dosw

You need "triple modular redundancy" if it *really* matters. That means, a third opinion, basically. The old sailor's saying was "Never go to sea with two chronometers; take one or three." But you're below 2:1; it doesn't matter enough to worry.

i can drive 4 minutes to a location where I'm at 5500 feet, and have clean line of sight to the entirety of the Salt Lake Valley, mostly 4200-5000 feet. The amount of traffic pulled in even by my MXTA26 at that vantage point is overwhelming. Even my home (5050 feet) has clear reception when transmitting to a repeater 45 and 64 miles away. Any further than that, and mountains block everything. But one time I hiked up Mt Olympus (near 10k feet) and was hearing a repeater in Wyoming, and another in Idaho with a Nagoya 771G antenna. I didn't try hitting them though. There are 2m and 70cm repeaters at the top of mountain peaks near Brighton and Snowbird ski resorts. Those things have a bubble that reaches three states: Wyoming, Idaho, Nevada. ...maybe Colorado but the Uinta mountain range gets in the way a bit.

I trust the NanoVNA more. Try hooking it up to your computer so you can get nearly infinitely fine-grained scan points. Or narrow your scan range, or set the center instead of start/end points. Also there's a menu buried deep within for increasing the scan power. I haven't used it, because "auto" seemed good enough. I've found the two tools disagree a bit, too. Be sure you're calibrating for the exact range you're sampling.

Do you know the name of the menu option that needs to be enabled for this to work? I wanted to hook it up through 70dB attenuation to a TinySA, to see what is happening. UPDATE: Found it. Menu option 41: Voicepri (on/off). I don't see it doing anything. I suspect I would need two device both with this set up to actually work. When I key up, I just see the frequency I have selected being used, within the TinySA, and also when I directly connect to my RTL-SDRv4 (both through 70dB attenuation).

A ground plane is more than just having the antenna mounted against a metal surface. It needs to be 1/4 wavelength radius (6.5 inches) or more, in all directions. It doesn't have to be electrically connected or grounded, just needs to be a fairly flat surface for the 6.5" radius (or more). A lip mount works for me because there's a flat metal panel aft of the hood, too. But if you're at the edge of the hood without a flat metal surface on the other side from the mount your propagation will be stunted in the direction of inadequate ground plane. But if you experience this issue at, say, 200 feet, it's less likely to be a ground plane issue. I'd still be looking for sources of electrical interference.

My experience has been different. Using Chirp, with the 5RM profile, I first downloaded a stock code plugs from the radio, then added a few air band frequencies and uploaded them to the radio without any problem. I guess YMMV.

Yes. The repeater has an awesome antenna at an elevation that provides near perfect line of sight to your radio's minimal-value rubber ducky antenna. Your friends within 1/2 miles are not "line of sight" to your antenna; there could be trees attenuating signal, buildings, hills, and other obstacles blocking your antennas. If you can see the other antenna, you can talk. If you cannot, all bets are off. The repeater must have a high gain antenna, may be outputting near 50w into the feed line, with high quality cable, the antenna may be on a tower, and it may be up above obstacles. Probably all of these things are happening. By way of example, a 70cm ham radio (UHF, very similar to GMRS) can transmit to the ISS (250 miles away) with a Yagi antenna pointing in the right direction, and with less than 5w output. On the other hand, two 5w handhelds may not be able to communicate with each other more than a few hundred feet away. The difference is almost always line of sight first, antenna design second, power a distant third.

There are not a lot of dual band options that cover GMRS while also being stubby. The full length monster of a mobile antenna, the Comet CA-2X4SR-NMO covers 2m, 70cm, MURS, and GMRS. It even has reasonable SWR in Marine VHF and 1.25m. But it's 40 inches long. However, it can be folded down when you need to get into a garage, as it has a folding hinge. Some say it's not super in GMRS range. I would say its ears aren't quite as good as my MXTA26, but that's a tradeoff you might need to make to get a multi-band antenna. I have used it to achieve impressive distances, though. I like it. But you'll have to fold it down to get into the garage. There are some very good reviews for it online, and a few mixed. I guess I'm in the thumbs up group. A ground plane for GMRS needs to be metal, with a radius of about 6.4 inches or more. More doesn't hurt anything. Less hampers signal propagation. It doesn't need to be electrically grounded to the antenna, it just needs to be directly beneath the antenna. Ground plane radials are common for fixed (immobile) installations, while using a vehicle body for the ground plane for mobile antennas is common in that application.

