Frequently Asked Questions
Q: I’m thinking about building a repeater, but I’m not sure where to start. Any suggestions?
A: First 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 to build 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 doesn’t 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 haven’t 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 plan to serve, and do you have a viable repeater site available? You will need to obtain geographic information for the site, including latitude, longitude, elevation, and the height above ground for the transmitting antenna. What kind of hardware do you plan to use, including transmitter, receiver, duplexing equipment if required, filtering hardware, antennas, controller, etc.? Based on the hardware selected, you will need to obtain parameters related to the transmitter power output, feedline loss, antenna gain, antenna pattern, etc. as required to complete the coordination application.
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: Click here for links to helpful sites.
Q: What is the process for applying for coordination?
A: First, download the appropriate coordination form and instructions from the ARCC web site. The form asks for general information such as who the coordination will be issued to, what features the repeater has, 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 won’t engineer your repeater, but if you have questions about the forms or the coordination process, we’re more than happy to help. Ask questions before submitting the application, as once it is submitted, ARCC cannot correct errors for you.
Q: I don’t know the exact coordinates of my repeater site. How specific do I have to be?
A: ARCC requires coordinates accurate to within 1 second in WGS84 datum. In the old days, this would have to be determined by a surveyor to achieve that level of accuracy. Nowadays, consumer software and public web sites can be used to determine coordinates with good accuracy. A global positioning satellite receiver (GPS), such as those built into many smartphones, is also an excellent tool. The reason precise coordinates are required is that the coverage analysis software ARCC uses requires precise location and elevation data in order to generate an accurate prediction of your repeater’s coverage. ARCC checks the supplied coordinates against satellite imagery to verify that there is a viable antenna structure at the location specified.
Q: I’m not a real technical type. I’m not sure what some of the things you’re 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. Do not 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.
Q: I have the forms filled out. Where do I send them?
A: Email completed applications to the address indicated on the form.
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. Every repeater has a unique coverage area, and as such, every repeater is treated individually during the coordination review process. ARCC analyzes not only what affect your proposed repeater will have on other incumbent, coordinated, repeaters that are on the same frequency, but in many cases, adjacent-channel operations also must be considered.
Q: If you don’t go by mileage, how do you decide whether a repeater can or can’t be coordinated?
A: ARCC performs coverage and interference analysis using high-end modeling software. The models take into account all of the parameters of your proposed operation, including EIRP, antenna pattern, location, elevation, terrain, frequency, etc. The result of the models are evaluated against those of other co-channel and adjacent-channel repeaters to predict whether or not your operation is likely to cause or interference to, or receive interference from, other existing coordinated operations. 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 councils’ 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 denied. There are a number of common reasons why a given coordination could not be granted, several of the more common of which are described below:
Predicted interference to/from another co-channel repeater. In other words, your repeater would cause interference to, or receive interference from, an existing operation on the same frequency pair. How can you fix it? In some cases, reducing power, lowering antenna height, using a different site, or using a directional antenna system may eliminate the predicted interference. The coordinator may make a note on the “suggestions” line on the coordination rejection form giving to give you some idea on how you might modify your proposed operation to make it “fit”.
Predicted interference to/from an adjacent-channel repeater. It is predicted that your repeater will adversely affect the operation of a repeater operating on an adjacent channel, or receive interference from the same. This is most common on the 2m band for repeaters operating above 146 MHz where the channel spacing is 15 kHz. Like #1 above, the interference may be able to be remedied by modifying your proposed operation and resubmitting the application.
Operation does not comply with ARCC bandplans or does not comply with Part 97 regulations. If either of this is the case, there is a major problem with the application, such as the frequency(s) requested are not eligible for repeater operation. If this is the case, there is no sense in resubmitting the application until proper frequency(s) are selected.
No frequencies available in band of interest. ARCC was unable to find a viable frequency for your proposed operation. At your option, you resubmit an application to be put on the waiting list, or re-apply for a different band.
Existing interference reports. If you put your repeater on the air before obtaining coordination, and interference reports have been presented to ARCC and have been found to be valid complaints or concerns, your coordination will not be granted. It is in everyone’s best interest to obtain coordination before putting the repeater on the air to avoid this situation.
If you feel that ARCC may have erred during the coordination review, you can appeal for a full board review of the application as described in the ARCC Constitution and By-Laws.
Q: I can’t see any way to modify my operation to get it approved, and there don’t 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 to whom your proposed operation would cause interference. For example, if it is predicted that your repeater will cause interference within repeater W3XYZ’s coverage area, if W3XYZ is agreeable, he may tolerate the interference voluntarily. This is often referred to as “negotiated interference”. 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 re-submission.
Another option is to apply for an SNP (Shared, Non-Protected) repeater pair. There are frequencies reserved on the most popular bands for shared use. SNP repeaters are COORDINATED repeaters, with the exception that they may, and likely will, share coverage with others. Unless an adjacent council objects to a proposed operation on an SNP pair, coordination will be approved without any interference analyses provided that all other conditions for use of an SNP pair are met. Note that, from a Part 97 standpoint, stations that are coordinated as SNP repeaters are still protected from interference from uncoordinated repeaters as is any other coordinated repeater. Given the scarcity of available repeater pairs in many areas, repeaters that can successfully share a frequency with other similar systems are strongly encouraged to chose the SNP option at the time of application.
