• All convention document packets will be “Will Call”
• Convention documents (badge, tickets, etc.) will not be mailed
• Your convention documents will be waiting for you at the Registration “Will Call” Desk at the convention.
To stay informed about SEA-PAC, subscribe to the low volume “SEA-PAC Waves” eMail list by sending an email with your name and callsign to email@example.com. To see the latest SEA-PAC “Waves” newsletter CLICK HERE
It’s taken some time to get off the ground, but I’m happy to announce the All Weather Solar-Powered Field Station project.
The All Weather Solar-Powered Field Station is my attempt to put together a man portable, rapidly deployable, 2 operator, solar-powered field station other operators, clubs or organizations in the emcomm or survival communities can replicate.
That said it’s also important to remember that this is just the template or kind of a guide. I’m just showing you how I’ve been able to implement my field station. How you implement yours will depend on your requirements, budget, and of course your individual goals. Remember there’s no right or wrong way here. There’s only the way we achieve our goals!
Portable Ham Radio Station on Solar Power | Introduction
In today’s video I’d like to discuss the concept of a solar-powered portable ham radio station field station for casual or emergency communications. Those of you who follow the blog, probably already know about this project. For the rest of you here is a video introduction of a concept I call the All WX Solar-Powered EMCOMM Field Station.
The concept for a rapidly deployable, man-portable ham radio field station, came to me after the grid down disaster caused by Hurricane Maria. Hurricane Maria knocked out electricity and communications throughout Puerto Rico. this was an Awakening for many preparedness minded amateur radio operators around the world.
Description. This course is designed to provide basic knowledge and tools for any emergency communications volunteer. Visit ARRL for complete course details.
Public Service and Emergency Communications Management for Radio Amateurs (EC-016)
Description. This course is designed to train licensed Amateur Radio operators who will be in leadership and managerial roles organizing other volunteers to support public service activities and communications emergencies.
ARRL Self-Guided Emergency Communication Course EC-001-S is Now Available On Demand
ARRL’s EC-001-S online “Introduction to Emergency Communication” course is now available to students in an on-demand format, allowing students to register for the course and begin work at any time. This course is designed to provide basic knowledge and tools for any emergency communications volunteer.
Mission: To support our emergency communications partners by promoting a standard for training and certification of amateur radio operators.
To develop training programs for Amateur Radio Emcomm Resources that meet the training needs of municipal, county, state, federal and private served agencies.
To manage a certification process for graduates of training programs which provides credentials that are modeled after NIMS/ICS resource typing.
To evaluate and accredit training programs and instructors for emergency communication training.
To develop and promote exercises in communications preparedness that allow operators to apply their learned skills.
History: Amateur radio has a long history of supporting agencies in need with a variety of communications services in the event of an emergency. Traditionally these services have been available under either a Radio Amateur Civil Emergency Services (RACES) program as outlined by the Federal Communications Commission (FCC), an Amateur Radio Emergency Services (ARES) program outlined by the American Radio Relay League (ARRL), or a combination of both programs.
The ACES program includes these and other emergency communications services including Auxiliary Communications Service (ACS), Civil Air Patrol (CAP), Community Emergency Response Team (CERT), Radio Emergency Associated Communications Teams (REACT), US Coast Guard Auxiliary (USCGA), Military Auxiliary Radio Service (MARS), Salvation Army Team Emergency Radio Network (SATERN) and others that can provide specific communications solutions.
Radio Relay International – Traffic Handling – We’re the leading traffic handling outfit for operators in the U.S.A. and Canada with affiliates worldwide including in the UK, EU, Oceania and beyond.
Decades of experience. Proven leadership. Quiet professionals doing our job. RRI is traffic handling the way it should be done with proven methods, new technology and a new sense of purpose.
A radio net is three or more radio stations communicating with each other on a common channel or frequency. A net is essentially a moderated conference call conducted over two-way radio, typically in half-duplex operating conditions. The use of half-duplex operation requires a very particular set of operating procedures to be followed in order to avoid inefficiencies and chaos.
