Leaderboard

The more I learn about the FCC's General Mobile Radio Service (GMRS), the more I am fascinated by RF in general. It touches everyone's lives every second of every day, yet few people pay much attention. How cool is it that after 42 years and 14 billion miles away, the 22-Watt radio on Voyager 1 is still sending data back to earth every day (how important is that antenna?). So why aren't more people interested in GMRS or RF in general? There's no test to get a license like amateur (ham) radio. It's $70 for a 10-year license, and is really easy to get started. So here are some theories. People don't know: GMRS exists Why GMRS exists Why they'd want to use GMRS How to envision themselves participating in GMRS What it takes to get started with GMRS What it takes to continue and improve with GMRS Technical information they should know about GMRS Etiquette when transmitting (TX) on GMRS What a GMRS "Net" is and why Most people within the GMRS community are helpful once you're in, but the community is very inviting in a go-figure-it-out-yourself way, and no one has assembled everything you need to know about GMRS all in one place. We GMRS people are putting the onus on outsiders to sift through thousands of painfully esoteric webpages with a winnowing fork, separating useful info from useless, poorly written, or incomplete info. When I first heard about GMRS on a 4x4 trip, I arrived home and Googled around and settled on a Midland MXT-275 because it seemed perfect for mounting on my truck dashboard. At the time, I had no idea that Midland doesn't manufacture a GMRS radio capable of operating on split-tone repeaters (Dear Midland, I know you're reading this: why do you squander so much potential?). Edit 6/28/2021: Midland heard our cry! They just updated the MXT-275 to include split-tone programming on repeater channels. So for example, now this radio is able to reach a repeater that receives (RX) incoming transmissions on 467.550 with a PL tone of 103.5 and repeats the transmission (TX) at 462.550 with a PL tone of 88.5. I didn't even know what "split tone" was or even what "tone" meant, or carrier or squelch or hundreds of other little things you all take for granted. Since then, I realized that if the big, bad manufacturers like Midland, Kenwood, Motorola, and iCom can't even invite the public to learn more and provide useful content for each stage of the customer journey—Awareness, Consideration, Purchase, and Loyalty—the 2-way radio industry has much deeper problems and aren't there to help guys like me. As we get involved deeper into GMRS, there's little-to-no hand-holding going on at each level of knowledge. I ending up relying on the Ham community here and there and a guy who is basically a saint at a little radio shop in Phoenix, Arizona (hope Tim over at Procomm and the others at the nonprofit AZGMRS.org don't mind me giving them a shout-out). Edit 4/14/2020: By the way, AZGMRS made this awesome list of FCC-approved GMRS radios that they recommend. If you live anywhere near Arizona and are reading this, now would be a great time to become a member. Their repeater network covers some 100 miles around Phoenix with more and more repeaters joining the network (check out their sweet coverage map). But it's still frustrating. I wish a GMRS expert—presumably a manufacturer—would just come out and say exactly what a total newbie needs at each stage of their involvement or level of need. Two-way radio manufacturers should stop wasting time trying to sell, and start marketing and branding, which means educating the public about the 5 W's (Who, What, Where, When, Why [+how, +how much]) without trying to sell to them. Most new users don't know what they need because they don't know what's possible. For example, I wish I knew that manufacturers don't typically include the best antenna on their radios right out of the box. It took me over a year to realize that the best bang for the buck for a portable base antenna to include in my go bag is N9TAX's Slimjim and that Smiley Antenna makes the best bang for the buck antennas for hand-held radios (which by the way, everyone just assumes newbies are supposed to know that hand-held walkie-talkie radios are called "HT" for "Handy-talkie" and what a "QSO" is). How would a newbie know that the cheap Nagoya 771 "upgrade" antenna for Baofengs that everyone talks about actually isn't the best bang for the buck for the GMRS frequency band of 462–467? How would a newbie know that antennas work best when tuned exactly to what they call a "center" frequency that accommodates 5 Megahertz in each direction (+5 and -5 Megahertz) at the expense of hearing other frequencies? I learned the hard way that in order to properly install an NMO antenna mount on the roof of my truck, I would need a drill bit specifically made for drilling NMO antenna mount holes, and that yes, it is worth the money to do it right the first time. I'm still in the middle of learning how a "quarter-wave" or "5/8 wave" antenna works, the difference between dB gain vs. dBi gain, mic gain, antenna gain, because again, everyone seems to just assume I already know what all this means. I still don't understand what antenna "tuning" means and why you have to "cut" an antenna to "tune" it. Can I make my own antenna right now in a pinch with a copper wire in my garage? Ok, show me! How do I measure it or test it? What is SWR? Can I measure it myself? What do I need in order to measure it? Is one SWR meter better than another for my level as a newbie? Is there something I should learn to make it worth buying the better meter that opens up a whole new world of capability? Is it worth learning all that? This graphic did a great job beginning to explain what dBd gain means for those of us who know next to nothing about it, but now I need to go find out on my own and sift through a thousand webpages to find out if dBd is something new I need to know. Speaking of dB, I know that "dB" is a decibel, but is it the same as my stereo volume? Why do I see manufacturers saying that the microphone and cable have a dB rating? What is going on here? This is madness! We can Google things all day, but which info is true and correct and the most helpful? I think that the entire industry is sitting on a Gold Mine of consumers sitting at home for weeks on end who would love to buy GMRS equipment and communicate via GMRS to friends, family, neighbors, and other GMRS users. Whoever provides the most useful, relevant, and engaging content that stops making assumptions about what people know or don't know will win. STOP ASSUMING. START EDUCATING.

