KAF6045

Height helps -- at the repeater site. The (grandfathered business, city owned) Grand Rapids MI GMRS repeater is on a 290 ft tower, and has a gain antenna providing 200W ERP. It has a range of 15-30 miles depending on intervening mountains.

My pre-reorg (decade old) GXT1050s have three power levels -- H approaches 5W. With the reorg it is now classified as GMRS (my Motorola bubble packs, similar era, meet the power requirement, but has repeater ability, so also is now classed as GMRS)

Per the current download of the manual It does NOT specify "SCAN 1 bank". You may need to select a bank first (Scan start/stop in this manual seems to show a Scan A and a Scan B option)

Apparently a change (or not covered by my old license manuals) (first is FCC regs, second is Wikipedia) So basically extreme NFM for most bands... 10m seems to have a small section that would allow regular FM (note NO (1) restriction). It's the only band that ARRL band plans explicitly list an FM section.

I'd suspect it is more a distance aspect than local. People near the original horizon cut-off with a low antenna are now well within the new horizon distance and likely also have less environmental losses vs a signal skimming over the ground. Some may be ground effect, but again, that is in the far-field radiation pattern, not near-field. I've not used the EZNEC Ground Wave Distance option before but... Half-wave dipole, vertical, /bottom/ at 3m (~10 ft), with distance 5km (ignore the window title -- I haven't found where to change the description): And at 10 meters (~33 ft) 10dB less loss at 5km. Turning off ground wave distance and plotting elevation... 3m elevation: Interesting, over high-accuracy ground type (medium 0.005 S/m Conductivity, 13 Dielectric Constant), the half-wave shows 6.6dBi at a 3deg elevation. Now at 10m: At 10m it shows 7.5dBi at a 1 deg elevation angle (at 3 deg angle it is only 5.6 dBi). Going back to the 3m elevation, at 1 deg take-off angle, it is only 1.85 dBi. So 3m elevation is 5.66 dB below the 10m height at the angle of max dBi at 10m. I also ran with Free-Space to confirm dipole pattern and dBi max: As expected, 2.15 dBi. If you (generic readers) don't already have EZNEC, GET IT. The creator has retired and stopped making updates, but has made EZNEC Pro+ v7 a free download (it used to be $$$) https://www.eznec.com/

Just to fill in blanks, I believe the only HF band (unless you count 6m as HF rather than VHF) that permits FM is 10m. Considering that common FM deviation for Amateur likely requires a 20-25kHz bandwidth, and the 20m voice region is only 200kHz wide, FM mode would allow for less than 10 non-interfering QSOs. Amateur AM mode is only 6kHz wide, SSB about 2.7kHz wide -- and both of those modes don't have capture effect, so it is possible to have overlapping QSOs which one can adjust filters to minimize interference (lack of capture effect is why aviation bands don't use FM -- it permits a distress call to be heard through an ongoing communication).

There is always the generic... https://www.amazon.com/Universal-Smartphones-Cameras-Talkies-Remotes/dp/B00006JPBY/ref=sr_1_4?keywords=adhesive+belt+clip&qid=1667340938&qu=eyJxc2MiOiI0LjU2IiwicXNhIjoiNC4wMCIsInFzcCI6IjMuNTEifQ%3D%3D&sr=8-4

If the HT is capable of exceeding 2W output or is capable of accessing repeaters, it WILL require a license. The 2017 FCC reorganization granted FRS radios up to 2W output (likely ERP, so fixed antenna to prevent adding a gain antenna -- except for the 0.5W ERP 467MHz channels). Radios sold after that reorganization must specify either FRS or GMRS -- no more bubble-pack FRS/GMRS radios.

MURS is, like current FRS, limited to just 2W output. If experimenting with some other radio, you may need to ensure you are on low or maybe medium power. MURS radios can be had for a small amount of money (I recently bought 6 [two 3-packs] Retevis RB38V radios -- a pair for each niece&spouse, and a pair for my brother/spouse -- for around $140... or $<25 each). I also have a pair of MURS bubble-pack radios from many years ago, when MURS was first defined. Primary is a BTech MURS-V1 (they provide "15 channels" so one could create multiple tone configurations for each of the 5 frequencies).