Nets operate either on schedule or continuously (continuous watch). Nets operating on schedule handle traffic only at definite, prearranged times and in accordance with a prearranged schedule of intercommunication. Nets operating continuously are prepared to handle traffic at any time; they maintain operators on duty at all stations in the net at all times. When practicable, messages relating to schedules will be transmitted by a means of signal communication other than radio.
allow participants to conduct ordered conferences among participants who usually have common information needs or related functions to perform
are characterized by adherence to standard formats and procedures, and
are responsive to a common supervisory station, called the “net control station“, which permits access to the net and maintains net operational discipline.
A net manager is the person who supervises the creation and operation of a net over multiple sessions. This person will specify the format, date, time, participants, and the net control script. The net manager will also choose the Net Control Station for each net, and may occasionally take on that function, especially in smaller organizations.
Net Control Station
Radio nets are like conference calls in that both have a moderator who initiates the group communication, who ensures all participants follow the standard procedures, and who determines and directs when each other station may talk. The moderator in a radio net is called the Net Control Station, formally abbreviated NCS, and has the following duties:
Establishes the net and closes the net;
Directs Net activities, such as passing traffic, to maintain optimum efficiency;
Chooses net frequency, maintains circuit discipline and frequency accuracy;
Maintains a net log and records participation in the net and movement of messages; (always knows who is on and off net)
Appoints one or more Alternate Net Control Stations (ANCS);
Determines whether and when to conduct network continuity checks;
Determines when full procedure and full call signs may enhance communications;
Subject to Net Manager guidance, directs a net to be directed or free.
The Net Control Station will, for each net, appoint at least one Alternate Net Control Station, formally abbreviated ANCS (abbreviated NC2 in WWII procedures), who has the following duties:
Assists the NCS to maintain optimum efficiency;
Assumes NCS duties in event that the NCS develops station problems;
Assumes NCS duties for a portion of the net, as directed or as needed;
Serves as a resource for the NCS; echoes transmissions of the NCS if, and only if, directed to do so by the NCS;
Maintains a duplicate net log.
Structure of the net
Nets can be described as always having a net opening and a net closing, with a roll call normally following the net opening, itself followed by regular net business, which may include announcements, official business, and message passing. Military nets will follow a very abbreviated and opaque version of the structure outlined below, but will still have the critical elements of opening, roll call, late check-ins, and closing.
A net should always operate on the same principle as the inverted pyramid used in journalism—the most important communications always come first, followed by content in ever lower levels of priority.
Identification of the NCS
Announcement of the regular date, time, and frequency of the net
Purpose of the net
A call for stations to check in, oftentimes from a roster of regular stations
A call for late check-ins (stations on the roster who did not respond to the first check-in period)
A call for guest stations to check in
Optional conversion to a free net
Each net will typically have a main purpose, which varies according to the organization conducting the net, which occurs during the net business phase. For amateur radio nets, it’s typically for the purpose of allowing stations to discuss their recent operating activities (stations worked, antennas built, etc.) or to swap equipment. For Military Auxiliary Radio System and National Traffic System nets, net business will involve mainly the passing of formal messages, known as radiograms.
Bob Bruninga, WB4APR, is credited as the father and creator of APRS. His early work back in the 1980’s creating object positioning systems developed into a unconnected object mapping system in the early 90’s. Soon GPS technology became available to the consumer market and an automated system was developed. By the mid 90’s a somewhat robust APRS framework had developed.
I call it a framework as it took the next decade for APRS to mature. But for APRS to be viable a few things needed to happen, so by the early 2000’s a dedicated APRS VHF frequency had been established. A full time internet gateway developed, and digipeat and path protocols formalized. The sign that APRS was ready for prime time was when radio manufacturers Kenwood and Yaesu released products with APRS functionality. Those wild west days of APRS may be gone, but the Automated Packet Reporting System has become an established, functional, and quite useful mode for amateur radio operators- especially those interested in Emergency Communications.
How APRS Works
So APRS works by transmitting unconnected packets containing a callsign, path, location, and other information. APRS is built on packet radio technology so the transmissions are in AX.25 format at 1200 baud. So you’ll need a device called a TNC or terminal node controller to take digital data and turn it into audio tones that an FM transceiver can transmit. In today’s world this sounds incredibly outdated, but the genius of the system is it’s robust nature.
