dosw

Don't forget about the long tail. Any future where digital signals supporting 65k or 1M users on a frequency can be stomped on by bubble pack radios from Walmart transmitting on those same frequencies in analog, just won't work out. People are going to pull a set of FRS or GMRS radios out of their sock drawer five, ten, fifteen years from now and push "TALK" on the things, potentially disrupting a lot of people using a frequency for digital. It will take a long time to phase out existing FRS and GMRS radios. Case in point: I've owned a few sets of FRS radios over the years. One set got lost by an airline losing a suitcase. Another set had one of the two handheld units stop working, and for some reason I tossed them both. But sitting in a drawer three feet from me right now is a Motorola T6300 FRS radio. It supports 14 channels, has 38 CTCSS tones, and has some scramble mode. Using that scramble setting is not legal under current FCC rules, but when the T6300 was marketed (twenty two years ago), it must have been ok. My T6300 was manufactured November 2000. The point is that I have GMRS radios I bought within the past 30 days, but also a radio that is mostly compatible with my GMRS radios that is 22 years old. Let's say five years from now the FCC legitimizes digital transmission for voice over GMRS frequencies. I'll probably still have my 22 year old FRS radio, which will be 27 years old. And I'll probably still have the GMRS radios I currently own. But not just me. People all over the US have sets of these radios, and don't use them often enough to bother replacing them. This is to suggest, if the FCC were to introduce a version of GMRS that allows for digital transmission, it's probably going to have to be on a different set of frequencies from traditional GMRS. Even if the FCC were to eliminate GMRS today, those radios are still going to be keying up for years to come.

They're fun, inexpensive radios (well, my experience is with the UV5G, but practically the same). However, true scanners they are not. Even a 22 year old Radio Shack scanner will breeze through 22 GMRS frequencies in the time it takes a UV5G to get through five to seven. Modern ones are even faster. One of the key elements to scanning is covering the scanned frequencies quickly enough that you don't miss a lot. Dedicated scanners are good at that. They also often allow for easily turning on or off scan banks, quickly.

Radios that are set to output 50w are designed to do so when supplied with 13.6 or 13.8v, and at that voltage might draw 13A while transmitting. When the vehicle is shut off, the battery is going to supply closer to 12.6v when fully charged, and at that voltage, the radio will draw fewer amps; maybe 10-12A. And that means you will probably be transmitting at a little under 50w. You would have to measure to find out more precisely. The FCC won't approve a GMRS radio manufactured with the capability to transmit more than 50w at 13.8v. That means manufacturers aren't going to risk producing one that outputs 50w at 12.6v, because it might exceed the FCC limit when being run in a vehicle with an alternator putting out 13.8v. That means, if you want full power output from your radio, it needs to have a power supply that produces the correct voltage, and that can meet the amperage needs of the radio. For your 50W radio, you would want a power supply that can produce that full 13.8v, AND that can provide 15A current (which is probably what the radio is fused at).

I used a label maker to stick one to my dash adjacent to the mobile handset, and one on the bottom of each of my handheld radios. A few days later I found that I had committed it to memory anyway. After you've hit a repeater a few times and done a few radio checks you'll commit it to memory, too.

ALL is not lost. Conventional scanners are still pretty useful, in that they can iterate through scanned frequencies at lightning speed. Scanning with a typical GMRS radio is very slow by comparison. So even if you're not picking up law enforcement, you can still put them to practical use. Even without digital trunking, scanners are pretty useful for: Normal GMRS scanning at very high speed Repeater input scanning High-speed acquisition of CTCSS or DCS tones/codes HAM bands MURS Marine VHF Air traffic / control Event scanning (race scanning, for example, if that's your thing). It's maybe not as fun as listening to the police operating, but still pretty useful. Do you happen to know... did all Michigan encrypt such that even current P25 scanners aren't able to listen? Just curious. I've been considering upgrading from my really old scanner to a newer digital scanner, but I'm holding off because Salt Lake City / County are going to be transitioning to Digital P25 Phase2 trunking sometime in the next 12 months, and I kind of want to wait and see before spending the money to upgrade.

I was in my vehicle the other day when my daughter reached out to me over GMRS (simplex). I was in a parking lot adjacent to some sort of construction business; they had some heavy machinery on-site. When I keyed up the MXT275 with MXTA26 antenna to respond, a tractor with an alarm in it started sounding off. When I released the PTT, the tractor quieted down. Keyed up again, and again the alarm started sounding. I was about 20 feet away from the tractor when this happened. Because I'm curious and can't leave things alone, I tried a frequency at the other end of the GMRS band, and the same thing happened. Is this common? Was something wrong with the tractor alarm system's wiring? Really, it's just curiosity getting me. I'm not likely to be hanging out in that particular parking lot... probably ever.

Are you experiencing receiver desensing? If I transmit to a repeater, with another radio in the same house receiving that repeater, it won't "hear" the repeater because of the desensing caused by the transmitting radio in close proximity. If I walk 50 yards away and try again, the receiving radio hears the repeater just fine. This can be a fairly common issue. If you eliminate CTCSS on the output (receiving) radio and it doesn't change anything, then it's most likely desensing.

It does seem like a security leak. As a software engineer we work really hard to avoid leaking information that could be used to compromise other users. In radio communications, with our call signs linked to our addresses, publically viewable, the FCC is leaking information. The act of identifying with a call sign gives "bad guys" two pieces of information: (1) our current general location; (2) our specific home address. A bad actor could determine that someone is identifying in Park City, and knowing that skiing typically takes all day, will know that person is not going to be home, in Salt Lake for a number of hours. The home may become a target. Fortunately for me I have someone who stays at my place when I'm away, and my neighbors are watchful. And I have other "precautions" and monitoring in place. But it would be better if we weren't giving out so much information.

