[AMPS] where to find info

Jon Ogden jono@webspun.com
Sun, 24 May 98 14:30:25 -0500

>Most tetrodes are that way. Some fellow keeps trying to sell 
>Ameritron on a G2DAF circuit, claiming it has "good and fully 
>acceptable performance".  He finally delivered IMD specs, and they are  
>-24 dB third order. An unbiased class C transistor will do that well.
>My point? Acceptable means different things to different people. IMO, 
>less than -35 dB is unacceptable for high power PA's. For that 
>fellow, -24 dB is good enough. I hope his neighbor uses one of 
>his amps real soon, before my neighbor buys one!

Yes, true.  However, all the "specs" I've seen both from Eimac and 
several editions of W6SAI's book say the IM at 4000 V is -34 dB and at 
5000 V it doesn't even list IM specs.  I suppose that's cause it's 
getting worse?  Hmm...interesting.

Although, how can one measure intermod without a spectrum analyzer?  I'd 
like to check mine, but have no idea how to do it and I no longer have 
access to an SA.

>Nothing wrong with nostalgia Jon, but let's keep in mind the guys 
>He wanted to get info on a 4-1000 PA because he wanted to build what 
>sounds like his first PA. 
>IMO, using an unstable tube that requires at least 5 kV to make 
>1200-1500 watts output with a 100 watt exciter is not a good 
>beginners project.

You're correct.  Yes, it's probably not a good beginner's project.  
You're right.



Jon Ogden


"A life lived in fear is a life half lived."

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