When I say unconnected, I mean that an APRS packet is transmitted without the expectation that it will be received by another station. Back in the olden days of packet radio you would use your TNC to connect to another station, much like a computer and modem would connect to another computer over the phone lines. So with an unconnected packets of APRS any number of receiving stations can potentially pick up the message and retransmit or digipeat it.
This has the potential of conflict and these retransmitted packets can collide over the air, so a method of filtering and packet deprecation built into the digipeater firmware eliminatea duplicate packets. The way an APRS packet’s distance is controlled is by the path information.
APRS Path Protocols
If you ever looked at an APRS packet you probably saw things like WIDE, WIDE1-1, etc. These are the path protocols. The purpose of a digipeater is to listen for a packet and retransmit it. Since digipeaters cover a wide area, they will automatically retransmit a packet with the WIDE designator. So when the digipeater receives the packet marked WIDE, it will take the packet, substitute it’s callsign for WIDE, and retransmit it. Since the generic WIDE term is no longer in the packet and another digipeater won’t retransmit it. The packet now expires. Of course multiple digipeaters could receive the packet and retransmit them but the callsign substitution feature of the protocol prevents that ping pong effect from happening.
Paths like WIDE1-1, or WIDE2-2 work in the same way, except that the 2-2 acts as a counter, extending the packet to multiple digipeaters. WIDE1-1 will go out 1 hop in all directions and WIDE2-2 will go out 2 hops in all directions. You never want to extend your packets out more than 3 hops as each hope introduces more chances for collision. Plus the goal of APRS is not to see how many maps you can light up, but instead travel just far enough for your packet to be picked up by an igate.
An igate listens to the over the air traffic and injects the packets into the APRS internet stream. Igates can also take packets from the stream and retransmit them over the air. This has the benefit of being able to send and receive messages to just about any station heard by the internet stream. With radio and internet technology you can send short messages to just about any APRS station around the world. Also thanks to igates, you can view the local APRS traffic of just about any location.
So how do we view the APRS information? The easiest way to get started is with an website called APRS.fi. APRS.fi transposes APRS packets onto a google map, making it very easy to view and query the APRS datastream. Some features, like messaging, are unavailable, but you can track stations and view their history, which are very useful features.
So you want to get involved in APRS. I think the easiest method is with a handheld radio, Btech APRS-K1 cable, and a smartphone. The APRS cable attaches to the 2-pin connector on the radio and plugs into the audio port on your phone. On your phone you’ll run an app like APRSDroid or APRS Pro Deluxe. The GPS in your phone will provide the location information and the app will emulate a terminal node controller. This setup lets you view and transmit to the local APRS channel and also view the APRS internet stream. Plus as you move the phone will cause the radio to beacon your location. You can purchase the BTech APRS-K1 Cable here.
When I first got started with APRS, I built trackers using mobile radios, gps bricks, and TNCs. The downfall of APRS is the number of cables and connections needed to make the whole thing work. Something always was getting disconnected or stopped working. When I started biking more I wanted to take APRS with me, so I invested in a Yaesu VX-8R handheld. This little radio has both the GPS, TNC, and transceiver all integrated into one package, so there are no cables to worry about. Kenwood also created APRS integrated radios, and it was these devices that actually made APRS a useful protocol.
But the common thread of APRS is the need of a TNC or terminal node controller. Whether you are using a tracker device like a Tinytrack or the Argent Data System, apps like APRSdroid, or a radio like the Kenwood D-710, all are using TNCs of some sort. APRS home stations often rely on a hardware TNC like the Kantronics KPC-3+, or older TNCs like the PK-12 or MFJ 1270. New KPC3+ TNCs have become outrageously expensive, and that value has trickled down to the used market. But there are still deals and you can pick up something like a PK-12, MFj 1270, PK-232 on the used market at a reasonable rate. Usually the key is scoping out hamfests with a keen eye to pick one up before someone else in the know spots it. But once you have your TNC you will be able to use some one of the standalone APRS applications, like the new PinpointAPRS on your shack computer.
A repeater, in concept, is not really a complicated device. A repeater is an automatically controlled transmitter and receiver that simply transmits what the receiver hears simultaneously. Imagine having a receiver on one channel, and a high power transmitter on the other, and then holding the microphone of the transmitter in front of the speaker of the receiver. Now make the operation fully automatic. Any user that can be heard by the receiver has the effectiveness of the high power transmitter at his control.
