AMATEUR RADIO REPEATERS
THE WEST VARS BRIDGECOM CS-540 REPEATER AND C.A.T. 250 CONTROLLER
FROM WIKIPEDIA >>>http://en.wikipedia.org/wiki/Amateur_radio_repeater
An amateur radio repeater is an electronic device that receives a weak or low-level amateur radio signal and retransmits it at a higher level or higher power, so that the signal can cover longer distances without degradation. Many repeaters are located on hilltops or on tall buildings as the higher location increases their coverage area, sometimes referred to as the radio horizon, or "footprint". Amateur radio repeaters are similar in concept to those in use by public safety (police, fire, etc.), business, government, military, and more. Amateur radio repeaters may even use commercially-packaged repeater systems tuned into an amateur radio frequency allocation, but more usually amateur repeaters are assembled from various sources for receivers, transmitters, controllers, power supplies, antennas, and other components.
In amateur radio, repeaters are typically maintained by individual hobbyists or local groups of amateur radio operators. Many repeaters are provided openly to other amateur radio operators and typically not used as a remote base station by a single user or group. In some areas multiple repeaters are linked together to form a wide-coverage network, such as the linked system provided by the Independent Repeater Association which covers most of western Michigan, or the Western Intertie Network System ("WINsystem") that covers most of California.
A Single Repeater system requires two separate frequencies for the receiver and transmitter and is used whenever greater coverage in a local area is required. The Single Repeater, usually located on a mountain top or tower, repeats any signal received allowing for greater range for portable or mobile radios.
Daniels Electronics Ltd., a North American leader in the design and manufacture of customized radio communications systems for public safety and other niche applications, is a privately held company.
Services provided by a repeater may include an autopatch connection to a POTS/PSTN telephone line to allow users to make telephone calls from their keypad-equipped radios. These advanced services may be limited to members of the group or club that maintains the repeater. Many amateur radio repeaters typically have a tone access control (CTCSS, CG or PL tone) implemented to prevent them from being keyed-up (operated) accidentally by interference from other radio signals. A few use a digital code system called DCS, DCG or DPL (a Motorola trademark).
The G.E. repeater is supplied with top and bottom covers, but shown here with the covers removed.
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In many communities, a repeater has become a major on-the-air gathering spot for the local amateur radio community, especially during "drive time" (the morning or afternoon commuting time). In the evenings local public service nets may be heard on these systems and many repeaters are used by weather spotters. In an emergency or a disaster a repeater can sometimes help to provide needed communications between areas that could not otherwise communicate. Until cellular telephones became popular, it was common for community repeaters to have "drive time" monitoring stations so that mobile amateurs could call in traffic accidents via the repeater to the monitoring station who could relay it to the local police agencies via telephone. Systems with autopatches frequently had (and still have) most of the public safety agencies numbers programmed as speed-dial numbers.
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Repeaters may be linked together in order to form what is known as a linked repeater system or linked repeater network. In such a system, when one repeater is keyed-up by receiving a signal, all the other repeaters in the network are also activated and will transmit the same signal. The connections between the repeaters are made via radio (usually on a different frequency from the published transmitting frequency) for maximum reliability. Such a system allows coverage over a wide area, enabling communication between amateurs often hundreds of miles (several hundred km) apart. All the user has to know is which channel to use in which area.
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In order to get better receive coverage over a wide area, a similar linked setup can also be done with what is known as a voted receiver system. In a voted receiver, there are several satellite receivers set up to receive on the same frequency (the one that the users transmit on). All of the satellite receivers are linked to a voting selector panel that switches from receiver to receiver based on the best quieting (strongest) signal, and the output of the selector will actually trigger the central repeater transmitter.
JPS Communications SNV-12 Voter
A properly adjusted voting system can switch many times a second and can actually "assemble" a multi-syllable word using a different satellite receiver for each syllable. Such a system can be used to widen coverage to low power mobile radios or handheld radios that otherwise would not be able to key up the central location, but can receive the signal from the central location without an issue. Voting systems require no knowledge or effort on the part of the user - the system just seems to have better-than-average handheld coverage.
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Repeaters may also be connected to over the Internet using voice over IP (VoIP) techniques. VoIP links are a convenient way to connecting distant repeaters that would otherwise be unreachable by VHF/UHF radio propagation. Popular VoIP amateur radio network protocols include Echolink, IRLP, WIRES and eQSO.
