dosw

Having watched the video, he definitely seems like a nice guy who probably just got a little hyperfocused on the things in life that he can control while other things might have been spinning out of control. Impressive, sad, brilliant, messed up. Doc from Back to the Future lives in southern California, I guess. But on the other hand, did you notice that despite the appearance of everything in shambles, his tires were in good shape? That's not a pavement princess / mall crawl vehicle. He maintains what's important to keep mobile and on the air, and lets the rest go.

I think we can now agree that the dangers of RF exposure are real.

Can we just take a moment to appreciate the dedication to insanity and unfettered IDGAF displayed in this photo? And now that we've gotten a moment of awe out of the way, what are those antennas, even? Edit: FOUND HIM! https://youtu.be/SKI1W01OelU?si=i9Z5MfgNuvs-4Yib

Putting it on the trailer could get it up higher, at least by a few feet. That probably matters more than the slight difference a few layers of wood and fiberglass contribute toward shadowing the signal that emanates from the truck's antenna. But going from a mount six feet up to a mount ten feet up probably isn't worth the trouble when you have to also add 20 feet more cable. The next problem to contend with would be the ground plane. If it's difficult on a vehicle, it's often even harder on an RV with a fiberglass roof.

Got it... don't tow the trailer near an airforce base!

Thanks for the quick responses.

I was looking for TPMS sensors for my trailer. I found the following on Amazon with good reviews: RV TPMS Sensors Something in the product description caught my attention; the sensors transmit at 433.92MHz, which is in the 70cm amateur band. That raises a couple of questions. First, does the FCC allow for these low-powered short-range devices to operate in the 70cm band? I assume that given the fact they last 6 months of run-time on a set of CR2032 batteries, and obviously couldn't have much of an antenna, that they are very short range and unlikely to cause interference at more than 150 feet. Does the FCC allow them to operate in an Amateur band? Second, will they cause interference to me; if I'm monitoring repeaters within the 70cm band, typically a little higher up in the band, would these interfere? I suppose to answer that question one would have to test. The ARRL band plan shows: 433.00-435.00 Auxiliary/repeater links ...so if these are well behaved they would not interfere with reception of a repeater itself, since they are usually in the 442-445 and 447-450 range. And the only way to be sure these are well behaved is to test with a spectrum analyzer or SDR. As an example, though, I've found that one of the USBC-to-HDMI dongles I use at my home office causes interference in the 440MHz range when I'm within about 30 feet of it -- enough interference with enough tertiary spikes that some of the 70cm band is unmonitorable to me when I'm too close to this adapter.

Live near a hospital? I got an MRI a couple of years ago, and as I approached the facility and drove away from it, channel 17 was picking up the exact sound I was hearing while inside the MRI tunnel. Otherwise I'd guess DMR or some other digital signal. My SDR is particularly good at letting DMR on nearby frequencies intrude into what it picks up in the GMRS band.

I have the GPK01, and really don't use it. First, you wouldn't drive with that thing. Its radials wouldn't stand up to highway speeds, or if they do, they would thrash wildly, destroying the finish of everything within their reach. Second, I had pretty limited success with it providing an adequate ground plane. With my Comet CA2X4SR-NMO it worked alright for UHF but was no use for 2m. With my others antennas it lowered SWR only a little. With my Laird TE B4505CN "no ground plane" antenna it seemed to make things a little worse. Third, it doesn't provide a good weather seal for NMO mount antennas unless they have minimal bases like the Comet. You're better off getting a no ground plane antenna such as the Laird TE B4505CN (for GMRS), or the Larson NMO-2/70 (for 2m, 70cm, and adequate GMRS), if you're ground plane challenged.

If you and your family member are both holding the radio at five feet off the ground, and there are absolutely no contours to the earth or other obstructions between you, you'll get about 5.5 miles range. This is because even lacking contours, at 5.5 miles the curvature of the earth will block your signal, if both antennas are at 5' off the ground. If you can get both antennas 20 feet off the ground, the curvature of the earth will attenuate the signal at just under 11 miles. So, again, if there are no contours to the terrain, and there is nothing else between you, the curvature comes into play at just under 11 miles. If you can get one antenna 30 feet off the ground, and the other is 5 feet (base station to handheld, for example), you will get 9.44 miles of range. To get ten mile coverage with one handheld radio (antenna 5 feet) and the other radio a base station, the base station's antenna needs to be 36 feet off the ground. Here's a formula you can use: range[miles] = 1.22459*sqrt(height[feet_antenna_A]) + 1.22459*sqrt(height[feet_antenna_B]) But that formula applies if the earth doesn't have any variations in the terrain. This is Kansas, but it's not *that* flat; there is some variation. That variation can help you or harm you. If you're able to take advantage of slight hills to get the antennas higher, great. If the slight hills block your antennas, not great. As for a repeater, it doesn't change physics, it just adds a third antenna to the mix that, if placed in a location between you and your family members, or if placed high on a hillside that all of you can "see" at the same time, is able to be the antenna you talk through. Repeaters make a lot of sense where I live; there are mountains around me, and everyone lives in a valley below the mountains. So if someone has the ability to place a repeater 1000 or 1500 feet above the valley, everyone can access that repeater all over the valley. But you're in flatter terrain, and may not find such advantaged repeaters. Also, this isn't a power issue. A 50w radio can't blast through the curvature of the earth. And if you all could "see" an antenna elevated a thousand feet over the area, you could all hit it at 2w from many miles away, until you reach the curvature limit again. A theoretical 1000 foot high antenna communicating with a handheld at 5 feet would have 41 miles range. The farthest repeater I can hit is 64 miles away, and I'm at 5000 feet elevation, the valley floor is 4200 feet, so we're both well above the obstructions around us and the curvature probably wouldn't eliminate our "line of sight" until we get to a distance of about 75 miles.

