The Mot App Note (and Engineering Bulletin) amps sold for linear service do
have active bias circuitry. I've built several of these, and took some data
on the EB-63 model a few months ago.
Using a CW drive signal, it was straight-line linear until ~120W output
power, with 13.8dB gain (5W drive = 120W out), then started going non-linear
and reached 1dB compression at 140W out (7.3W drive = 140W out). Its
"rated" output with a 13.8Vdc supply is 140W, which is overstating its
linear range, obviously. But if operated with <5W drive, it's as linear as
anything else I have. 1W drive yields 24W out (13.8dB), 2W yields 48W out,
etc, until about 120W.
However, looking at its output spectrum (CW), at 140W output its 2nd and 3rd
harmonics aren't too peachy, at typ -20dB (both) at 14 MHz. It needs
filters. Operated well below compression, it's much cleaner.
-WB2WIK/6
"Success is the ability to go from failure to failure with no loss of
enthusiasm." -Winston Churchill
> -----Original Message-----
> From: Tom Rauch [SMTP:w8ji@contesting.com]
> Sent: Wednesday, March 12, 2003 3:14 PM
> To: Steve Katz; 'Vic Rosenthal'; N8WNB@aol.com
> Cc: amps@contesting.com
> Subject: Re: [Amps] Speaking of Palomar
>
>
>
>
> If the amp does not have a filter, you can be sure it has no bias and
> probably is not correctly impedance matched. A filter would make it a CW
> amp
> (but add clicks if it was non-linear) or an FM amp, but not a linear amp.
>
> How would you correct that Steve since the IM would tear other users of
> the
> band up?
>
> Seems to me people often think a filter will cure splatter
>
> 73 Tom
>
>
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