In addition, communications satellites called OSCARs (Orbiting Satellite Carrying Amateur Radio) have been launched with the specific purpose of operating as spaceborne amateur repeaters. The worldwide amateur satellite organization AMSAT designs and builds many of the amateur satellites. Several satellites with amateur radio on board have been designed and built by universities around the world. NASA and AMSAT coordinated the release of SuitSat which was an attempt to make a low cost experimental satellite from a discarded Russian spacesuit outfitted with amateur radio equipment.
AMSAT SATELLITE REPEATER
Having two repeaters operate on the same radio frequency is problematic, as they can interfere with each other, even with selective calling methods enabled. To help minimize this issue, regional repeater coordination organizations have been created. In some jurisdictions, coordination may be required by law or regulation. In others, coordination is done on a voluntary basis, but with a regulatory preference for coordinated repeaters.
In the USA, coordination is optional, but Part 97 rule 205(c) prefers a coordinated repeater over an uncoordinated repeater in disputes over interference. Coordination is overseen by the National Frequency Coordinators' Council (NFCC), a non-profit organization that certifies regional coordinators.
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In the UK, repeaters are managed by the Emerging Technology Co-ordination Committee (ETCC) of the Radio Society of Great Britain and licenced by Ofcom, the industry regulator for communications in the UK.
The most basic repeater consists of an FM receiver on one frequency and an FM transmitter on another frequency usually in the same radio band, connected together so that when the receiver picks up a signal, the transmitter is keyed and rebroadcasts whatever is heard.
Ham repeaters are found mainly in the VHF six meters (50-54 MHz), two meter (144 - 148 MHz), 220 MHz band (222-224 MHz) and the UHF 70 centimeter (420 - 450 MHz) bands, but can be used on almost any frequency pair above 28 MHz. Note that different countries have different rules; for example, in the United States, the two meter band is 144-148MHz, while in the United Kingdom (and most of Europe) it's 144-146MHz.
6 METER ~ 2 METER ~ 70 CENTIMETER
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Repeater frequency sets are known as "repeater pairs," and in the ham radio community most follow ad hoc standards for the difference between the two frequencies, commonly called the offset. In the USA two-meter band, the standard offset is 600 kHz (0.6 MHz), but some non-conforming oddball-split repeaters can be found in various places, and for various reasons, usually technical. The actual frequency pair used is assigned by a local frequency coordinating council.
In the days of crystal-controlled radios, these pairs were identified by the last portion of the transmit (Input) frequency followed by the last portion of the receive (Output) frequency that the ham would put into the radio. Thus "three-four nine-four" (34/94) meant that hams would transmit on 146.34MHz and listen on 146.94MHz (while the repeater would do the opposite, listening on 146.34 and transmitting on 146.94). In areas with many repeaters, "reverse splits" were common (i.e., 94/34), to prevent interference between systems.
Since the late 1970s, the use of synthesized, microprocessor-controlled radios, and widespread adoption of standard frequency splits have changed the way repeater pairs are described. In 1980, a ham might have been told that a repeater was on "22/82" -- today they will most often be told "682 down." The 6 refers to the last digit of 146MHz, so that the display will read "146.82" (the output frequency), and the radio is set to transmit "down" 600kHz on 146.22MHz.
Repeaters typically have a timer to cut off retransmission of a signal that goes too long. Repeaters operated by groups with an emphasis on emergency communications often limit each transmission to 30 seconds, while others may allow three minutes or even longer. The timer restarts after a short pause following each transmission, and many systems feature a beep or chirp tone to signal that the timeout timer has reset.
A type of system known as a simplex repeater uses a single transceiver and a short-duration voice recorder, which records whatever the receiver picks up for a set length of time (usually 30 seconds or less), then plays back the recording over the transmitter on the same frequency. A common name for them is a "parrot" repeater.
SIMPLEX REPEATER WITH VOICE PROMPT
The FLEX SERIES Simplex Repeater.
This controller records up to ninety seconds worth up voice and tones. On playback the unit plays back not only the recorded message, it plays back a precorded message.
This unit is programmed by a telephone plugged in the rear of the unit and using the keypad from the telephone,
This unit is available in desk top and rack mount.
Programming is via a Windows based computer or remotely over the air using the DTMF keypad of the radio.
