Correct me if I am wrong, but aren't "harmonics" exact multiples of a
As such, they should be differentiated from the spurious frequencies
generated by an amplifier which usually are NOT an exact multiple of the
Those spurious frequencies are, correctly as stated, not filtered by a
LP between the Xcvr and amplifier.
The original question I raised was concerning HARMONICS, not spurious
frequencies generated by the amplifier.
Perhaps operating an amplifier ONLY within the linear portion of its
curve would cure most of the spurious frequencies and limit the need for
a LP filter post-amp.
As for the statement that 'amps do not amplify harmonics' that was
posted by another submitter .. I defer to the "experts" as to why
harmonics ARE amplified by a well-designed amplifier .. a FACT that can
be easily measured.
Jim Lux wrote:
> At 01:10 PM 8/16/2005, Don Havlicek wrote:
>>Why don't hams place the LP filter between the Xcvr and the Amp? That
>>way, the amount of harmonics reaching the Amp will be minimized,
>>rendering their output levels relatively the same, if not lower, than if
>>the LP filter was AFTER the Amp.
>>BTW: this is what I have done since the 50's. Never blew up a LP
> probably because the harmonics people are concerned about come from the
> power stage, not the exciter.
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
> Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
> questions and ask for Sherman, W2FLA.
> TowerTalk mailing list
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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