> ---------- Initial message -----------
>
> From : owner-amps@contesting.com
> To : Eric Moore <emoore@windemullerelectric.com>,
amps@contesting.com, "'Maurizio Panicara'" <i4jmy@iol.it>
> Cc :
> Date : Thu, 30 Nov 2000 08:46:14 -0000
> Subject : RE: [AMPS] Low Pass Filter
>
>
> Mauri says:
>
> >A decent PI and an HF antenna itself easily limit the radiated
harmonic
> >content to neglegible values.
>
> Regrettably, not enough to meet the requirements of the ITU Radio
Regulations
> or, for Europeans, the requirements of the CEPT Recommendation T/R 74-
01 on
> Spurious emissions.
>
>
> 73
>
> peter G3RZP
Because the requirements involve the equipment itself, but practically
speaking even a -40 dB rejection combined with the HF antenna losses at
TV frequencies is generally enough to prevent a generic TVI trouble
that's mainly a matter of strong HF field and overloaded TV devices.
Of course, when the harmonic drops exactly within a local TV channel
the story is different and even CEPT Recommendation T/R 74-01 hardly
can cure the trouble.
In this case even a multi-pole low pass filter is generally not enough
to stop at high VHF and UHF and has to be combined with a notch filter
like a stub that can drastically reduce the harmonic content.
73,
Mauri I4JMY
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