- Part 15 devices are allowed in many different frequency bands; refer to part 15 for details. Rules and power levels vary according to band. Most keyless entry and garage door remotes, etc. operate under the ~300-400 MHz. rules, for example.
Spread spectrum is allowed up to one watt xmit power in the 900, 2400, and 5 GHz. ISM bands. Recent changes have modified the rules around the 5 GHz. ISM band to create a "NII" (natinal information infrastucture) band for local wirless data; I don't know the details on this yet.
It is true that hams have precedence over wireless data at 900 MHz., although I think government is still primary. Hams are allowed more power than ISM, though.
This is interesting, because a high-power narrowband carrier can completely wipe out a direct-sequence receiver if the signal is strong enough compared to the desired signal (say, roughly 10 dB stronger). For a voice ham signal this wouldn't cause problems very often but if it were a continuous packet beacon it could have a significant impact under the right circumstances.
Keep in mind that although hams take precedence, the number of hams using the 900 MHz. band is miniscule compared to the number of wireless lans, and there is always strength in numbers.
Also, I don't think that baby monitor yu mentioned is authorized for 3 or 7 MHz.; it is probably a 49 MHz. device that is putting out trash on HF. Legally you could probably force them to shutdown, but of course FCC enforcement is almost non-existent, and a baby monitor would get sympathy compared to a ham operator, and there are many times more baby monitors than there are ham rigs.
73 N3GDE Brian Robinson
`On Dec 5, 4:32pm, Art B Allen wrote:
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> Subject: Re: Re: My Spread Spectrum Letter to FCC
> On Thu, 5 Dec 1996 09:41:30 -0500 (EST) Bernie Doehner
> >> Obviously, part 15 devices DO NOT belong in the ham bands-shouldnt
> >we be
> >> more interested in getting these devices OUT of our bands??? Never
> >> should have been there to start with...
> Hey Bernie, are you a ham or a comm'l interest who is subscribed to our
> list? Don't see your callsign in the message, but your address is
> ''uhf.wireless.net". Interesting....
> >Will never happen! 900 MHz. is another wasteland that the FCC doesn't
> >give a damn about and it is quite happy about the proliferation of ISM
> If 900 Mhz is to be considered a 'wasteland', then lets get ALL the part
> 15 devices and all the wideband SS stuff put on that band, that way we
> can protect our OTHER bands.
> Heck, maybe this SS stuff is a blessing in disguise-and perhaps we can
> now think about going on the offensive. ECM (Electronic Counter
> Measures) isn't such a big deal, perhaps our PC's could run ECM under
> windows (while performing other functions)? As long as we only use part
> 15 power levels and type accepted transmitters, this should be allowed?
> Even if done at ham power levels and with REAL antennas, the part 15 user
> is not provided with any protection because hams have the primary use of
> the band.
> >> Obviously, 50 or 100 part 15 devices operating within a mile or 2 of
> >> weak signal user is going to create probs (whether ists SS or not).
> >So how much money are you prepared to pay to the FCC for exclusive
> >access to
> >902-928 MHz?
> Bernie OB, you missed the point-hams are a non-comm'l interest and cannot
> pay for spectrum. By expecting hams to compete for spectrum with the
> comm'l boys, well, obviously it can't happen. I hope the ARRL is working
> on this angle...we need special protection due to the non-$$$ limitations
> placed on us.
> Also, 902-928? I think you would find that part 15 devices are allowed to
> operate on ANY ham band, (not just UHF). A single video signal from your
> neighbors video baby monitor would wipe out 3.5 and 7.0 mhz bands in a
> single shot. Its not just 900 mhz that has a problem with part 15
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>-- End of excerpt from Art B Allen
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