In general, repeater systems are usually located in places of high elevation (on tall towers, on top of mountains or tall buildings) and are equipped with large and efficient antennas, extremely low loss feedlines, and a transmitter and receiver that is very durable, rated for continuous duty, and built to be as immune as possible to interference.
The end result? People using a repeater get much greater range from their radio equipment than would be possible talking from radio to radio. This is how an individual with a portable walkie-talkie (handheld) transceiver can communicate with people many miles away with good clarity.
Repeaters are used in police, fire and ambulance service communications (commonly called “Public Safety”), Commercial (Business) Communications, Federal, State and Local Government agencies, Emergency Communications, and by Amateur Radio Operators. Repeaters can be powered by the regular commercial power lines, or they can be connected to multiple sources of power, including batteries and/or generators for when commercial power is lost. Repeaters can be built that are extremely power efficient and may run exclusively from batteries; recharged by solar, wind or water power.
Simplex is point to point communications without the use of a repeater. Simplex operation utilizes the same frequency for receive and transmit, like a CB radio. I.E. Portable to Portable or Mobile to Mobile. The commercial 2-way world calls Simplex operation ‘Talk Around” because you are talking around the repeater, not through it.
There are such things as Simplex Repeaters. These machines listen on the frequency for activity, when it recognizes something it will begin to record that activity for a pre-determined time; usually 1 minute. A slang term for these is a “parrot repeater”. After the activity ceases or the time has expired, the unit will repeat what it has recorded. This method of communications is somewhat cumbersome over a conventional repeater; because you are forced to listen to what you said earlier in time and the channel usage is problematic as you never know when someone else is recording; however it should not be discounted as these types of systems can be very beneficial.
What is Duplex
The simple explanation of full duplex operation is like the telephone, where both people can talk at the same time. In contrast, a pair of handhelds operate in half-duplex mode because only one person can talk at a time. Since the ‘repeater’ listens and talks at the same time in relaying your message, it operates in full duplex mode.
How does a Repeater work
At first glance, a repeater might appear complicated, but if we take it apart, piece by piece, it’s really not really so difficult to understand. A basic repeater consists of several individual pieces that, when connected, form a functional system. Here’s a simple block diagram of a repeater:
The collection of the antenna, the feedline, the duplexer, and the interconnecting cables is frequently called the “antenna system”.
Most repeaters use only one antenna. The antenna simultaneously serves both the transmit and receive RF (Radio Frequency) signals that are going in to and out of the repeater. It’s generally a high performance, durable, and very efficient antenna located as high on a tower or structure as we can get it. Antenna systems of this type can easily cost $500 or more, and that’s not including the feedline. On the other hand, when properly installed and maintaned they can last from 10 to 25 years.
The feedline on most repeaters isn’t just a piece of standard coax cable, it’s what’s called Hardline. This stuff is more like a pipe with a center conductor than a cable. It’s hard to work with and very expensive. So why do we use it? Performance! The signal loss is much lower in hardline than in standard cable, so more power gets from the antenna to the receiver and weaker signals can be received. A hard rule is that once any percentage of a received signal is lost that you can’t get it back – ever.
Remember, the signal at a repeater site doesn’t just travel a few feet to an antenna like in a mobile rig. It may go hundreds of feet up the tower to the antenna. Just for fun check out the specs on a roll of coax some time and see how many dB of loss you’ll get from 200 feet of cable, and remember 3 dB is 1/2 of your power, and 10 dB is 90% of your power. Hardline also tends to be more durable than standard cable, which increases reliability and helps us minimize the financial expense, and the tower climbs to replace it.
This device serves a critical role in a repeater. To make a long story short, the duplexer separates and isolates the incoming signal from the outgoing and vice versa. Even though the repeaters input and output frequencies are different, the duplexer is still needed. Why? Have you ever been in a place where there’s lots of RF activity, and noticed the receive performance of your handheld radio degrades to some degree? This is called desensitization, or desense, and it’s a bad thing on a repeater. The receiver gets noisy or gets desensitized to the point of total deafness from the strong RF signals being radiated in its vicinity and confused about which signal it should receive.
