Repeaters What they are Basic Use And Using Linking Systems

1. RepeatersWhat they areBasic UseAnd Using Linking Systems Presented by Bill Elliott VE1MR

2. This presentation is a combination of elements from presentations given byRob Ewert, VE1KSAndBill Elliott, VE1MR

3. The presentation given byRob Ewert, VE1KSwas originally prepared for Amateur Radio operators and net control operators.

4. The original presentation given by me was originally prepared for Provincial government officials and Emergency Measures Organizations that would include non Amateurs.It was modified for presentation to Amateur Radio ClubsIt was later modified for presentation to a Basic licensing classThis latest modification was the result of several requests for viewing on a web page instead of as a slide show

5. Introduction I will try to introduce you to repeaters and the use of repeaters and various linking systems. Explanation of some terms 1) VHF and UHF 2) User radios - base, mobile and handheld 3) What a repeater is

6. Explanation of Some Terms VHF The radio spectrum is broken up into several broad bands according to frequency. In this presentation I will be using acronyms for 2 of these. I will also be using acronyms for several sub bands that Amateurs use VHF is Very High Frequency covering frequencies between 30 to 300 MHz. Amateurs have 3 exclusive bands in VHF. 6 Meters or 6M - 50 to 54 MHz. 2 Meters or 2M - 144 to 148 MHz. 1.25M or 222MHz - 222 to 225 MHz.

7. Explanation of Some Terms UHF UHF is Ultra High Frequency covering frequencies between 300 to 3000 MHz. In UHF Amateurs have several sub bands that are shared. 70 cm - 430 to 450 MHz. 33 cm - 902 to 928 MHz. 23 cm - 1200 to 1300 MHz. 13 cm - 2300 to 2450 MHz.

8. Explanation of Some Terms VHF and UHF In this presentation VHF will be 144 - 148 MHz and UHF will be 430 - 450 MHz unless otherwise noted. Both of these broad bands are considered to be most useful at line of sight, meaning the transmitting antenna should have an unobstructed path to the receiving antenna.

9. Explanation of Some Terms User Radios Base - usually a larger radio used at a home station feeding a fixed antenna. But can be a simple mobile radio or even and hand held radio covering one or several bands. Mobile - generally a smaller radio for use in a vehicle feeding an antenna mounted on the vehicle. Hand Held - a small hand held radio as the name suggests, usually using a flexible antenna mounted on the radio. Often the first radio an Amateur will get.

10. Explanation of Some Terms What a repeater is A repeater is made up of several parts which you can think of as a collection of magical black boxes. These generally operate on a particular VHF or UHF band. Repeater parts These boxes are: Receiver - receives a radio frequency signal and provides several signals to other boxes. Transmitter - transmits a radio frequency signal.

11. Explanation of Some Terms More Repeater parts Controller A controller generally refers to a piece of equipment to control a repeater or link or both. It takes signals from the receiver and passes certain signals through to the transmitter. The programming of a controller can be quite simple or very complicated depending on functions required and auxiliary equipment added to it.

12. Explanation of Some Terms More on the Controller A controller takes care of things like: Tail - the transmitter stays on for a few seconds after the received signal ceases. Courtesy beeps - a tone when the received signal ceases. ID - identification of the repeater Messages, timers, functions like connecting ports together. Port A Port refers to a controller input/output for controlling a radio. Each port controls one radio for transmit and receive functions. In general the more ports a controller has the more it will cost.

13. Explanation of Some Terms More Repeater parts Duplexer A Duplexer is a piece of equipment that allows one antenna to be used for both receive and transmit at the same time. Multi-Coupler A multi-coupler is a piece of equipment that allows one antenna to be used for many receivers and transmitters at the same time. They are a set of filters to pass a certain frequency and block other frequencies. (There are limitations) Each Receiver and each Transmitter must have a set of these filters. (You can see the costs going up)

14. Explanation of Some Terms More Repeater parts Cabling There are a lot of various cables for interconnecting parts such as RF cables to filters, power cables, signal lines and external things like temperature sensors etc. Feedline Of course the repeater must connect to an antenna. Depending on the distance to the antenna will determine the best feedline to use. Antenna The antenna is the final piece of a complete repeater.

