FASMA receives many requests for low power, limited coverage repeaters for experimental, mobile, temporary “emergency” systems, neighborhood CERT teams and for just plain “fun”. The FCC refers to such temporary operation as “Itinerant” users. Due to the number of repeaters on the air, it is difficult to find available frequencies to manage this need, due to protection contours of existing machines. In some areas, there are no available frequencies to assign within the repeater band plan spectrum.
Our technical committee proposes the following plan to accommodate these needs in a simple, easy to understand manner. We hope this policy will promote more experimentation in repeater systems, add to the body of experienced repeater operators within FASMA’s members and serve the public interest in times of emergency with a planned deployment guide and coordination of, portable, emergency and mobile (such as those used at Hamfests for group communications) repeaters that can add to the general usefulness of Amateur Radio systems. Plus, we hope it allows everyone to have more fun messing around with Ham Radio gear!
Due to existing band plans and congestion, this proposal only identifies suitable frequencies on the 70 centimeter band. Research has shown the two meter band is too congested and no standard frequency pairs are available statewide. 220/902/1.2 GHz would likely support such itinerant operation and is best the subject of future study.
There is now a plethora of inexpensive 70cm radios now on the market that can service users of Itinerant repeaters. Itinerant repeater pairs are available on a non-exclusive, first come, first served on line application environment for interested parties.
The application process is designed to help applicants learn and understand the basics of the RF parameters needed to plan a working system. FASMA staff is available, on a volunteer, as time permits, basis, to consult with applicant’s system details, however, applicants will be required to “do the math” on their application. Through this process, FASMA hopes to encourage learning and broaden the understanding of the details of repeater planning, service contour definition, interference potential and other facets of repeater systems and add to the available technical talent of Florida amateur radio operators as a whole.
Itinerant Repeater Proposal
These repeaters are the Amateur Radio analog to the new FCC licensed Low Power FM stations now being shoehorned into the FM broadcast band. They are intended for short range, local, limited coverage.
Itinerant repeaters may use any appropriate modulation formats, either digital or analog. The only limitation to the modulation parameters is that any modulation used must not exceed 20 kHz for wideband or 11.7 kHz for narrowband pairs. Multiple modulation formats may be used on a single machine at any time, even concurrently. Repeaters may be designated as analog, digital or mixed format by operators.
Itinerant repeaters can be designated by as “closed” systems for their users only. However, in keeping with FCC regulations for the Amateur Service, no form of encryption on either digital streams or analog modulation may be used.
Registration of Itinerant Repeaters is predicated under the parameters illustrated in this policy.
As in any FASMA coordination, any deviation or relocation greater than 8km distance, 5m in height or 10% transmitter power will require re-coordination.
Itinerant repeater sub band frequency pairs:
All pairs MUST use a standard offset. i.e. Receive Frequency = Output Frequency + 5.000 MHz
There are 5 pairs available for wideband (25 kHz) channel use, with 14 pairs for narrowband (12.5 kHz) only use.
Pairs 6-9 are narrow band only, with 1A-4B local option only if 6-9 are in use.
Pair 5 Wideband and 5A/B Narrowband is intended to be a truly itinerant use system.
- The intent of this channel is for hamfest or other mobile repeaters.
- No permanent install on this frequency is permitted.
- Users MAY temporally deploy a system on these frequencies for no longer than 36 hours. During an emergency, this rule is waived for the duration of the emergency.
- No registration is required for this channel; however, it is encouraged.
- Narrowband users are encouraged to use pair 5B before 5A
Frequency Agile repeaters
This plan was engineered taking into account the performance of a typical “flat pack” duplexer. In a UHF duplexer of this type it is common to have 100-150 kHz of usable notch depth bandwidth. This allows a wideband repeater to use a duplexer tuned to 441.8750/446.8750 on channels 1-5 with acceptable performance. A narrowband repeater could use a duplexer tuned to 441.9625/446.9625 on channels 5-9 with acceptable performance. Please note this is simply an explanation for the frequency layout, any duplexer should be individually tested by a competent technician prior to use and FASMA assumes no liability caused by such use.