A cross-band repeater (also sometimes called a replexer), is a repeater that converts the original band of frequencies of the received signal to a different radio frequency band for retransmission after amplification. This technique allows for smaller size and less complexity of the repeater system. Repeating signals across widely separated bands allows for simple filters to be used to allow one antenna to be used for both transmit and receive at the same time, avoiding the use of complex duplexers to achieve the required rejection for same band repeating. This type of system is used in the OSCAR repeaters.
A crossband repeater system enables system interoperability by changing frequencies between two radio systems. For applications where a radio user on one frequency band needs to communicate with other users in a different frequency band, a crossband repeater can convert the frequency between the two radios.
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GO TO THE MID-PAGE POINT FOR THE "X" MODELS
Standard repeaters require either the use of two antennas (one each for transmitter and receiver) or a duplexer to isolate the transmit and receive signals over a single antenna. The duplexer is a device which prevents the repeater's high power transmitter (on the output frequency) from drowning out the users' signal on the repeater receiver (on the input frequency). A diplexer allows two transmitters on different frequencies to use one antenna, and is common in installations where one repeater on 2m and a second on 440MHz share one feedline up the tower and one antenna.
When a radio operator gets out of their mobile and wants to have their hand held portable get back to the far away repeater or base station use of a "Same-Band Vehicular Repeater" does a reat job of extending the range of communications with the portabls radio retransmitting back through the "mobile vehicular repeater".
Most repeaters are remotely controlled through the use of audio tones on a control channel.
Repeaters can be setup as a "Link System" where transmitting on one repeater simultaneously transmits on all repeaters in the system. These systems are used for area or regional communications, for example in Skywarn.
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Another form of repeater is used in amateur packet radio, a form of digital computer-to-computer communications, and are dubbed "digipeaters" (for DIGItal rePEATERS). These repeaters are used for activities and modes such as packet radio, Automatic Position Reporting System, and D-STAR.
KPC-3+ Packet Communicator
Turning a Kantronics TNC into an APRS tracker
So, you've decided to set up a KPC-3 or KPC-3 Plus as a stand-alone APRS tracker. Just one problem... it doesn't work for some reason! Time to do some basic troubleshooting. Most of this will also apply to ANY Kantronics TNC that has version 6.x or later software, but I have only confirmed the software settings with the KPC-3/3 Plus. There are special considerations when dealing with dual-port TNCs, such as the KAM or KPC-9612, which will be dealt with in at the end of this document.
Note that there are special features available in the latest software for the KPC-3 Plus (v8.3), which make it a better tracker TNC... and make it also require some special settings. See the special setup file if you've got v8.3!
Let's check the connections - starting with the serial connection.
The most basic problem is usually the connection between the TNC and the GPS, either in the the data wires being swapped, or the baud rate used. We'll start with the first.
Are you using the same cable to connect your TNC to the GPS as you use to connect it to the computer? If so, it is important that the data in and data out lines of the GPS be "reversed" from "normal".
In this case, "normal" is defined as the connections necessary to read the output of the GPS on your computer. If both your GPS and TNC can talk to the computer, you need to reverse pins 2 and 3 on ONE of the cables to make the GPS and TNC talk together.
In the case of a Nextel "GPS-ready" phone, you need to use the OEM Data Cable and a null-modem adapter to make the signals work out (see below).
Suggestion: If your GPS does not require any initialization strings, or if you are not interested in sending anything to the GPS, try wiring the output of the GPS to both pins 2 and 3. It has its disadvantages, but, for troubleshooting purposes, it can speed the process of verifying that you are getting something out of the GPS.
If just making this change "fixes" the situation (i.e., your packets are now going out), swap lines 2 & 3 on the GPS side, OR purchase a "null modem" adapter (I use a Radio Shack 26-264 plus a 26-1495 F-F Gender Changer), which does the same thing for standard cables. This is probably the most viable way to do things, if you want to be able to use the GPS with your computer, as well as as a stand-alone tracker.
Go to your GPS, and check the setup page; verify that it is set to output NMEA 0183 format sentences; from the factory, the NMEA output is usually turned off, and all of the instructions below become moot!
Plug the TNC into a computer with a terminal program set for the baud rate you've programmed the GPS to use (try 4800 if there isn't a setup option for baud rate in the GPS). Turn the TNC on. Do you see a Kantronics copyright? If yes, you weren't in GPS mode; we'll come back to that.
