The input, or the frequency the repeater receiver transmits on 443.700, but receives on 448.700 (+5 MHz offset) The good news is, that most of the modern ham radios take the offsets into account and will compensate automatically.Įxample: If the repeater output is 443.700 Mhz (70cm band). On other bands, the offsets will be different. If the output frequency (transmit) of the repeater 447 MHz, then the input frequency (listening) is 5 megahertz above.The 70 cm band offsets are 5MHz apart (again, rule of thumb) If the output frequency (transmit) of the repeater 147 mHz, then the input frequency (listening) is 600 kilohertz above.The 2-meter band’s offsets are set 600 kHz apart (As a rule of thumb), That would be a loop, and that seems really, really bad. Think about it this way, if the repeater used the same channels for both transmit and receive, it would only hear itself. One frequency is for it’s transmitting frequency and the other is it’s receiving frequency. Repeaters need to listen and transmit at the same time, therefore they use two different frequencies. This is due to it’s short (small) antenna and it’s the fairly low height with respect to the radio horizon (unless you are on the side of a mountain).Ī Repeater is used to rebroadcast your transmissions and received signals to much higher levels, electronically, using large, very efficient, high gain antennas, low loss feed-lines and transmitters and receivers, that rated for heavy-duty or continuous use.Ī repeater boosts your signal and receives the station you are talking to, over a far greater range and coverage area! You benefit from the repeater’s higher elevation, which increases your effective transmitting and receiving area! Your handheld transceiver or mobile ham radio has a very limited range. Basically, it handles the repeater station ID using either voice or CW and activates the transmitter at the appropriate times. The controller is the brain of the repeater. The exciter modulates the audio from the receiver while the power amplifier boosts the audio level so the signal can travel further. TransmitterĪ transmitter has two main components: an exciter and a power amplifier. The receiver is generally very sensitive and selective so the repeater can hear even the weaker stations. ReceiverĪs the name implies, this component receives incoming signal. It prevents the receiver and transmitter from hearing one another by the isolation it provides. The duplexer separates and isolates the incoming signal from the outgoing and vice versa. Basic Components of a RepeaterĪn antenna is used to transmit and receive signals that go in and out of a repeater. The signal must also have a tone to determine that the station being received at the repeater wants its transmission to be re-radiated. This signal should be strong enough for re-transmission. Before it opens up, the receiver must receive a signal on its input or receive frequency. Repeaters are designed to not transmit noise and spurious signals. Despite these differences, the overall concept of how a repeater works and how it must be operated is generally the same. The actual operation of a repeater will vary depending on several factors such as the country where it is operated, the band being used, and the make or model of the repeater. It receives transmissions on one frequency, then re-transmits those same transmissions on another frequency at the same time.
You can find a list of repeaters, nationwide in the ARRL Repeater Directory.Ī repeater is just another two-way radio. If you can’t reach anyone, then you may have to take things to the next level and use a repeater. You should make your connection then decide on an alternate frequency to communicate on so that you don’t tie up that high usage channel. This channel should not be used to chew rag (talk) on, but only to sync up with another HAM. On the 2 meter band, you can use 146.520 MHz. This means that you have the same channel for transmitting and receiving.
The simplest method to communicate on a HAM radio is simplex.
RADIO REPEATER HOW TO
How to Use a Ham Radio Repeater Simplex Communications You can have the old reliable HAM devices, however, there are so many unanswered questions for the new HAM licensee.Īnd now I’m bringing in HAM Radio 101 – Intro To Repeaters: We’ll start to answer these questions to make HAM simple. Communication is very important during an SHTF.
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