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Everything posted by WRNA236

  1. I think not enforcing the need to get a call sign had more to do with the decline of CB than anything.
  2. I agree that it shouldn't take $500 to get some of this stuff but I do think it's unreasonable to expect all the way down to a $20 radio. Bubble pack radios aren't even made to be repaired or aligned, they are use-and-toss. So expecting more than a basic user manual is at best hopeful. Also the talent you allude to is not limitless. If you want a radio to hit a price point there's only so many NRE hours they can afford to throw at it. So if you want the time spent writing manuals it will likely come at the expense of design or quality in the actual device. Same with including CPS. I'm one who thinks a radio should have free or reasonably priced software to program it but I also don't expect it to be a feature-rich experience. A basic tool to get the job done is fine.
  3. How did your buddy program them? I'd have figured he'd be including CPS. Anyway, there's ways to work around band limits on many Motorola radios (even 1st gen XPR). It requires reading the radio and changing variables in that blank, generic code plug with a hex editor. You can edit and write the modified code plug all you want. The pain is it makes using CPS no longer a completely seamless affair in the future. If you don't have access or lose the original code plug file when you read the radio CPS will revert the code plug back to the default band limits for the radio and you have to start back at square one with hex editing. It's also important to note that just because two radios are both UHF the different band splits mean they may not necessarily be identical. So extending the limit up or down a couple of MHz is usually fine but forcing a 450-512 down to 403 might be way beyond the filter skirts and not work even if you trick the radio into tuning it. If you're just trying to make a radio tune for RX it shouldn't hurt anything. It may not be very sensitive way out of band though. Now trying to transmit that far out of band might be damaging, you need to be careful.
  4. tl:dr: Some CCRs are really bad clinkers while others work reasonably well. That's the same situation as anything coming out of China, though. They'll make anything you ask them to make at whatever price point you want it to meet. So read reviews and test reports on this (or any) radio. If they work alright and seem well built then don't worry about the architecture. Long answer: Don't get wrapped around the axle about SoC or similarly the terms direct conversion, direct sampling, SDR, hybrid, double conversion, heterodyne, etc. The words are thrown around indiscriminately. Basically a good radio is a good radio no matter its architecture while a bad radio will be bad regardless. The RDA1846 chip that most of these radios use can perform adequately if the design is sound otherwise. It's one particular frequency agile wideband RF chip but not the only by far. There's tons of them now, some that cover HF to SHF. One I'm familiar with is an Analog Devices part that can TX and RX on 2x2 MIMO from 70 MHz to 6 GHz. It's not something intended for cheap consumer HTs though. The chip is $300 alone and a drop-in SoM (System on a Module) is $1,600... You might generalize saying it's easier to make a straight superheterodyne radio that performs fine but is less expensive. Mostly it's reliability and build quality that suffers. After decades of engineering churn there's not much fat left to cut in the fundamental architecture to significantly improve performance so all you're left with is using cheaper components. So it won't last as long being tossed around but the actual RF performance is indistinguishable otherwise. But such a radio is inflexible and doesn't lend itself to adaption to something else. DSP techniques are still evolving and proprietary. So there's a lot more ways to screw up a direct conversion radio. Algorithms and firmware are where established companies (Motorola, Harris, Yaesu, Kenwood, whomever) can really distance themselves from competitors. Motorola is probably using direct conversion in the XPR7000 and EVX models and it works well. But then again no one other than Motorola knows really what is inside their ASICs to know for sure. But the guts don't matter, they aren't able to bend the laws of economics, physics or engineering. What matters is where the rubber meets the road - does it work or not? And if they can do it other companies can, too. In fact Harris builds most of the high performance, high reliability radios for the military and one portable example, the AN/PRC-152 (Falcon III), is a highly frequency nimble (covers 30-512 MHz and 762-870 MHz without gaps) 5 watt TX SDR that can do several analog and digital modes, some of which (like APCO-25, amongst other things) were added with a firmware upgrade after the radio was accepted and put into service. That sort of flexibility is why SDR is where it's at. The reason these CCRs proliferate is once a basic design is done they can adapt it to just about anything. That comes with up- and downsides. They can just make them faster and cheaper or they can add interesting form factors or features, whatever. And even heterodyne architecture have DSP, so the line isn't really that distinct to say this-or-that. If you're still interested after that diatribe you can start digging into the engineering behind various architectures and RF generally here: https://analog.intgckts.com/wireless-receiver-architectures/
  5. We do recognize reciprocal amateur radio operating privileges, which generally require applying for a temporary license. https://www.arrl.org/us-amateurs-operating-overseas But AFAIK that's about the only global reciprocity from an individual's standpoint. There's agreements between the US and Canada for FRS/GMRS and commercial and public service on the border and on the Great Lakes. But those are special exceptions due to our proximity. Otherwise the FCC (and I think other countries) issue what are known as restricted radiotelephone operator licenses when you need to use radios internationally. These would be radio operators on aircraft or ships, for example, and not usually informal operators (e.g. hams). https://www.fcc.gov/wireless/bureau-divisions/mobility-division/commercial-radio-operator-license-program/commercial-0 I don't know either if there's a written rule on this but with ham radio it's AFAIK accepted that operating things like Echolink, IRLP or DroidStar that when you key a radio you need a license. IOW say you're talking on a mobile radio to someone via EchoLink on their computer you both still have to be licensed. The app is like a very long mic extension cable. GMRS is a little different in that the license covers a family. But GMRS has the stipulation that you cannot link radios via the PSTN, only non-interconnected VoIP or RF link. Since it's an app that doesn't require dialing it's probably OK but it's kind of fuzzy with the "non-interconnected" statement. But if you're not family then you'd both need a GMRS license either way and the FCC only issues those to citizens, so back to square one.
