AREA REPEATER COORDINATION COUNCIL (ARCC), Inc.
Amateur Radio Repeater and Auxiliary Link Frequency Coordination
ARCC Repeater Coordination FAQ
Revision E, 04 February 2008
Q: Iím thinking about building a repeater, but Iím not sure where to start. Any general suggestions before I get started?
A: Well, first of all, ask yourself, is this repeater going to serve a useful purpose, either to you or to other amateurs in your area? Before spending a lot of time, effort, and money in putting up a repeater, think about it a little. Unfortunately, there are quite a few repeaters in existence which are underutilized, often because there is an overabundance of repeaters in the area. If you are interested in building a repeater for the purposes of learning and technical achievement, you might save yourself a lot of money and provide a great service to an existing repeater owner in your area, such as a local club, or even another individual repeater owner, by offering your assistance in helping maintain or upgrade an existing repeater. ARCC doesnít want to discourage you from building a repeater; we only ask that you put a little forethought into the decision before applying for coordination.
Q: OK, you havenít talked me out of it, I definitely want to put up a repeater. Where do I begin?
A: First, you need to decide on a few basic issues. What band are you interested in, and are there any frequencies available? What area do you want to serve, and do you have a viable repeater site available? If so, you will need to obtain geographic information on the site, including latitude, longitude, ground elevation, and the height above ground for the transmitting antenna. If not, selecting and negotiating to get a site needs to be addressed. What kind of hardware do you plan to use, including transmitter, receiver, duplexing equipment if required, filtering hardware, antennas, controller, etc.? Then, based on the hardware selection, you will need to obtain parameters related to the transmitter power output, feedline loss, antenna gain, antenna pattern, etc. as required on the coordination forms.
Q: Seems that there is a lot I still need to learn. Where can I find more information on repeaters, especially the technical stuff?
A: The ARRL Handbook and ARRL Antenna Handbook have some basic information regarding repeaters. There are a number of resources available on the Internet as well, a few of which are listed below:
Repeater Builderís Technical Information Page: www.repeater-builder.com
Q: What is the process for applying for coordination?
A: First, download the coordination forms and instructions from the ARCC web site. At first, the forms may appear to be asking for a lot of information. After closer inspection, and with the assistance of the instruction documents, it is really not a difficult process. The forms ask for some general information such as who the coordination will be issued to, what features the repeater has, the repeater input and output frequencies, and the location of the repeater. In addition, there are a number of key pieces of engineering data required, such as the latitude and longitude of the repeater, transmitter power and antenna system parameters, and other factors that are required for the coordinator to accurately analyze your proposed operation. Some of these may take a little research in order to provide accurate data, but none of it is particularly difficult. If you do get stuck, feel free to ask ARCC from some assistance. We wonít engineer your repeater, but if you have questions about the forms or the coordination process, weíre more than happy to help.
Q: I donít know the exact coordinates of my repeater site. How specific do I have to be?
A: ARCC requires coordinates accurate to within 1 second, NAD27 datum. In the old days, this would have to be determined by a surveyor to achieve that level of accuracy. Nowadays, consumer software such as Street Atlas, TopoUSA, and other cartography programs can be used to determine precise locations. A global positioning satellite receiver (GPS) can also be used to obtain precise coordinates now that selective availability (SA) dithering is no longer being used. The reason precise coordinates are required is that the coverage mapping software ARCC uses requires accurate location data in order to achieve accurate predictions of your repeaterís coverage.
Q: Iím not a real technical type. Iím not sure what some of the things youíre asking for on the forms mean or how to calculate them. Can I just put down my best guess?
A: No. Accurate data is mandatory. Consider learning what those things mean, how they are determined, and what their importance is, part of an educational experience. Donít try to cheat and put down numbers that just "look good" or are nice round numbers that are easy to work with. Guesses are easy to spot, and will result in your application being rejected and sent back to you without any action. The two most common places where errors are made are in determining EIRP and HAAT. There are worksheets available on the web site to assist you in determining these values accurately; please utilize them and submit them with your application.
