nokones

And some use recorded audio

Also, it is a great feature so that you do not have to use another channel position in the radio for a simplex or mobile-to-mobile with the same freq and tone settings.

Yes you can have multiple microphones connected to one radio device and it is done all the time in the Aviation industry. It is not rocket science, it is basic electronics in matching levels with each microphone circuit with the radio device. Don't forget, if you're going to have separate microphones in separate locations, you will need to have separate speakers and you will need to factor in if you are going to have side tone without causing feedback (audio loop) or if you're going to automatically mute the receive audio circuit. It will be a little more involved than just coupling (doubling) two microphones to one radio. Also, fire apparatus have multi-comm systems similar to aircraft systems. And, Rugged Radios has on-board radio/Intercom systems for multiple users in one vehicle for off-road applications. You might want to checkout Racing Radios or Racing Electronics.

The factory specifications of the subject radio should list the voltage operating range. Anything outside of that parameter would be detrimental to the electronics components of the radio.

Probably not since he/she lives in San Diego.

Connecting the ground lead directly to the battery is not the best procedure. It is best to connect the ground lead to a factory chassis grounding points on later vehicles to prevent electrical noises being introduced by the vehicle's electrical system and modules into the radio. However, that wouldn't be the cause of your high VSWRs. I would whack off the connector and install a new amphenol connector. Be cognizant of the little Itty bitty wire strands when installing the new connector. Just for giggles, disconnect the cable from the radio and remove the antenna from the NMO. Get a multimeter and at the coax connector, check and see if you have any resistance between the center pin and the outside connector. You should have "OL" or zero ohms meaning no continuity between the two conductors. If you have any reading, then there is a direct short. If you get zero or "OL" then check the center pin and the center pin contact on the NMO for continuity and then check the outside of the connector with the outside contact point of the NMO for continuity. You should have continuity end to end and if not, you have an open circuit. Unless you have an antenna analyzer to check where the open circuit may be, it would be best to whack off the coax connector and recheck for an open circuit again. If you have an open circuit, return that cable assembly. Arcadian is easy to work with and they will take care of you.

I believe Telewave still has Lowband VHF duplexers with a minimum spacing of 600 KHz.

Works fine for me on Windows 11. I'm not sure why I would want to see if it worked for me, but I did anyways and more than likely I probably won't do it again.

And, all FRS Part 95, subpart B Type-Accepted radios are defaulted with narrowband emissions. Also, the channels you have identified as FRS 1-8 are not FRS channels. Those channels are GMRS 467 MHz Main Channels (GMRS channels 23-30 or RP15-RP22) for transmitting directly through a repeater only and if you are a GMRS Licensee, you can transmit up to 50 watts. Non-licensees cannot transmit on these channels. The channels you have identified as FRS 9-14 are the 462 Interstitial channels and are known as FRS/GMRS channels 1-6. If you are a GMRS licensee you are only allowed 5-watts ERP otherwise only 2-watts ERP. You are missing the 462.7125 MHz interstitial channel known as FRS/GMRS channel 7. However, FRS type-accepted radios operate narrowband only on those channels, but as a GMRS licensee you can operate either wide or narrowband emissions.

Since, I have all my Saturday chores done, I decided to do a quick bench test. I don't have a 20-watt Mobile to test, but I do have a 25-watt Mobile and I highly doubt that 5-watts of RF output power would make a difference in any farz or much of a power draw. I used a Kenwood TK-880-1 UHF 25-Watt Mobile radio, Bird 43 that was recalibrated last year, EMC Corp 150-Watt 50 Ohm Power Terminator (Dummy Load), and a Powerwerx 30-amp variable power supply. My first test was with the voltage regulated at 12.9 volts. The stand-by power draw was .3 amp, the transmit power draw at 6.3 amps, and RF Output at 23 watts. At 13.8 Volts the stand-by power draw was .3 amp, the transmit power draw was at 6.6 amps, and the RF output was 26 watts. The voltage did not drop one iota That is .533 dBm difference in RF power levels and my Farz guesstimate for difference could probably be measured with a short tape measure or maybe a yard stick.