  6. You should record and post it. If it's periodic it's man-made and probably can be identified. It's possible there's nothing you can do about it. Interference like this is why subtones were invented in the first place.
  7. That 8" per mile rule of thumb tells you from your eye level how far the horizon is away from you if you're laying on the surface. If you're off the deck it's not a straight linear calculation because you're perpendicular to a curved surface and your view is a line tangent to the horizon to something else perpendicular to its surrounding chunk of the sphere.. The formula you use is: So if your eyes are about 5 feet above the surface the horizon appears to be about 3 miles, not 7 like the 8 inches per mile would say. Then if you have two observers trying to talk on perfectly flat ground that means the most they can be apart is 6 miles, each seeing 3 miles and meeting in the middle at their common tangent intersection. Note that this is the optical line of sight, in reality you can see and radios can hear beyond the horizon due to diffraction, which in this case complicates the basic geometry. Remember that "flat" is relative. You're actually perpendicular to the surface of a round object. So the question is how tall does something have to be relative to the surface for you to see it. This calculator introduces that using the concept of an "obscured part." https://www.omnicalculator.com/physics/earth-curvature#how-far-can-i-see-before-the-earth-curves So if your observation point is 5 feet high and the distance over the curved surface of the sphere is 230 miles the object has to be 34,414 feet tall for you to see the top of it. If you move your observation point to 200 feet the horizon becomes 17.3 miles away but something 230 miles away from still needs to be 30,144 feet tall. Think about it with things you know. Like a city skyline. When you're driving into any city with tall buildings you can watch something several hundred or thousands of feet tall come into view as you travel just fractions of a mile on the surface of the Earth. Also the military relies on this heavily, particularly for radar and for pilots and ships. Their height or altitude is a critical way to stay obscured or knowing how high something should be so you have a clue to how far away they are. For a radar antenna 100 feet high you can only see 12 nautical miles away, for example. https://www.rfcafe.com/references/electrical/ew-radar-handbook/radar-horizon-line-of-sight.htm
  8. The thread proposes the plausible possibility that it's a radio operating illegally. If it's actually a 433 MHz ISM then it's not really likely to be that far off. I'd think it's more likely intentionally using GMRS/FRS frequencies in that case. It's kind of a cat-and-mouse. There's more users from 400 to 450 MHz that will notice - hams, government, military, public service, etc. Operating on 462/467 is impacting fewer users and I'd wager ones that are less likely to figure it out or know what to do about it. There's certainly possibilities for interference, intermod, FM capture on close frequency or mixing image, though. Just knowing it's static is a hard starting point since it could be hash, like motor brushes, switching (e.g. a microprocessor or power supply) or a faulty electrical connection. Although it does sound like it impacts a lot of radios, which makes it easier to track down as it will have a fair bit of power. ETA: Just remembered a common source of interference - solar panel charge controllers. They will be a constant noise source but only during the day. And some of them can be really bad, a cheap PWM making lots of harmonics. This particular problem is going to get a lot worse as more solar is installed, both the controller/chargers and on the flip side inverters that will run at night, distributed on houses everywhere.
  9. There's no ISM band around GMRS so if you're hearing baby monitors it's an image. They typically use 49 MHz, 902 MHz or 2.4 GHz. There is an ISM band in Europe and Africa (ITU Region 1) at 433 MHz that hams there have to co-exist with. Here on 70cm hams are secondary users on part of our allocation to military radar. The only user I can think of near the spectrum GMRS covers are meteorological satellites (such as GEOS) that have a downlink at around 468.8 to 468.9 MHz for DCP Interrogate.