Q: Alright, I have the forms filled out. Where do I send them?
A: All correspondence should be sent to ARCCís mailing address:
Q: Can I email or fax the forms?
A: At this time, no. ARCC only accepts coordination applications through standard mail. The only exception to this rule are "administrative changes" which do not affect the technical parameters of the coordination, such callsign changes (e.g. vanity callsign assignments), repeater "features" exclusive of access control modifications, web site URL, and updates to contact information such as mailing addresses, email addresses, and phone numbers. Such requests for administrative changes may be sent directly to ARCCís Database Manager via email.
Q: How many miles does my repeater have to be from other repeaters on the same frequency in order to get coordination?
A: ARCC does NOT use fixed mileage spacings when reviewing coordinations and analyzing the potential for interference to/from incumbent operations. Every repeater has a unique coverage area, and as such, every repeater is treated individually during the coordination review process. In addition, ARCC analyzes not only what affect your proposed repeater will have on other repeaters on the same frequency, but in many cases, adjacent-channel operations are also considered during coordination review.
Q: Well, if you donít go by mileage, how do you decide whether a repeater can or canít be coordinated?
A: There are a number of factors that go into the decision. ARCC relies heavily on computer analysis that are done using high-end coverage modeling software. The modeling software takes into account all of the parameters of your proposed operation, including EIRP, antenna pattern, location, elevation, terrain, frequency, etc. and produces a plot of your predicted coverage area. The result of the model is compared to the models of other co-channel and adjacent-channel repeatersí in ARCC territory as necessary to predict whether or not your operation is likely to cause or interference to, or receive interference from, any other existing coordinated operation. In addition, real-world testing to verify the accuracy of the computer models is often done. If no interference is predicted, and if the application meets all other relevant criteria for coordination, the proposed operation is then cross-coordinated with the adjacent coordination councils. The adjacent councils then review the application in a similar manner to how ARCC reviewed the application to ascertain if the proposed operation will cause interference to any operation in their respective territories. If so, they can object to the coordination, in which case it will be denied. If everything passes muster, both within ARCC territory as well as the adjacent councilsí territories, the coordination is granted.
Q: I applied for coordination but it was denied. What can I do to get it approved?
A: Well, it depends on WHY it was rejected. There are a number of common reasons why a given coordination cannot be granted, several of the more common of which are described below:
If you feel that ARCC may have overlooked something during the coordination review, or if this other information or details that were not adequately addressed during the initial coordination review, you can appeal for a full board review of the application as described in the ARCC Constitution and By-Laws.
Q: I canít see any way to modify my operation to get it approved, and there donít appear to be any other frequency pairs I could use instead. What else can I do?
A: If your application was denied due to predicted interference to another existing coordinated operation, you might consider working out a mutually agreeable solution with the party with whom you would cause or receive interference to/from. For example, if it is predicted that your repeater will cause interference within repeater W3XYZís coverage area, if W3XYZ is agreeable, you might both tolerate the interference voluntarily. This is often referred to as "negotiated interference" or "self coordination". Whether or not the affected party is agreeable to this sort of arrangement is purely up to them; ARCC cannot force them to enter into such an agreement. If you are able to work out a negotiated interference agreement, have the other party (or parties) provide you with a letter of consent, and include it with your coordination application resubmission.
Q: What is the "waiting list", and how do I get on it?
A: Due to ever-increasing congestion and a general lack of available repeater frequency pairs, particularly on 2m, there may not be a viable frequency available for a proposed operation. In such cases, the applicant may request to be put on the waiting list. As of this writing, ARCC only accepts and process repeater applications via the waiting list for 2m repeaters located in New Jersey and in Bucks, Montgomery, Chester, Philadelphia, Delaware, Lehigh, Northampton, and Berks counties in Pennsylvania. Applications for new FM repeaters in all other counties are accepted and processed in the usual manner, as are applications to modify existing repeater coordinations.