UV-5G and 5G Plus are GMRS radios and come configured with channels for repeaters that are already with the +5MHz offset. You should only have to add the tones. First, how are you testing? If you're testing by keying up one radio and wanting to hear yourself on another radio, that won't work. If the radios are within a block of each other, there's a good chance one is desensing the other. Think of it this way: If your wife is talking to you in a normal voice from the next room, you will hear her. Now turn on the window air conditioner in your room and keep listening. You can't hear her. Her voice is just as loud as before, but your ears and brain are desensitized by the fact that there's another loud noise nearby. Radios work similarly; if a radio is transmitting on 467.7000 (repeater input) at 5w and another is listening at 462.7000 (repeater output) only a few feet away, the dreaded "spurious emissions" and the "poor selectivity" of your radio are such that it's like the transmitting radio is shouting in its ears, so the listening radio cannot hear the repeater 20 miles away that is only whispering. So you have to adjust your test; someone needs to take the listening radio a block away. If you've done that and still aren't getting through, turn OFF the tones on your radio and keep them turned off for a few days of listening. Do you hear people occasionally? If yes, then your tones were probably wrong. If no, then you haven't learned much; it could just be a quiet repeater. If you determine your codes were wrong, check them again and enter them more carefully. Retest. What about a kerchunk? Do you hear that when you key up the repeater? If not, take antenna out of the mix. Get in your car and drive closer to the repeater. Set the tones that the repeater needs before you leave the house. Drive close to the repeater, and key it up. Do you hear the kerchunk? Yes? You're good. No? You're not configured correctly. Now let's assume you get the kerchunk meaning you're configured correctly. Drive back home. Now do you get it? Then your antenna is also adequate. Not getting it? You're out of range. A different antenna *may* help, but more probably won't help.

I have an AR-5RM that will do 2w and 10w. I have a 701 style rubber duck, and a 771 style. And adapters to hook up to a variety of mobile antennas. And I can set up a radio at home to record into a VOX-activated recorder. So I think I have all the tools necessary to perform this test from a variety of locations around my city. I can say that I've done similar tests in the past, and that at the fringes, things will get more scratchy at 2w than at 10, but that other factors are more important such as not sitting IN the car with the rubber duck antenna, and not having my signal blocked by terrain. In such situations, being in the car vs out of the car can make the difference of getting a recording to take place (ie, squelch breaking on the radio at home) and not getting through at all. Power has only ever made the transmission a little clearer, better quieting, and only at fringe areas. But I'm happy to run the test with this specific equipment. I'll have some results Saturday. Ideally I'll be able to post the recordings and others can decide if they constitute proof or disproof.

I have a "cheap" Jesverty SS-30V switching power supply. It has a pair of screw pole connectors, two Anderson ports, and both USB-A and USB-C. It works fine with my Wouxun KG-UV980P, Retevis RA87, and Midland MXT-275. I've never needed to plug in more than one thing at a time. I also bought a cig-adapter to Anderson port, so that I could plug in the Midland using its 12v plug. Anyway, I sort of put off buying one, but once I did, I'm glad to have it. It makes a lot more sense for the PSU to be a separate piece. Building a PSU into each "mobile" device to call it a base station device just adds cost and size to the radios and limits where they can be used a little more. It's pretty nice to just be able to use any 12v powered radio with this PSU. Plus it will easily handle any 12v accessory, not just radios, so long as they're under 30A.

100%, grandma kept telling him to turn it off to save the battery whenever he wasn't using it. Kids left to their own aren't going to be thinking those invasive thoughts; they'll leave it on in their sock drawer for six months, or until years later when you clean out their room after they moved away to college (whichever comes later).

That wouldn't prevent one from hearing the other over simplex within range.