15. Repeaters 1) How a repeater works 2) Why use a repeater

16. How a Repeater Works A repeater is a Receiver/Transmitter on a particular VHF or UHF band with several other pieces of equipment as just described that immediately transmits what it hears on the receiver. Repeaters are generally situated on a high piece of ground with a tower to get the antenna up as high as possible. The height of the antenna above surrounding terrain will determine its coverage area. Receiver sensitivity and transmitter output power also play a part in coverage.

17. How a Repeater Works A VHF repeater will receive on one frequency and the transmitter will be repeating what is received on another frequency. Generally the frequency difference is 600 KHz. This is called the offset. An example is VE1PSR/VHF that receives on 147.870 MHz and transmits on 147.270 MHz. There are guide lines for offset direction dependant on where in the band the repeater operates. There are band plans for all Amateur bands which give guide lines for what type (mode) of operation is where in a band. Modes of operation can include CW, SSB, FM, Digital and others.

18. How a Repeater Works Repeaters can be found on; 10 M: 28 to 29.7 MHz: - 100KHz offset. 6 M: either +/- 500 KHz or usually +/- 1MHz offset. 2 M: +/- 600KHz offset. 1.25 M: - 1.5 MHz offset. 70 cm: +/- 5 MHz offset. 33 cm: - 25 MHz offset. 23 cm: either - 12 MHz or - 20 MHz offset. Many newer radios will automatically select the correct offset for repeaters that follow the standard.

19. How a Repeater Works As a repeater user you will program your radio to receive the repeater (repeater transmit frequency). If your radio does not set the correct offset then you must select that as well. With the correct offset you will transmit on a different frequency than you receive on. Your signal will be automatically repeated as it is received by the repeater and other users will hear what you transmit as you are speaking. Repeater listings give the repeater transmit frequency and offset direction. Example - VE1PSR/VHF 147.270 +

20. Why Use a Repeater You can use Simplex where you transmit and receive on the same frequency to communicate with another user. You will be limited by the power output of your radio, your antenna and the antenna of the other user’s radio. Terrain will also be a factor - remember VHF and UHF are line of sight, you must have a reasonably clear path between both radios. A repeater is usually situated on high ground and will have a much better antenna and usually more transmitter power. There can be buildings and hills between you and the other user but both can “see” the repeater because it is much higher.

21. QUESTIONS ON ANY THING SO FAR ??????

22. TAKE A SHORT BREAK

23. Introduction I will try to introduce you to the various linking systems. Explanation of some terms 1) What a link is 2) Types of links 3) What a hard link is 4) Why use different types of links

24. What a Link is Link A link is generally a radio on a different frequency than the primary repeater. There are several types of links. Our system uses 4 different types. 1 - UHF HUB Repeaters 2 - UHF Half Duplex links 3 - UHF Full Duplex Links 4 - Simplex links

25. Types of Links Simplex link Simplex refers to a link radio that uses the same transmit and receive frequencies but at any given time only transmits or receives, not both at the same time. When a Simplex link radio is transmitting it cannot receive. When a Simplex radio is receiving it may go into transmit depending on the situation. You will see later how this may affect operation.

26. Types of Links Half Duplex Link Half Duplex refers to a link radio that generally uses different transmit and receive frequencies but at any given time transmits or receives, not both at the same time. It can also be on a simplex frequency. When a Half Duplex link radio is transmitting it cannot receive. When a Half Duplex radio is receiving it may go into transmit depending on the situation. You will see later how this may affect operation.

27. Types of Links Full Duplex Link Full Duplex refers to a link radio that uses different transmit and receive frequencies and can transmit and receive at the same time. When a Full Duplex link radio is transmitting it can receive without affecting what it is transmitting. When a Full Duplex radio is receiving it can also transmit without affecting what it is receiving. You will see later how this affects operation.

28. Types of Links UHF HUB Repeater A HUB repeater is a true repeater in that it immediately transmits what it hears on the receiver. These repeaters normally do not have any tail - that is the transmit stops as soon as the received signal ceases. You will see later how these are used in the system.

