dosw

This is just a nitpicky question so I can arrive at a better understanding. Considering: https://www.ecfr.gov/current/title-47/section-95.1767 (47D/95E/Transmitting Power Limits) As I read it, the following device restrictions exist: All GMRS must be type approved. The 467 Interstitials (8-14) are handhelds only. The 462 Interstitials (1-7) are for mobile, handheld, portable, and base only (no fixed, and no repeaters) The 462 mains (15-22) are for mobile, hand-held portable, repeater, base and fixed stations The 467 mains (repeater inputs) are for mobile, hand-held portable, control and fixed stations. Additionally the transmit power on each: 467 interstitials: 0.5w 462 interstitials: 5w 462 mains: 15w for fixed, 50w for mobile, base, repeaters. (No mention under the "power" section of handhelds). 467 mains: same power restrictions as the 462 mains. The question is what is the limit for handhelds on the mains? They're omitted from mention under power requirements on the mains. We should intuitively understand that it's not desirable to have a 50w handheld with a rubber duck antenna adjacent to peoples' heads. In fact with the recent introduction of 8w GMRS handhelds (10w in amateur bands), it seems that manufacturers are (responsibly or not) exploring higher power limits than 5w for handhelds. There may be radiation exposure requirements that limit how much power a manufacturer can throw into a radio for the sake of selling "features" to people who don't know better. But within the FCC guidelines, what IS the limit for handhelds on the mains? (We should also know that it really doesn't matter. A theoretical 50w handheld is both unhealthy and more of a hand-warmer / battery-drainer than a radio).

If you are hearing crazy old guys talking on Sat night over ch 20, you're hearing a repeater. They won't hear you if you call out on simplex. You would need to figure out what repeater they're using, program your radio with the correct TX PL/CTCSS/DCS tone to access the repeater, and then retry. Step one: Find the repeater listed here in mygmrs, hopefully. Step two: Set your radio to repeater mode for that repeater's frequency/channel. Step three: Set the PL tone you learned from finding the repeater listed on this site. Step four: Call for a radio check.

Take power out of the equation for a moment and assume that the only thing that matters is like of sight (since that's actually 95% of what matters): The purpose of the repeater is to be located somewhere that has line of sight to two remote radios that do not have line of sight to each other. So if your repeater is up high, and the two radios that want to talk to each other can see the repeater, it doesn't matter that the radios can't see each other; the repeater relays the conversation. Now to further take power out of it, consider that with a 5w handheld radio a ham operator with a rather directional Yagi antenna can send a signal through the ISS (International Space Station) repeater, and someone else with a decent antenna can hear him a thousand or more miles away. The biggest requirement is that both parties have line of sight to the ISS, which is at an elevation of 1,243,200 feet above sea level (240 miles). So when there are no obstructions at all, 5w will travel hundreds of miles to the space station which may be passing hundreds of miles to the north, for example, but still within line of sight. That's not to say that power doesn't help. It does. If you have two people in a room ten feet apart, and one person whispers, the other person might hear it. Turn on a fan in the room, and now the person has to talk a little louder to be heard. Run a vacuum and the person has to shout, and may need to cup his hands in front of his mouth while the other person cups his hand behind his ear to improve the signal path of the voice. This is like both increasing power and increasing the antenna gain. Now put a 30 foot high brick wall between the two people. At this point the only way the two people will hear each other is if someone is standing on top of the wall to relay the message.

No, there WAS a travel channel 30 years ago. There is no travel channel today.

For GMRS: 64 miles from my home to the Promontory Point repeater. But I can easily drive another ten or twelve miles further out from it and still hit it, so 76 miles. But it is at least a couple thousand feet over the terrain around it. For 2m ham, the Snowbird repeater is an Intertie repeater. The repeater itself will reach Nevada and Wyoming (from the middle of northern Utah). But it's also tied into a linked network that extends into Oregon, Washington, Idaho, Nevada, Wyoming, Colorado, Arizona and Montana, with multiple nodes along the I-15 corridor from Ogden to Provo. The Snowbird repeater is at 11k feet, with the valleys below at 4200-5200 feet. So propagation is pretty amazing.

Yeah, nobody's really watching GMRS that closely. Even amateur. But I'm guessing if you looked at the enforcement database for hits on marine VHF and aviation there would be some stories. Marine VHF has become less strict in the past decade; it used to be that you weren't allowed to talk ship-to-shore except to licensed shore stations. But a web search says that "In 2016 the FCC relaxed its rules and now allows portable VHF radios to be used “in areas adjacent to the water” when this use relates to the “needs of the associated vessel."

