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Old May 1st 09, 11:45 AM posted to rec.radio.amateur.homebrew
Scott[_4_] Scott[_4_] is offline
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First recorded activity by RadioBanter: May 2008
Posts: 115
Default Frequency doubling: Is bandpass filtering needed?

Joerg wrote:
Harold E. Johnson wrote:
BTW, in the olden days we preferred 3x, 5x per stage. Two 3x stages
would give you 9x. The most brazen ones (not me) did a direct 7x or
even 9x. We just drove transistors in class C real hard.
Or today, many of us just overdrive an untuned MMIC amplifier and
filter out the unwanted harmonics...

Scott
N0EDV

And often have unwanted sometimes unfound parametric oscillations that
have nothing to do with harmonic content.


If a huge drab-green truck stops in front of the house and folks in
fatigues and army boots hop off then the unfound oscillation has been
found ;-)


Listening to all the "crap" on the bands these days, I doubt ANY truck
from the government would ever show up However, that being said, as
hams, we all need to make sure our "house is clean"...now about all that
other "crap"...has anyone else noticed all the interference these days
on 2M from other sources of "spurious junk"??? Examples: I pull up to
gas pumps and the squelch opens on my 2M radio...driving down the
Interstate, I pass semi trucks and get a static burst from the
speaker...Drive through town, listening to 145.19 and get static bursts
(this just happens to be a cable TV frequency...isn't the idea of cable
TV to keep the signals INSIDE the cable?)....

Scott
N0EDV