"...My prospective customer said the frequencies are between 902 and
927 MHz! Is that not the 900 MHz Ham band? I would expect the Canopy
system is secondary to Ham use or is it the other way? Anyone
know?..."
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Yes, the 902 to 928 MHz band is the same band shared by amateurs.
There are three types of operations in this [and other so-called ISM
bands]. Those would be primary licensees, secondary licensees, and
part 15 unlicensed operations.
As this is not the place for such discussions - please refer to
applicable FCC rules for information about the handling of
interference issues between these classes of users.
>From a technical perspective, there probably is not a large body of
facts to help predict co-site compatiblity of NBFM voice repeaters and
Canopy wireless data. There are two likely scenarios. First, the
wideband characteristic of the data operation has the potential to
significantly raise the noise floor thereby impairing your NBFM
receiver.
Second, although the Canopy system was probably designed to be very
tolerant of individual in-band, narrow-band emissions [such as
cordless phones], the high level of your NBFM repeater transmitter
could significantly impact the performance of the data system.
I was involved in one problem investigation where a public safety
repeater was being desensed at a site co-habited by several phone
carriers and a wireless data network. As the site was a water tower,
all the antennas were in the same plane. By disabling the other
operations [with the aid of their respective techs] it was determined
that the wireless data system was at fault.
The public safety user resolved the issue by moving.
Obviously, your best defense against problems would be as much antenna
isolation as possible. You could ask the prospective customer if
their vendor can provide engineering compatibility analysis. Also, as
tower owner, you could write the site agreement in such a way as to
protect your operations and stipulate that they are to accept any
uncorrectable interference from your operations.
Field trials may be required to determine actual compatibility.
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