----- Original Message -----
From: "Jim Brown" <jim@audiosystemsgroup.com>
To: <amps@contesting.com>
Sent: Friday, December 23, 2011 10:04 PM
Subject: Re: [Amps] Fwd: Linear Amplifier Tuning---PROPERLY!
> On 12/22/2011 10:32 AM, Frank wrote:
>> I can see how you can improve IMD 2 or 3 db by agonizing over the
>> "proper way to tune" but your probably already at 20 to 30 db IMD to
>> start with. That 3 db will never be noticed by anyone except the fellow
>> looking at the lab equipment.
>
> IMD in the -30dB range means a LOT of RF trash in your sidebands, both
> from modulation and from the transients of your keying. That means
> you're TOO DAMNED BROAD! Keeping our signals as clean as possible DOES
> matter. When your signal is 20 over S9, sidebands that are only 30dB
> down are S7, and prevent me from working guys at that level in your
> sidebands. Ten dB cleaner means S5. Have any hams as neighbors? How
> would you like THEM to have -20dB sidebands? I had one, two miles away
> with a big dirty amp, and he wiped out all of whatever phone band he
> worked a contest, and called CQ ALL the time. Another neighbor, only
> 0.3 miles away with a clean amp, only burns about 10 kHz.
>
> 73, Jim K9YC
If you want to see garbage look at the QST review of the TE 2M brick in the
Jan issue. A mighty -17 3rd and none of the others are great either.
Carl
KM1H
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