29. Explanation of Some Terms Hard Link A Hard link is one that is always up. This means that a Hard Link between 2 or more repeaters allows what is received on one repeater to be transmitted out all hard linked repeaters simultaneously. Hard links can use UHF HUB repeaters, Full Duplex links, Half Duplex links or Simplex links or any combination that will work.

30. Why use different types of links 1 - Primarily due to equipment costs and availability of antennas on a particular tower. 2 - A HUB repeater can service many links to different sites with one antenna. The disadvantage is that links to a HUB repeater must be Half Duplex. 3 - Half Duplex or Simplex links require less equipment and space. If a Half Duplex link does not go to a HUB repeater then it can be easily made into a Full Duplex link in the future with some modifications and the addition of a Duplexer. 4 - A Full Duplex link is the preferred method of linking as you will see later.

31. Repeaters and Linking \ Introduction / • Linking Repeaters - Why do we link? (MAVCOM & IRLP) - How do we link repeaters? - How are links controlled - Tips on being a knowledgeable link user - Types of linking in NS - MAVCOM (Description, Maps, Functional DWG) - IRLP (Description, Functional DWG, Maps & Pics) - Echolink • Operating Etiquette - MAVCOM Linking usage - IRLP Linking usage - Nets (checking in) - Net controllers – How to use and manage the link system

32. Repeaters and Linking \ Linking Repeaters / • Why do we do it? - Extends the range of a single repeater - It REALLY extends the range of a mobile or HT - Allows a VHF/UHF net to encompass more regions - Enhances emergency communications - Adds more value to the 2M experience - Combining different methods of linking can make repeaters available around the world

33. Repeaters and Linking \ Linking Repeaters / • How do we link repeaters? - Terrestrial RF (MAVCOM) - Microwave RF (NB IRG System) - Telephone company leased circuits (TMRS) - Internet (IRLP or Echolink)

34. Repeaters and Linking \ Linking Repeaters / • How are links controlled? - DTMF is Dual Tone Multi Frequency, often called touch tone. For the linking system DTMF signalling uses a touch tone key pad normally mounted on the microphone or radio. - Repeater controllers control the link radios - Linking uses DTMF on and off codes - 3 or 4 digit codes with an asterisk or pound - Some systems use just numbers - Off codes can sometimes be one unique code (73) or a Coordinated Dialing Plan code (107*) - Repeater controllers are programmed to respond to DTMF commands and connect/disconnect that repeater to the link system and other commands - They can also direct links in particular directions

35. Repeaters and Linking \ Linking Repeaters / • What do I need to know to use the linking system? - Where are you right now? - Where do I want to link to? - What are the DTMF codes that are needed to link? - Entering DTMF codes, listening for the right audio responses - Timeout timers on links to be aware of - Interpreting courtesy beeps - Network propagation delays: Addressed later in the presentation - OCTD (One Code To Destination) - DTMF regeneration over links - Will I form a linking “Loop”?

36. Repeaters and Linking \ Linking Repeaters / • - Where are you right now? You should know the on and off codes for this repeater - Where do I want to link to? You should know the on and off codes for this repeater - What are the DTMF codes that are needed to link? The Maritime Call Book has most of the linking codes listed and new repeater codes are listed in several places. The Halifax Club web page - http://www.halifax-arc.org Also http://ve1cra.net/main/linkcode.htm

37. Repeaters and Linking \ Linking Repeaters / • - Entering DTMF codes, listening for the right audio responses On code example - Putting your local repeater on the link system 108* - Welcome to Shubenacadie, VE1SHU, link on. - Putting the remote repeater on the link system 190* - Welcome to the Pictou County area, VE1HR link on. Off code example - Taking the remote repeater off the link system 191* - Good by from the Pictou County area, VE1HR link off. - Taking your local repeater off the link system 109* - Goodbye from Shubenacadie, VE1SHU, link off.

38. Repeaters and Linking \ Linking Repeaters / • Timeout timers Link activity timer is generally 3 minutes. Most controllers are set to drop the transmitter after 3 minutes of continuous receive carrier - this applies to both repeaters and links. So if you think your monologue will be longer than 3 minutes take a short break to allow all timers to reset. • Link inactivity timer is generally 5 minutes. This will ensure the link will time out if there is no activity on the link for the set time. So if you drive out of the coverage area of a repeater you up linked, do not worry, the link will time out with no activity. • Sometimes the inactivity timer on the repeater side will be set to a longer time typically 20 minutes. This allows listening to a net when no one is checking in from a particular repeater. Not all controllers allow this.

