KAF6045

Shouldn't that be w0of (zero-oh) {caveat -- W0OF is an actual assigned call}

DMR/P25/NXDN (as I recall) all use the /same/ AMBE CODEC; they just wrap the encoded audio in a different set of headers. D-STAR uses a different, incompatible, AMBE CODEC. Fitting both CODECs into one radio means paying the license fee for both. D-STAR uses actual call-signs for routing and identification -- which wouldn't be of use in the commercial realm where a system (and all associated radios) operates under a single call-sign (hence the 7-digit IDs used internal to DMR for radio identification).

I went 20 years (until I rolled the Jeep Cherokee) with a Yeasu FT-100 (HF/6/2/70) main unit located under the passenger seat using double-sided CARPET TAPE. The control head was remote mounted just under the parking brake hand-lever (enough clearance that all buttons could be seen and manipulated). The key feature was that I ran the power cable directly to the battery (out from under the seat, under the running board, up the kick-panel, around the door gasket and through the outer fender -- this was a No-Hole mounting all the way). I'd expect lots of noise potential from a rubber duck located inside a vehicle, especially one with half a dozen displays running who knows what frequencies (ARM-based embedded controllers tend to have clocks running from 50-200MHz, start adding harmonics and intermod/heterodyning and you could have lots of potential signals to contend with).

Biggest problem with ten codes is that they tend to be agency specific -- even among police, much less add the CB variations https://copradar.com/tencodes/ <== look at Norfolk!

Expect to see those used prices drop drastically once the 75 reaches market... I don't need another radio (I have both a D74 and ID-52 -- along with half a dozen other dual-band [or even 3.5 bands for the VX-8DR -- flea power 222MHz doesn't deserve a full band if Kenwood can manage full power in the D74]). However, it is nice to see that Kenwood is still in the arena -- the most recent HRO catalog showed NO Kenwood HTs, not even their old 2m-only standby.

It (BNC) will reduce wear on the SMA. SMA is, last time I checked, only rated for ~500 disconnect/connect cycles.

More information is needed: In particular -- what are the HTs in question, and how have they been programmed (as has been mentioned, if the HT is on a channel that does not have a receive tone defined, it will open squelch on all traffic -- and repeater outputs are the same frequencies as the simplex channels; I really hate that the FCC and manufacturers shove repeaters in as "separate channels", in the old days one went by frequency [assigned to a channel memory] and had a button that toggled between simplex and repeater operation).

I've been using https://www.everythingrf.com/rf-calculators/line-of-sight-calculator but, while the input can be feet or meters, the results seem to only be km. 60 miles requires a very tall antenna tower for LoS (Presuming you are on a Florida beach at sea level, a 1000ft tower only gets you 60km : ~37 miles [I'm ignoring radio horizon which tends to bend over the line of sight by a small amount]). Now, if you are standing on the top of a 1000ft skyscraper, and the target is also on such a skyscraper, you each have a 37 mile line of sight to the horizon for a 74 mile communication range.

Channel 21 is a SIMPLEX channel. The corresponding repeater channel would be #29 (in those radios that used a linear scheme) OR will have a notation near the number -- something like "rp21", "21r". For the MXT115 (I don't have the manual for the 400) you have to /enable/ repeater mode -- see page 23 of the manual (in short: MENU, ^/v until rP is shown, MON/SCAN to select, ^/v for ON, MON/SCAN to confirm). When active, you will have channels 15rp to 22rp available. Set the input tone on 21rp, NOT 21

When the requirement for Morse was dropped, I spent two weeks with the General guide. Come Thursday night I ran through something like 10 example tests from a web-site -- passed all 10 tries. I then tried a few of the Extra example tests. Passed about 75% of them. Saturday, drove up the bay to the testing site (my memory says San Mateo, but may have just been Menlo Park). Took both the General and Extra -- not really expecting to pass the latter; I had two weeks to go over the guide until the next test session closer to home (Sunnyvale). Passed both! My impression is that the Technician license was the most difficult to pass -- keeping track of all those band edges, etc.

This goes back a few decades -- when the FCC mandated "narrowbanding" for land mobile/business/law-enforcement... GMRS and Amateur essentially were exempted from "narrowbanding". This is also why you'll find posts about having to find a non-narrowbanded commercial radio if one intends to program it for GMRS.

75Ohm (RG-6 and kin) are used by cable TV systems. Among other things, it made it easy to work with old-fashioned TV twin-lead (300Ohm) as one just needed a 4:1 BALUN to convert between the cables.

The V1 tends to be quite restricted. You'll probably need to carry a sheet of paper with repeater frequency/channel and tone configuration as you'll be front-panel editing the tones into the appropriate 23-30 slot. In contrast the V2 model can have GMRS repeaters added past slot 30, so one can do a one-time set up of all relevant repeaters, leaving 23-30 for ad hoc field usage.

The entry level test is focused on knowing the FCC regulations for Amateur radio: modes, permissible frequency bands and what can be used in those bands, interacting with international traffic, etc., and individual licensing. None of which are applicable to what was a short range service with only one mode (FM) and fixed channel allocations, allowing family members to operate under the single license (originally, it was against regulations for two base stations to talk to each other -- base stations were meant for mobile<>base communication only: think large farm with base in the house, and mobiles/HTs on family working the fields). It does not exist in other countries (the Canadian "GMRS" regulations are basically a match for the US FRS regulations -- simplex, <2W, NO 467MHz channels [our 8-14]) so no concerns about international traffic (though there is still the Line-A matter, even though the simplex frequencies are now part of the Canadian "GMRS" and not some obscure government agency).

