Re: 4 Watt transmitter question

From: Tim Wescott (tim_at_wescottnospamdesign.com)
Date: 11/16/04 

Date: Mon, 15 Nov 2004 17:10:00 -0800

Tam/WB2TT wrote:

> "Joe McElvenney" <ximac@btinternet.com> wrote in message
> news:VA.00000048.002614b7@btinternet.com...
>
>>Hi,
>>
>>
>>>This circuit is not going to perform 4 watts is it?
>>>
>>>http://www.electronics-lab.com/projects/rf/021/index.html
>>>
>>>too simple to be true
>>
>> There is more than one method of rating a transmitter's power
>>and simple DC input is a common way to do that. Seen this way, in
>>the circuit given the power input lies between 1.2W and 6.4W and
>>4W is then a conservative figure. How long it would last, and how
>>efficient it would be, is another story.
>
>
> I think you hit the nail on the head. I once ran a 2N2219 at 28 MHz off a
> 20V supply, and got a couple of W out of it. Would not expect anywhere that
> much at 100 MHz. First thing it would need is a BIG heat sink.
>
> On the tube amp, I have the 807 data ***, and that looks like it may
> legally do 20W out at 100MHz. Somebody mentioned the 6146, which sort of
> replaced the 807, 50 some years ago. It will do around 40W at 100 MHz, but
> has nothing in common with the 807. Different size, and different number of
> pins. I don't know where the EL34, or equivalent, comes in. I thought that
> was a single ended audio tube.
>
> Tam
>

The 807, 6146 and EL34 are all beam power tetrodes with similar power
ratings, with circuit adjustments and taking frequency limitations into
account they could probably each do about the same thing. The EL34
possibly has the same frequency capabilities as the 807, possibly less. 

-- 
Tim Wescott
Wescott Design Services
http://www.wescottdesign.com