Lscott

"No GMRS transmitter will be certified for use in the GMRS if it is equipped with the capabilities to operate in services that do not require equipment certification, such as the Amateur Radio Service." That's rather confusing. I have my Part 95A FCC certified TK-3170 programmed with a bunch of Ham simplex and repeater frequencies in addition to GMRS stuff. Depending on how you interpret the above the radio may not be legally used on GMRS?

I know this is a bit late but how much of the railroad communications takes place using digital NXDN? At one time I understood the railroads were switching over to it in place of analog. https://www.scannermasterblog.com/railroads-nxdn-and-ptc/ https://forums.radioreference.com/threads/railroads-and-nxdn.362261/

The last rule change by the FCC they just "throw in the towel" in regards to what people were already doing, using those "dual service" FRS/GMRS radios without getting the required license. It was easier for the FCC to make the wide spread illegal practice legal by a rule change. Now they can ignore the issue. I expect at some point the same will be done with the use of Part 90 radios on GMRS. The FCC can't really say with a straight face they are enforcing the rules when they let the practice of using Part 90 equipment on GMRS go on, except were you pointed out, when its in conjunction with other rule violations. As discussed on the forum many times your typical name brand LMR/Part 90 radios meet and or exceed the technical specifications for GMRS. The only element missing is the official blessing by the FCC, certification. I personally expect to see the FCC sooner or later to again to "throw in the towel" on the issue. Likely with language along the lines of if it was certified for Part 90 with no front panel programming, and maybe a cut off date, its good to go, with no ambiguities. I suspect there are a LOT of Part 90 only radios being used everyday with no issues on GMRS. So long as the technical specifications, power - bandwidth - channel frequency - frequency stability - no digital - no encryption/voice scrambling, are met how would would one even know a radio was Part 90 only just from monitoring on the air? If you can't does it even really make any difference?

Not only that but the metal sub-chassis of the radio along with your hand/arm combo forms part of the ground plane. https://www.hamradio.me/antennas/ht-antenna-comparisons.html I've tried checking the SWR on a bunch of HT antennas, well the results are mixed. I got widely varying results depending on how the antenna was mounted, directly to the analyzer - SMA type magnet mount on a ground plane (yes I found one at a swap) etc. About the only ones you can reliability check are 1/2 wave types since they don't require a ground plane. I've seen a few for the Ham 2M band. I don't recall seeing anything for UHF. https://www.smileyantenna.com/product-p/14686.htm

I agree with your points. If necessary a short simple beep is enough. Personally myself I don’t use Roger Beeps either. I have used some Ham repeaters that had no courtesy tone. Trying to do a round table discussion with 3 or more people often resulted in somebody getting stepped on.

Well that depends. If the radio supports operation through a repeater it may serve a useful propose. Most repeaters have a "hang time" which can be as short a a fraction of a second to several seconds or more. The hang time function is to keep the repeater keyed up and ready without the constant COR, carrier operated relay action. The Roger Beep lets everyone on the repeater know when the other party is done so you don't have to wait for the repeater to dropout, without the usual squelch tail, before commencing with another transmission. Of course it should be a common practice to wait a few seconds before jumping in anyway. That gives another party out there a change to announce their call sign and use the repeater. At least people are not using "echo mic's" with their radios, which seems commonly used on 11M. Now that's annoying.

https://www.faa.gov/hazmat/packsafe/more_info/?hazmat=7 https://www.tsa.gov/blog/2013/06/11/travel-tips-tuesday-safely-packing-batteries-your-trip

I traveled a lot through airports some years back, mid 2000's, and never had an issue with the radios. Now battery packs are another thing. I had a fanny pack with a 5Ah gell cell in it, for extended portable operation. That got a "lot of interest" because it showed up as completely black on the x-ray machine with wires coming off it to a round cylinder, 12 volt accessory socket, to use a battery charger eliminator. The TSA inspector almost had a heart attack when the accessory socket popped out like a Jack-In-A-Box, due to the coiled up wire cord, when he unzipped the fanny pack flap and slowly pulled it open. He forgot to let go of the fanny pack when it tried to throw it, otherwise it would have gone about 10 feet across the screening area. Oh well. Everybody saw what happened. And no I didn't get into any trouble and was allowed to proceed to the gate area.

The Kenwood HT's I've had direct experience with are the following: TK-370G-1 https://mra-raycom.com/wp-content/uploads/simple-file-list/Specifications/portables/TK-270G-370G-Product-Brochure.pdf TK-3140 https://mra-raycom.com/wp-content/uploads/simple-file-list/Specifications/TK-3140-Product-Brochure.pdf TK-3170 https://5.imimg.com/data5/MT/AL/MY-2136226/tk-3170-handheld-portable-walkie-talkie.pdf TK-3173 http://www.comspecinc.com/PDF/TK-3173.pdf TK-3180 https://pdfs.kenwoodproducts.com/10/TK-2180&3180Brochure.pdf All are Part 95 certified. Either listed as "Part 95" or "Part 95A". The 95A was the older section for GMRS whereas the new one is Part 95E, same thing. It seems like the favorite is either the 3170 or 3173. Both use the same version of the programming software and will use the cheap Baofeng type Chinese radio programming cable and accessories like speaker microphones. The other two radios also use the same plugin accessories and programming cable too. The 3140, 3170 and 3173 all use the same type battery pack and charger so if you get the different models at least you can share them saving some money. The trick is find one of the above in good condition for a reasonable price. Don't forget you will likely need an antenna, new battery pack and charger too.