That radio is not made for transmitting on airbands, and it is, in fact, illegal to use it for transmitting within the airband. There are a lot of areas where you may get away with dumbassery, but transmitting on an aviation frequency with a UV5R is likely to be one of those areas where you won't get away with it very long. https://aviation.stackexchange.com/questions/94091/what-licenses-do-i-need-to-transmit-on-airband-frequencies

This has been my experience, as well. There are better radios out there for a lot more. And there are worse radios for a lot more. There are not many better radios for less. I use mine with the stock antenna or a 771 depending on the situation. The UV5G Plus is the GMRS-correct, type approved version, of course.

There's this one from DX Engineering: COMPACtenna Model 2m/440 Dual-Band NMO Mobile https://www.dxengineering.com/parts/can-2m-440?seid=dxese1

Meter was connected backwards? The radio was on the antenna side of the meter, and antenna on the radio side?

For portability get a Uniden scanner. It will scan 25-50 channels per second. The Baofeng will scan 3 per second. And the Uniden will cover from 10m (maybe even 11m) to 33cm. For "as many frequencies as possible", an SDR. Even the lowly RTL-SDRV4 will pick up from 300kHz to 1.72GHz, with some antenna swapping necessary to get all that.

What are you trying to accomplish? Ham radio in the US, for the bands this radio is compatible with, is going to be 144-148MHz, 222-225MHz, and 420-450MHz. If you are transmitting because you have your amateur license, you would probably want a dual-band 2m/70cm antenna. If you are just listening, it's not as important to have a perfectly matched antenna. But typically an antenna like a discone antenna will cover a broad enough range to be useful from 108-509, for listening. If you are using the radio for GMRS the antenna should cover 462-468MHz. Again, a discone could be a pretty good antenna for 2m, 1.25m, 70cm, and GMRS. Or the Comet CA2X4SR. Both a discone or the comet will be external antennas. For built-in antennas a Nagoya or even abbree would be fine so long as it's listed as working for the bands you intend to transmit on. There are a lot of other ham bands that are outside of this radio's capacity. But it covers the most common ones used with a Tech license.

Awesome. We've got a mountain between us (I'm in east Sandy near LCC), so I won't be able to hit it or hear it, but when I get down that direction I'll give it a listen.

Per antenna height. a 100ft antenna has 14 miles line of sight to someone laying on the ground below. But it has 28 miles to another 100 foot antenna.

I have the Ghost antenna (MXTA25), the whip (MXTA26), and the Comet CA2X4SR-NMO. On my old '95 Bronco I use them with a lip mount on the hood that is just forward of the air-vent cowl. The ground-plane that provides is a minimum of eight inches to the aft, and more in all other directions. I find the best of the bunch on GMRS is the MXTA26. The CA2X4SR-NMO is invaluable as a dual-bander/broad-bander, though; great for 2m/70cm plus GMRS (different radios, sure). I don't really use the Ghost all that often anymore. It was okay. SWR was a little higher than the others, and as I drive around testing propagation by recording at home what the signal sounds like, I just get more umph out of the bigger antennas. Plus, where I have it mounted on the Bronco, my FM Stereo's antenna is still longer than the MXTA26. But the Ghost isn't bad. If I'm in a group where we're within a couple miles of each other, I don't need anything better. And actually if I'm parked in the lot at a ski resort, the Ghost is probably a better option for reaching someone on the slopes, since the mountains can be so abrupt.

Yeah, that's the hard part. We had two windows today, but it will be a few days before the next good one, and probably in the middle of the night. A few weeks ago I heard Sunita Williams taking questions from school kids and answering them. I guess some ham operators were volunteering at various schools to facilitate. This wasn't on the repeater, it was on their 2m/70cm amateur frequency pair. Pretty cool. From what I've read, the ISS repeater and amateur voice downlinks are transmitting at 25w. Pretty amazing that a 25w FM voice transmission over UHF can reach me over 2000 miles away and be readable, when I'm using nothing more than a mobile antenna and a small LnA.