Applicants who wish to request that their application be put on the waiting list for a 2m pair should submit a standard coordination application that provides all of the technical parameters for the proposed operation except for input and output frequencies, and check off the box on the application form to request to be put on the waiting list. ARCC will review the application when received, and if there already exists an available frequency pair suitable for the proposed operation, the coordination will be processed normally. If not, the application will be put on hold and recorded on the waiting list.
Waiting lists help insure that coordination applications will be processed in a more timely manner by eliminating the burden on ARCC's staff of having to process the many applications that ARCC regularly receives for repeaters in areas where there are simply no repeater pairs available. It also helps ensure that applicants who are truly interested in putting up a new repeater will have the best chance of obtaining coordination as pairs become available, and in doing so, applicants who have been waiting the longest will receive the highest priority.
Q: How are applications that are on the waiting list processed?
A: As frequency pairs become available, either through cancellation of an existing coordination or modification(s) to an existing coordination that result in a potential pair becoming available, the waiting list will be examined to determine if any of the applications on the list could be processed. The applications on the waiting list will be evaluated in the order received; that is, the oldest application will have the highest priority.
ARCC will not attempt to "re-engineer" an application that is on the waiting list to make it "fit" into an available channel/location. Once put on the waiting list, the technical parameters of the proposal cannot be changed unless the applicant requests that the existing application be dismissed and a new application submitted in its place. However, the revised/resubmitted application will be placed at the bottom of the waiting list; it will not take the place of the former application.
Q: Can I submit multiple applications to be added to the waiting list?
A: No. Only ONE waiting list application will be accepted from a given individual or club/group for a particular band. Individuals who are members of a club or group may not submit an additional application for the waiting list if the club/group they are associated with already has an application on file.
Q: How long will my application remain on the waiting list?
A: In the interest of preventing the waiting list from accumulating applications for new repeaters from applicants who have since lost interest in applying for a 2m repeater pair, waiting list applications will remain on the list for a period of two years, after which time they will expire. ARCC will notify the Primary Contact that the application is about to expire. Applicants may choose to reinstate the application at that time, without modification, if they so choose. Applicants who request reinstatement will retain their current position on the waiting list provided that the technical parameters of the proposal are not modified in any way. Please note that is the responsibility of the applicant to keep ARCC apprised of any changes to contact information. If your waiting list application is about to expire and correspondence to you fails, the application will be removed from the waiting list upon expiry.
Q: Our club is very large and wants to put up a repeater. I know that frequency pairs are scarce in many areas. Will you consider the fact that our repeater will be sponsored by a large club with many active members when you review our application?
A: Simple answer: NO. ARCCís coordination review process takes into account ONLY whether or not the proposed operation will adversely impact existing, coordinated operations, or be adversely affected by the same. It is a purely technical analysis. No other factors, such as association with any club or government agency, number of members, repeater features, etc. go into the decision.
Q: Do I have to pay to get coordinated?
A: No. No fee is required to apply for coordination. However, ARCC, as a non-profit corporation, does have a dues structure as part of membership in ARCC. Dues paid as part of membership in ARCC go to defray the costs of operating the organization, including postage costs, printing and duplication costs, and other expenses. We encourage coordination applicants to become members in ARCC, but it is not required to obtain coordination. Members also receive the ARCC Newsletter, are eligible to nominate and cast votes for elected ARCC positions, and other benefits as described in ARCCís Constitution and By-Laws (available on the ARCC web site).
Q: How should I gauge whether or not a frequency I have found is likely to be coordinated?
A: If you think you have found a viable pair, you can contact ARCCís Database Manager and ask that a search be done to see what other "hits" come up. You will need to provide all of the technical parameters for your proposed operation in order for a search to be performed. Keep in mind that in many cases, not only do other co-channel repeaters affect whether or not a new repeater can be coordinated on that pair, but adjacent-channel repeaters may also weigh into the decision, particularly on 2m where repeater pairs above 146 MHz are spaced at 15 kHz, and on 70cm where every adjacent pair is inverted.
