axorlov

If you want to keep repeater private, you may set a different input tone, that it's not so easy to be scanned. Thus, repeater owner can control, to some extent, who can use the repeater. Also, till recently, only the good quality Part 90 and Part 95 radios were able to do split-tones. Using split-tones it is a way to keep people with CCRs off your repeater.

After 2017 rule change FRS and GMRS use same frequencies, except FRS cannot use repeater inputs 467.xxx0. Kids may be clean in the eyes of the law if they use FRS radios. Just for your information...

TK3170 also operates on Ham band. At least on upper portion of it, where repeaters are. I did not do any tests with any measurement equipment. Same thing with the software: it brings a pop-up saying that frequencies are out of range, but still allows to program them.

I think everything is covered (capacitive coupling), but I can add that 1/4 wave antenna works like half of the 1/2 wave dipole, where the other half (other 1/4 wave piece) is an imaginary part created by the reflection from the flat groundplane. So, DC ground is not needed, but the closer the groundplane to the ideal RF ground the better. Capacitive coupling between magnet and metal roof provides low impedance on UHF frequencies, good enough to work as an RF groundplane.

And Ham license is also now $35. Historical move. Ham license, aside of the testing costs, was always free in US, right?

Sooooo-o-o, according to the Table 2 to Paragraph C the new license is $35. And schedule is effective April 19. Do I read it right?

Longer cable will make the electromagnetic field from the cable stronger. The coiling may or may not make it stronger, but will not reduce it on UHF. You need to suppress the common mode current on the outside of the cable shield (this is why quad shield will be no difference). On UHF this suppression is not as trivial as on VHF or HF. The 1/4 wave stubs are often used, but they are very narrow filters. Another approach is to have several ferrite beads (4-7) on the outside of your cable.

https://www.theantennafarm.com/catalog/index.php?main_page=index&cPath=191_192_196_215 But I don't have personal experience with any of them.

I don't have one. Judging by photos (post 29), it has two radiating elements with a phasing/loading coil between them. Upper element is probably 1/2 wave. But hard to tell.

It's not just the dummy load that radiates, it's the whole system ht + cable + dummy load. You would need to have a good RF choke on your cable to judge the radiation just from the dummy load.

If no ground plane, the answer is simple: 1/2 wave. 5/8 will work with reduced efficiency, 1/4 will also work but your SWR will be high.

Congrats!

Alternative is to use 1/2 wave antenna, that does not need ground plane. https://www.theantennafarm.com/catalog/index.php?main_page=index&cPath=191_192_196_215

If you think of it from everyone's (other than Ham) perspective, it is very simple. FRS/GMRS sliver is in the middle of UHF business band. Allowing ham equipment will certainly wreak a havoc. Part 90 radios have much tighter spec than Ham radios from yesteryear (and today) and lower power limit too. Allowing 1500W ham radios will make these bubble-pack FRS unusable in densely populated areas. There is a thread here about how 1W baby monitors bring GMRS repeaters to their knees. Pity. Imagine what 100W (or 1500W) Ham radio would do to the same repeater and to adjacent land-mobile installation. The point of FRS and GMRS is to give cheap communication option to every random Joe, not to facilitate just another eight (fifteen) 25Hz channels for Hams. Hams do not need them, there is nobody ever on 446.000, and let's not even start on 220MHz - not funny. But you certainly can use your 'carefully selected' Part 90/95 radios on Ham bands, if you have license.

The reference is for the exhaust tuning of the internal combustion engines. This is not only similar physics behind it (and fallacies) but exactly the same. The same wave theory applied to processes inside exhaust pipes and antenna feeders. The point is to match the impedance and reduce the amplitude of reflected waves to not waste energy on pushing exhaust gases through the pipes, and the current through the feeder line and antenna. Two-stroke engines are especially sensitive to exhaust tuning, because they relay great deal on the wave processes inside the pipes (SWR, if you wish) to ventilate out the wasted gases and fill the combustion chamber with the fresh fuel/air mixture. Four-stroke are less sensitive to exhaust tuning (but still are!) but more sensitive to intake tuning for the very same reasons - wave behavior in the transmission lines (intake and exhaust manifolds and pipes). So, the nature of the phenomena is different, but the physics behind it the same, so are misunderstandings.