I should also mention: What YOU need to be able to do this... Although an SDR is really, really convenient for listening, because it allows you to observe the waterfall, I have also listened to the ISS with a Baofeng amateur radio (AR-5RM), the same antenna, a few adapters, and the same tiny linear amplifier, this time powered with a micro-USB cord. You still have to set your frequency step as narrow as possible in VFO mode, start high, and step down as the Doppler shift sweeps down. But it's not hard to do. Turn off squelch. Parts list: AR-5RM (<$30), LNA (<$20), antenna ($80), mount ($30), a couple of adapters ($10): still about $170. (And you'll need your Amateur Technician license -- ham)

There are a few websites on this topic, but I just had a fun experience and thought I'd mention here what was involved. Background: The ISS operates an amateur repeater. The downlink for that repeater is at 437.8000 MHz. What you will hear on that repeater is mostly people trying to make DX contacts through the repeater. As an example, if I can hit the repeater 400 miles away, and someone else can respond back, from 400 miles away, we could have 800 miles between us (not counting the 260 mile trip to space and back). An 800 mile contact over VHF through a single repeater is kind of cool, so amateurs are working this repeater constantly as it passes near enough to reach. Today's pass, the one I heard, was never any closer than Calgary, Canada (I'm in Salt Lake City). The measuring tool on Google Earth put the land distance at about 850 miles. And if you calculate the hypotenuse of 850 miles base plus 260 miles elevation that's about 888 miles. Accounting for the curvature of the earth changes the angle of that 260 mile leg, changing the shape of the triangle, and making the hypotenuse (the distance from me to the ISS) closer to 950 miles. I wasn't trying for contact; I assumed it was too far away, which it probably was for my setup. But I started hearing it before it hit the west coast of British Columbia, Canada, and kept hearing it all the way to New Brunswick. That's well over 2400 miles maximum distance. How do you know you're hearing the ISS repeater? First, you'll hear it starting to show up at the approximate fly-by time here: https://spotthestation.nasa.gov/tracking_map.cfm Next, you'll notice that the transmission is coming in off-center from the downlink frequency. This is due to the Doppler effect of the ISS moving 17,000+ miles per hour. Today when I first started hearing it, it was coming in at 437.8065 MHz, and by the time it faded out, I was listening on 437.7935 MHz. That's a 13kHz Doppler shift (+6500Hz to -6500Hz). Sensing that Doppler shift pass from above the center frequency to below the published center frequency is a dead giveaway you're dealing with the ISS moving 17500MPH. But here's what's cool, in my mind. My setup wasn't extravagant: RTL-SDRv4 (<$40) with SDR++ software (free). Cheap no-name (<$20) inline linear amplifier powered by the Bias-T setting of the SDR. And the big massive antenna? Hold onto your britches: Comet CA2X4SR-NMO mobile antenna ($80) mounted on a Midland magnetic mount ($30) stuck to an old 16" square steel griddle. Laptop computer to run the SDR and its software. Total cost (excluding laptop): $170, all of which I have cobbled together already. My technique was just to look up the fly-over time, and set the SDR++ software to just a few kHz high, then start watching the waterfall and listening. When I started seeing the FM signal in the waterfall I centered on it and listened. And by watching the waterfall I was able to continually adjust the frequency center through the fly-over until it was out of range. It was amazing to me that I was able to follow it all the way from the west coast of Canada to the east coast, and that I did it with a simple mobile antenna just sitting on the window sill -- not even a yagi. I wasn't expecting to hear anything at this time since it never got closer than about 950 miles. The pile-up on the frequency was pretty heavy, so I imagine the people getting through are using good, directional antennas to transmit with. I don't expect to be able to get a contact out of it without a directional antenna. But it was impressive to me today to be able to hear it over such a great distance.

This is what you're looking for: https://www.ecfr.gov/current/title-47/chapter-I/subchapter-D/part-95/subpart-J "The highest point of any MURS station antenna must not be more than 18.3 meters (60 feet) above the ground or 6.10 meters (20 feet) above the highest point of the structure on which it is mounted." Other interesting sections: "A grant of equipment certification will not be issued for MURS transmitters capable of operating under both this subpart (MURS) and under any other subparts of this chapter (except part 15)." (We know this; MURS type approval precludes being approved for transmission in other bands, and vice versa.) "Each MURS transmitter type must be designed such that the transmitter power output does not exceed 2 Watts under normal operating conditions." "A MURS transmitter must transmit only emission types A1D, A2B, A2D, A3E, F2B, F1D, F2D, F3E, and G3E. Emission types A3E, F3E and G3E may include selective calling or tone-operated squelch tones to establish or continue voice communications. MURS transmitters are prohibited from transmitting in the continuous carrier mode." What do those mean? A1D = AM, 1-channel digital without subcarrier, data, telemetry, or remote control A2B = AM, One channel digital with subcarrier, telegraphy (such as teletype) A2D = AM, one channel digital with subcarrier, data, telemetry, or RC. A3E = AM, one channel analog, voice. F2B = FM, one channel digital with subcarrier, telegraphy (such as teletype) F3E = FM, one channel analog, voice (this is what most people are buying 2-way MURS radios for) G3E = PM (phase modulation), one channel analog, voice "The occupied bandwidth of emissions transmitted on the center frequencies 151.820 MHz, 151.880 MHz, and 151.940 MHz must not exceed 11.25 kHz. The occupied bandwidth of emissions transmitted on the center frequencies 154.570 MHz and 154.600 MHz must not exceed 20.0 kHz. The occupied bandwidth of type A3E emissions must not exceed 8.0 kHz." (Narrowband FM for channels 1-3, Wideband FM allowed for Blue and Green, AM has to be 8kHz or less.) This section talks about unwanted emissions: https://www.ecfr.gov/current/title-47/section-95.2779 ... and it has some interesting information about audio filtering to avoid interference.

