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
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