Q: Should I try to find a pair that is the furthest away from any other repeater on the same pair?
A: A pair that is "wide open" for a hundreds miles isnít necessarily the best pair. The best pair for a given operation is one that serves the coverage of the proposed repeater while wasting the least amount of geography between other co-channel and adjacent-channel repeaters. For example, assume two co-channel repeaters that are 160 miles apart, each with a simplified 30 mile radius circular coverage area. That leaves a 100 mile "dead zone" between the two. If a new proposed repeater also has a 30 mile coverage radius, it can be fit mid-way between those two repeaters, but in doing so, it leaves two 20-mile "dead zones" between the each of the original repeaters and the new repeater. The likelihood of fitting a fourth of fifth repeater in those 20-mile dead zones is unlikely, thus that geo-spectrum ends up being wasted. ARCC does not attempt to crowd co-channel repeaters together excessively, but at the same time, any waste of spectrum is to the detriment of the amateur community, thus we try to recommend pairs for new operations that are the best fit for the proposed operation.
Q: If I become a member of ARCC, will that help get my coordination approved?
A: Again, the answer is NO. Whether or not you are a member of ARCC has no bearing on the coordination review process. In fact, neither the coordinators, database manager, nor anyone else involved in the coordination review process knows who is or is not a member of ARCC. The membership database is maintained by ARCCís Treasurer, and the coordination database is maintained by the Database Manager. The two databases are intentionally kept separate as a matter of policy.
Q: Are CTCSS (PL) tones part of the coordination?
A: Yes. The PL tone, or other access control mechanism such as a digital code (DCS/DPL) or touch tones (DTMF) that are necessary to access the repeater are part of the coordination. They must be chosen so as not to conflict with any other repeaters that are currently coordinated. The access control cannot be changed without applying for a modification to the coordination, just like any other coordinated parameter. Generally speaking, you should not select a PL tone that is use for any other repeater in ARCCís territory or that of an adjacent coordination councilís territory. All repeater receivers and auxiliary links must utilize some form of access control; carrier-squelch operation is not allowed. Digital and ATV repeaters and auxiliary links are presumed to have a de facto means of access control by virtue of the transmission mode.
Q: I heard someone talking about a "paper repeater" in my area. Whatís a paper repeater?
A: A "paper repeater" is a derogative term for a coordination that was issued for a repeater, but the repeater has been off the air for a lengthy period of time, or perhaps was never constructed. The "paper" in "paper repeater" is the coordination, i.e. there doesnít exist any real repeater, just coordination paperwork. ARCC approves quite a number of coordination applications every year for repeaters which end up never being constructed. As such, we ask that anyone applying to coordinate a new repeater should be certain that they (and their wallet) are up to the task, for "paper repeaters" that exist in congested bands in congested areas only serve to deprive other willing applicants from operating a repeater. If you are aware of a "paper repeater", particularly in congested areas on a congested band where there are no other frequency pairs available (particularly 2m), you should contact ARCC so a regional representative can check up on the status of that repeater. Along the same lines, if you know of someone who holds a coordination for a paper repeater, you might suggest that they turn in their coordination voluntary rather than waiting for ARCC to de-coordinate the repeater.
Q: Iím planning on running this repeater from my house, at least initially. Later I might want to move it to a better site. Can I do that?
A: ARCC approves or denies coordinations based on the exact information supplied at the time of coordination. Any changes to the repeater that will affect its coverage area, such as relocation, changing power or antenna system, changing antenna height, etc. require that an application to modify the coordination be submitted and approved before the changes are made. This is the only way ARCC can ensure that any changes will not adversely affect other coordinated operations. There is no way ARCC can guarantee that later improvements to your repeater will be able to be coordinated; we can only review and act on the data provided at the time the application is presented to us. As a caveat, if changes are made without first getting the coordination modification approved, it is grounds for canceling the existing coordination.