Ok, since I got into GMRS I've added to my pre-existing collection that included a scanner, a couple of Marine VHF radios, a shortwave radio, and FRS radios, the following: Radios: UV-5G (2), UV-5G Plus (1), AR-5RM (1), MXT-275 (1), RA-87 (1), GTX1000 (2). Antennas: MXTA25, MXTA13, MXTA26, HYS SDN-1T, Laird TE B4505CN, Comet CA2X4SR (2). Nagoya NA771G, NA771 dual band, NA701G, ABREE dual band, Tram Marine VHF 5.1dB whip. Ground plane kits: Nagoya GP01 (2) Test equipment: Surecom SW102, NanoVNA, TinySA, 50w dummy load, 40dB, 20dB, and 10dB attenuators, and a whole bunch of various adapters and patch cables. SDR: RTL-SDRv4 (4), Raspberry Pi (2) Software: Chirp, SDR++, SDRAngel, TrunkSDR, nanovna-saver. Cables: LMR400, RG8X, RG58A/U, various lengths, plus various short length connectors. UHF/VHF diplexer (to use radios on two different bands on the same antenna). Mounts: NMO through-deck mounts, GP mounts, Midland magnetic mount, Midland hood mount. Multiple MXT275 brackets. Upcoming: Another Comet CA2X4SR and another diplexer to share a dual-band antenna. A mobile 2m/70cm dual band radio. A 2m/70cm Yagi antenna because I want to experiment with listening to / working through the ISS repeater, downloading NOAA imagery (using the SDR), and so on. Prep for General.

https://chirpmyradio.com/issues/11566 "Unable to upload to AR5RM": Closed as "not a bug" because the person reporting the bug resolved the issue by following the instructions of downloading from the radio first, not from some other similar radio. https://chirpmyradio.com/issues/11535 "No programming for UV-5RH": Different radio, but either way, this one was rejected because it's a duplicate of https://chirpmyradio.com/issues/10889, but also not applicable to the AR-5RM. https://chirpmyradio.com/issues/11529 "Add AR-5RM to the model alias map": Closed as done, implemented. https://chirpmyradio.com/issues/11474 "Error downloading from AR-5RM": This issue is still open, presumably because nobody's been able to reproduce it. Is that the same issue you're seeing? Adding your screenshots and radio pictures may help if that's the issue you're having. https://chirpmyradio.com/issues/11333 "Error reading data from radio: not the amount of data we want": This one is still open, and I'm not sure why. It looks like it's actually providing a solution of making sure that the driver for the cable be installed. But again, if this is the same issue you're having, providing more diagnostic information would probably help. But also that one is the UV-5RH, not AR-5RM. Which bug, specifically, addresses the issue you're seeing? This is active development, volunteer software. They only improve what they know about.

I've reviewed the Chirp code for the 5RM and the 17Pro. It's largely the same code (5RM class inherits from 17Pro class). There is no reason that I can see that the 5RM radio of the same version as mine, would not work with the 5RM entry in Chirp, unless you downloaded your code plug from a different radio and then modified it and tried to upload it as a 5RM. I suggest that if you cannot use the 5RM model in Chirp for your 5RM radio, you file a bug report with Chirp, because it's clearly not the intent for that to not work. As a software engineer it drives me crazy that two people with identical hardware and identical software would not get the same result. If you file that bug report, you will help all the people who are experiencing the same problem you are experiencing. Here is a link to the code in question: https://chirpmyradio.com/projects/chirp/repository/github/revisions/master/entry/chirp/drivers/baofeng_uv17Pro.py#L1313 That code encapsulates both the 17Pro and 5RM classes of radios. And here is a link for submitting bug reports: https://chirpmyradio.com/projects/chirp/issues I've seen that the developers for Chirp are highly responsive. Your bug report will get addressed. The address may be "We can't reproduce", but I rarely see bugs closed that way in the Chirp issues stream. Usually they either result in a patch being created, or the developers discovering an issue with how the software is being used. But either way, someone learns, the developers improve their knowledge base too.

I cannot explain why your experience with Chirp would be so different from mine, for the same radio. I have the vendor set to Baofeng, and the radio set to 5RM. I set channel 193 to 121.300, named it AirGround1, and immediately the software selected "AM" as the mode. I set Duplex to "off" which disables transmitting (though the radio won't transmit, regardless). I saved the image. I uploaded it to the radio. I turned on the radio and selected channel 193. It has AirGround1, and it can hear ground control traffic. That's with Chirp next-20240919 on Python 3.12.3. Could you try with that configuration? My radio is firmware version v0.14. Hardware version v01.

