KAF6045

An antenna analyzer would be a good thing to have -- many can test for open/short conditions in a cable (and, given velocity factor, may even be able to measure distance to fault [though that is frequency dependent as they calculate based upon phase -- one cycle of a wavelength; for a 35ft cable, that may mean testing at 7MHz). However, most of those are in the >$200 range, which is more than a 50ft length of decent coax would cost (presuming common connectors at both ends -- the coax I bought for my 2m/70cm antenna ran $200 or so for 70ft, half of the cost was PL259 at one end and N-connector at the other [my window pass through has an N connector -- the 2ft jumper from window to radio with N->PL259 was near $90!]). A nanoVNA v2 is a bit cheaper (the v1 is no longer sold by the originator, but there are many clones of it with questionable quality).

How large is "our community" (distance, not population), and what type of environment (flat, mostly open fields, or lots of concrete/steel multi-story buildings)? (presuming the GR 575 is using similar specs as in 1997, it has a 50W output feeding a 6dBd antenna to produce 200W ERP, on a near 800ft tower belonging to the city -- as is the grandfathered repeater, in 1997 it was available to public for /emergency/ use only. On a good day, the 6" Midland mag-mount on my rust-bucket can receive it from ~20 miles away). If you are within city limits, you will need to study the zoning regulations... Many cities in my area limit antennas (top) to 35ft above ground (unless one is in a rare four story building [there may be one or two in town center, having been built before zoning laws were a common matter] where it may be 10-25 feet above the roof). 35ft is about the equivalent of residential power lines/poles. The only exception in my town is for /AMATEUR/ antennas -- permitted 75 ft above ground if the lot is large enough that broken tower won't damage neighbors' property. GMRS is not Amateur -- so 35 ft max unless you can get a zoning exemption for a taller tower. If you are in a flat, sparsely populated, region -- you can probably get by with just 5W HTs used outdoors (my aluminum siding and metal roof cause strong attenuation). Note that going from 5W HT to 50W mobile (10dB increase) will probably only double the distance you can reach -- a good (gain) antenna might be more economical. Repeaters gain their distance mostly through antenna height and antenna gain. You'll need a repeater controller that can handle making ID announcements (per the regulations, the only situation in which a repeater does not need an IDer is when ALL users are operating under one license [which means the "immediate family" category] AND said users properly ID with that license's call sign -- IE: a private repeater not accessible to the public). Also, a strict reading of the regulations requires that there be a designated control operator monitoring who can shut down the repeater if it goes wonky (stuck on transmit, etc.), or has some abusive user tying it up. Remote operation is permitted, but that likely means using some other means to contact the repeater and issue commands (if an abusive user -- you might not be able to override them from your own radio so DTMF commands over GMRS channels may not be usable).

OUCH... 10dB loss per 100ft at 450MHz... Over 3dB for 35ft, not counting any losses at connectors. How borderline are those attempted stations? If they are only a few s-units to begin with, you may have enough attenuation to fall below the receiver threshold. Don't think I'd use RG58 for anything over 10ft (automotive routing), and even then I'd probably limit it to <100MHz (ie: HF and 6m).

Unless you are running a swap file on the SD card, its size is not really relevant. The R-Pi 3B has 1GB of RAM. Log-in and try running something like top top - 11:40:50 up 7:40, 1 user, load average: 0.87, 0.93, 0.92 Tasks: 122 total, 1 running, 121 sleeping, 0 stopped, 0 zombie %Cpu(s): 3.1 us, 6.1 sy, 0.0 ni, 90.7 id, 0.0 wa, 0.0 hi, 0.1 si, 0.0 st MiB Mem : 972.8 total, 660.6 free, 113.2 used, 198.9 buff/cache MiB Swap: 0.0 total, 0.0 free, 0.0 used. 789.6 avail M Note the Mem and Swap lines (this is on a running Pi-Star system). You could then look at the list of processes to see what is using memory.

Short distance, and primarily with users all under the same license (family farm, small business) -- licensee to licensee was extremely rare if not actively discouraged. It's really only after the FRS fiasco that the "General" in GMRS took primary aspect (rather than the "Mobile" -- it used to be that base-station to base-station was not permitted at all, and base-station to repeater was [and may still be depending upon how one interprets that "base-station" is listed under the 462MHz simplex category, but not under the 467MHz repeater category -- essentially, the base-station would have to BE the repeater with a microphone front-end attached... and again that means only 462MHz outputs ? [) also not permitted.