Q: Well, can I get a coordination for a high-profile site now, operate the repeater low-profile for a while, and then move it to the better site later?
A: No. You must specify the parameters that the repeater will be operating on at present. Later, you can apply to modify the coordination when the time comes. The coordinated parameters must always coincide with those parameters the repeater is operating with at all times. The coordinated parameters are not "minimum" values or "maximum" values, they are exact values that must be adhered to, otherwise the coordination may be terminated.
Q: How do I know what frequency or frequencies might be available for my repeater?
A: The first step is to do some research on your own. The information published on ARCCís repeater directory on the web site may help you find some prospective frequencies. Adjacent coordination councils also publish their own repeater directories on their web sites as well (links to those sites can be found on ARCCís web site). However, keep in mind that some repeaters are not listed by request of the coordination holder, so even if you find a pair that "looks good" based on the databases, it may be occupied. On-air monitoring of the prospective frequency may help determine if the frequency is already occupied. If you have found a frequency pair that appears to be usable for your operation, specify it on the coordination form. If you are unsure as to how suitable the pair or pairs you have found are, there is a checkbox on the form that asks that ARCC supply you with a list of prospective frequencies. If you select this box, ARCC will send you a list of prospective frequency pairs (if any) that appear to be good possibilities for your proposed operation. However, keep in mind that ARCC does not "assign" frequency pairs, nor is there any guarantee that any of the frequencies suggested by ARCC can be coordinated for your operation. All applications require analysis by the coordinator, and cross-coordination with the adjacent coordination councils, any of whom may object to the proposed operation. All we can do is help steer you toward pairs that appear to be good choices based on the data we have available at the time the application is received. Aside from the 2m band, it is very rare that ARCC receives an application that requests a list of possible frequencies and we are unable to ultimately suggest and coordinate a suitable repeater pair or auxiliary link frequency for the applicant.
Q: Should I build my repeater and put it on the air first to see if there is any interference and then apply for coordination, or should I apply for coordination before putting it on the air?
A: You should apply for coordination first. If you put the repeater on the air before receiving coordination, any interference reports ARCC receives prior to processing your coordination only works against you. ARCC has the most accurate and up-to-date information on all repeaters within ARCCís territory as well as the adjacent councilís territories for helping to identify which frequency(s) are would likely not cause interference to other existing coordinated operations.
Q: How long is my coordination good for, and can it ever be cancelled?
A: Generally speaking, coordinations are valid for the life of the operation with a few stipulations, including:
These are some of the conditions for maintaining your coordination. Others can be found in the document that is included with your coordination certificate.
Q: How long does it take to process a coordination application?
A: It depends. Since ARCC is staffed by volunteers, coordinations are often processed in batches to make the most efficient use of their available time. The coordination application passes through several ARCC posts. It is first received by the Vice President of Administration who records that the application was received, and immediately sends back a "Speedy Reply" to confirm to you that your application was received. The application is then sent to the Database Manager who reviews the application to see if there is any missing information, does some preliminary investigation and database searches to ascertain what other operations may have an affect on the application, sends cross-coordination notifications to the adjacent councils to solicit their approval or comments, and then forwards everything to the coordinator for review. The coordinator may consult with other Board members, adjacent coordination councils, the Regional Representative for the area in which the repeater is located, etc. during the review process. Once the coordinator has reached a decision, it is conveyed back to the Database Manager and to the Vice President of Coordination for concurrence. The Database Manager updates the database and other internal records to reflect the final status of the coordination (approved or denied), and prepares whatever paperwork is required to be sent to the applicant: either a Certificate of Coordination if the coordination was approved, or a notice of rejection if it could not be approved. Between the internal process, and the mandatory 30-day notice period required by the adjacent councils, an application typically takes 6 to 10 weeks to process. Modifications that are considered "administrative changes" that do not affect the coverage of the repeater, such as updating contact information, vanity callsign changes, repeater features, etc. are processed much quicker as there is no adjacent-council communication required nor coordinator review.