  10. You mentioned a comparison to your FT-857D elsewhere. Have you checked (or had checked) the filters in your FT-857? They are getting up there in years and there are ceramic band pass filters in the IF section that can fail. It's actually a pretty common failure point with all radios from the late 1980s on. And the radio is old. The FT-857 came out nearly 20 years ago now and the FT-857D was introduced 14 years ago, so all of them are getting up in years. The main symptom is your radio suddenly going deaf and it's worse in mobile radios due to their compact size and the vibration, temperature, humidity, unstable power. https://dh1tw.de/replacing-yaesu-ft857-if-filters/ The VHF and UHF on an FT-857 won't ever blow away a good dedicated FM mobile, but then again those don't do 2m and 70 cm SSB or AM, not to mention any HF/6m, in a book-sized box so there's a matter of expectations with everything that's stuffed in something has to give. None-the-less, my FT-857 (-D also like yours) wasn't really that much worse than a similar vintage FT-8800 or TM-V71 I've had. Compared to a current Chinese radio they will all seem less sensitive, although they will be more selective and less prone to intermod. That's the trade off that's made. But even so I'd bet your radio's front end could use some TLC, maybe some parts (there's low and high pass filters in the VHF and UHF RF front ends that could also drift and fail) and alignment.
  11. Here's a few to scan through. https://www.theantennafarm.com/catalog/index.php?main_page=index&cPath=191_193_258_977_978
  12. Keep in mind that when you use a Yagi antenna it will be directional. You're probably used to what's known as omnidirectional antennas, which cover all directions around you. Pictures may help. An omni is just a vertical like you're probably familiar. The horizontal is like a bird's eye view looking down at the top. It covers 360° around in all directions. The vertical is the pattern up and down as though you're looking at it from the side like in the photo. This particular antenna is high gain so the pattern is very flat, you usually won't see it so squashed like that but I hope it gets the point across. A Yagi looks like this, with the elements BoxCar mentions. This example has 5 elements. From left to right they are the reflector, the driven element is black and 3 directors. It's pattern will look like this. See how it focuses all the energy to one side? That means it won't work well to the other side. Just want to make sure you understand the distinction before you decide to use a directional antenna. You usually use a Yagi (or other directional, like a dish for example) if you're truly only interested in a dedicated link. It has to be fixed in place fairly rigidly because even a few degrees off and signal drops off fast. Height is usually the better first step to better coverage as has been recommended.
  13. D-STAR is actually an open standard paid for by the Japanese government and owned by the Japanese Amateur Radio League. Icom and Kenwood are the only to have ever implemented it but anyone can. It's not really any different than DMR, which is an open standard controlled by ETSI. It was originally intended as an extension to analog FM PMR as I understand it. I'm all for experimenting but I guess I don't see the point to buying a radio that can only ever be what it is when you can take any radio capable of tier 1 DMR and program it to do the same thing. It would be like using an FRS radio for 70cm ham and that would be at least a relatively interesting challenge to hack and re-tune it.
  14. Are you just wondering if anyone's heard it or considering trying? If you're thinking about using one it would be nominally legal as long as you hold a ham license but consider that their channelization is probably inconsistent with your local band plan. Here in Colorado the simplex channels are all aligned +/- with 446.000.000 Hz as that's the suggested ARRL 70cm calling frequency. The simplex channels are 16K0F3E set on 25 KHz steps from that starting point covering 445.700 to 446.300. Within that channelization we have some suggested digital narrowband (8K0F3E) on 12.5 KHz steps that would work for PMR but they start at 446.200 and go up, so 446.2125 and on. Which is unfortunately just beyond the top of the PMR channels. Some of the PMR channels would I think nearly fall as interstitial where a wideband user probably wouldn't even hear it. Some would almost certainly interfere with other traffic being just 6.25 KHz off center. There's nothing requiring you to use the band plan. They are just for convenience and to be considerate. And simplex is not technically coordinated anyway. So if no one's using the simplex channel(s) potentially affected then who would know or care? It would be pretty insulting to step on repeaters, SSTV, weak signal, etc. But sticking within the plain simplex, meh, using the spectrum is better than not.
  15. That's the hitch, Bulletin 65 hasn't been updated since 1997 and the handheld exception does not mention Part 95 or Part 97 in detail. I don't think it mentions Part 95 at all. So the handheld evaluations may or may not apply. It's written pretty vague in many respects. There's assumptions for other services like cellular, aviation, maritime, Part 90 that the radios are "evaluated routinely," or some such statement. Also understand that portable in context, which means more than what we think of as a handheld two-way radio but could mean a cell phone or something else, too. So how's it's used isn't a universal situation.
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