The Web Page of Kristopher Linquist

My tech interest of the day has been radios. I am a member of a caravan of BMWs that drive to Santa Barbara every year. We all communicate via Motorola Talkabouts (FRS/GMRS) radios.. which basically give you the range of about 10 cars ahead & behind you. Not very practical for a caravan of hundreds of cars. I started investigating higher powered radios to see what was possible. Here are my discoveries:

• The mileage claims by FRS "bubblepack" are not .. even .. close. I knew this before, of course, but even the latest Motorolas labeled "25 miles" will have a very hard time reaching even 1 or 2 miles.
• Most of the FRS radios you by now are actually FRS/GMRS combo radios. FRS has 14 channels, GMRS has 15 channels. The first seven of each share the same frequency. Therefore, on most talkabouts, channels 1-7 are FRS & GMRS, channels 8-14 are FRS only, and channels 15-22 are GMRS only.
• The FRS channels are "license free" but have a maximum transmit power of 500mw (1/2 a watt)
• A license is required to legally transmit on GMRS (that means a license is required to transmit on "high power" [above 1/2 a watt] on channels1-7 or to transmit at all on channels 15-22). This information is in very fine print on every Talkabout package/manual. You do not have to pass a test for a GMRS license, you simply have to pay $85. If you are only talking on Talkabout radios.. should you get a GMRS license? Legally, yes. Will you ever get in trouble for not having one? Doubtful. The one thing the FCC has done right is prohibit Talkabout style radios from accepting an external antenna, effectively limiting their range. This keeps people with Talkabouts from interfering too much with license holders that have professional radios.

Now... lets say you want to become a license holder and buy a professional radio. No problem. Make your way over to the FCC's web site and sign up then apply for a "ZA - GMRS" license. You pay your $85 and in a week or two you receive a call sign (similar to amateur/ham radio) in the mail. Your single GMRS license covers your whole family!

Now, it's time to get a radio! GMRS/FRS frequencies are in the Ultra High Frequency (UHF) band, so you want to get a UHF radio. You can get either a handheld (often abbreviated HT - handheld transceiver) or a mobile unit (either for your vehicle or your desk at home with a power supply). As far as handhelds go, a good choice is the ICOM F21GM. It's a purpose-built FRS/GMRS radio that requires no programming. Now, if you're like me and you actually enjoy doing things like programming radios, you may want to step up to the ICOM F43GT. Most resellers will do a limited amount of programming for you ... or you can buy the programming cable and software.

Both of these radios broadcast at 4 watts. Even the most powerful Talkabouts are only 2 watts, and if you look at their actual power output, it's actually less (they are not very efficient). Another advantage of the ICOMs is the antenna - it is not only removable, but it is also larger and tuned for the FRS/GMRS frequencies. Although doubling the power does not double the distance for radio transmissions, it is likely that you will experience at least double the range with these higher powered more efficient radios.

As far as mobile radios go, the ICOM F221 is a good choice. Now you're getting into serious range! This radio broadcasts at a full 50 watts - the GMRS legal maximum. It does not get an antenna, so you'll need to pick one up as well. Most mounts come with the cable. You simply need to pick a mount connection type and then choose an appropriate antenna. The two primary antenna types are UHF and NMO. NMO mounts spread the weight over a slightly larger area, so thats what I prefer. You can pick up a trunk mount, which mounts to the lip of the trunk and requires no drilling, at your local Fry's Electronics or Ham Radio Outlet. As far as an antenna goes, the Larsen NMOQC is only $14 and will do a great job - you just have to cut it yourself! You see, antennas function best when cut to specific lengths depending on the frequency wavelength. You can cut to the full length, 1/2 of the length, 1/4, etc. The Larsen is designed to be cut to 1/4 wavelength and it includes a handy guide to tell you exactly how long to cut it depending on what frequency you want (if I recall, you cut to 5 1/4 inches for 460mhz, which is closest to GMRS/FRS frequencies). The bottom of the mount gives approximately 3/4" additional length, making the total height just over 6 inches. Very small - I covered mine in black heat shrink tubing to be a little less conspicuous on a dark car.

One advantage of these "professional" GMRS (UHF) radios is that they will allow for offset (transmitting on a different frequency as receiving) allowing you to communicate through a repeater. A repeater will simply repeat your signal at a higher power real-time. They are often placed up on hills to maximize coverage. This will allow you to communicate over a much wider area with many more people! Some repeaters are open, others are private (you must request or purchase permission to use it). For a list of GMRS repeaters in your area, check out http://www.myGMRS.com.

For your reference, here is a list of GMRS/FRS frequencies available on most Talkabouts (source: http://www.buytwowayradios.com/blog/2006/07/frs_and_gmrs_frequencies.aspx)

Now, a little about "Privacy codes". Most Talkabouts have 38 of them - the newest ones have 121 of them. It's a bit of a misnomer because choosing a privacy code does not grant you any privacy - it simply transmits a sub-audible tone along with your voice. Your radio will also then only then allow you to hear transmissions that contain that same sub-audible tone.

If you have your privacy code set to zero, you will hear ALL transmissions on the given channel, whether the transmitting side is using a privacy code or not. If you try to talk back, the receiver will not hear you if they are using a privacy code.

Privacy codes 1-38 use an older standard called CTCSS (motorola abbreviates it 'PL'). Privacy codes 39-121 use a newer standard called DCS (wikipedia it for more information). The professional radios like the ICOMs will not have easy to remember privacy code lists - you'll have to program in the specific CTCSS frequency or DCS code. There are many more CTCSS and DCS codes available than the ones the Talkabouts give you access to; therefore, if you are talking to someone else with a professional radio, you can choose a code that the Talkabouts do NOT use for less interference in busy areas (festivals, amusement parks, ski resorts, I'm sure you've experienced more than your share with a Talkabout).

I found several web pages listing the CTCSS frequency to Motorola Talkabout privacy code "translation" list, but I couldn't find any web sites listing the DCS code equivalents for privacy codes 39-121 - so for your benefit, I used my amateur radio that has DCS scanning capabilities to go through each privacy code one by one. Remember that each FRS radio manufacturer does not have to be compatible with another manufactuer's privacy code list. This information is correct for "bubblepack" Motorola Talkabouts.

If GMRS does not work out for you, there are several alternatives:

• MURS radios: MURS uses the VHF spectrum, so you get more distance for a given power output. MURS has a 2 watt maximum, only 5 channels, and is license-free. As you can imagine, it's much less popular and therefore you have significantly less unwanted transmissions/intereference.
• Amateur radio: Amateur radios can have significantly more power than even GMRS and has less restrictions. It requires a license which can be obtained (without learning any morse code these days!) easy and cheap - usually the study materials and the test are less than $40 total.