[BC] FAA RF rulemaking

[Mike McCarthy]

In these cases, there were emissions which were not compliant with existing 
rules.  So I fail to see why the FAA's shorts are all in a bind.  The rules 
are already in place.

I just went through a 9th harmonic case with a cell carrier.  They were 
bound and determined to blame us until I showed up with a SA, notch filter 
and did the old coupler gain calculation (with is -20dB at the 
9th).  Hmm..we were -86dBc.

I then asked to see the signals arriving between the first active stage and 
passive band-pass filters.  There was no increase in the noise floor 
between operational states of the FM when looking at the antenna through 
the filters.

Spectrum analyzer and accessories...$30K.  Stammered expressions by cell 
phone people....priceless.

MM



At 06:20 AM 6/28/2006 -0500, Dave Dunsmoor wrote
>     Well, my experience has been spurs, (energy generated and radiated well
>outside the frequency of interest). Say perhaps a transmitter on 93.7
>generated a ninth harmonic that landed directly on top of one of a cell
>tower's channels. Or one that generated "extra" channels up and down the FM
>band. In another case, a spur landed right on, (or close to) the VOR
>frequency, and the FM had to be shutdown until it's IPA was repaired Anyway,
>that's where I heard the problem was.
>
>     IMD is slightly different, but can cause similar problems, and that is
>usually avoided by frequency and siting selections.
>
>Dave
>
>
>
> > At 06:54 PM 6/27/2006, Dave Dunsmoor wrote
> > >It's been my experience that NAV and Comm frequencies
> > >are not bothered by "overload" so much but by RFI from transmitters
>outside
> > >the NAV/COMM frequency bands. Specifically FM transmitters, and they do
> > >generate spurs occasionally.
> >
> >          Are you talking about intermod products, Dave?
>
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