Repeater How-To

This is some general information on getting started with handheld transceivers and using repeaters. It’s based on some common questions the club receives from newly licensed amateurs. It is also common for entry-level handhelds to have documentation that is difficult to navigate and understand.

First, if you have not yet bought a radio, an inexpensive handheld is a great first acquisition; it lets you figure out what kind of things you want to do in the hobby before investing a lot of money. These handhelds have all the features you need to talk on local repeaters and simplex. Though you can certainly spend more if you want, and obviously you’ll get a better rig with more features for $300 than $30.

In the Boston area, 2 meters (144–148 MHz) is the workhorse band. This is partly due to a cold war–era early warning system that restricts the output power that can be used on 70 centimeter (420–150 MHz) repeaters in New England. Still, a dual-band radio that includes 70 centimeters as well as 2 meters is a good choice.

First of all, what is this ‘repeater’ thing? A repeater is simply a radio that listens on one frequency and retransmits what it hears on another, slightly different frequency. Repeaters usually have more power than the average handheld, but what makes them useful is they usually have a good antenna at a high elevation. You’ll recall from studying that VHF and UHF signals are generally line-of-sight, so if you and the person you want to talk to are both at low elevations but you can both see a repeater antenna, you can communicate.

The frequency that is used to identify repeaters is the machine’s transmit frequency, that is, your receive frequency, or what you would tune the dial of a scanner or a receive-only radio to. You transmit at a different frequency (the machine’s receive frequency), and the difference between the two frequencies is the offset. The offset can be either positive, in which case you transmit at a higher frequency than you receive, or it can be negative, in which case you transmit at a lower frequency than you receive.

The good news is that you often don’t need to worry about calculating all this. The offsets and offset directions are standardized in the US by frequency range, and programming software (and programming using the front panel) will usually do the right thing.

So, for the W1BOS Boston repeater, whose details are here, the line “Frequency: 145.230(-)” means that you receive on 145.230 MHz. The standard offset is 600 kHz, and the “(-)” means you subtract it to get your transmit frequency, (145.230 − 0.600) or 144.630 MHz. On many radios, you’ll see a little minus sign somewhere on the display when you tune to 145.230 MHz.

Of course there’s one more thing! In addition to the frequencies in use, the other information you need to access almost every repeater is the CTCSS tone (also called “PL” for historical reasons, or an “input tone”). A CTCSS tone is a sub-audible tone that, when added to a normal FM voice transmission, causes a receiver to open its squelch. Repeaters use this to control access; without the correct tone they will ignore a transmission. So you have to enable it, and the tone has to be correct, to use the repeater. (On most handhelds this is called “Tone” mode, or perhaps, “TX Tone”.)

Most repeaters will also transmit a CTCSS tone (an “output tone”), which you can use to open the squelch on your radio instead of just sensing a carrier. The use of this feature is optional; it’s called “Tone squelch”, “TSQL”, or “RX Tone” on most handhelds. As you’ll see in the page I mentioned, the Boston machine requires an 88.5 Hz input tone, and it transmits a 100.0 Hz output tone. Your radio may not allow you to use these split tones, in which case you should set the CTCSS to 88.5 Hz, and use Tone mode, not TSQL.

It is possible to set all this information using the front panel, but it is a pain; it’s much better to use a computer program to store this into one of the radio’s memories. Some manufacturers have a free application to do this, which is rarely a marvel of programming or interface design, but it’s free. There’s a free application called chirp that a lot of people use. Chirp is also your only choice if you’re on Linux. There are also non-free programming applications from RT Systems.

To find repeaters, there’s a repeater directory here that is very comprehensive. You can do a geographical search to find machines near you. A curated list of repeaters close to downtown Boston is here. Farther afield, the frequencies used by the SKYWARN program include most of the main active repeaters in southern New England: see the list here.

You occasionally hear some simplex (non-repeater) activity in the city. The national call channels (146.520 and 446.000) are good to have programmed in, and BARC occasionally uses 147.420 simplex at events and as a talkaround frequency at Artisans Asylum. Also, 146.580 MHz is starting to gain traction as an ‘adventure’ frequency for hiking and the like.

Now to make your first contact! A good rule of thumb in amateur radio is listen, listen, listen, but at some point it will be time to press the PTT (push-to-talk) button on your radio and make some waves.

There is a guide to making your first contact here; look under the “FM Repeaters” section. You should know your call in the standard phonetic alphabet, which is also on that web page. Do not use non-standard or cute phonetics. On the Boston repeater, you can try checking in to the daily NTS traffic net at 8 pm (do listen first to get the hang of things, but they are very friendly), or the BARC club net at 9 pm on Mondays. Or you can send a note to either or the bostonARC group on and arrange a schedule with an Elmer (what a mentor is called in ham radio).