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Re: [Amps] 1 tube or two ??

To: "EP Swynar" <gswynar@durham.net>, <Jim.Isbell@gmail.com>,"kenw2dtc" <kenw2dtc@comcast.net>
Subject: Re: [Amps] 1 tube or two ??
From: "Tom W8JI" <w8ji@w8ji.com>
Date: Sun, 11 Feb 2007 16:59:55 -0500
List-post: <mailto:amps@contesting.com>
> Face it: a 4-1000A is LOAFING at Amateur Radio power 
> limitations --- TWO
> 4-1000A's would loaf along even more under Ham power 
> rules...

No.

It is actually at maximum stressed at amateur power limits 
in grounded grid class AB2. It really isn't that big or that 
good of a tube, we just have rosy colored memories just like 
we do of the gas guzzling low performance cars of the era 
and acreage consuming antennas that had less gain than a 
4-element Yagi from the era when most of us were growing up.

Consider at 60 percent efficiency at 1500 watts output 
(legal limit in the USA)  a 4-1000A would be running 2500 
watts input and dissipating 1000 watts...right at the limit.
Worse yet it would take about 120-150 watts of drive to do 
that.

>> I clearly stated "at the limit for Ham Bands."  Therefore 
>> two tubes
>> does not have an advantage in power.  Both circuits can 
>> run at maximum
>> legal limit without strain.

Not true. It take a pair of 4-1000A's to run "no strain" 
legal limit in grounded grid, and a heap of drive power.

The 4-1000A is old technology that gives us a warm fuzzy 
feeling and makes our aged brain cells call for saliva. It 
creates memories of big conservative power where there 
really was none compared to today when a bottle 1/3 the 
physical size does almost everything better except perhaps 
warm our hearts with that white-glowing filament and red 
glowing anode.

Don't let nostalgia get in the way of fact.

73 Tom 


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