Can't speak definitively to programming airband frequencies, as I haven't tried setting up specific ones. But on my version of Chirp, the Vendor setting should be Baofeng, and the Model should be set to 5RM. If you don't have this configuration you might be running an old version of Chirp. You're using Chirp-Next, right? I can say that when I tried programming 118MHz into Chirp for this radio, Chirp automatically selected "AM": I set Duplex to "off", as that's actually the setting that disables transmitting, though I'm fairly certain the Baofeng won't transmit on airband AM frequencies either way. I haven't tried uploading it to the radio. But Chirp does accept the frequency and auto-selects AM.

Yes. My 2021-era USB-C style MXT-275 uses wideband FM for the repeater channels with the stock firmware. Don't believe everything Midland's support communicates. They're often just wrong. There is no way to *set* wideband or narrowband on an MXT275 with stock firmware. But I've tested several ways that I've mentioned in other threads, and have verified that it does switch to wideband on the repeater channels. I've seen support messages posted here and there that are confusing, probably because support, themselves, are confused by the fact that you can't set it explicitly. The FCC signal description is: 16K0F3E - Frequency modulated (FM) analog voice, 4 kHz deviation (NPSPAC); (FM mode) The FCC test report is here: https://fcc.report/FCC-ID/MMAMXT275/5301846 You'll find that 4kHz deviation is wider than "narrowband", which must remain within 2.5kHz deviation. A narrowband transmitter would be classified as 11K or 12K, not 16K. Additionally, the test results in the document I linked to showed its bandwidth envelope at significant levels to be within 16kHz, which is again wider than 11K or 12K you would expect to see of a Narrowband radio. It is true that a full wideband implementation would be a 20K envelope / 5kHz deviation. But it's quite common to find "wideband" radios with a 16K designation like this one. I don't love the MXT275. I'm particularly annoyed that you can only set one repeater per channel. But it's a solid radio, works correctly out of the box with minimal configuration, and very little to screw up.

Tested again in the 467 0.5w channels, also didn't see a difference. Then I switched to the RTL-SDR because the software is easier to take a screenshot of. Also this time I spoke into the mic rather than just keying up. I think that was where my previous measurements fell down. Within the waterfall (the lower section of the screenshot) there are two transmissions. The top transmission (more recent in time) was narrowband, the bottom transmission (more distant in time) was wideband. You can see the bandwidth peaks are wider. The red shading above is a 20kHz span, 10kHz deviation. The actual deviation of the radio is supposed to be around 2.5kHz in narrowband, and up to 5kHz in wideband. I see some difference when measured this way. In this example I fed the radio on low power mode into the 61.5dB attenuation, and then into the RTL-SDRv4 on channel 19, and used SDR++ to observe the waterfall.

I have a Baofeng UV-5G Plus. I set it to channel 15 / 462.5500 and tested it in narrowband mode, as well as in wideband mode. I've been able to observe bandwidth using a TinySA with other radios (Retevis RA87, Baofeng UV-5G --not "plus", and MXT275). But with this radio I don't see a difference in transmissions between a narrowband and wideband setting. The test setup: Baofeng UV-5G Plus -> 10w 40dB attenuator -> 10w 20dB attenuator -> TinySA TinySA is set to center frequency of 462.5500, span of 12kHz, -61.5dB attenuation offset*. Here are a couple pictures of the TinySA: Narrowband setting for the UV-5G Plus: And by comparison, here is wideband: See the difference? I don't. * (At 12kHz it still shows a broader band, because there's room on the screen. At 25kHz span, it's still identical). * (-61.5dB, because my NanoVNA says that my total attenuation is -61.5dB, not "40+20=60".) Is the radio just not switching to narrowband?

This has been my experience, too. I tested this four different ways using an RTL-SDR with SDR++ software to observe the waterfall, using the NanoVNA as an RF generator, using the TinySA to observe output, and so on. The USB-C version of the MXT275, which I've had since late 2021, uses wideband in the "R" channels.

Not true. It quietly switches to wideband on repeater channels. I confirmed this looking at an RTL-SDR waterfall, watching a TinySA spectrum analyzer, but first by observing that listening to 15R sounds just a little quieter than 15, which is a hard symptom of switching to wideband to explain, but expected. Ultimately do what you want. But the problems you're facing have nothing to do with using the simplest 15w mobile radio made. There are fantastic alternatives, of course, but you're in analysis paralysis right now. Just use the thing.

