What is a Repeater?
Repeaters are to be found across the country, mainly on 145MHz, 433MHz and 51MHz. A repeater is an un-manned station that will retransmit on its output frequency any signal heard on its input frequency that satisfies certain conditions. On the 2m band (144-146MHz) repeaters are found on the following frequencies: Output Input Channel no. (MHz) (MHz) 145.600 145.000 R0 145.625 145.025 R1 145.650 145.050 R2 The input frequency 145.675 145.075 R3 is always 600kHz below 145.700 145.100 R4 the output frequency. 145.725 145.125 R5 145.750 145.150 R6 145.775 145.175 R7 On the 70cm band (430-440MHz) repeaters are found on the following frequencies: Output Input Channel no. (MHz) (MHz) 433.000 434.600 RB0 433.025 434.625 RB1 433.050 434.650 RB2 433.075 434.675 RB3 433.100 434.700 RB4 433.125 434.725 RB5 The input frequency 433.150 434.750 RB6 is always 1.6MHz above 433.175 434.775 RB7 the output frequency. 433.200 434.800 RB8 433.225 434.825 RB9 433.250 434.850 RB10 433.275 434.875 RB11 433.300
A repeater is an automatically controlled transmitter and receiver that simply transmits what the receiver hears. By placing repeaters at sites with high elevation and antennas atop large towers, workable coverage is greatly increased. What is a courtesy tone? A courtesy tone is a short tone or series of tones that sound over the transmitter of a repeater when someone unkeys a radio. So, when you let up off the mike, you hear a tone. This tone serves three purposes: 1) to let the other people on frequency know you are finished talking; 2) to let the repeater timer reset (more on this later); and 3) to give a one second pause for anyone who might need to break into a conversation for emergency purposes. More advanced repeater systems will provide information by courtesy tone. Some repeaters will give a tone that does up or down in pitch according to how well your signal is to the repeater. For instance, a low tone may mean that the repeater is hearing you S1, while a high tone may mean
A repeater, in concept, is not really a complicated device. A repeater is an automatically controlled transmitter and receiver that simply transmits what the receiver hears simultaneously. Imagine having a receiver on one channel, and a high power transmitter on the other, and then holding the microphone of the transmitter in front of the speaker of the receiver. Now make the operation fully automatic. Any user that can be heard by the receiver has the effectiveness of the high power transmiter at his control. In general, repeater systems are usually located in places of high elevation (on tall towers, on top of mountains or tall buildings) and are equipped with large and efficient antennas, extremely low loss feedlines, and a transmitter and receiver that is very durable, rated for continuous duty, and built to be as immune as possible to interference. The end result? People using a repeater get much greater range from their radio equipment than would be possible talking from radio to
A repeater acts on a purely electrical level to connect to segments. It amplifies and reshapes (and, depending on the type, possibly retime) the analog waveform to extend network segment distances. It does not know about addresses or forwarding, thus it cannot be used to reduce traffic as a bridge can in the example above. Switches can be repeaters. A hub cannot.
Related Questions
- I know that my Icom dual band handheld, or a mobile radio can do crossband repeat. Can I use them as a repeater with both receive and transmit frequencies on the same band?
- Can I use a PL-259 or UHF connector with a cellular amplifier or amplifier/repeater?
- Can a cell phone repeater be used to cover more than one floor?