I didn't touch the West books either -- but also didn't touch the skinny ARRL Q&A books. I preferred the thicker versions that had explanatory text and theory while stuffing the question pool in the back of the book. Spent two weeks reading the General book when the code requirement was officially dropped... Found an online practice test site -- verified that I could pass every General test I took on the site. On a whim, I then tried the Extra class license tests, and passed 75% of those I tried. Two days later, I attended a VE session and passed both (granted, the Extra was by just one question) -- spent the following week actually reading the Extra class manual I found in my book backlog. ADDENDUM: Something to consider regarding GMRS license plates... Original GMRS was basically designed for family (eg: large farm) and small business usage. Talking to someone with a different license was extremely rare, mostly limited to Emergency&Traveller Assistance. Hence, no purpose existed to label a GMRS license holder on vehicles. In contrast, Amateur has long been focused on making contacts using minimal power at long distances, radio experimentation and circuit development, and backup service in the event of emergencies. As for vanity plates... Well, consider the following: KRO3607 KAF6045 AF6VN and (please forgive me for grabbing yours S.Shannon, but it was staring me in the face during this edit) WROM258 WHICH of the above are GMRS licenses? Okay, AF6VN sticks out like an amputated thumb -- but can you, just on sight, tell the difference between KRO3607 and KAF6045? Answer: KRO3607 is the class D CB call sign I held from 1976 to whenever the FCC dropped licensing CB radios. KAF6045 is an OLD GMRS license, from back in the day when one was authorized for only two of the eight main frequencies (and when they came out, the seven interstitials). With only two main frequencies, the odds were good that any other GMRS user wouldn't have any frequencies in common -- so again, "advertising" a call sign would have been relatively meaningless. Here in Michigan, license plates are commonly a 3x4 (Alpha x Digit) -- so a regular license of KAF6045 could easily have been issued already. Amateur licenses have a easily recognized feature -- they only have ONE digit surrounded by a TWO [very rare, mostly special events] to FIVE alphas; such a pattern doesn't really appear in any state's regular license scheme (CA was something like 9AAA999[9] [they may be squeezing 8 letters onto plates by now]). It is unlikely that, even if a state could be persuaded to issue a GMRS-marked (as Amateur plates are marked) plate, that they could issue one with letter/numbers matching an existing plate. They'd have had to reserve all Kxx9999/Wxx9999 and Kxxx999/Wxxx999 numbers for use as call signs. (And maybe sequences starting with A...)

I suspect the need to supply radios to volunteers is why Kent County is still using the analog fire dispatch -- volunteer fire mostly used /scanners/ to hear the dispatch, they didn't even have 2-way capability until they reported for duty. County isn't going to suddenly issue digital/trunked/encrypted radios just to put volunteers on the statewide system. As for second point -- these days a government entity can't even obtain a GMRS license (but is permitted to renew any that they possessed prior to the regulations changing -- hence the activity on the Grand Rapids .575 frequency; mainly downtown paid parking lot stuff).

Lucky you... Zoning limits at my location are a MAX of 35 feet (which was basically equivalent to the power lines, before the city moved the power lines underground and removed the poles) -- EXCEPT for licensed AMATEURs who are permitted 75 foot (of course, in my lot, even a 35 foot would risk falling into a neighbor's yard -- lot is only around 80 feet wide; I'd have to install dead center to have any leeway.