Based upon the manual, it was also created before the 2017 reorganization -- lots of "GMRS/FRS" entries... Love Midland's "maximum power" blurb... Power levels aren't mentioned anywhere in the documentation, only on their Q/A page (5W, when maximum for GMRS is 50W)

https://www.walkie-talkie-guide.com/retevis-rt29-review/ Retevis does not state the power output of the unit. The manual seems to emphasize use as a 2m/70cm Amateur radio. Having a replaceable antenna means it would never qualify for FRS usage. You might be able to program it for GMRS simplex frequencies (NOT the 467MHz interstitials, as I'm quite certain this "high power" radio does not have a 0.5W ERP mode -- maybe even repeater, but I'd suggest not if you are expecting children to use it). They would have to learn to use you call sign to ID (under the "immediate family" clause in the regulations). The RB38V MURS radio may be suitable -- no license needed (so no ID needed). It does have a display but that blanks out with inactivity. Only five channels, so less searching if someone accidentally toggles to a different channel. 2W/0.5W power levels. Pretty much everything has to be programmed from a computer. For MURS, channels 1-3 are only NFM; 4&5 are wide FM but can be set to NFM if desired. The screen shot is how I set up the ones I provided my brother and nieces (factory volume setting is 8, I set the side keys for power toggle and CTCSS setting [I think, didn't really test it] -- the key definition is for long-press, the default short press equates as volume up/down) No knobs or other protrusions -- just an up/down channel toggle, power button, PTT/key1/key2

Said channel may not be of use if you are in lower Kent County. Grand Rapids has a grandfathered license and a repeater on 575. Mostly used by the downtown parking lot staff -- calls about gates stuck up/down, machines refusing to accept cash (or cards) for lot payments, etc. Worse, the city is experimenting with DMR (I presume that low bzz-bzz-bzz... is DMR -- really need to see if I can set my Anytone DMR HT into promiscuous mode accepting anything on the frequency, to confirm)... Back in 97 PRSG repeater guide states that the repeater was available for /emergency/ only -- suspect these days if you made a call for help the dispatcher would just say "What's wrong with your cell phone?" 300ft tower, 200W ERP -- on a "bad" day I can hear them from Lowell (~15-20 miles east) and even into the county south...

FRS wasn't involved there... The original GMRS interstitials are 20kHz bandwidth, and overlap with the GMRS main channels on 462MHz. "8-14" are 0.5W ERP ONLY, and are interstitial on the 467MHz (repeater inputs). (emphasis mine) The 462MHz interstitial channels predate FRS as a service.

The angle isn't clear, but I'd be concerned about -- the airbag! It's the grey vinyl above the glove box, and if it has any side spread could result in launching the radio toward the driver position. Especially for something like the ID5100 which uses a pair of magnets to hold the control head to the mounting plate.

If it sticks... Until it was totaled in a roll-over last year, I'd gone twenty years with only two holes in a Jeep Cherokee. The Yaesu FT-100 transceiver was carpet taped under the passenger seat, remote control head mount taped "under" the parking brake (enough offset to reach the controls, but that was the flattest spot to tape the mount), microphone in a hanger taped on the dash. The holes? I decided the speaker wasn't that audible, so put an external speaker in at the knee region of passenger seat, side of central console. All wires were routed under trim panels (and power went around door jamb and along inside fender space). "Replacement" rust-bucket has plastic that just won't take adhesive tapes... I've tried double-face tape, foam mounting squares, 3M Command Strips, etc. And none would hold. If it wasn't for the presence of rust and other wear (a 2008 Liberty with 190k miles, vs my former 1999 with just 75k) I wouldn't have a radio of any type. No room under passenger seats (passenger present sensor for air bag is in the way, transfer case bulge under driver seat, no flip up rear seat). ICOM 5100 is mounted in the plastic bin under the rear cargo area, wiring (in plastic flex conduit) clamped along side panels, etc.. The MXT-115 has been swapped out for a DB-20G, but I still need to fabricate a quick-disconnect power lead for it, currently using the lighter plug for power Similar conduit (next size smaller) running on the other side has the antenna cables from CB & GMRS mag-mounts.

