Larry,
Yes, it would, although a bandpass cavity usually has more loss than an
isolator. A cavity also filters
out synthesizer noise and other spurious signals that may be generated in the
exciter or PA.
73, Eric Lemmon WB6FLY
"[EMAIL PROTECTED]" wrote:
> I trust that if there is no Low-Pass filter at the isolator output, a
> passband cavity would do the job?
> LJ
>
> -----Original Message-----
> From: Bob Dengler <[EMAIL PROTECTED]>
> Sent: May 9, 2005 10:13 AM
> To: Repeater-Builder@yahoogroups.com
> Subject: Re: [Repeater-Builder] Low-Pass Filters for Ferrite Isolators
>
> At 5/7/2005 10:53 AM, you wrote:
> >Steve,
> >
> >There is nothing special about the low-pass filter that might require you
> >to use a
> >particular brand name. A ferrite isolator is a nonlinear device, and
> >therefore it
> >will generate a strong second harmonic which must be attenuated by either
> >a notch
> >filter or a low-pass filter.
>
> Not always. If the isolator is driven far below it's rating, it may not go
> nonlinear. We once tested an EMR Corp. 220 MHz isolator being driven with
> ~90 watts. The output spectrum from our RFPA was no different with the
> isolator in line (no increase or decrease in harmonic content).
>
> If you have a power attenuator handy, it might be worth actually looking at
> the harmonic levels coming out of your isolator with a spectrum
> analyzer. You can't use a coupler for this test because it's frequency
> response will taint the measurement.
>
> Bob NO6B
>
>
> Yahoo! Groups Links
>
>
>
>
> Yahoo! Groups Links
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>
>
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