The result is poor receive quality, or in extreme cases, complete lack of receive capability. Keep in mind that in this example, the radios are picking up radiated power from one another and that’s enough to cause trouble. Now imagine how much trouble there will be if you not only have the transmitter and receiver close together, but connect them to the same antenna!
Transmitting only a few hundred kHz away in frequency would blow away the input to the receiver if the equipment was simply connected together with a Tee. That’s where the duplexer comes in; it prevents the receiver and transmitter from ‘hearing’ one another by the isolation it provides. And the more isolation the better.
A duplexer is a device that is referred to by several different names like cavities or cans. A duplexer has the shape of tall canisters and is designed to pass a very, very narrow range of frequencies and to reject all others. There is some loss to the system because of the duplexer (called the “insertion loss”), however, the advantage of being able to use a single antenna and a single feedline usually outweighs the drawbacks.
Receives the incoming signal. This receiver is generally a very sensitive and selective high performance one which helps weaker stations to be heard better by the repeater. It’s also where CTCSS (Continuous Tone Coded Squelch System) or “PL” decoding takes place. More on this later.
Most machines have a transmitter composed of two parts: an ‘exciter’ and a power amplifier. The exciter created low level RF energy on the proper frequency and then modulates it with the audio. The power amplifier stages simply boosts the level so the signal will travel further. Transmitters come in two types: intermittent duty and continuous duty. One that is rated for continuous duty is preferred.
The term “Station” is used to describe a stationary two way radio set; which includes the transmitter, receiver and sometimes the control circuitry. One example is the dispatch radio for a fire department. A ‘Repeater Station’ is a station designed to be used as a duplex repeater.
This is the brain of the repeater. It handles station identification (through either CW or voice), activates the transmitter at the appropriate times, controls the autopatch, and sometimes does many other things. Some machines also have a DVR (Digital Voice Recorder) for announcements and messages. The controller is a little computer that’s programmed and optimized to control a repeater.
The various models of controllers have different useful features like speed-dial for phone patches, a voice clock, facilities to control a remote base or linking, etc. The controller gives the repeater its ‘personality’. Whenever you’re using a repeater, you’re interacting with its controller. In the early days of repeaters the controller was a large chassis full of relays and timers. These days a controller is most often a microcomputer based unit.
What is a Phone Patch or Autopatch? AKA “The Patch”
Many repeaters have a feature that allows you to place a telephone call from your radio. Phone calls are generally restricted to the local calling area of the repeater to avoid long distance charges to the repeater’s sponsors. If in doubt, ask if the repeater has an open patch and how to access it.
When using the patch it is common courtesy to announce your intentions, e.g. “This is N3XZY on the patch”. This may help to prevent anyone from keying up while you are trying to use the function. In most areas when you are finished with the patch the accepted protocol is to announce it, e.g. “This is N3XZY clear the patch”.
DVR A DVR is a Digital Voice Recorder, or in modern terms a “voice mail” system for the repeater. Usually it’s an option that is installed into the controller.
Repeater Operation Operating using a repeater isn’t difficult. A good source of info is the ARRL Repeater Directory. It’s an inexpensive book with repeater listings all over the US. It contains frequency, offset and whether the repeater is + or – in shift (see “offset” below), whether or not it requires a PL tone, and other features (like an autopatch, or repeater-to-repeater linking).
What is Offset In order to listen and transmit at the same time, repeaters use two different frequencies. On the 2 meter ham band these frequencies are 600 kHz apart. As a general rule in the USA, if the output frequency (transmit) of the repeater is below 147 MHz then the input frequency (listening) is 600 kHz lower. This is referred to as a negative offset. If the output is 147 MHz or above then the input is 600 kHz above. This is referred to as a positive offset. However in any given area the offset rules can be different.
Virtually all ham radios sold today set the offset once you have chosen the operating frequency. As an example one repeater output is 145.270 MHz. The input, or the frequency it listens on is 144.670 MHz (600 kHz below). If you have your radio tuned to 145.270 MHz with the offset enabled, when you push the PTT switch (Push-To-Talk) your radio automatically transmits on 144.670 MHz. When you release the PTT to listen, the radio reverts back to 145.270 MHz to listen on the repeater’s output frequency.