Same with me. I enabled all three of my TK-880 for the front panel programming, and I used it, let me remember how many times... oh yeah, never! I do keep a printed reference card in the glovebox, just in case of apocalypse, or when I'm tooooo bored. With the handhelds TK 3170 I did not even bother to enable FPP. Too much trouble.

Not really va the FPP, but rather OST feature - Operator Selected Tone. Kenwood 3170/73 can store up to 40 combinations, they can be split tones too. You'd need to program a button on the HT to chose the tone combination.

Yes, I forgot to mention, the BR-178-S ("S" is for spring at the base, there is a version without the spring too) has a cut table, and you are supposed to cut the whip according to the frequency to fine tune the antenna. I cut according to the table and have SWR 1.7, which I find acceptable. Perfect is the enemy of good. So, in the end, the antenna will have much narrower useful bandwidth than 380-520.

But you still have to work on your Midland or BTech. You need to come up with antenna mount, hook up and route power wires and fuses, place mounting bracket. In the big picture, putting an antenna connector and power connector are small things, comparing to other things. Also, there are plenty of radios with connectors intact. Complexity of used commercial radios does not come from missing connectors - these are easy. Complexity comes from finding programming software and learning to program your radio. This is why I'm sticking to Kenwood - in general they are easier to deal with than Motorolas. And used commercial gear will keep you on air for much longer than BTech (LOL!), It kept some sheriff department or transit bus company on air for 15 years or so, it certainly will hold to GMRS use. And the price should not be ignored, right? Below $100 vs $250 for MTX400. And you are getting superior radio in every aspect.

I use Browning BR-178-S. Works well. I did not compare it with 1/4 wave, but I did compare it with Browning BR-170-S, which is 5/8+1/2. The 170 (longer) is marginally better in flat lands. Both 178 and 170 require ground plane, but I see you have XJ, so you're good.

Memory map: from my experience as a HW and FW developer, that is usually the mapping of the microcontroller's registers to memory addresses, and also the microcontroller's memory too. They can be read-only, read-write and write-only. But I think, somebody who succeeded hacking the installer, already knows that. You certainly can look up serial number, but it is open question if you can change it, i.e. the system will accept the write attempt at the specific address.

Before I drilled my roof for NMO, I pondered 1/2 wave antenna, mounted on fabricated mount that would go under the bolts that hold the hinge of the rear hatch on Durango 2014. Advantages: no need for groundplane, ok to be on the edge of the roof (it's 1/2 wave), no roof drilling. Disadvantages: longer than 1/4 wave antenna. I went with drilled through the roof NMO, but I had something as big as your roof tent, I would consider again. You probably can fabricate something on the back, for the hinge mount, and it probably will be further from the tent (you need to open that hatch somehow, right?) than what's on your photo. Just a thought. Also, in Taipei, the half of the cabbies carry the setup similar to what I just described. Prius or other hatchback with longish (for 70cm) antenna mounted with bracket that's attached under the bolts that hold the hutch strut. I tried to ask, but was met with the blank stare. I do not speak Mandarin, and cabbies probably do not know the details of the radio setup anyway.

Nope, haven't had any experience not in Virginia. North California has a 70cm restriction because of the missile defense site located near Yuba City, Beale AFB. Because of that almost all 70cm Ham repeaters in SF Bay Area and Sacramento either went quiet or go with severely reduced power. We still have our microwave ovens allowed! GMRS is allowed too. In a contrast, Los Angeles area has a thriving fauna of 70cm repeaters, unimpeded.

Yes, knife-edge propagation is why I'm able to watch off-air TV being in the shadow of a mountain ridge.

dxengineering.com has mag mounts with RG-8X cable. Ebay too.