"least amount of signal loss", taken literally -- the largest diameter hardline you can find. Try out https://kv5r.com/ham-radio/coax-loss-calculator/ and plug in numbers. Obsolete Heliax LDF-6 (and a 1.25:1 SWR) only loses 10%. LMR-400 loses 38%.

Yes -- and it occurred with two units shipped by Amazon. While I'll concede the meter used could be reading a bit low, I'd expect it to read low for all equipment tested. The DB20-G is (per manual) rated 18W for GMRS -- it was to replace an MXT-115 (NFM only) rated 15W. Presuming both devices were putting out the rated powers, I'd have expected my meter to show the MXT being ~3W lower in power (I say ~ as I could see it being a proportion of full meter capability). Yet the MXT tended to exceed the DB20 in most of the important GMRS frequencies (in particular, the repeater input frequencies). Mounted on the dash of the rust bucket, been there since last fall. Seems okay so far. Mostly left in scanning mode. (Unfortunately, this photo was with the Midland, but the DB20 is mounted in the same location -- but using lighter socket; weather was too cold for me to pull the wiring from under the dash that runs direct to the battery)

I was going into a dummy load.

No problem here -- but I have Firefox configured to open PDF files in Adobe Acrobat Reader (after downloading the file) -- NOT opening PDF files in the browser itself.

As of 2017 reorganization, there are NO "FRS/GMRS" radios. The radio is EITHER FRS or GMRS, based upon features. There are no FRS mobiles (the antenna would have to be part of the radio box itself). FRS is NFM only. FRS is FIXED antenna, 2W MAX on 1-7/15-22 and 0.5W ERP on 8-14 GMRS is (w)FM (but many may be switched to NFM, and some Midland mobiles are only NFM). GMRS allows for interchangeable antennas. It is 5W max on 1-7, 50W max on 15-22 (and repeater 15rp-22rp/23-30 depending on radio), it also gained 8-14 at 0.5W ERP (which really conflicts with the interchangeable antenna capability). 8-14 would be permissible on a mobile IF it had a 0.5W capability and only a unity gain antenna.

When I did the testing I was getting around 12-13W on 467MHz (less than the MXT-115), about a watt higher on 462MHz, but 22W on 2m. I suspect it fits a linear plot.

FYI: The first seven interstitials (462MHz) were GMRS frequencies before FRS ever existed. They were allowed up to 5W (HT power range) and (w)FM, and interchangeable antennas. They were available for use by any GMRS license -- the eight MAIN frequency pairs (simplex/repeater) were allowed up to 50W but... A GMRS license could only specify up to two such pairs. That restriction (of specifying which two pairs on the license) went away around 1999. FRS originally was only allowed 0.5W ERP, NFM, and fixed antenna on those frequencies, AND was permitted the 467MHz interstitials with the same limits. With the 2017 reorganization -- GMRS retained (w)FM and 5W power on the 462MHz interstitials, 50W power on the main (pairs), and gained access to the 467MHz interstitials at 0.5W ERP NFM. FRS was given access to the eight main 462MHz frequencies (but NOT the 467MHz repeater inputs), the 467MHz interstitials remained 0.5W NFM, but all other frequencies were boosted to 2W NFM (and fixed antenna). So... Prior to 2017 FRS had 14 frequencies, seven shared with GMRS. GMRS had 23 frequencies (when counting repeater inputs separately), seven shared with FRS. Under current regulations FRS has 22 frequencies ALL shared with GMRS; GMRS has 30 frequencies (again, when counting repeater inputs separately), 22 shared with FRS.

Going to have a lot of polarization mismatch losses -- most all 2m/70cm (and GMRS) are vertically polarized signals (mobiles and HTs)

Channel 11 started as the trucker frequency but they moved it as (given the equipment of the time) it could bleed over and interfere with the FCC designated emergency channel (9). Just /why/ they shifted to 19 rather than something else I can't say. Possible for mnemonic 9 vs 19. Once the 40 channel allocation was made, 19 makes more sense -- being nearly dead center in the frequency band allowed an antenna tuned for that point to still be usable at both channel 1 and 40. If they'd chosen channel 1, for example, tuning for best SWR on #1 would likely have left #40 unusable. That was also back in the days when a GMRS license would specify up to TWO frequency pairs chosen by the licensee requesting the license. Those two "main" frequencies (and the seven 5W interstitials) were the ONLY frequencies the licensee could use -- with the exception of 462.675/467.675 for an emergency. Since radios tended to be commercial business band stuff, the radios often only had "A" and "B" channels and required shop programming to match the license. The only way to gain access to 462.675 was to have that pair listed as one of the two frequency pairs on one's license (and if it was listed on the license, it was NOT restricted to emergency-only usage). The Maxon GMRS 210+3 HT supported a total of 10 "channels". 1-7 were hardwired to the interstitials (usable by any GMRS license without listing them on the license); channel 8 was hardwired to 462.675 pair (usable by any GMRS licensee for emergencies, whether or not listed on license); channel 9&10 were to be shop programmed with the two licensed main frequencies).

USB to 9-pin serial adapters are (or were) fairly common (my former employment made use of lots of them as all the calibrated test equipment was RS-232 from the the 80s-90s) https://www.google.com/search?client=firefox-b-1-d&q=usb+serial+adapter I've probably got three or four laying around -- since my old Parallax BASIC Stamp boards have DB-9 connectors for programming. There's one now! right next to a SIIG USB<>Ethernet adapter ?

Any current bubble pack that advertises more than 22 channels (yes -- that's you, Midland!) has preset/fixed tones on the extra "channels". https://midlandusa.com/collections/lxtgxt/products/gxt1000vp4