If you only want to connect to the repeater, I.e. unidirectional, go for a good quality, high gain, yagi, or, if you can find one, a parabolic reflector. Because you will mount the antenna in an attic, you may not need an antenna that can survive -40° and hurricane force winds. But, beware of low-priced antennas.

Another data point: I have antenna approx 25' off the ground (10 feet mast on top of single-story house). In flat suburbia reliable communication range between base (TK-880H) and HT is around 5 miles. Anything in excess of 5 miles drops to nothing very quickly. Same base station can talk to mobile (also TK-880H), with antenna on a flat roof of SUV, to 8 miles reliably. And I can't check distance longer than 8 miles because I'm in the valley. Get some altitude and 20 miles between HT and base becomes easy (Mt Diablo to Livermore, for locals).

so you have a 408 and a 404 or are they a 411 and a 420. 404 https://www.commscope.com/globalassets/digizuite/262254-p360-db404-b-external.pdf?r=1 408 https://www.commscope.com/globalassets/digizuite/262257-p360-db408-b-external.pdf?r=1 411 https://www.commscope.com/globalassets/digizuite/262260-p360-db411-b-external.pdf?r=1 420 https://www.commscope.com/globalassets/digizuite/262263-p360-db420-b-external.pdf?r=1

I am using the 712EFC antenna with Timesmicrowave LMR400 for my household repeater. Now my range isnt too great because of the height, (17' above ground, thanks to not owning my property and the landlord being afraid of the insurance costs of a tower on his land) but upgrading the feedline and antenna nearly doubled the range I had. (Originally I was running RG8X and a Diamond 200U) Still there are other factors in play. What is the terrain between your house and the repeater you are trying to hit? If there is a mountain or very large hill between you and the repeater, chances are you'll need a taller antenna structure, not just a higher gain antenna. If you have a ton of pine trees, you may find the new setup (Higher power and better antenna) works well for you as it punches through the trees. You may also benefit from a lower loss feedline meaning less dB loss for the radios receiver, and more power getting into the antenna from the transmitter.

I have been looking for a way to do RoIP between some arbitrary computer/phone and a GMRS radio and your project seems like it might employ the technology I am looking for. I have found your new web page (https://central625.wixsite.com/gmrs/) and see you have switched from the DingoTel to using a SignalLink and Zello. Given the low cost of the DingoTel (I found one for $12 on eBay) and the very simple needs of my project, that would seem to be the way to go. So, I would love to hear about your experiences and any advice you might have. Thanks

With centimeter radio and cheap cable, the cable length is not going to change anything even remotely close to noticeable... likely not even measurable. Also, anything under 3:1, you won't have any risk of damage. Anything 2:1 or better is good. Anything 1.5:1 is really good. getting a 1:1 match usually means the antenna is not resonant at your target frequency. You should be very pleased with 1.4:1. Normally I target about 1.75:1 at the antenna feed point and then use an LC network to maximize output power to the antenna. Get that antenna 40+ feet in the air and you will dramatically increase your coverage and performance in the covered areas.

I hope to write some of these at some point, just waiting for the site rebuild

How about some how to, or tutorials, on basic topics. GMRS is mainly aimed at non technical people who simply want a good means of communications and don't have much interest in the theory or radio as a hobby. For that there is Ham Radio. For example one wants a mobile installation. Basic info on how a mobile radio should be wired up for electrical safety, battery connections, fuses etc. What type of coax cable to use, cable connectors, antenna location and antenna mounts. Recommended mobile radios, antenna manufactures and models. Some sample photos of other people's installations for ideas to go along with the written material. Another would be for portable radios. Recommended manufactures and models. Issues with using a portable radio in a mobile setting, speaker microphones, heat sets, battery types, battery eliminators, cable adapters from the portable radio to mobile antenna. Again some sample photos. Repeater operation. What are they used for. What specific channels are reserved for them. Explain why there are two frequencies used and in general how this is programed in to the radio. Explain what a "PL" tone is used for and why it's typically required. The how to's should be kept at a low simple technical level. The idea is to help somebody setup a functional radio installation without getting mired in a lot of theory. After the system is up and running there is plenty of time and people who can provide additional info for those that have the interest.