If the power leads are sufficient gauge for the length of the runs, you have no problem. But in case of "oops" moments, the wiring should be selected with a gauge big enough to handle transmitting on both radios at the same time. You never will do this, intentionally. But if the wiring is inadequate, you'll do it once on accident and blow a fuse or melt the wiring. Take the maximum draw of both radios combined, and plan your fuse and wiring accordingly. As for antennas, you need at bare minimum 1/4 wave, which at VHF is 2'1", minimum. And that will still mess with your propagation pattern somewhat. Pumping out 50w with that antenna spacing is not ideal. It's probably not great for the other radio either. Another alternative is a dual-band radio with certain unspecified adjustments that will allow you to get by with a single radio, passed into a broad-band antenna like a Comet CA2X4SR.

This is a great question (except it wasn't asked as a question), and great topic. SDRs are somewhat game-changing for amateur radio, even for GMRS. Start with a traditional scanner. In a traditional scanner such as a Uniden or old Radio Shack scanner, the scanner walks step by step through a frequency range (at a predetermined step size), or through a bank of channels. A good scanner will run through 20-50 steps or channels per second. This is pretty fast, though it means a scanner will hit all GMRS channels in about 1/3rd to 1 second. Now consider a 2-way radio like a Baofeng. Such a radio does have both a VFO and channelized scan mode, where you can scan frequency steps, or channels. In either mode, it will run through 2.5-5 steps or channels per second. I think Baofeng states the RM series (UV-5G Plus, for example) will step through 3 per second. Very slow. It would take four to five seconds to get through all GMRS channels. Scanners and 2-way radios can be good at filtering in only those frequencies they're looking at (good selectivity) and can have pretty good sensitivity for those frequencies they're receiving. An SDR works differently. You select a band, about 2.4MHz wide for the RTL-SDRv4 ($40) or wider for some more expensive models, and the SDR will take 44k samples per second of that entire band's RF spectrum. An SDR doesn't have particularly good sensitivity -- often you need linear amplifiers or band amplifiers, and they don't have great selectivity because they're designed to "hear everything." Band reject filters are commonly added to reject FM Broadcast, AM Broadcast, or band-pass filters to only allow through specific bands. But an SDR allows you to do a lot of neat things. And its view of a swath of bandwidth is instantaneous. No stepping through channels. It's an instant, continuous snapshot in realtime of a 2.4MHz wide swath of bandwidth. As a scanner, an SDR (or a few of them) can work to follow trunked systems, to scan frequency bands at any step (or really any frequency, not only by step), instantly. SDRTrunk is good software for this. SDR-based scanning, the scanner picks the strongest signal, not the first signal in sequence Scanning bands larger than 2.4MHz requires more than one SDR As a spectrum analyzer You get to watch the spectrum, watch the waterfall Record the raw spectrum in realtime Adjust gain / attenuation Add attenuators in front of the SDR so that you can direct-connect a radio to it and observe its spurious emissions and its power output (calculations required) Verify your radios are centered on the frequency they're supposed to be transmitting on. As a radio for listening It's really easy to watch the waterfall, and soon you'll start recognizing FM, USB, LSB, AM, WFM, CW, even digital mode transmissions in the waterfall. This makes it REALLY easy to point an SDR at a swath of 20m amateur, and then at just a click or two you're listening to someone in another country DXing. It's really easy to focus on the repeater swath of 2m and start clicking and listening. It's easy to use an SDR to verify you're receiving a new radio, or to set it to VOX record mode so that you can drive around and let the SDR record your signal. Great way for checking propagation. Lots of other hobbies Following the ISS repeater and ISS amateur signal is really cool. You can SEE the doppler shift in effect as you listen. You can see the repeater on ISS coming in a few kHz high, and then as it passes overhead and begins to depart, you see the signal coming a few kHz low. And you can easily listen to it just by clicking through the Doppler shift. With a 2-way you sort of have to program it in and step down through the shift blindly. You can use an SDR to pull in signals from digital (transmitting) thermometers and weather stations, with a down-verter (or an SDR that handles 2.4GHz range) pick up digital modes like wireless keyboards and mice, Bluetooth, Wifi.... these are pretty advanced projects. I haven't dabbled in them at all. You can get into it pretty inexpensively; you need an SDR ($40 for an RTL-SDRv4 which handles 500kHz to 1.76GHz), an antenna for the bands you wish to listen to, and later on you can add accessories such as more SDRs, or a HamItUp (up-verter for improved HF listening), HamItDown (down-verter for 1.9GHz and above), band reject filters, linear amplifiers, and so on. Software is free. I mostly use SDRTrunk, and SDR++. You can also get your feet wet by tinkering with other peoples' SDRs by visiting http://www.websdr.org/ . That's mostly useful for HF.

