur (think Isle of Man-TT)that lasted
only the briefest of time (a second or so and I can see up/down the road
quite a ways.

Unless they crash into my house, I don't care.  It's no skin off my nose.
I
don't like it. I think it's stupid but it doesn't directly affect me so
long
as they don't run over a kid on my road. (btw, a guy on a sport-bike hit a
deer not 500' from my driveway a couple years ago and barely survived.  I
was not here as a witness but some locals said he was going way too fast,
so
he paid the price of maybe going too fast and not being able to avoid the
deer I guess).

Anyways, if it's a guy across town thumping me into the ground every
contest, every pileup who's running 5, 10 or 15kW then it forces me to
care.
It AFFECTS me. It's not just someone doing something that's stupid,
illegal
or whatever.  It has consequences.

You can never convince me somebody is running a 5 or 10kW capable amp
loafing it along at 1.5kW.  C'mon, get real. That's ludicrous.

Respectfully,

VE9AA

Mike - Keswick Ridge, NB, Canada

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