I'm not sure what happened to the hundreds of the conventional (non-simulcast) GE Master IIs that were taken out of service several years ago in California and what make stations that replaced them a few years ago. The replacement stations may take a while until they are taken out of service because of migration to 700 MHz system. Also, there are almost a hundred Micors Simulcast and about 50-60 Quintron Simulcast stations that were taken out of service. However, these simulcast stations do not have the local CTCSS encoding modules for these stations because the CTCSS was centrally generated from the control point. Good luck in trying to obtaining the parts. These stations were not repeater stations. The mobile inbound (voted audio) traffic was rebroadcasted from the control point and the receivers used a separate antenna than the transmitter antenna with vertical separation. The stations were either 39, 42, 44, or 45 MHz transmitting stations. A lot of cavities and intermod panels had to be used

I do know and have experience with lowband VHF with FM emissions skipping from California in an easterly direction, just to name a few states, Wyoming, Missouri, Illinois, Indiana, Ohio, and North Carolina.

Where will the Lowband VHF freqs come from? I doubt that the FCC will entertain any proposal at this time and I'm pretty sure that APCO will put up a great fight to keep the Public Safety freqs for Public Safety use for several more years, or maybe a decade or two more, until everyone has migrated off the lowband VHF spectrum. Look how long it took to get the TV Broadcasters off of TV Channels 14-20 for public safety use in the T-Band in the large metropolitan cities/regions throughout the country; and then there was refarming of the UHF spectrum; getting public safety to change to narrowband missions; let alone getting Nextel to give up the 800 MHz spectrum for public safety use after getting public safety to give up the 2.1 GHz spectrum. As the Queen stated, nothing will happen relatively soon and I suspect not less than 10 years, at the minimum.

The Talk Around Feature is selected from the menu and you have to follow the procedure to enable the feature. I don't recall if you select and enable the feature if it is global to the radio on the RP channels or just channel specific on the selected channel.

I think it would be a good idea to have some lowband VHF channels allocated for the Personal Radio Service with repeater operation like GMRS. Finding vault and tower space and services for a lowband VHF remote repeater will be challenging and may discourage such a project. The geographical lowband plan still exist and requires frequency coordination, pursuant to Part 90 rules and regs. At this time, it doesn't appear there are any lowband VHF spectrum allocated/available for the Personal and/or Amateur Radio Services. 30 - Business Radio 31 - Forestry Conservation and Business Radio 33 - Fire 35 - Business Radio 37 - Police 39 - Police 42 - State Police Only 43 - Business Radio 44 - Some Police and Some Business Radio 45 -Police 46 - Fire 47 - Highways & Roads 48 - Utilities 49 - Business Radio 32, 34, 36, 38, 40, and 41 - These freqs are not regulated by Part 90 and the FCC. They may be allocated to and regulated by NTIA.

I kinda recall that Canada allows GMRS, but not with repeaters and I don't remember what the RF power limitations were.

The farz was not a big difference, but it was about a 1/4 mile to less than 1/2 mile better for FM.

I wrote "may" propagate further and if it doesn't so what. What I was conveying is that with FM modulation I was able to communicate further than I could with AM modulation.

The AM signal may propagate further, but it will be noisier and not usable whereas, the FM audio will not be affected by the noise factor as AM thus you will more farz with intelligible audio.

A tad more communication distance of usable audio because of the noise factor. With 3 1/2 watts that equates to almost a 1/4 mile more in Farz.

Wikipedia is getting screwed up by A.I.

“Road” means any existing vehicle route. A “roadway” is that portion of a highway improved, designed, or ordinarily used for vehicular travel. “Freeway” is a highway in respect to which the owners of abutting lands have no right or easement of access to or from their abutting lands or in respect to which such owners have only limited or restricted right or easement of access. Highway” is a way or place of whatever nature, publicly maintained and open to the use of the public for purposes of vehicular travel. Highway includes street.

You are a tad off on that date. GMRS was known as Class A Radio Service and CB Radio was known as Class D Radio Service back in the 60s. In the 70s, the FCC changed the Class A Radio Service to General Mobile Radio Service (GMRS).

Same here. I haven't heard anyone on FM.

Those are the "Sad Hams". They have been pissed off and angry for a long time since Thrifty Drug stores closed up so they can test their radio tubes with the tube tester and get a 5 cent ice cream cone at the same time.