LESSON 20

Repeaters; repeater and simplex operating techniques,
offsets, selective squelch, open and closed repeaters, linked
repeaters

During the 1950’s business two way radio using VHF repeaters became popular. As the popularity increased it became apparent that there was not enough room on the VHF band so they were forced to operate simplex (transmitting and receiving on the same frequency) on VHF and go to UHF for repeater. This along with the rapidly developing technology made used out of date repeaters available for Amateur radio use at reasonable prices. This also meant that vehicle radios and base stations were becoming available also for reasonable prices. A little conversion and tweaking frequencies and they became ham radios.

So during the late 1960 and into the 1970 amateur radio repeaters were growing in numbers daily. The purpose of the repeater is to extend the range of mobile and low-power stations. Under ideal conditions normally maximum mobile to mobile communications would be less then 14 miles (distance to horizon) and most of the time is actually less then 5 miles because of objects blocking the signals. Using the Sutter Buttes repeater mobile communications between Lodi and Reading California are possible under normal conditions of operation. That is a distance of over 120 miles.

As the number of repeater increased it became necessary to establish a local frequency coordinator. The local coordinator should approve the frequency of all new repeaters before they are installed to minimize interference between repeaters and make the most efficient use of the available frequencies.

Many times a repeater will have a courtesy tone which is a beep that occurs when the transmitting station unkeys the mike so the receiving station will know it is ok to transmit without having to wait for the repeater to drop out or stop transmitting. There are some repeater that require the operators to wait for the repeater to stop transmitting before starting a new transmission

A repeater’s input frequency (the frequency the repeater’s receiver) and the output frequency (the frequency of the repeater’s transmitter) are not the same. An operator must know what these two frequencies are before operation is possible. Most of the times the input and output frequencies of a repeater on the 2 meter band are separated by .6 MHz (600 KHz) and the 70 CM repeaters are normally separated by 5 MHz.

Repeaters are usually shared by many hams in the area and you will not become popular on a repeater if you “Hog” the repeater for yourself. Always give a little time after the station being worked has stopped transmitting so if any other station would like to break in and use the repeater it will be possible.

Not all repeaters are open to all amateur radio operators; access to any repeater may be limited to club members or some other special group by the repeater owner. These repeaters are officially known as an auxiliary station but more commonly called closed repeaters.

If simplex operation is possible then it should be used to avoid tying up the repeater when direct contact is possible. Initials contact can be made on the repeater then move to a simplex frequency that is not a local repeater. If it is questionable if simplex communications is possible or not check the repeater’s input frequency to see if the other station can be heard.

To increase the coverage to an even greater range sometimes repeater can be linked together into a system known as a “Linked repeater system”.


1. T5C01 (B)
What is one purpose of a repeater?
A. To cut your power bill by using someone else's higher power
system
B. To extend the usable range of mobile and low-power stations
C. To transmit signals for observing propagation and reception
D. To communicate with stations in services other than amateur
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2. T5C02 (B)
What is a courtesy tone?
A. A tone used to identify the repeater
B. A tone used to indicate when a transmission is complete
C. A tone used to indicate that a message is waiting for someone
D. A tone used to activate a receiver in case of severe weather
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3. T5C03 (A)
Which of the following is the most important information to know before using a repeater?
A. The repeater input and output frequencies
B. The repeater call sign
C. The repeater power level
D. Whether or not the repeater has an autopatch
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4. T5C04 (C)
Why should you pause briefly between transmissions when using a repeater?
A. To let your radio cool off
B. To reach for pencil and paper so you can take notes
C. To listen for anyone wanting to break in
D. To dial up the repeater's autopatch
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5. T5C05 (A)
What is the most common input/output frequency offset for
repeaters in the 2-meter band?
A. 0.6 MHz
B. 1.0 MHz
C. 1.6 MHz
D. 5.0 MHz
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6. T5C06 (D)
What is the most common input/output frequency offset for
repeaters in the 70-centimeter band?
A. 600 kHz
B. 1.0 MHz
C. 1.6 MHz
D. 5.0 MHz
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7. T5C07 (A)
What is meant by the terms input and output frequency when
referring to repeater operations? A
A. The repeater receives on one frequency and transmits on another
B. The repeater offers a choice of operating frequencies
C. One frequency is used to control the repeater and another is
used to retransmit received signals
D. The repeater must receive an access code on one frequency
before it will begin transmitting
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8. T5C08 (A)
What is the meaning of the term simplex operation? A
A. Transmitting and receiving on the same frequency
B. Transmitting and receiving over a wide area
C. Transmitting on one frequency and receiving on another
D. Transmitting one-way communications
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9. T5C09 (B)
What is a reason to use simplex instead of a repeater? B
A. When the most reliable communications are needed
B. To avoid tying up the repeater when direct contact is possible
C. When an emergency telephone call is needed
D. When you are traveling and need some local information
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10. T5C10 (A)
How might you find out if you could communicate with a station using simplex instead of a repeater?
A. Check the repeater input frequency to see if you can hear the other station
B. Check to see if you can hear the other station on a different frequency band
C. Check to see if you can hear a more distant repeater
D. Check to see if a third station can hear both of you
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11. T5C11 (C)
What is the term for a series of repeaters that can be connected to one another to provide users with a wider coverage?
A. Open repeater system
B. Closed repeater system
C. Linked repeater system
D. Locked repeater system
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12. T5C12 (A)
What is the main reason repeaters should be approved by the local frequency coordinator before being installed?
A. Coordination minimizes interference between repeaters and makes the most efficient use of available frequencies
B. Coordination is required by the FCC
C. Repeater manufacturers have exclusive territories and you could be fined for using the wrong equipment
D. Only coordinated systems will be approved by the officers of the local radio club
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13. T5C13 (B)
Which of the following statements regarding use of repeaters is true?
A. All amateur radio operators have the right to use any repeater at any time
B. Access to any repeater may be limited by the repeater owner
C. Closed repeaters must be opened at the request of any amateur wishing to use it
D. Open repeaters are required to use CTCSS tones for access
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14. T5C14 (D)
What term is used to describe a repeater when use is restricted to the members of a club or group?
A. A beacon station
B. An open repeater
C. A auxiliary station
D. A closed repeater



Answers to today’s questions.

B B A C A D A A B A C A B D