Q: Iíve had a repeater for a number of years now and have lost interest, so Iím thinking about selling it. Can I have the coordination transferred to whoever buys my repeater hardware?
A: The shorter answer is no, coordinations cannot be bought, sold, or transferred. The only exception to this rule is if the repeater is sponsored by a club and the original holder of coordination is no longer able to serve as the caretaker of the repeater coordination, due to illness, relocation, death, or disassociation with the organization. Under such a circumstance, the coordination may be re-issued in the name of the club, but not in the name of another individual. Transfer of coordination between clubs, or between individuals, is not permitted under any circumstances. Youíre obviously free to do whatever you want with your repeater equipment, you own it, but the coordination doesnít go with it.
Q: Iím confused. Whatís the difference between "trustee", "holder of coordination", "sponsor", and "primary/secondary contact"?
A: A trustee is the person responsible for the operation of the repeater in the eyes of the FCC. The trustee of a club license is responsible for the proper operation of the station(s) utilizing that callsign, including any associated repeater and auxiliary link stations. ARCC does not use the word "trustee" anywhere in the coordination application or process. ARCC uses the notion of "holder of coordination" to denote who "owns" the coordination. The holder of coordination is the only person or entity that has rights or claims to the coordination, irrespective of who is the trustee or licensee of the callsign used on the repeater, who owns the repeater hardware, who the contact person(s) are, who "sponsors" the repeater, or any other factors. The primary contact is simply the person to whom ARCC sends correspondence, but in no way has a bearing on who holds the coordination. The secondary contact is the person ARCC will attempt to contact if communication with the primary contact fails. The Sponsor is used solely in repeater directories to denote, in sometimes abbreviated form, what club or organization sponsors the repeater but has no other bearing on who holds, or has rights to, the coordination.
Q: Iím the officer of a club. Our club is thinking about building a repeater, and Iíve been nominated to handle the coordination application. Should I have the coordination issued in my name, or in the name of my club?
A: Generally speaking, it is always best to have the coordination issued to the club rather than an individual. That is, at the top of the coordination form, where it asks who the Holder of Coordination should be, it should be the name of the club. If the coordination is issued to an individual, such as a club officer, instead of to the club as a whole, and that individual decides to disassociate himself/herself from the club, the club would have no claims to the repeater coordination. In other words, the club member who the coordination is issued to can leave, taking the coordination with them. Who owns the repeater hardware (the club or the individual) has no bearing on the matter. The holder of coordination can not be changed; this relates to ARCCís policy of not allowing transfer of coordination.
Q: Iíd like to put up an ATV repeater. Is coordination only for voice repeaters?
A: No. ARCC coordinates all repeaters and auxiliary links, be they FM, ATV, or digital. Each is treated differently, but all are coordinated operations in ARCCís service area.
Q: Exactly what areas does ARCC provide coordination services in?
A: ARCC serves the following counties:
Pennsylvania: Adams, Berks, Bradford, Bucks, Carbon, Chester, Columbia, Cumberland, Dauphin, Delaware, Juniata, Lackawanna, Lancaster, Lebanon, Lehigh, Luzerne, Lycoming, Monroe, Montgomery, Montour, Northampton, Northumberland, Perry, Philadelphia, Pike, Schuylkill, Snyder, Sullivan, Susquehanna, Tioga, Union, Wayne, Wyoming, and York.
New Jersey: Atlantic, Burlington, Camden, Cape May, Cumberland, Gloucester, Hunterdon, Mercer, Ocean, Salem, Sussex, and Warren.
Q: Do you coordinate packet activities such as digipeaters, PacketCluster, and BBSís?