Standard Repeater Input/Output Offsets
6 meters (50-54 MHz)
No real nationwide standard, it varies widely. Most common are -500 kHz, -600 kHz or -1.0 MHz
2 meters (144-148 MHz)
Up and down 600 kHz, depends on frequency
1.25 meters (222-224 MHz, also called “220”)
Down 1.6 MHz
70 cm (440 MHz, also called “UHF”)
Up or down 5 MHz, depends on local area usage
33 cm (900 MHz)
23 cm (1200 MHz)
Note: There are exceptions to the above so check local repeater listings.
Why do Repeaters use an Offset To use a repeater a user station must use a different transmit frequency than receive frequency. This is a form of duplex, or two frequency operation. It is known as half-duplex as you do not receive and transmit at the same time but normally use the push-to-talk button on your microphone to switch between the two.
Most repeater installations use the same antenna for transmit and receive. Without having an offset the repeater would simply hear itself when it was transmitting on the same frequency it was listening on. Even with the offset, the two frequencies are close enough that antenna system isolation is required. Again, this isolation is afforded by the duplexer.
What is Carrier Access, Tone Squelch, CTCSS or a PL Tone Carrier Access, or Carrier Squelch means that the repeater is looking for a carrier on the receiver frequency to open the squelch. A circuit called a Carrier Operated Switch (COS) or Carrier Operated Relay (COR) senses the squelch opening, and tells the repeater that there is a carrier on the input. The controller keys the transmitter, thereby repeating the signal.
Continuous Tone Coded Squelch System, or CTCSS, is a radio communications industry standard signaling scheme. It provides an electronic means of allowing a repeater to respond only to stations that encode or send a very precise audio tone at a very low level superimosed on the transmitter along with the microphone audio. The CTCSS system is used to prevent the repeater receiver from responding to unwanted signals or interference (it’s looking for both the carrier and the tone before the signal is considered as valid).
If a repeater is “in tone mode” that means it requires a CTCSS tone to activate the repeater. If it is in “Carrier mode” then it is ignoring the CTCSS decoder, if there is one. Modern repeater controllers offer a way to switch back and forth, even automatically, between the two modes. Originally there were 32 standard tones, now there are 37.
Some manufacturers offer more, but most repeaters use one of the original 32 so as to allow the older radios to use the system. Aftermarket tone generators from several differnet manufacturers allow any station to be set up to transmit a CTCSS tone. The tones are in the 67-250 Hz range and are called sub-audible, because they’re below the normal voice audio range of 300-3000 Hz. This doesn’t mean you can’t or won’t hear them; they can be quite noticeable depending on the radio you’re using.
PL, an acronym for Private Line, is Motorola’s proprietary name for CTCSS. General Electric uses the name “Channel Guard” or CG for the same system. Other names, such as Call Guard, Quiet Channel or Quiet Tone are used by other manufacturers.
In days of old, repeaters that used PL were considered to be closed or private. This is no longer the case as tone operation has become more the rule instead of the exception. Uninformed people use CTCSS to “solve” interference problems. It doesn’t. It just covers them up, or hides them. The unwanted signal is still on the repeater input, the tone decoder simply prevents the repeater from making it obvious.
Of course, everything these days is digital. A later system called Digital Coded Squelch (DCS) uses 85 different sub-audible digital bit streams. Motorola uses the name Digital Private Line, or DPL for this. Other manufacturers use different names. DPL is gaining in popularity since more radios now come with it as a standard feature.
How do you call someone on an Amateur Repeater? First, listen to make sure that the repeater is not already in use. Then listen some more. If you are a new ham that has never used a repater before it might pay to listen for a week or so and see what goes on, who seems to be the “regular users”, and if you know any of them, perhaps from the local ham club meeting.
When you are satisfied that the repeater is not in use, begin with the callsign of the station you are trying to contact followed by your callsign. e.g. “W3ABC this is N3XYZ”. If you don’t establish contact with the station you are looking for, wait a minute or two and repeat your call.
If you are just announcing your presence on the repeater it is helpful to others that may be listening if you identify the repeater you are using. e.g. “This is N3XYZ listening on 6-2-5”. This allows people that are listening on radios that scan several repeaters to identify which repeater you are using (and therefore which microphone to pick up to answer you).
