Repeater Basics & Software Programming Repeater Basics Covering Offsets, Tone, Repeater Components & Software Programming...

How Signals Travel Basic #1: The signal from the transmitter has to get to the receiver.

Where Do Signals Go? Typically, VHF/UHF signals cannot go around things. Mountains, hills, and even structures can block the signal.

HF Signals HF Signals will bounce off the upper layers of the atmosphere...

VHF/UHF Signals Generally, VHF/UHF Signals do not bounce off the atmosphere. They can, but typically do not.

Line of Sight Generally, VHF/UHF is considered ‘Line-of-Sight’ communications. Here in Colorado, 50+miles LOS not uncommon from a “hill.”

We Use Repeaters The Repeater ‘repeats’ your signal so it can go further; repeaters typically have wide coverage, like W0CFI.

Back to BASICS SIMPLEX: both radios are transmitting & receiving on the same frequency. When you transmit, the other radio is listening & vice versa.

The Repeater is going to listen to your signal & retransmit it. Repeater Time The Repeater is going to listen to your signal & retransmit it.

Wait...What’d He Say? If two radio are transmitting on same frequency, at same time, they will interfere with each other. The third listener will not be able to understand; AKA, “DOUBLE.”

Offsets... The sender (you) & the repeater each have to transmit on a different frequency. You are going to receive the repeater on the repeater transmit frequency, 146.655Mhz and you are going to transmit on the repeater’s receive frequency (input) of 146.055.

QUESTIONS?

Offsets, Continued The difference in frequency between the sender and the repeater is called the SHIFT, AKA, OFFSET

Shift Direction The direction (+ or -) tells you if you are transmitting at a lower frequency than you receive (minus - ) or a higher frequency than you receive (plus +)

Tones, PL, CTCSS... PL Tone = Private Line; Motorola Copyright. CTCSS = Continuous Tone Coded Squelch System Subaudible tones that are used to prevent the repeater from responding to signals that are not meant to be repeated (adjacent interference, static, etc.)

Tones, PL, CTCSS

Tones, PL, CTCSS When the transmitting station sends the correct tone, the repeater repeats the signal.

Tones, PL, CTCSS Types of Tone/PL/CTCSS: There are 50 Common Used Tone Frequencies (Hz) They are preprogrammed in most modern radios, you just need to activate! Tone Squelch (AKA, TSQL) Adds PL tone OUTBOUND from repeater. Your radio can be set so that squelch only opens when the specified tone is heard. Radio still needs inbound tone… Inbound/Outbound tones may be different! DCS Mode (Digital Tone Squelch) Uses Digital Tones instead of a tone to do the same thing. Not very common in this area.

Overview / Summary

That was a LOT of Work! QUESTIONS?

Repeater Hardware A basic repeater consists of several individual pieces that, when connected, form a functional system.

Repeater Hardware Antenna Antenna - most repeaters only have one antenna. The antenna simultaneously serves both the transmit and receive RF (Radio Frequency) signals that are going into 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 maintained they can last from 10 to 25 years.

Repeater Hardware Feedline Feedline - 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.

Repeater Hardware Duplexer AKA - Cans/Cavities Duplexer - the duplexer separates and isolates the incoming signal from the outgoing and vice versa. Even though the repeater's 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.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.

Repeater Hardware Receiver Receiver - 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.

Repeater Hardware Transmitter Transmitter - Most repeaters 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.

Repeater Hardware Controller Controller - 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, etc. 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.

Repeater Hardware

Radio Programming Software rtsystemsinc.com Excel-like layout. Each Programmer is designed for specific radio model. Purchase software ($25) and RT Systems cable ($30)separately or as a BUNDLE ($49). Auto import capability from online sources. Regular updates provided FREE.

Radio Programming Software chirp.danplanet.com Excel-like layout. Multiple manufacturers and radios in one package Software is FREE!! Auto import capability from online sources. Simply provide your own cable...buy one or make one! Solid, easy-to-use FREEBIE software.

Radio Programming Software Similar Excel-like layout, just harder to navigate. Software is defined per radio. Software is FREE with most D-Star radios. No Auto import capability from online sources. Simply provide your own cable...buy one or make one!

Radio Programming Software Software covers multiple radios. Software is expensive. No Auto import capability from online sources. Simply provide your own cable...buy one or make one!

Radio Programming Software - Hands On