Duplex means the radio is transmitting on one frequency (467.xxx MHz for GMRS) and receives on the corresponding frequency (462.xxx MHz). Simplex means the radio is transmitting and receiving on the same frequency in the 462 MHz range (except for the now-permissible 0.5W ERP NFM channels 8-14, which are 467 MHz). I really abhor the FCC channel number scheme which treats the simplex main channels and repeater as /separate entities/. As seen in a number of threads on this forum, it just leads to confusion (in the old days, one had a button on the radio that toggled between simplex and duplex on a given channel, and the channel was commonly identified by the .xxx portion of the frequency [one's license only authorized TWO of the eight main channels, so your channels A&B might not be the same as my A&B). Channels 15-22 and 23-30 (aka: rp15-rp22, 15r-22r, and other naming schemes) receive on the 462MHz, with the result that people with simplex only radios (FRS) or tuned to simplex 15-22 still receive the output from repeaters, but can not transmit to the repeater. Most R-Pi configurations (I'm only accustomed to Amateur Pi-Star usage) are simplex from radio to Pi-Star -- only one side can transmit at a time (a true repeater is receiving on 467 and SIMULTANEOUSLY sending what it received back out on 462). If the R-Pi side is transmitting, it will not hear anything you try to send until the board goes silent (toggles to Listening mode). For Amateur, there ARE boards that support duplex mode -- they have two antenna on the board (not to be confused with dual-band boards, which can be configured for 2m or 70cm usage). Take into account that these boards run VERY LOW power... <50mW is not uncommon, I don't think I've heard of any that gets as high as 100mW! Strangely, my radios can pick up my Pi-Star system from down the block (500 feet or so), but it won't receive my transmissions, even on high power. Probably evidence of how much more sensitive the Kenwood/Icom HTs are compared to an SoC radio chip on top of a potentially RF-noisy processor board. Once your signal hits the internet, simplex/duplex is irrelevant -- it only applies to the link from radios to node and node to radios, and most R-Pi nodes are probably running simplex. If someone has managed to connect the R-Pi to an actual repeater, then it is duplex at that repeater. If it is linked to another simplex node, well -- it is again simplex.

The biggest problem is that you are not just "cross-banding" (which essentially only exists in Amateur usage as that service has multiple bands). You are "cross-service" linking: GMRS -> MURS -> MURS -> GMRS. That also opens up the problem that, someone with a MURS radio that is configured with the same channel and tone, is going to be picked up by your output radio, and repeated in the GMRS band -- AND DOES NOT HAVE A GMRS LICENSE/CALL. Also, there are only five MURS channels vs eight GMRS main/repeater channels. Three of the MURS channels are narrowband-only! (4&5 are wideband with narrow optional). Proper GMRS is wideband.

Probably the predecessor FT-2900r HRO catalog entry for the 2980 has:

"Out of the box" they should be set on factory defaults. RPT-1..RPT-8 are duplex: transmit on 467MHz receive on 462MHz. Channels 15-22 are simplex, transmit&receive on 462MHz. RPT-1/15, RPT-2/16... If you are hearing the same on RPT-1 AND 16 either someone modified the frequency of one of those channels, or you are so close to the repeater it is overloading the front-end of the receiver (but I'd expect that to be heard on 15&16 then)

Well, technically by NAME, APRS is Amateur (Packet/Position) Reporting System, so it is no surprise that most APRS software wants an Amateur call sign. That BTech is using the APRS protocol to send position just makes it another position reporting format -- like some Garmin GPS/FRS radios. The other matter is if they are using AX.25 data packets -- that's what Amateur TNCs are using for analog APRS (D-Star and DMR /digital/ modes send position reports in a different format -- D-Star embeds position data within the non-voice portion of each packet)

The owners may not have entered that repeater into the MyGMRS system. I don't touch "search" -- I prefer to leave the first two "off", and use "Advanced Search" -- selecting the state, and scrolling down the listing it generates.

If he'd been "active" on the Amateur bands, it may have been (former) Official Observer/(now) Volunteer Monitors https://www.arrl.org/news/arrl-thanks-official-observers-as-volunteer-monitor-program-is-set-to-debut that detected him, and forwarded the information to the FCC. You may have gotten him to stop before the FCC itself could verify the behavior.

Possibly even worse -- two beams: receive from one direction, send 180 degrees opposite.

There are many grandfathered repeaters from the days when business/government could obtain a GMRS license (and they are allowed to renew said licenses, but can not make changes -- in those days they probably only requested one frequency pair for the repeater, if they want to change to a different frequency pair they will have to move to land-mobile channels and get a suitable license for that). The Grand Rapids 575 is one such repeater. Back in my 1997 GMRS repeater directory the access tone was published with the caveat "for emergency and traveller assistance only". I'm quite certain anyone popping up on it today, asking for assistance, is going to get a lot of yelling from the dispatcher about "use your cell phone to call 911" or some such. The channel seems to be used by downtown parking lot control -- most traffic concerns gate stuck up, gate stuck down, machines not accepting credit/debit cards, machines not accepting cash, etc.

