Repeaters
By Paul Germscheid, WAØWRG
A Repeater is a transmitter and receiver combined together to simultaneously receive and retransmit radio signals. A voice repeater operates in the duplex mode. In other words, you listen on one frequency and talk on another. It's not too complicated as your radio does the switching for you.
The repeater output (the frequency on which the repeater transmits) is what you see displayed on your rig. If you watch your radio as you then transmit, you'll see the repeater input (the frequency on which you transmit) displayed on your dial.
On the 440 band, the split is 5 MHz. You'll have to read your radio manual to see what buttons to press to put your rig in the "repeater" mode. An easy way to check is to look at your display and you should see a "+" for the 440 band to indicate the frequency shift or "offset".
You will also hear the term SIMPLEX. This is when your transmitter frequency is the same as your receive frequency. All repeater owners encourages you to use the repeater as needed but when you are close together (inside a mile or two) please use simplex on a different frequency. The most common SIMPLEX frequency is 446.000 MHz on the 440 band. SIMPLEX is also used if a jammer or other interference is on our frequency.
Private line or PL is a way to keep the frequencies free from other interference on our frequency. Sometimes its use is to make the repeater available to club users only. This is not true for KØFHC/R. Another term for PL is CTSS (Continuous Tone Squelch System). What this term means is that when you transmit your voice to the repeater, your rig also transmits a set tone with it. You as the operator have to set your rig to transmit this particular tone.
Once again, it is merely a function of reading your manual and pushing a few buttons. The repeater is set to transmit only when it receives that tone that it hears with your voice. In other words the repeater is not in "carrier access" (voice only) and will not respond to a voice only transmission nor will it respond to any other transmission unless it contains that one preset tone.
You normally cannot hear the PL tone (although some claim they can); it is used merely as a key to use the repeater. All KØFHC/R repeaters use PL tones.
Repeaters are typically located in optimal radio locations, such as on top of hills or towers, to give them wide coverage. In the case of the main KØFHC repeater, it's located high atop the IDS Building in downtown Minneapolis. As a result, a radio with very low power, such as a portable hand held or mobile radio can increase its range from a couple of miles to 50 or more miles.
Ham radio operators who maintain both the technical and organizational requirements operate amateur Radio Repeaters.
For more information about repeaters we suggest: http://www.repeater-builder.com/rbtip/repeater101.html