39. Repeaters and Linking \ Linking Repeaters / • Interpreting courtesy beeps The normal courtesy tone when the repeater is not on the link is usually a single beep. A courtesy tone sounds after a short delay to allow others to join when the other party unkeys. Hearing the courtesy tone also lets you know the other person has unkeyed or finished speaking. If you are talking and when you unkey you hear a double or a distinctively different courtesy tone then the link is on. At this point you will probably ask the person on the link to go ahead or maybe wait a moment. Please acknowledge that the link is up. When the link is on you should hear a distinctive beep when someone on the link system unkeys. In most cases an unkey on port 2 will give 2 distinctive beeps while port 3 gives 3 beeps. This can tell you from which direction the signal is coming from once you know the layout of your local repeater.

40. \ Linking Repeaters / Repeaters and Linking • - OCTD (One Code To Destination) Some controllers have a built in or programmed means to regenerate DTMF codes to turn on a remote repeater. When you dial an on code for a remote repeater the controller recognizes it and regenerates this code out on to the link system and puts the local repeater on the system so only the remote code needs to be dialled by you. You should hear the link on response from the remote repeater. If you do not then it is OK to send the remote repeater on code again until you hear the correct response. More repeaters can be brought on to the link system by dialing their on codes. The normal 2 code link on sequence will always work as well - this is where you dial the local repeater on code then the remote repeater on code. The only downside to OCTD capable controllers is that on dialing an off code they will also remove your local repeater from the link once the link off response (or a short time period of no response) is heard from the remote repeater. If you have linked up more than one remote repeater then the others will stay on the link unless you reconnect the local repeater and dial another off code.

41. Repeaters and Linking \ Linking Repeaters / A linking loop is when something is connected to the UHF backbone system that would repeat your audio back on to the system. This is possible if there are Echolink or IRLP nodes on the linked repeaters. When 2 repeaters having IRLP are on the system and someone dials an IRLP code for an IRLP reflector both nodes will connect to that reflector and repeat what is heard on each one. In this case it will be your audio and there will be feedback and reverberation causing all audio to be unintelligible. Also connecting one node to another on linked repeaters will also form a loop. If it is planned to connect an IRLP node to a reflector (perhaps for a net) you must connect one IRLP node before bringing up any repeaters that also have IRLP on them. • Will I form a linking “Loop”?

42. Repeaters and Linking \ Linking Repeaters / • MAVCOM - Maritime Amateur Voice Communications System - Terrestrial UHF Repeater linking - Consists of UHF radio hubs and trunked sites - Link sites are rarely over 60 miles apart - 55% of MAVCOM is half duplex, 45% is full duplex - Uses 4 digit DTMF on and off codes - Link codes are executed when you unkey (Enter) - Audio, voice or CW link status messages are heard - Different courtesy tones used when linked - Link inactivity timer is generally 5 minutes - Link activity timer is generally 3 minutes - More than one repeater can be linked at a time - New links always being added (Work in progress) - Method of controlling links is always evolving - Uses Coordinated Dialing Plan (106* on, 107* off)

43. QUESTIONS ON ANY THING SO FAR ??????

44. TAKE A SHORT BREAK

45. Repeaters and Linking \ Linking Repeaters / Overview We will take a quick look at the complete system more or less as it stands today. You will see the complexity of the backbone system but you actually do not need to understand all the paths involved but knowing some of the routes and the types of links involved will help you understand why certain things happen. The UHF backbone system is like a party line - any linked repeater will hear what is on the backbone. I will then explain how some of the links work.

46. OVERVIEW This map shows most of the repeaters in nova Scotia Not all are linked

47. OVERVIEW Red lines = Hard linked Yellow lines = UHF backbone system White lines = under construction VE1BBC

48. OVERVIEW The white links under construction will be hard links VE1BBC

49. OVERVIEW

50. OVERVIEW