One has to add in the cost of the two radios to be used... FRS bubble packs will not suffice (actually unless the radio has VHF/UHF [many Amateur units], even GMRS units won't work -- Repeater capable GMRS can transmit on the 467MHz repeater inputs, but can not receive those frequencies [I'm not sure if I've seen a low-cost GMRS that has repeater REVERSE [meant to determine if the other person is close enough for simplex usage -- if, reversed, you can hear their 467MHz signal, you can go to simplex]. The other aspect is that, as a cross-band repeater, it will also repeat traffic from the other radio (ie; receive 462MHz, and feed that to the radio configured for 467MHz -- which is just RF noise to most of the world that doesn't receive that frequency)

For the RT97, the INPUT/Rx frequencies will be 467.xxxMHz, the OUTPUT/Tx frequencies will be 462.xxxMHz (xxx being the same for input and output: 467.550->462.550). Tone codes, if not the same, are also reversed. 467.600 is a repeater input frequency -- do you have a repeater on that frequency? If not you want both input and output set to 462.600 (except for repeaters, none of those radios receive 467.xxx frequencies -- with one exception; the former FRS-only #8-14, which are limited to 0.5W ERP, and NFM). Note that for simplex (radio to radio -- no repeater involved) you will need to use the SAME tones on TX and RX if you want general inter-unit communication. For the most part, GMRS radios are simplex (radio to radio) or duplex (radio to repeater to radio). GMRS duplex is always a 5MHz offset (your receive 462.xxx + 5MHz => 467.xxx). When you exclude the 467MHz interstitials (I know of no mobile unit that includes them, as their low power is 5W) their are only 15 total simplex channels (and 1-7 are limited to 5W) and you are asking to tie up two of them at once. A radio with dual monitor might be used, receive on "B" transmit on "A". But you will run into the same problem as with mixed tones on simplex -- no general inter-unit communication. There is NO privacy on GMRS (nor Amateur) -- neither are permitted encryption. TONES only mean YOU do not hear others unless they send the tone. Any radio on the frequency with no tones set will hear ALL traffic. Another Shannon? ?

Content copied to thread in Technical...

In GMRS mode, you can only define nine GMRS transmit channels (and I wouldn't be surprised to find they are automatically repeater mode). That gives you 39 functional GMRS channels, and 461 receive only channels. Unlocked grants one Tx/Rx on /any/ of the 500 channels. Only reason I unlocked -- the state has something like 11 repeaters, and the RT97 allows for 16 configurations; that's 27 entries to be squeezed into NINE? ? The 144-148/420-450 mode will transmit on Amateur 2m and 70cm bands, and only Tx on those bands. Considered legal (if you have a license) -- commerciall available Amateur radios have to be submitted to check for things like spurious emissions, but tend not to require certification (after all -- it is legal to build your own radio from parts)

Midland GXT1050 (April 2010) has three power levels. Motorola MR356 (April 2012) has repeater capability.

7 is one of the original (pre-FRS) interstitials, allowed up to 5W ERP 21 is one of the eight original MAIN GMRS channels, allowed up to 50W output. Channels 8-14 were originally FRS only, 0.5W ERP NFM-only; now allowed to GMRS since the 2017 reorganization (with same limitations). Original FRS was 1-7/8-14 with both groups limited to 0.5W NFM; it was the "FRS/GMRS" bubble packs that provided higher power on 1-7 (and also 15-22) that complicated the system.

It will... MURS is 2W max output (at least it doesn't state 2W ERP ? ) In the US, 470-512 is shared between Land Mobile, Fixed, and UHF TV 14-20 (frequencies, not what you see on a modern TV -- ATSC can broadcast on a frequency but the channel ID is embedded in the signal; during the NTSC->ATSC transition stations were sending standard definition on their original channel/frequency, but sent high definition on some other frequency, yet identified by the original channel). If you mean FCC regulations -- the only mode that meets FCC Part 95 E is the one labeled "GMRS".

Since the 2017 FCC reorganization -- pretty much 90% of the bubble-pack units sold before 2017 are NOW classified as FRS radios, which do not require a license, and now have access to all the GMRS simplex channels. Naturally, both of my archaic bubble-pack sets came out on the GMRS side of the reorganization -- one has three power levels, with H being >2W, the other is <2W but has repeater capability. I haven't seen any GMRS bubble-packs in local stores; they are all <2W NFM FRS radios. Might need to check Cabella's and REI -- they might be specialized enough to offer GMRS and FRS packages.