If no, do you see an '*' and/or some garbage characters? If yes, you probably don't have the ABAUD set correctly. The '*' means it's trying to auto-baud; follow the manual instructions for setting the baud rate.
If there's no garbage characters, hit Ctrl-C three times. Do you now get the copyright? If not, you may not have the ABAUD set correctly; try powering down again and restarting (I had to do this three times to mine the other night, and the baud was set correctly. I suspect a Win95 problem). Hit the three Ctrl-Cs each time; you need to get to the cmd: prompt, and that means seeing the copyright notice.
If you can't get to a cmd: prompt, that's one thing we can deal with separately.... you may need to perform a hard reset (see your manual) to get it working. Follow the manual's instructions to set the ABAUD to 4800, or whatever is necessary to match your GPS.
At this point, I must assume we're at the cmd: prompt.
[in the following, don't type the ' characters, and <enter> means to press the 'Enter' or 'Return' key on your keyboard]
Type 'INT TERM<enter>' to make sure all commands are available to you.
Type 'MYCALL<enter>'. Make sure it has a proper call sign in it, because Kantronics TNCs won't transmit with a blank callsign.
Type 'PACLEN 0<enter>'. This sets the TNC to not break up packets unless the length of the information exceeds 256 characters; if it were to break them at a smaller size, it is possible that your packets would not be interpreted as valid positions by APRS. GPS packets will not exceed about 80 characters, but, sometimes, PACLEN is set as low as 70 or 72!
Have you verified that the transmit audio, receive audio, and PTT lines are properly attached to the radio, by trying to send something in CONVerse mode? To test this, type 'conv<enter>', then hit <enter> again, watching the front of the TNC to see if the you get the [red] transmit LED to light. If not, you have a TNC problem; these are rare, but they do happen!
If you do see the transmit LED light, hit <enter> again, only this time, watch for a transmission on the radio. Does the radio key for about a second? If not, check the cable between the TNC and the radio, especially if it is a "store bought" unit; quite often, these are NOT wired correctly! Verify the wiring, and try this step again.
Assuming you get your transmission, can you see your signal digipeated by another local station?
Type 'GPSHEAD<enter>'. What is displayed? Somewhere, you should have one of the strings set to '$GPGGA' and/or '$GPRMC', all upper case. If it's in lower case, it won't work. Correct as needed.
Type 'LTP<enter>'. Make sure that the path with the same number as the $GPGGA and/or $GPRMC string above says 'APRS v WIDE1-1,WIDE'; if not, type 'LTP 1 aprs v WIDE1-1,wide<enter>' (substitute for the '1' as needed to match the path number for the string you want to send).
Type 'BLT<enter>'. Make sure that the time interval with the same number as the $GPGGA and/or $GPRMC string above says something other than 'EVERY 00:00:00 (disabled)'; a good starting value is 'EVERY 00:01:30', depending on how busy the local network is. If not, type 'BLT 1 E 00:01:30<enter>' (again, substitute for the '1' as needed to match the string you want to send).
Finally, type 'INT GPS<enter>'. Power down the TNC. Attach the GPS and turn it on. Power the TNC up. Within 90 seconds of the GPS getting a signal lock (displaying position information), you should see a transmission.
If, after following these procedures, you still aren't being tracked, I don't know where to start looking. The above covers just about all the possibilities, short of the RECEIVING radio and TNC being screwed up, and this guide doesn't go into that possibility!
What follows are the settings that MUST be configured for a Kantronics TNC to act as a tracker. Of course, substitute your call in place of mine, and you can change which GPS string you wish to send, as well as the timing between packets, the call sign attached to the remote SYSOP command (you did realize that you can control this beast remotely, didn't you?), the password string, etc, from these samples, but these should always be set to something:
GPSHEAD 1 $GPRMC
GPSHEAD 2 $GPGGA
BLT 1 EVERY 00:03:00 START 00:00:10
BLT 2 EVERY 00:03:00 START 00:01:40
LTP GPSLJ V WIDE1-1,WIDE2-2
LTP GPSLJ V WIDE1-1,WIDE3-3
RTEXT this IS The sTring That yOUr PasSwORd Is GeNERaTed FroM.
[Why is CONOK OFF? Because of a bug in v8.2 - if you let someone connect to your TNC, and you have LTRACK set to anything other than zero (disabled), the frequency will be useless for the length of time it takes the TNC to send the entire contents of its tracking buffer at 1200 bps.... Definitely a bad thing in a busy network!]