It's pretty common to do one or more of the following: Upgrade your HT antenna to another, more adequate HT antenna such as a Nagoya NA-771G. This is a 15" antenna, and claims to produce 4.71 dBi gain. Still portable, but also long enough that you can't exactly be inconspicuous when using it. Get an adapter (so239 to sma-f or so239 to sma-m depending on your radio), and then connect the HT to a mobile or base-station antenna. As an example, I can connect my UV-5G via an adapter to an NMO magnetic mount, and then screw in whatever antenna I want, so long as it matches to NMO. I own a couple of options, the Midland 3db Ghost antenna and the Midland 6db 31" whip antenna. But with an adapter you can really mate it up to any GMRS antenna as long as one end is SO239. The second approach is far less convenient for "handheld" use. It would be practical for using the handheld as a base-station radio, or in a vehicle. Not as practical for walking around on a hike.

If it will run on a PI zero, in fact, that would be a great choice in a solar powered setup, since that little Pi-0 draws so little.

If you figure the conversion to RF output is only 33% efficient, then a 30w radio would consume 7A. If it's 25% efficient, it would draw 9.2A. From what I read, you should expect a lot better than 25%, probably closer to 33% efficiency. So even at 30W, your 10A plug should be adequate. My 28 year old Bronco (1995 Bronco XLT 5.8L), which is my camping / outdoorsing vehicle has one 12v plug designed for 20A, and one 12v plug designed for 10A. The fuses are in those ranges, too. So it's not necessarily a foregone conclusion that your plug is limited to 10A. Check the fuse. And check the owner's manual. Maybe you have a lot more room than you think.

I mostly hear net check-ins Sunday afternoons and evenings. That is a lower-traffic time, anyway, I think. If they're going to do their check-ins and verify their equipment and skills are up to date, I see no reason to discourage that use. It is neither an improper use, nor something I have any reason to be annoyed about. Net check-ins are certainly less annoying than the after-school blister-pack kiddies filling up a channel with screeches, feedback, and relentless roger beeps. Can't do anything about them either, and again, it's not my place to issue edicts from atop my high horse. It would be great if the blister-pack kiddies could stick to 500mw channels, but there's no restriction or governing authority guidance that says they must do so. The nets are a welcome bit of sanity. I don't mind listening in and trying to figure out where they're transmitting from.

Usually the repeater published range is just a number as a radius from the antenna. In real world RF propagation it's not that simple. I can pretty easily hit a repeater 22 miles away from me with a 40 mile published range. There is another repeater five miles away that I usually cannot hit from home, and it has a published range of 20 miles. The difference, really, is that I have almost perfect line of sight to the repeater 40 miles away. The one 20 miles away has a mountain between us. It doesn't matter if you're only five miles apart if there's several miles of dirt and rock between. In your case, you may be hearing a repeater over 45 miles away because the conditions are such that you can pick it up. Those favorable conditions may include one or more of the following: Most importantly, line of sight. After that, a good receiving antenna and good receiver. And of course factors such as minimal interference on the frequency, a good transmitter and good transmission antenna.

Midland's GTX1000 handhelds are sold this way: 50 channels. Of those 50, 22 are frequencies corresponding with GMRS 1 through 22. And then 23 through 50 are those same frequencies preprogrammed with either CTCSS or DCS codes. Those codes are squelch codes. This means that they are codes someone must transmit for your receiver to open squelch and listen to the transmission. Or that your transmitter must send so that receivers programmed with the same codes will open their squelch and listen. Any receiver that is not programmed to require a squelch code to open squelch will default to receiving all transmissions on a given frequency. And those transmissions are in no way encrypted (GMRS doesn't allow for scrambling). So conversations held between transceivers operating with squelch codes are openly available to transceivers or scanners that are not set to limit by squelch code. There is no privacy. At any rate, channel 50 in a Midland radio, for example, is going to be one of the 22 GMRS frequencies, and one of the conventional CTCSS or DCS codes. If you transmit on channel 50 at the same time someone is transmitting on the equivalent standard GMRS channel, you'll be stomping on each other, because they're analog transmissions on the same frequency. There are only 22 real channels. Everything else is just a preset code on top of one of those 22.

Again, it seems like the call feature is a noisemaker, and essentially intended for entertainment. I don't know why the FCC allows manufacturers to include the feature. We'd be better off without it.

I read the entire Part 95 section yesterday, and one thing that stood out to me is this: § 95.1733 Prohibited GMRS uses. (a) In addition to the prohibited uses outlined in § 95.333 of this chapter, GMRS stations must not communicate: .... (4) Music, whistling, sound effects or material to amuse or entertain; Every blister-pack GMRS radio I see has a "call" button. This button causes the radio to transmit either: Music, whistling, or sound effects. The rule above prohibits music, whistling, and sound effects OR material to amuse or entertain. Every GMRS sold in a blister pack will, with its call button, transmit a sound effect, so breaks the left-hand side of that OR clause. The purpose of the call button could arguably be "to amuse or entertain" as well, though I understand manufacturers will claim it is not intended to amuse or entertain (not even the duck calls... definitely those are neither amusing nor entertaining). Again, to violate 95.1733a4, the transmission is either music, or whistling, or a sound effect, OR material to amuse or entertain. I would love to see that feature excluded from radios, or at least harder for kids to discover.