Well, after rescaling to GMRS from 2m... And reducing segment count... putting in real ground, and raising the antenna to ~20 feet SWR looks better... (hmm, maybe even better with the higher segmentation of the original file -- likely because the feed/load moved with fewer segments -- yes, going back to 90 segments did put SWR at design frequency) OUCH! Rather high take-off angle. Beam toward horizon is 1.7dBi, vs 5.03dBi at 37 degrees above horizon. Might be great if at the bottom of a valley hitting mountain-top repeaters ? The horizon is seeing half the power seen at 37deg. Still not usable as MURS - as modeled - with a 25:1 SWR, but it does have a nicer pattern for reaching the horizon. Moving it up another 10 feet (approximate match to original plots) changed the max GMRS to 40 deg, 5.34dBi, horizon to 2.44dBi (only -2.9dB from max -- still, practically half the power)

And is one of the stated clear-channel stations per https://en.wikipedia.org/wiki/Clear-channel_station#List_of_all_clear-channel_stations

Per the table at https://www.ecfr.gov/current/title-47/chapter-I/subchapter-D/part-90#90.35 NONE of the GMRS frequencies are Part 90 allocations. GMRS main/repeater channels start at 462.550 and end at 462.725 -- the entire GMRS frequency band fits between the Part 90 462.5375 and 462.7375. However, grandfathered GMRS licenses (possessed by businesses) are allowed to be renewed -- but not modified; for the most part such grandfathered licenses are from the days when a GMRS license was good for -- at most -- two frequency pairs (repeater access). Business GMRS licenses probably only specified one frequency. Per Wikipedia https://en.wikipedia.org/wiki/Business_band (emphasis mine)

I'd need to study to figure out how to represent a 5/8 wave in EZ-NEC. As a simple wire with four (not-tilted) radials, I'm getting an SWR of 25:1. (Also need to check where EZ-NEC is getting the description from; it is not in free space, and not a dipole) Plotted for an antenna at 10m elevation. I tried running for MURS frequencies, but it shows SWR >100:1

A few weeks ago, we had a situation (Amateur 2m) on the W8IRA linked system (basically covers US131 and I94 [some I96], in Michigan) in which two users in Wisconsin -- who were not within range of a common Wisconsin repeater -- were talking to each other via the W8IRA system.

There is also the minor problem that the FCC would have to be monitoring both the input and output of the repeater to determine if it 1) IS a repeater (ie: traffic going in on 467.xxx, and coming back on 462.xxx), 2) if it is open or private (if multiple calls ID on the 467.xxx, or all users have the same call). After all, users might be using simplex and just happen to also have the same tones as the repeater is using. Unlike Amateur, and pretty much all land-mobile/business systems, GMRS operates both simplex and repeaters ON THE SAME FREQUENCIES. Land-mobile is mostly a repeater/dispatch and remote/mobile stations -- remote to remote (police car-to-car, for example -- used to free up the dispatch/repeater) is typically a dedicated frequency. Amateur has "band plans" which are negotiated by the ARRL and Amateur groups (not FCC) to allocate segments of the Amateur bands solely to repeater usage, while other segments are for simplex. Nonetheless, for subparagraph (c) to apply, BOTH (c)(1) AND (c)(2) must be TRUE. It would be best to follow that criteria. While there have been no reported prosecutions (well, for the FCC: Notice of Apparent Liability with associated fines), there is always that "first time" -- just as stringent police office might pull over and ticket someone doing 57 in a 55 zone (though they tend to be more strict in 25 and/or 35mph "school zones", allowing NO excess speed margin).

In the old days, before everyone ended up with a $$$ cable feeding their TVs, weird weather could relay TV signals way beyond the target area. I recall our rooftop antenna (about 25ft above local ground level) picking up stations from Detroit or even the Canada side of the border... FROM GRAND RAPIDS AREA! 175-200miles.

Filtering I suspect... Typically higher codes (especially CTCSS, but I suspect DCS may also be using multiple actual tones, not just a pair of tones in FSK equivalent). These tones are supposed to be "subaudible" -- even though human hearing can go down to around 30Hz, the typical radio only passes 300-3000 for audio so the tones are not audible. The tones are likely on a (different) low-pass filter, and that filter is not sharp enough to pass the upper-most tones (those around 200Hz and above)

If using enough radials, you could try cutting half for 467MHz and the other half for 462MHz. A halfwave should not require radials regarding SWR, but could have the radiation pattern affected by the presence of radials (the radials may appear as a ground close to the base of the halfwave, rather than the real ground some feet below -- the likelihood is that it would cause the main beam to be at a higher elevation).

They aren't that expensive (unless you're buying from a culinary shop ? ). Some medical thermometers (see your pharmacy) may have an "open use" mode covering a wider temp range.