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Re: [Amps] Fwd: Linear Amplifier Tuning---PROPERLY!

To: "Fuqua, Bill L" <>
Subject: Re: [Amps] Fwd: Linear Amplifier Tuning---PROPERLY!
From: "Roger (K8RI)" <>
Date: Thu, 29 Dec 2011 02:01:46 -0500
List-post: <">>
On 12/28/2011 10:56 PM, Fuqua, Bill L wrote:
>    The problem is that when things become more nonlinear , driven harder, you 
> start seeing the
> stronger 5th order IMD and 7th order IMD which do increase the bandwidth 
> beyond the 2x bandwidth
> you are using in your example.
Like trying to get a KW out of a single 3-500?
or the ham's voice getting louder as he/she tries to get just another 
watt out to make it through the pileup.
Another reason for getting an amp with a fair amount of headroom. Course 
there will still be some that think they need just one more watt.<:-))

Drive the snot out of it. You get more power out it shows on the 
meter<:-)). Unfortunately the signal isn't any stronger, it just gets 
wider as the tube(s) go farther into non linearity and the average power 
contains all those extra signals and with the frequencies in our voices 
that can be a lot!

I'm a firm believer that running QRO cuts down on the QRM because I can 
work them on the first or second call while I hear stations in there 
calling for as much as a half hour or more. Sometimes they keep calling 
while the DX is now talking to some one else which makes the money spent 
on a 40 meter yagi with a front to back and front to side, look worth 
while.  MOre than a few times I've heard a DX station give up in 
frustration, call one of these stations and say, station XXX would you 
please shut up! You keep calling while I'm working some one else. Due to 
your poor operating procedure I am not going to work you so please stop 
calling.  OTOH I have great admiration for the guys who know when to 
call and have the timing down to a science.

>    One small thing. The signals must be half RMS voltage or 1/4 power
Or even less as the number of signals increases.
>   because they will become in phase
> at times doubling the voltage thus producing 4x power combined.


Roger (K8RI)
> 73
> Bill wa4lav

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