Q: What is a “waiting list”, and how do I get on it?
A: Due to ever-increasing congestion on the most-popular frequency bands, particularly in densely populated areas, frequencies may not be immediately available for new operations. For areas/bands where waiting list policies are in effect, applicants who wish to request that their application be put on the waiting list submit a complete coordination application that provides all of the technical parameters for the proposed operation, and mark 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 list policies 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: Whenever there is a cancellation of an existing coordination, or a modification made to one or more existing coordinations, the waiting list is examined to determine if any of the applications on the list could be approved as a function of the recent cancellation or modifications. The applications on the waiting list will be evaluated in the order received; that is, the oldest application will have the highest priority.
Once an application is 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. 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 renew waiting list applications prior to their expiry, in addition to keeping ARCC apprised of any changes to contact information while on the waiting list.
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. ARCC’s 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 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 ARCC’s Constitution and By-Laws (available on the ARCC web site).
Q: Should I pick a frequency on my own and 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 and allow ARCC to find a viable frequency first. If you pick a frequency on your own and put the repeater on the air before receiving coordination, there is no guarantee that the frequency you chose can be coordinated, or will be coordinated.
Frequency coordination and the application process is not a race; putting a repeater on the air before applying for coordination affords the applicant no additional benefit. Coordinations are processed in order they are received. "First on frequency" does not result in priority in the processing of coordination applications, and likewise, Part 97 and the FCC's enforcement thereof does not give any preference to was there first, only who is or is not coordinated. Furthermore, any interference reports ARCC receives prior to issuing coordination only works against the applicant.
Q: I've researched public repeater lists on the Internet and elsewhere - can I just pick a pair that appears to be "clear"?
A: Not a good idea, for a number of reasons. First, repeater lists found on the Internet, and even those from pay services, are notoriously inaccurate are not authoritative. While there are some web sites that admirably do their best to weed out bogus listings, the fact remains that the only data that matters when it comes to coordination is what is in ARCC's database, and what is in the databases of the neighboring councils that ARCC recognizes and with whom ARCC has agreements.
Furthermore, adjacent-channel interference, intermodulation mixes and/or receiver desensitization of co-located systems, difference in bandplans between coordination regions, "inverted" frequency offsets, non-compliant grandfathered operations, unlisted repeaters, and a host of other issues cannot be identified by simply looking at repeater lists on the web or elsewhere.
And, there are many coordinated repeaters that are not listed in public directories.
A repeater pair that seems to be “clear” for a hundred miles or more is not necessarily the best pair. The ideal pair for a given operation is one that serve to protect the coverage area of the proposed repeater while wasting the least amount of geography between other incumbent coordinated stations. 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 has a 20 mile coverage radius, it can be fit mid-way between those two repeaters, but in doing so, it leaves two 30-mile “dead zones” between the original repeaters and the new repeater. The likelihood of fitting a fourth of fifth repeater in those 30-mile dead zones is unlikely, thus that geo-spectrum ends up being wasted. ARCC does not try 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 find pairs 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: 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 ARCC’s 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), color code for DMR repeaters, etc. that are necessary to access the repeater are part of the coordination. They must be selected at the time of coordination so as not to conflict with any other repeaters that are currently coordinated. Like any other coordinated parameter, access control tones or codes may not be changed without applying for, and receiving approval of, a coordination modification. Generally speaking, a tone or code that is use by any other co-channel repeater in ARCC’s territory or that of an adjacent coordination council’s territory may not be selected or requested. All repeater receivers and auxiliary links must utilize some form of access control; carrier-squelch operation is not allowed. For SNP repeaters, ARCC will assign a tone/code that does not conflict.
Likewise, the emission of the repeater is a part of the coordination and may not be changed without a coordination modification. For example, it would not be permissible to change a repeater coordinated for analog (FM) operation to a digital mode without recoordination. Depending on the band and mode, such a change may also require a move to a different frequency.
Q: I heard someone talking about a “paper repeater” - what is that?
A: A “paper repeater” is a pejorative term for a coordination that was issued for a repeater, but the repeater was never constructed or has been off the air for an extended period of time. The “paper” in “paper repeater” is the coordination, i.e. there doesn’t 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 on a congested band where there are few frequency pairs available such as on 2m, please report it to ARCC so that a regional representative can check up on the status of that repeater.
Q: I’m 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 long is my coordination good for, and can it ever be cancelled?
A: Generally speaking, a coordinations is valid for the life of the operation with a few stipulations, including:
Any new repeater coordination, or modification to an existing coordination that results in change of coverage, is subject to an initial 90-day probationary period. If reports of interference to another coordinated repeater within ARCC or one of our adjacent councils' territories is received during the probationary period and it cannot be adequately addressed and remedied in a timely fashion, the coordination will be cancelled.
