KAF6045

Unfortunately, UHF is more affected by vegetation than VHF. You may actually find that 2W MURS radios (same power output as /now/ permitted for FRS) gets through the trees somewhat better. VHF is less effective in cities -- the wavelength involved tends to be "screened" by things like window and door frames, while shorter UHF penetrates (one reason cell-phones keep going up into the microwave region, and public service is moving into the 900MHz range). MURS is also no-license required, but only has five frequencies/channels, and no repeaters.

For direct house<>house, you might be better served using a pair of Yagi directional antennas (try them in both horizontal and vertical polarization -- one might refract over the hill better than the other).

One thing you'll need to take into account for any /shared/ tower is that you will have to have an RF Exposure evaluation performed. For a single repeater on a tower, that is relatively easy -- but as soon as you have multiple transmitters on that tower you must take into account ALL of them, including any potential mixing products from different frequencies. The single transmitter case can be done with most antenna modelling software (provided a reasonably accurate model of the antenna and maybe the tower too), but multiple transmitters may require on-site examination with various calibrated sensors... $$$

COAX was created explicitly to be IMMUNE to the surrounding environment (electrical behavior, not immune to fire, etc.). It is meant to be run through conduits and around wiring bays. So, no -- copper tube/metal mesh won't change it... Unless the coax connections are NOT unbalanced, and there is signal (losses) on the outside of the coax shield (in which case a tube or mesh is just going to couple to the unwanted/lossy part of the signal). When used with a balanced antenna (dipole), one normally needs a balun/choke to force the signal into the coax core and block it from the outside of the shield. Ladder line tends to run 450-600 ohm impedance, and is a balanced line (no balun needed for dipole -- BUT you need a matching network to convert from that high impedance down to native antenna [dipoles tend to run between 33-75 ohm depending upon height] and if your radio doesn't have a balanced input, you'll need a balun to convert down to the unbalanced/50 ohm connector). Also ladder line (window line, 300 ohm TV twin-lead) MUST be kept away from metal objects as there is no shielding and it will couple to any metal running nearby.

Some radios provide the ability to program "unused" channel SLOTS with a "copy" of existing repeater channel configuration (Tx/Rx frequency, bandwidth, etc.), then modify the tone mode for that copy. This allows, for example, having two repeaters that are on the same FREQUENCY (pair) but use different tone configurations to coexist in the radio -- instead of having to remember the tone configuration for each and manually changing it when switching repeater. There are only eight frequency pairs available for repeaters. Some radios may also allow this to be done for non-repeater frequencies (the eight main simplex, seven 462MHz GMRS interstitials, and -- with the 2017 reorganization -- the (formerly) 467MHz low-power FRS interstitials). Radio manufacturers tend to refer to these added channel slots as "custom channels".

Note that if one repeater is NOT USING an INPUT tone -- it will respond to any signal on the frequency, whether that signal has a tone or not. In that situation, setting one channel with the input tone of the other repeater, but leaving the output tone empty, will result in one's radio basically receiving whichever repeater has the stronger signal (FM "capture effect").

o/~ If you want to be happy for the rest of your life, Never make a pretty woman your wife; So from my personal point of view, Get an ugly girl to marry you o/~

Also note that these are SIMPLEX frequencies -- digital data is not permitted on repeaters.

Dash mount mobile, right-angle connector/adapter... And a ceramics drill to put a hole through the windshield ?

For purposes of visualization: dBi (isotropic) is an imaginary point source radiating in an even sphere. dBd (dipole) is a, well, half-wave dipole radiating in a "doughnut" pattern. Also to be considered is that often the antenna gain rating may be based upon "free space", not real ground conditions. Compare: Half-wave dipole in free space... Same antenna over real ground conditions. Elevation view -- while a dipole in free space is 2.15dBi, note that this example actual peaks out at 7.51dBi (this antenna is modeled at 330 ft [100m] above ground)

One: there is only ONE name on the GMRS license; the regulations permit "immediate family" to use the call sign but all responsibility for correct usage is on the named licensee. Two: when multiple members are using that regulation, they all identity with the SAME call sign -- and each MUST ID (as each radio is considered a "station"). But common practice is to append some notation identifying which member is operating which "station" (KAF6045/HT1 from KAF6045/mobile...; KAF6045/mobile, KAF6045/HT1...)

