A 2M REPEATER PRIMER

Hi, everyone. Over the past weekend, I programmed my 2M rig for local repeaters and I thought the Club would like hearing what luck I had. If you are a new Technician or someone who has not been active on 144 MHz lately, listen up!

The basics:

Repeaters allow communicating over greater distance than direct (simplex) contacts on 2M, especially when you are using a hand-held radio. Your signal travels to the repeater on one frequency, and the repeater hears you and immediately retransmits your signal on another frequency. What your radio does and what the repeater does are mirror images in the way it switches from the transmit to receive frequencies.

For instance, our BARS Net meets on the W1DC repeater in Billerica (every Wednesday at 8PM except club meeting nights, by the way!). The repeater transmits on 147.12 MHz which is called the OUTPUT FREQUENCY. It listens on a frequency +0.6 MHz above that, 147.72. The standard band plan for 2M means that for most of the time, the user has a predictable way to program his radio. What I have described is termed the SHIFT (positive) and OFFSET (0.6 MHz), keywords you will need to know for using repeaters. My Yaesu has a menu item called AUTOMATIC REPEATER SHIFT (ARS) so I turn that on and the rig knows what to do based on the frequency in use. You simply program in the output frequency, which is where everyone will be listening.

Now, in the old days, anyone could transmit through a repeater. As things got busier, and for the possibility of interference, most repeaters use a way to control access called PL TONE or CTCSS. This is another setting that you need to program into your radio. As you transmit, your rig sends a continuous, sub-audible tone which the repeater looks for to allow passing your signal through. These tones are between 67-254 Hz and should be publicized if the repeater wants everyone to use it. W1DC uses 103.5 Hz and like most repeaters it only requires it on transmit or “encode” as it is termed in my Yaesu manual.

A good reference for finding repeaters is www.repeaterbook.com. There is also a Repeaterbook mobile app. You can put the search results into Excel and keep track of the channels you have programmed in your radio. Another site to check out is www.nerepeaters.com.

The proximity search might be a good place to start:

https://www.repeaterbook.com/repeaters/prox.php

I looked up all repeaters within 75 miles of Chelmsford and began setting up my radio to see if I could be heard on them. Although I could “hit” almost 50 repeaters using a 65W mobile rig in the house, with a twinlead J pole antenna, you don’t want to be scratchy and weak for repeater conversations. So I pared the list down to the following strong repeaters. I was very pleased to have this many to choose from!

You may remember from your exam study that hams are supposed to communicate with the minimum power necessary. So be sure to try contacting the repeater with lower powers and set the minimum necessary in memory when you store it.

My rig allows labeling memories alphanumerically so I can see right on the display that I am tuned to the DANVERS repeater. Do this if you can – and some rigs can be programmed via the computer, even easier.

Note that W1DC Billerica repeater uses 147.12 output frequency, 103.5 Hz CTCSS tone frequency, positive .600 MHz shift. That’s all you’ll need to program. The other repeaters on this list will be set by the same method. Sometimes there are exceptions – note the Uxbridge repeater does not use a CTCSS tone.  Use this list as a starting point if you live near Billerica. If you are more than a few miles distant, use Repeaterbook to search for ones surrounding you. VHF comms are line of sight and “your mileage may vary” especially if you are using an HT at 5W or are mobile in a car.

Also note that my rig is simply FM at the moment, not any of the digital modes (C4FM, D-Star, DMR, etc.). If your rig does those modes you can search for repeaters that have those functions.

Frequency Offset Tone Call Location ST Mi Dir
145.230 -0.6 MHz 88.50 KB1BEM Boston MA 22.2 SE
145.410 -0.6 MHz 74.4 W1DVC Harvard MA 13.9 WSW
145.450 -0.6 MHz 74.4 W1GZ Fitchburg, Burbank Hospital MA 23.4 W
145.470 -0.6 MHz 136.5 NS1RA Danvers MA 21.3 ESE
146.625 -0.6 MHz 131.8 K1KKM West Newbury MA 22.8 NE
146.640 -0.6 MHz 136.5 W1MHL Waltham MA 16.5 SSE
146.715 -0.6 MHz 146.2 KC1US North Reading, Tower MA 10.1 SE
146.730 -0.6 MHz 88.5 N1IMO Hollis NH 15.9 NW
146.745 -0.6 MHz 114.8 NM1D Derry NH 19.4 N
146.820 -0.6 MHz 127.3 K1BOS Boston MA 22.2 SE
146.835 -0.6 MHz 77 N1LHP Andover MA 11.4 E
146.850 -0.6 MHz 85.4 K1CA Derry NH 19.4 N
146.955 -0.6 MHz 74.4 WB1GOF Westford, Prospect Hill MA 5.1 WSW
147.045 +0.6 MHz 100 WW1Y Nashua NH 12.9 NNW
147.120 +0.6 MHz 103.5 W1DC Billerica MA 4.9 SE
147.150 +0.6 MHz 100 W1FY Framingham, MEMA MA 22.5 S
147.210 +0.6 MHz 107.2 KC2LT Derry NH 19.4 N
147.240 +0.6 MHz 71.9 WA1NPN Marlborough MA 20.5 SSW
147.270 +0.6 MHz 146.2 W1MRA Marlborough MA 20.5 SSW
147.285 +0.6 MHz 100 W1VYI Topsfield MA 20.4 ESE
147.345 +0.6 MHz 100 N1MNX Pepperell MA 13.1 WNW
147.390 +0.6 MHz NONE KB1MH Uxbridge MA 38.9 SSW

Though I care most about our Wednesday BARS net, I am not a snob and would encourage ALL our members to check out the other repeater systems in the area and enjoy yourselves checking into nets run by other clubs. In fact, feel free to mention club nets you like on the BARS email list, or highlight particularly active times of day for those in the list above.

Another tip, be sure to give your call out every once in awhile, like “…KA1GTT, Chelmsford MA, listening!” If everyone is waiting for a call then the repeater will seem dead. 🙂

Have fun and GET ON THE AIR!

Andy

KA1GTT

About Andy Wallace

President, Billerica Amateur Radio Society

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