They can’t let their license lapse either. If they do the FCC won’t renew it as a business and they lose any priority they enjoyed over secondary users. I have a similar issue by me. A local mall’s house keeping is operating a repeater on GMRS channel 16, yes it’s a repeater with PL tone, it’s been “tested”. The problem is their license expired in October 2015 per the FCC database. It was never renewed as far as I can tell while the house keeping staff continues to use their radios and the repeater. I’m waiting to see how long before somebody gets the idea to hijack the repeater and use it for local non mall related communications. If the mall complains to the FCC it likely will get shut down while the mall gets a $10k fine for unlicensed GMRS operations. Their other choice is pay for a regular business license, get a coordinated frequency, then get the repeater reprogram and tuned. The house keeping staff use those Motorola Mag One BPR40 radios which can easily be reprogramed. https://www.motorolasolutions.com/content/dam/msi/docs/business/products/two-way_radios/portable_radios/small_business_portable_radios/bpr40/_documents/static_files/mag_one_bpr40_brochure.pdf At least they’re not using those CLS1110/1410 radios. A number of the smaller stores their personal I’ve observed using those. You might mistake them for an FRS radio at first. https://www.motorolasolutions.com/content/dam/msi/docs/business/products/two-way_radios/portable_radios/small_business_portable_radios/cls1410/_documents/static_files/cls_specsheet.pdf

Excellent point. Battery packs are something people are going to buy sooner or later. They don’t last forever. I wore out the lithium pack on my BTECH triband radio I use at work as cheap scanner while working in my office. Scan all day, then recharge overnight. After about a year it wouldn’t even make it through 8 hours before the radio shut down due to low voltage on the pack. The typical life of a battery pack is 300 to 500 charge/discharge cycles. Depending on the owners radio use a battery pack might last one to several years.

As a point of reference the service manual for a Kenwood KSC-25 charger can be found here. https://manuals.repeater-builder.com/Kenwood/ksc/KSC-25_B51-8626-00.pdf Looking at the second page from the back it shows the circuitry for several different battery packs. I would imagine that battery packs from other manufactures likely do something similar. The "charging terminals" on the base of the battery pack is only accessible by the charger base while the "discharging terminals" are only accessible by the radio when it's installed. One thing about the Lithium Ion battery pack schematic are the cells are shown connected to a boxed area. That is a "protection" circuit. I noticed when running pack discharge tests using a simple power resistor, before using the E-load, if I discharged the Lithium pack much below the 6VDC I use for a cut off point the voltage will suddenly drop to zero. Lithium batteries will be permanently damaged if discharged below a certain voltage level. The protection circuit disconnects the cells internally from the discharge terminals to prevent this.

The blocking diode is built into the battery packs, not the charger. Modifying the charger wouldn’t do any good.

That won't work with the Kenwood battery packs. The charge contacts isolate the battery from accidental discharge. There is an isolation diode inside. I have to go directly to the radio power contacts to do the rating tests. I suspect most radio battery packs are designed this way. If not then its dangerous. Sticking a radio in a pocket with metal coins or a key ring/chain won't end well in that case.

I don't have any single cells to test. What I do have is a pile of used battery packs for radios. I must 20 to 30 battery packs of different chemistry types. Maybe 30 to 40 percent actually test at 80 percent or better under my test conditions. Some tested as low as 21 percent, garbage. If I did have any 18650 cells that would be an interesting test to do. The whole test thing is automated through the E-load. Once it's setup I just start the test and walk away.

I thought about doing that too. I have several different types where each would need it's own jig. I'm just too lazy to build them. Now if I had a 3D printer, that would be a different story. That's at the bottom of the "toy list" with the spectrum analyzer, RF signal generator and Bird power meter with slugs ahead of it. Waiting to see if the government mails out any more "stimulus checks" to help out with the financing.

That depends on the connector type. If you're using a constant impedance type like, "N" - BNC - SMA, it doesn't make much difference. There should be little loss in the connectors and the impedance bump should be nil so no real impact on the SWR. I wouldn't try this with PL-259/SO-239 connectors. I use patch cables in my Jeep. I have several patch cables with BNC connectors spliced to a Mini RG8 type on the end of the cable to my luggage rack antenna mount. The Mini RG8, which look like miniature PL-259/SO-239 connectors, are really constant impedance type and low loss.