Look at how much power that first one is putting out; I'm picking up Florida in Salt Lake, and AM, not SSB. Then this guy shows up: Notice how when he keys up his carrier sweeps from nearly channel 5, swooping up to slightly below channel 6. And you can see two parallel carriers; that's people talking over each other. But that sweep is wild. Here it is again, and you can see the bleed over into 5 and 7. The amount of power they're pushing, it's no wonder they only shout for a few seconds at a time. They probably have to stop every few seconds to let capacitors load up for the next big drain, lest they cause a brown-out in the neighborhood.

Here's the link I use for those elevation plots: https://www.scadacore.com/tools/rf-path/rf-line-of-sight/ And for earth curvature I prefer https://www.everythingrf.com/rf-calculators/line-of-sight-calculator That second one requires that you add together two calculations; your antenna height-to-horizon, and the remote antenna height-to-horizon, and it assumes the terrain is flat except for the curvature, as would be found on the ocean. By the way, here's a repeater, 63.5 miles away, that I can hit very reliably: Here's another that is very reliable for me at 43.3 miles: And this one, closer at 21.95 miles: One of the best near me is on 2m ham, with propagation all the way to the Colorado border: But look at its elevation: 11,068 feet!

That's what I'm thinking, too. I'm in the SLC area. There are 2m linked repeater networks that reach into Wyoming, Idaho, Colorado, and even down to Las Vegas, which is a six hour drive from here. But that's not a single well-positioned repeater. It's a fully linked network known as the Intermountain Intertie: https://en.wikipedia.org/wiki/Intermountain_Intertie To use that network one would need an Amateur Technician class license. I would be surprised if there weren't similar networks between southern California and Vegas. 2m and 70cm are where you'll find interconnected repeaters. The other alternative is an Amateur General class license. With that the 20m, 40m, and 80m bands will be available to you, and getting signals to bounce off the atmosphere from Riverside to Las Vegas will be a fun pursuit. HF radio isn't going to be quite as reliable as repeaters. Well, that's not entirely true. With a repeater, you're depending on other peoples' equipment, goodwill, and competence. With HF it's all on you. But with HF you're relying on mother nature to a much larger degree. You have to figure out when bands are open at various times of day, times of the year, and solar cycles. If you're unassisted by online tools, you would need to listen for known beacons to spot band openings. More challenging but it seems like it would be fun. (I've got the Tech but not General, so I'm sidelined in HF except for a small section of 10m).

Let's have a look to see the elevation plot through the desert between Riverside (at valley level) and Vegas (at valley level): Let's also assume there's a repeater at the highest point between, and look at the plots between Riverside and that highest point, and between that highest point and Vegas: It looks like the path from Riverside to this high point is mostly okay. Between Vegas and that point, though, it's looking like the southern end of the Red Rock Canyon NP and north end of Bird Springs HP mountain range are getting in the way. If both stations were 200 feet above ground at the same elevation with nothing but the curvature of the earth between them, 64 miles is going to be about the limit, plus a little for atmospheric ducting. It's not impossible that a great repeater could cover this distance with a mountain range between, but without additional information explaining the conditions that would make it possible, the safer assumption is that it's not happening. I don't mind finding out I'm wrong, but I'd prefer that enlightenment, and supporting evidence not be withheld from us; this started out a public conversation. It's fine being incorrect publicly if there's some information that should have considered. But please do share it with us all so we're all more informed.