Mark Forbes, January 2002
One thing I'd like to reiterate, with regard to output power and the like;
Ham radios with wideband modifications are *NOT* approved for use on the business-band frequencies. Only type-accepted business band radios may be legally used on those frequencies. Ham radios may be used legally on the ham radio frequencies only, and only by licensed hams with a callsign.
Now....I know that sounds a bit legalistic, but here's why it matters and what you need to pay attention to:
The USHPA business-band authorization allows us to use five frequencies in the "transient" band allocation. These are intended for users who are mobile, like construction crews and such. The intent is that congestion will be minimized because nobody's "camped" on a frequency long-term, such as would be the case for a taxi dispatcher or a roofing company. We share these frequencies with many other users, most of whom are operating with legal radios and business interests. The USHPA authorization only permits the use of type-accepted business band radios....no others.
The reason that only "type-accepted" radios may be used is that the output power and frequency can be adjusted only by a licensed radio technician on such sets. Our modified radios can be set to *any* frequency, including the ones used by police/fire/ambulance/pagers/etc. Our radios have the ability to cause major interference to people who have a lot of clout. We have to be *very* careful not to intefere with other users of the business band, and we must NEVER operate on emergency frequencies unless it's the most dire of life-threatening emergencies. Even then, expect to face an FCC review and have your equipment confiscated. The fine is $10,000 per incident.
Similarly, the output power of business band radios is limited, so they don't interfere over long distances. Ham radios can operate at higher power levels, because that's a different band and licensed hams are supposed to know enough to resolve their own interference issues. Lighting up a high-power rig on the business band can antagonize a lot of people, much farther than you can hear them. So that's another thing you have to pay close attention to.
So long as we keep the power level down to the minimum required to make contact, and we avoid any business-band frequency where other users are operating, we can operate on the fringes without anybody noticing. We also mostly fly on weekends, when a lot of these other users are off work. And we tend to fly in locations that are away from population centers, where the risk of interference is lower.
The ham radio no-code technician test is fairly easy, and once you've passed it you get a callsign and the legal right to operate on the ham radio bands. You can then use higher power, repeaters, better antennas and so forth, which can greatly improve your communication range. Whether you do that or not, you need to understand the limitations and risks of business-band operations, and avoid calling any unwanted attention from the FCC or other users of the business bands.