If the repeater you are using is a busy repeater you may consider moving to a simplex frequency (transmit and receive on the same frequency), once you have made contact with the station you were calling. Repeaters are designed to facilitate communications between stations that normally wouldn’t be able to communicate because of terrain or power limitations. If you can maintain your conversation without using the repeater, going “simplex” will leave the repeater free for other stations to use.
Repeater Etiquette The first and most important rule is LISTEN FIRST. Few things are more annoying than someone that “keys up” in the middle of another conversation without first checking to make sure the repeater is free. Saying that your volume control was down too low and you didn’t hear any conversation is no excuse – it just says that you didn’t chack your own station before you used it. If the repeater is in use, wait for a pause in the conversation and simply announce your callsign and wait for one of the other stations to acknowledge your call.
When you are using the repeater leave a couple of seconds between exchanges to allow other stations to join in or make a quick call. Most repeaters have a “Courtesy Tone” that will help in determining how long to pause. The courtesy tone serves two purposes. Repeaters have a time out function that will shut down the transmitter if the repeater is held on for a preset length of time (normally three or four minutes). This ensures that if someone’s transmitter is stuck on for any reason, it won’t hold the repeater’s transmitter on indefinitely.
When a ham is talking and releases the push-to-talk switch on their radio, the controller in the repeater detects the loss of carrier and resets the time-out timer. Many of the modern computerized controllers allow the owner to program a “beep” to indicate that the timer is reset. This beep is called the courtesy beep, or the courtesy tone.
If you wait until you hear this beep (normally a couple of seconds) before you respond, you can be sure that you are pausing a suitable length of time. After you hear the beep, the repeater’s transmitter will stay on for a few more seconds before turning off. This is referred to as the “carrier delay”, or the “hang in timer”. The length of the delay will vary from repeater to repeater but the average is about 2 or 3 seconds. You don’t have to wait for the transmitter to drop off the air before keying up again, but you should make sure that you hear the courtesy tone before going ahead.
Note: If you don’t wait for the beep the time-out timer to may not reset. Some repeater clubs have a rule that if you time-out the repeater you get to buy a round of coffee at the next ham club meeting.
What is “Doubling” ? When two stations try to talk at the same time the signals mix in the repeater’s receiver and results in a buzzing sound or squeal. When you are involved in a roundtable discussion with several other stations it is always best to pass off to a specific person rather than leave it up it the air. e.g. “W3ABC to take it, this is N3XYZ” or “Do you have any comments Fred?, this is N3XYZ”. Failing to do so is an invitation to chaos and confusion.
It is for this very reason that when groups hold scheduled Nets (network of hams meeting on air at a predetermined time), they assign a Net Control station. The Net Controls job is to make sure there is an orderly exchange and that all stations get a chance to speak. Listen to a local net and you will get an idea of the format and how the Net Control juggles the various stations and traffic.
It’s a job almost anyone can handle, but as you will discover, some are much better at it than others. And if you try your hand at being Net Control for a night, you will discover just how hard it can be! (and you will gain a lot of respect for those that have the knack to do it and make it sound easy). A well run net is both informative and entertaining!
What is a Control Operator? The Part 97 of the FCC Rules requires all stations in the Amateur Service that are capable of operating unattended must be monitored for proper operation while in the unattended mode. This monitoring function is accomplished by a control operator. The Control Op can be the licensee of the station or anyone he or she chooses. In many cases, he or she also ends up being the person that answers questions about the repeater.
What is White Noise? White noise is a term used to describe a spectrum of broad band noise generated in a receiver’s detector and sampled to control the receiver’s squelch. When you open the squelch control and hear the rushing noise from the speaker, this is white noise. When the receiver is in carrier squelch mode the squelch circuit uses the presence of that noise to decide that the signal has gone away and it should mute the receiver speaker.
When the receiver is in tone squelch mode it uses the abscence of the tone AND the presense of the noise to indicate loss of signal. The “squelch tail” is that burst of white noise that you hear that starts when someone unkeys and ends when the squelch circuit actually mutes the receiver audio (some people mistakenly use the term to refer to the carrier delay mentioned above).
I hope this article has explained the Repeater in enough detail that you understand what it is and how to use it. If there is any part of this article that seems vague or confusing, please write me and I’ll do my best to explain it better.