For sporadic /short/ transmissions, where listeners can not tell that the conversation is on-going... ID at end of transmission is safest -- otherwise you run the risk of some third party taking over the frequency just when your 15-minute ID period comes up.. For those short, spread-out, transmissions, you'll probably be IDing anyways: <call>-<unit2> from <call>-<unit1>, I'm leaving the store now

11m/CB is sensitive to sunspot cycle. 1995 was the LOW in the cycle which would make 11m essentially dead. 2000 would have been near peak.

A lot of radios have BCLO (busy channel lock-out) capability, which may work in this situation.

In the old days (say, 1997, when repeaters tended to be owned by a business or radio dealer) CTCSS tones would have been assigned to user groups sharing a repeater. Company A gets one tone, company B gets a different tone -- Other than having to ensure a clear channel, this meant the companies did not hear each other's communications.

Unfortunately -- the manual doesn't seem to show a scan function that works on memorized channels, only on VFO frequency ranges (which suggests one needs to set the frequency step to match the normal distribution used in your area, and the ranges to be on step boundaries).

During the last major storm event (Skywarn activated, so repeater was tied to Skywarn net and local NWS), the storm took down the Lowell repeater that was the primary system used in Kent county (the repeater appears to be on a farm silo a few miles north of me -- with two hills intervening so HTs from inside my faraday cage house may break squelch, but voice is not usable -- but the repeater has remote receivers throughout the county and some adjoining regions so coverage from HTs is normally quite good [the remotes use courtesy beeps of Morse code identifying the remote the signal came through]). I hadn't caught the frequency of the alternate repeater, nor the last ditch simplex frequency...

Another complexity to take into account: the bandwidth of the mode you are using. A radio with +/-5.0kHz deviation would need to be at 144.005MHz (minimum) to keep the deviation edge at 144.000MHz, any lower and you are transmitting outside of the band. Similar for the upper end (147.995MHz).

Interstitial #1 is 462.5625MHz, Interstitial #13 is 467.6875. Main #18 /is/ 462.6250. 467.7000 is the input frequency for Repeater channel #rp21 (aka #29)

To my understanding "Duplex: OFF" just means -- transmit in SIMPLEX mode (use the Rx frequency for Tx, rather than using some offset from Rx to get to Tx frequency). If the radio is truly "unlocked" it should allow transmit on any frequency within operating capability.

FYI: The Raspberry-Pi OS is a customized version of Debian. USB are /SERIAL/ data streams. GPIO are individually controlled pins. That said, I do have an experimenters board that takes commands via USB and operates (reads/writes) GPIO pins (not sure if I have the Windows driver installed). May not be fast enough to handle the required pin controls.

MURS is 154MHz, the 900MHz stuff is NOT MURS -- heck 900MHz is not even a Part 95 service (as I recall, the devices fall into Part 15 and the Industrial/Scientific/Medical band https://afar.net/tutorials/fcc-rules/ )

x86 is a completely different architecture. You'd basically have to build all the software from source (same work as porting to another ARM-based board), along with mapping GPIO pin-outs which are likely much different.

A cab full of RF... Amateur HT (2m/70cm) to some hotspot (WiFi) to some cell-phone (whatever band those are in these days)... To hit D-STAR REF030C seems to be popular for long haul. While a lot of local (+/- two counties) trucks seem to use the local 2m FM repeater. CB may still show up on a few long haul trucks going through the prairies, but I don't hear any of them in the city.

Check the derating curve for that dummy load. I have a 300W dry dummy load -- the derating curve gives it 4.5 minutes at 25W before needing a long cool-down. (It's only 1.5 minutes at 100W!) I have the DB20-G -- advertised as 20W but the manual states 18W for GMRS. A 15W Midland MXT115 actually reads almost a watt higher than the 13W I get on repeater (467MHz) channels. It does exceed 20W on 2m VHF, and is a bit stronger (13.5W?) on GMRS simplex (462MHz). NOTE: this is the second DB20-G; I returned the first one for the same low power output, but the replacement showed the same.