A: Digital (packet) activities that operate on simplex channels are not coordinated activities within ARCC. As those channels are inherently shared by the nature of the mode(s), both by users as well as host systems, coordination is not practical, and any such "coordination" would have no standing in the scope of Part 97 which allows for coordination of only repeaters and auxiliary links. Duplex real-time bit-regenerative digital repeaters may be coordinated on 70cm and above in the respective digital repeater subbands. Whether the digital repeater is being used for data, digitized voice, a combination thereof, or any other digitized medium or mode does not matter, they are all treated as digital repeaters.
Q: Do you coordinate D-Star, Project 25, and other digital voice repeaters?
A: Yes. Digital voice repeaters may be coordinated on channels in subbands reserved for digital repeaters. On bands where there are no channels reserved exclusively for digital repeaters, digital voice repeaters may be coordinated on standard analog (FM) repeater pairs subject to all of the usual coordination requirements including channel spacings defined in the current bandplans.
Q: Do you coordinate IRLP, EchoLink, and other radio-over-IP types of operations?
A: Nodes which operate on simplex frequencies are considered remotely-controlled stations. They are not repeaters, and as such, are not eligible for coordination as such, nor should they be operated in the coordinated repeater or auxiliary link subbands. In some instances, such operations may utilize auxiliary links as a means of control or interconnection, and in such cases, they may be coordinated as such provided they meet the applicable standards for coordination. Auxiliary links which operate within the repeater subbands, such as a remotely-located radio interfaced to the Internet that transmits into a repeater receiver and receives the repeater output, are not eligible for coordination and are contrary to ARCC bandplans and coordination policies.
Q: How about control receiver frequencies? I see there is a place on the coordination form to specify a control frequency.
A: Because control receivers are used on a relatively infrequent basis, ARCC does not issue a separate coordination for control. However, ARCC will assist you in selecting a frequency which will not interfere with other operations, and suggest a PL tone for the control receiver unique to that frequency, to allow shared use of the control frequency. If you plan to use a control frequency often and on a fairly regular basis, such as for remotely controlling a remote base station, it can be coordinated as an auxiliary link provided both endpoints are at fixed locations.
Q: Do I have to have a control frequency/control receiver?
A: It depends. If you have a non-RF means for controlling the repeater, such as a phone line, then you may not need a separate control receiver. However, if you rely on a phone line for control, keep in mind that the line must always be available for controlling the repeater. It cannot also be used for an autopatch, for if an autopatch call is in progress and the repeater needs to be controlled (such as if someone is making prank calls or dialing 911 maliciously), your control mechanism is unavailable, thus rendering the operation in violation of FCC rules. Some repeater controllers have provisions for two phone lines Ė one for control and one for autopatch. You may be able to legally use the repeater receiver as a means of remote control provided the repeater receiver operates on a frequency eligible for auxiliary link use per Part 97. A few minutes spent reading the sections of Part 97 dealing with Station Control, Repeater Station, and Auxiliary Station should help clarify what is required for remotely controlling a station.
Q: What are auxiliary links, and what are they used for?
A: Auxiliary links are dedicated point-to-point paths between two sites. Auxiliary links are allowed only on 222.15 MHz and above by Part 97. There are subbands available in ARCC bandplans in compliance with Part 97 band segments available for auxiliary link use. Typically auxiliary links are used to interconnect two sites. Examples would be to link a repeaterís autopatch to a phone line located at a location other than the repeater site, to deliver audio from a remote receiver to the repeater transmitter site, or to link two repeaters together. An auxiliary link requires two sites, one designated the transmit site, and one designated the receive site. Information for both sites is required. If the link is bidirectional (duplex, either half-duplex or full-duplex), it requires a transmitter at each end. Each transmitter requires its own coordination, hence a duplex link actually requires two coordinations.
Q: Whatís the difference between an auxiliary link and a control link?