All pairs require CTCSS/DCS/NAC/Color Code/etc. (hereafter CTCSS) transmit and receive by all users at all times. All users of these pairs MUST use CTCSS transmit and receive in all user radios. Proposed CTCSS codes must be coordinated via consultation with FASMA coordinators.
Operational system parameters for Itinerant Repeaters must adhere to the specifications described below. Any deviation must follow normal coordination procedures.
- Maximum service contour for the purposes of planning co-channel assignments is 20 km (12.5mi) (assuming the maximum 15.3m HAAT (50 ft. Height Above Average Terrain).
- No protection of service coverage past the above defined service contour description
- Maximum Transmitter Power Output (TPO): No more than 40 watts into antenna
- Maximum total allowed Effective Isotropic Radiated Power (ERP) in the system: 110w
- Maximum allowable antenna gain: 6 dBd.
This is in the range of the common Diamond X50 and its clones, which is one of the typical antennas for these applications. For better null fill “close up”, such as for CERT applications within a neighborhood, a simple unity gain ¼ ground plane is recommended due to the broader radiation pattern of these antennas.
- Maximum antenna height to center of radiation: 15.3m (50 ft.)
A 43-foot tower could wear a Diamond X50 at its apex to qualify. This is technically within the reach of people wanting a local repeater and enabling their deployment in most normal city/suburban areas in Florida.
- Height above Average terrain must not exceed 60 feet out 25 miles.
This typical of a suburban location in Florida terrain. This precludes someone living at the base of Bok Tower from applying for an Itinerant repeater system – The HAAT for this location is out of range.
Prior registration would be required and these repeaters will be listed in FASMA based repeater coordination lists and reports. All FASMA requires for this repeater service coordination from the applicant are the following system parameters:
- Ownership Group/Individual address, contact telephone number and email address
- Callsign of both the trustee/owner and the repeater itself (if different)
- GPS coordinates of the location (degrees and minutes to two decimal places)
- Repeater equipment make, model and maximum power output
- Feedline loss figure
- Antenna make and model with gain figure
- Effective Radiated Power
- CTCSS tone choice
- Emission designator (preferable) and/or modulation type (WBFM, NBFM, D-Star, DMR, etc.)
Any proposed change in facilities to increase repeater range would require re-coordination to a “main band” frequency, if such a frequency is available for the proposed site. In cases where, for a given metropolitan area, a “main band” frequency becomes available, Itinerant repeater operators can request a facilities upgrade to that frequency. Applications will be processed in accordance with normal coordination procedure.
Itinerant repeaters must accept interference from adjacent channel systems close to their coordinated pairs. Itinerant repeaters operate on their frequency on a “secondary” basis and must accept any interference from other co-channel or adjacent channel users. Itinerant repeaters shall not continuously utilize a channel via broadcast or other transmissions. Users shall restrict all transmissions to the minimum practical transmission time and must employ an efficient operating procedure designed to maximize the utilization of the spectrum. This is analogous to the FCC FB2 station class code in the land mobile spectrum.
The only interference abatement available to Itinerant repeater operators is either antenna terrain shielding or CTCSS tone management. Only one CTCSS tone shall be used for access to Itinerant repeaters. Multiple CTCSS tones are not allowed. Changes to CTCSS tone must updated in the repeater’s registration in the FASMA database.
Build Out Notification
Itinerant repeater application and grant will be a fully automated service via the FASMA website. System owners/trustee will have a maximum 60 days to report operational status (build out). If operational status is not reported to FASMA after 60 days, the repeater registration will be revoked and the frequency will be available for reassignment. If any Itinerant system is found to be off the air, the repeater registration will be revoked.
If the operator ceases operation for any reason, the operator shall notify FASMA.
This is a proposed policy was open for public comment before adoption. Our policy making is candid process; we continually seek input and new ideas from the community. We encourage any amateurs wishing to effect change in the operation of coordination in Florida to submit a proposal or comment on existing proposals. We request all comments to email@example.com.
This policy has been enforce since 2018 without issue. It is adopted for use of all amateurs in Florida.