[CQ-Contest] Coax Stubs for SO2R

Joe nss at mwt.net
Mon Jul 25 08:47:18 EDT 2016


This also puzzles me.
OK if an amp because of it's tuned matching circuits, block out of band 
energies.

The why do we have these energies at all in the first place?

Does not a Radio have the equivalent of an "Exciter" ( the ummm low 
level driver )

And the "AMP"  ( the final output amplifying system )

So, i9f all this filtering is happening why do we have spurious out of 
the radio, but not an amp?

Joe WB9SBD
Sig
The Original Rolling Ball Clock
Idle Tyme
Idle-Tyme.com
http://www.idle-tyme.com
On 7/25/2016 5:48 AM, Rudy Bakalov via CQ-Contest wrote:
> Jukka,
>
> It is the statement below that really puzzles me. All amp people I know, including those that manufacture commercial amps, categorically state that amps do not generate harmonics on their own. That is, amps merely amplify them.
>
> To me this seemingly minor difference is huge. If amps only amplify but do not generate harmonics then there is no scientific reason for filtering after the amp assuming the same amount of filtering is applied before the amp. In practical terms, this would mean that low power BPFs before the amp are as effective as high power BPFs after the amp.
>
> The key point here is GENERATE vs AMPLIFY harmonics. Can the average commercial, well stabilized amp generate harmonics?
>
> Rudy N2WQ
>
> Sent using a tiny keyboard.  Please excuse brevity, typos, or inappropriate autocorrect.
>
>
>> On Jul 24, 2016, at 5:14 PM, Jukka Klemola <jpklemola at gmail.com> wrote:
>>
>> In case you do that, you still need stubs after the amp.
>> Amplifier creates harmonics out of the fundamental frequency.
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