A: An auxiliary link is a point-to-point RF connection between two sites comprised of a transmitter and a receiver. As far as coordination is concerned, the endpoints of an auxiliary link are fixed and are not subject to change. In contrast, a control link is typically comprised of a control receiver at a fixed location, such as a repeater site, but the transmit side is not fixed. For example, a 900 MHz control receiver used to control a 2m repeater may be accessed by control operators of the repeater who may be operating from their respective home stations, while mobile, or portable, i.e. not from a single fixed location. From a Part 97 standpoint, control links utilize auxiliary links. From a coordination standpoint however, control links and auxiliary links are treated differently. ARCC coordinates auxiliary link transmitters as described above, but generally does not coordinate receive-only control receivers. A simple way of thinking about it is that ARCC coordinates transmitters, and only when those transmitters are at a known, fixed location.
Q: I plan to have multiple receivers for my repeater as part of a voting system. Do I need to coordinate each receiver?
A: ARCC coordinates transmitters. If your remote receivers are going to use auxiliary links to deliver their respective audio back to the repeater transmitter site, then each will require an auxiliary link coordination. However, if the receivers are going to use leased lines or other non-amateur-RF mediums, then no additional coordination is required. Keep in mind that ARCC performs coordination review analysis and defines a repeaterís protected service area based on the repeater transmitterís coverage. If you add remote receivers, your coordination will not protect your receivers beyond the repeater transmitterís coverage area.
Q: A few of us have gotten together and decide to link our 1.25m repeaters together. We figure we can pick the repeater that is most centrally located and use it as a hub, and have all of the other repeaters link into it by transmitting on its input and receiving its output. How do we coordinate those links?
A: "In-band linking" or "linking on the input", as this method is frequently referred to, is not eligible for coordination. All link transmitters that interconnect repeaters must be coordinated on frequencies in the auxiliary link subbands. Linking on the input is poor practice as there is a very good chance that such link transmitters will cause interference to other repeaters which operate on the same pair as the targeted "hub" repeater given the crowded band conditions in most of ARCCís service area. "Passive linking" or "receiver-only" linking, where each repeater receives the output of another repeater but otherwise has no additional link transmitter involved does not require coordination as there are no additional transmitters to be coordinated. Of course, being uncoordinated, the additional receivers involved may experience interference from other repeaters on the same channel as the repeater being received, and therefore are afforded no protection from such interference.
Q: I have a repeater that is coordinated by ARCC. I am receiving interference from some uncoordinated repeater on the same pair. Can you get the other repeater to QSY or shut down?
A: For better or for worse, coordination councils do not have enforcement powers. ARCC cannot order another repeater off the air. We can apprise the other repeater that they are causing interference to your coordinated repeater, but other than that, we have limited resources to solve the problem on your behalf. If you have not already contacted the other repeater owner, you should do that as a first step. If the problem cannot be resolved amicably, and if conditions so warrant, you can contact the FCC to ask for assistance. Often when an interference complaint is filed involving repeater-to-repeater interference, the FCC will contact ARCC to verify the coordination status of both partiesí operations, and obtain any technical or historical information necessary as part of the investigation. ARCC has an excellent working relationship with the FCC, and they have been very helpful in dealing with interference matters and some particularly sticky coordination matters as well.
Q: How about the ARRL, will they help?
A: Perhaps, but keep in mind that the ARRL has nothing to do with frequency coordination. The ARRL does not certify coordinators, nor oversee the operation of coordinators. The ARRLís main involvement with coordination is in publishing the ARRL Repeater Directory. The ARRL solicits information for publication in the Repeater Directory directly from repeater coordinators, but thatís the extent of it.
Q: This FAQ was helpful, but I still have more questions. Who can I contact?
A: The easiest way to reach ARCC for general questions is through email at . Although email is convenient for routine questions, coordination applications and other correspondence related to formal matters should be sent via paper-mail to the aforementioned mailing address.
Email any comments or suggestions regarding this FAQ to