Do you know what the lowest voltage that unit will function at? I have something like that from Powerwerx but when the battery voltage drops too low the meter quits working. For the 7.2 to 7.4 VDC nominal battery pack voltages i deal with it didn't really work. https://powerwerx.com/watt-meter-analyzer-inline-dc-bare-wire I've purchased a lot used hand held radios and many came with battery packs. Almost universally the seller stated they have no idea what condition the battery packs were in. Also you find battery packs at the Ham swaps with the same caveat. I think I spent a week testing battery packs after I got the electronic load. The E-Load is also good for testing solar panels and general power supplies out. You confirmed what I've read elsewhere about people getting burned purchasing battery packs that don't live up to the capacity claims. Without testing you have no idea if you really got what you paid for.

How many people test their battery packs for capacity? Buying the cheap Chinese packs you can't really be sure you're getting what you paid for. There are documented cases of battery packs that are rated for more than the actual cells that are used internally. I see people questioning the common UV5R battery packs, for example, where people have noted the standard included pack has been marked with several different ratings. I use an electronic load to test my battery packs, and use the OEM charger to ensure I start with a "fully charged" pack. Some people have a combo battery pack tester, reconditioning and charger system. Having several portable radios with spare battery packs can get expensive. The cheap Chinese Lithium Ion packs run anywhere from a low of $20 to $25 and up to almost 2 to 3 times this amount. The real OEM packs are really expensive.

That looks like how I have my dual band Ham antenna mounted on the Jeep. The difference is mine in on the roof rack cross rails but in about the same location. I need it there so I can quickly, and easily, take the antenna off when having to navigate low overhead clearance areas. My antenna is nearly 60 inches tall by the way. The main problem is the antenna height. You really have to watch where you drive. Going through a drive-thru window or parking garage does a nice job of tearing off the antenna or bending it over. Then there is the occasional tree branch strike too. What a few people have done is use a motorized mount that can lower the antenna. It isn't exactly cheap but does solve problem, mostly. As noted you need to use a ground plane independent antenna. https://www.diamondantenna.net/k9000lrmo.html

This site has a lot of info on repeater building. There are specific pages for different manufacturers. You might find something here. http://www.repeater-builder.com/rbtip/mojoindex.html

Oh, the VHF versions make great MURS radios. Just watch the bandwidth and power settings.

If you don’t mind the lack of FCC Part 95 certification then the Kenwood TK-3160 or the newer model TK-3360 16 channel radios might fit your usage. These radios are just about impossible to screw up the settings since they lack many user accessible features. In some ways they are easier to use than your common cheap FRS radio. https://mra-raycom.com/wp-content/uploads/simple-file-list/Specifications/portables/TK-2160-3160-Product-Brochure.pdf https://www.kenwood.com/usa/Support/pdf/TK-2360_3360.pdf The TK-3360 has 5 watts output verses the 4 watts on the TK-3160. The power level can be changed from 5watts/1watt and between wide or narrow band FM. The programming software isn’t hard to find on the Internet to download. The programming cable and speaker/mics are the same you find for the cheap Chinese radios. I routinely use a Baofeng cable to program many of my Kenwood’s that use the two pin type connector.

I guess that all depends on the capacity of the AA cells. https://rightbattery.com/118-1-5v-aa-duracell-alkaline-battery-tests/ The rechargeable packs I tested were of three different chemistry types, Nickle Cadmium, Nickle Metal Hydride and Lithium Ion. The rated capacities were typically 1200mAh, 1450mAh, 1800mAh and 2000mAh. To test a battery pack you need to check it at a known discharge rate. Manufactures use several. One common rate is the 0.2C, or called a C/5< rate. That means a pack rated for example 1000mAh is discharged at a constant current equal to the capacity of 0.2*1000, or 1000/5, which works out to 200mA. In general a higher rate results in less usable capacity. The time from the beginning of the test to the voltage level used to end the test is measured. So a pack that reaches the test termination voltage after 4 hours in the above example results in a total of 4*200mA= 800mAh, 80 percent of the new rating, of "usable" capacity. For my tests I used 6.0VDC since that's where the Kenwood radios will automatically shut down. This particular voltage is based on the pack's cell type and the manufactures recommended lower limit where the cell is almost completely discharged. The generally accepted value of 80 percent is used as a cutoff between a pack that is still serviceable verses one that is considered EOL, end of life. It's not unusual for a handheld radio to draw as much as 1.5 amps to 2.0 amps from the pack at the 4 to 5 watt TX power level. The RX current draw is considerably less. Even a crappy battery pack may seem to last a long time when a radio is just simply sitting around on standby with the squelch occasionally opening up when a signal is present. But the pack my quickly die after a few minutes of use when the TX function is engaged. Of course if you know what the capacity is, even if it's below the 80 percent mark, the pack may still be useful so long as you plan for it by carrying extra packs.