[Why 'GPSLJ' instead of 'APRS' in the path? See SYMBOLS.TXT for information on how to get ANY APRS icon for a tracker, rather than just those that can be had with the SSID method.]
These settings will send out a position beacon every 90 seconds, alternating between the $GPRMC and $GPGGA strings.
Dual-port TNC differences: The dual-port Kantronics TNCs will allow you to select different paths and intervals for each port. These are handled in the standard "multiport command" format, i.e., the values for the first and second port separated by a '/'. What follows is recommended settings for a KAM/KAM Plus, but the KPC-9612/KPC-9612 Plus are similar in format.
LTP 1 GPSLJ V GATE,WIDE2-2/GPSLJ V WIDE1-1,WIDE2-2
LTP 2 GPSLJ V ECHO,GATE,WIDE2-2/GPSLJ V WIDE1-1,WIDE3-3
BLT 1 E 00:15:00 START 00:00:35/E 00:01:30
BLT 2 E 00:20:00/E 00:05:00
These lines, when used in place of the coresponding lines from above, will send out the $GPRMC data out on HF every 15 minutes, and every 90 seconds on VHF, and the $GPGGA string will go out every 20 minutes on HF, and every 5 minutes on VHF. The START parameter allows you to "slot" the beacons, if desired. Remember: ALWAYS limit your HF beacons as much as possible, since the bandwidth is EXTREMELY limited down there!
Final note: If you're like me, and don't want to have to turn the tracker on and off when you stop the car, but you also don't want to QRM the net unnecessarily with stationary GPS packets, KD4RDB has designed a small 'Hold Off' circuit for the KPC-3 (will work with most other TNCs, too), which will cut the report rate by 90% when you turn off the car. You'll find the diagram on his 'Hold Off Circuit' page. Or, get a TNC with version 8.3 software, and use the technique listed in the KPC-3 Plus v8.3 tracker file.
ABOVE INFORMATION FROM >>>http://www.dididahdahdidit.com/kpctracker.php
An SSTV repeater is an amateur radio repeater station for relaying of slow-scan television signals. A typical SSTV repeater is equipped with a HF or VHF transceiver and a computer with a sound card, which serves as a demodulator/modulator of SSTV signals.
SSTV repeaters are used by amateur radio operators for exchanging pictures. If two stations can not copy each other, they can still communicate through a repeater.
To activate a repeater the station must send a tone of frequency 1750 Hz. Then the repeater is activated and sends K in morse code. The station must start sending a picture in approximately 10 seconds. After reception the received image is transmitted on the repeater's operation frequency.
Repeaters should operate in common SSTV modes, but it depends on the software used (MMSSTV, JVComm32, MSCAN). Some repeater are not activated by audio tone, but instead by the SSTV vertical synchronization signal (VIS code).
When there is no activity on the repeater's frequency, it works as a beacon and periodically send a random picture with identification and a timestamp.
ATV repeaters are used by amateur radio operators to transmit full motion video. The bands used by ATV repeaters vary by country, but in the US a typical configuration is as a cross-band system with an input on the 33 or 23 cm band and output on 421.25 MHz or, sometimes, 426.25 MHz. These frequencies happen to be the same as standard cable television channels 57 and 58, meaning that anyone with a cable-ready analog TV can tune them in without special equipment.
There are also digital amateur TV repeaters that retransmit digital video signals. These are more prevalent in Europe currently.
Amateur transponder repeaters are commonly used on amateur satellites. A specified band of frequencies, usually having a bandwidth of 20 to 800 kHz is repeated from one band to another. Some transponders may be inverting or non-inverting. This means that a 70 CM to 2 M transponder which repeats 432.000 MHz - 432.100 MHz to 146.000 - 146.100 MHz would take a signal at 432.001 MHz and repeat it to 146.099 MHz; vice versa.
Timing Out is a term used to describe the situation where a person talks too long and the repeater timer shuts off the repeater transmitter.
Kerchunking is a term used in ham radio that refers to the act of transmitting a momentary signal to check a repeater without identifying. In many countries, such an act violates amateur radio regulations.
The term "Kerchunk" can also apply to the sound a large Amplitude Modulation Transmitter makes when the operator switches it off and on.
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Information provided here as a courtesy for all of our ham radio friends
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