Periodically ARCC may contact you to ensure that we have accurate data on file. If correspondence to the primary contact fails, ARCC will try the secondary contact. If all attempts at communication fail, the coordination may be cancelled. Thus it behooves you to keep ARCC apprised of any changes to your contact information, such as mailing address, phone numbers, and email address.
If any modifications are made which result in the operating parameters being different than the coordinated parameters without first applying for, and receiving approval of, a coordination modification, the coordination will be cancelled.
If any attempt is made to sell or transfer the coordination, the coordination will be cancelled.
If the coordination is for a new repeater, and the repeater is not put on the air and operating in compliance with the coordinated parameters within the 180 day construction period, the coordination may be cancelled.
If the repeater is off the air for more than 30 days and ARCC is not notified, the coordination may be cancelled. If the repeater has to be taken off the air for more than 30 days due to extenuating circumstances, ARCC may extend the downtime grace period if requested in writing prior to the expiry of the initial 30 day grace period. In areas where there exist a waiting list for a particular band, downtime in excess of 90 days will result in termination of the coordination.
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. Upon receipt of the application, a “Speedy Reply” is sent to the applicant via email to confirm it was received. The application is then sent to the VP of Coordination who reviews the application for flawed or missing information, and then forwards it to the Database Manager for processing, including finding potentially-viable frequencies for the proposed operation. Analyses, including computer models, are performed to ascertain what other operations may be adversely affected. Cross-coordination notifications to the adjacent councils are sent to solicit their approval as required by established agreements. 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 course of the review process. Once a decision has been reached, it is conveyed to the Vice President of Coordination for concurrence. The Database Manager then updates the database and other internal records to reflect the final status of the coordination (approved or denied), and prepares whatever paperwork is needs to be sent to the applicant -- typically either a Certificate of Coordination if the coordination was approved, or a notice of rejection if it could not be approved. Between the internal processes, and the mandatory 30-day notice period required by the adjacent councils, an application typically takes 6 to 10 weeks to process if cross-coordination is approved on the first attempt. If cross-coordination fails, the process restarts at the point of the Database Manager searching for another potentially-viable frequency pair. 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 (other than access control tones/codes), etc. are processed much quicker as there is no coordinator review or adjacent-council approval required.
Q: I’ve had a repeater for a number of years now and have lost interest, so I’m thinking about selling it. Can I have the coordination transferred to whoever buys my repeater hardware?
A: The short 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, 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. Posthumous transfers are not permitted; the coordination dies with the coordination holder. You are obviously free to do whatever you want with your repeater equipment -- you own it -- but the coordination doesn’t go with it.
Q: I’m confused. What’s the difference between “trustee”, “holder of coordination”, “sponsor”, and “contact”?
A: 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 party 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, what group or club “sponsors” the repeater, or any other factors. The "sponsor", if any, 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: I’m the officer of a club. Our club is thinking about building a repeater, and I’ve been nominated to handle the coordination application. Should I have the coordination issued in my name, or in the name of my club?
A: 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 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 ARCC’s policy of not allowing transfer of coordination.
Q: Exactly what areas does ARCC provide coordination services in?
A: ARCC is the frequency coordinator for 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 BBS’s?
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 are eligible for coordination. 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, DMR, and other digital voice repeaters?
A: Yes. ARCC coordinates all repeaters and auxiliary links, be they analog or digital, whether they repeat voice, data, video, or any other payload. Each is treated differently, but all are coordinated operations in ARCC’s service area. 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, or where there are no digital repeater pairs available, digital voice repeaters may be coordinated on standard analog (FM) repeater pairs. See the ARCC bandplan for details.
Q: Do you coordinate IRLP, EchoLink, and other radio-over-IP types of operations?
A: Nodes which operate simplex (same frequency for transmit and receive) 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: Must I have to have a 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, as 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 – 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 repeater’s 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: What’s 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 repeater’s protected service area based on the repeater transmitter’s coverage. If you add remote receivers, your coordination will not protect your receivers beyond the repeater transmitter’s coverage area.
Q: A few of us have decided to link our 1.25m repeaters together. We are thinking 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 high likelihood that the link transmitter 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 ARCC’s 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. If you have not already contacted the other repeater owner, you should do that as a first step. Or, ARCC can apprise the other repeater that they are causing interference to your coordinated repeater on your behalf if you desire. 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 contacts ARCC to verify the coordination status of both parties’ operations, and to obtain any technical or historical information necessary as part of the investigation. ARCC has an excellent working relationship with the FCC.
Q: How about the ARRL, will they help?
A: The ARRL has nothing to do with frequency coordination. The ARRL does not certify coordinators, nor oversee the operation of coordinators. Historically, the ARRL’s only involvement with coordination has been publishing the ARRL Repeater Directory using data supplied by frequency coordinations, but that relationship has since ended and the ARRL no longer queries frequency coordinators for annual data. The listings on ARCC's web site are the most accurate and up-to-date public information available.
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