Yes. Out of the box the 275 doesn't have repeaters enabled. To set it to use repeaters you must go into the menu by pressing the Menu button, then up or down arrow until you arrive at "Rp" which will probably have a value set of "off". Hit the lock button (that's like "enter" on the Midland menu system). Now you're able to use the up/down arrow (on the volume rocker) to set "on." At that point repeaters are enabled. As a person pages through the channels using the arrows at the top of the mic, they will see 1, 2, 3, 4, 5, 6, 7, 15, 16, 17, 18, 19, 20, 21, 22, 15R, 16R, 17R, 18R, 19R, 20R, 21R, 22R. The repeater he is hearing will be one of those 15R-22R channels, though he will also hear the repeater on one of the 15-22 channels, since simplex and repeaters both use those same frequencies. Once he's selected the correct R channel, he will need to go into the menu again and set Tx and Rx tones. The manual only shows Pt but when on a Repeater channel, it will have Rx and Tx Pt tones. The options will be off, ∿, and ⎍. The first one is for PL tones, and the second one is for DCF tones. The user will have to look up in his manual how to translate conventional PL and DCF codes into the appropriate number options for Midland.

Don't second guess your purchase yet. The possible factors are: * Others have tones set and you don't have the same tones set. * Others are on a repeater and you're just talking on a simplex channel, also without tones. * Nobody wants to talk to a random stranger yet. * Poor signal propagation. * 800 other things not related to a defective radio. * Bad installation (severed coax for instance) * 200 more things. * Finally, maybe a defective radio. But if you can hear the radio on another GMRS or FRS radio such as a cheap handheld, it's not probably defective or in need of updating. It's one of the other 1003 factors. You have a simple and reasonably good quality radio.

There are some nuances I haven't seen mentioned. One is that the "strongest signal" is the strongest from the perspective of the receiver. Another is that two comparable signals will cause strange intermodulation. You hear that when two kids both key up their cheap FRS radios at the same time in different rooms of their house.A nearby listener will hear odd sounding interference. Last, even if you have squelch tones set on your receiver, you may still hear unwanted transmissions. Sometimes someone will transmit the code necessary to open squelch on your receiver but the stronger (different, unwanted) signal will be what you actually hear.

I was setting up 2m and 70cm repeater in a radio, and while my area has a really thorough website enumerating repeaters and their locations, it was hard to know which ones have propagation useful to me, and how they're used in practice. Rather than program them all into a scanner I used an SDR to observe swaths of those bands all at once. Then as CW call signs got transmitted, or as nets occurred, 8 could see them in the waterfall while listening. It was also possible, by doing this, to see what repeaters are interconnected. If two or more show up at almost exactly the same time, you've found connected repeaters. Anyway, I mention this because with one SDR I can see all of the 462 range. With two I can see 462 and 467. It takes two cheap SDRs to cover lower and upper MURS. SDRTrunk software can manage multiple SDRs, or running two instances of SDR++ can allow you to visualize the entire lower and upper MURS bands.

It's just two channels over from the baby monitor net, one down from the Tuesday Mr Microphone Simplex group. MURS net? That's the Walmart all hands meeting. Sorry it was just funny. You should be able to scan for it Monday.If you don't hear it, it's because it's too far away, and MURS doesn't have repeaters. You're allowed external antennas with MURS, though, so you might try using one, and getting it as high as you can. I imagine people doing a MURS simplex net are tinkering with external antennas to see what kind of range they get. Can you get to higher ground somewhere close, like an overlook point? That may help in hearing it so you can ask the participants a few questions. Also, if you hear it mentioned in the GMRS net, you could check in with that net and ask for more details.

I bought a 24pc assorted adapters kit, plus a few SMA-M and SMA-F to PL259 and SO239 short cables, and a few PL259 to PL259 short cables. Less than $60 for all that. At this point I never run into things I can't connect to my NanoVNA, TinySA, and SW102. But your connectors are possibly more esoteric. Nevertheless you should be able to find adapters for them on Amazon, which is where I found all the other assorted adapters.

You shouldn't have to specify an input frequency for the repeater, you should set your radio up with the output frequency: 462.xxxx, the offset: +5MHz, and the tx/rx tones. RX tone is not as important except that it will help you reject hearing kiddies playing walkie talkie. What radio are you setting up, and what software are you using to do it?