Lscott

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.

What were the error codes you got on the Kenwood 3170? I know the radios with generate a low battery alarm at some point then the radio will shut down at about 6 VDC. You can't depend on measuring the open circuit voltage of the battery pack to determine if its completely discharged. When batteries discharge their internal resistance increases so under load the terminal voltage is lower than the open circuit voltage. I've used an electronic load to test a pile of used battery packs for my Kenwood radios. The test automatically terminates once the pack voltage under load drops to 6 VDC. Then when the now open circuited battery pack is checked the terminal voltage jumps up to 6.5 VDC to 6.7 VDC. The nominal battery pack open circuit voltage is around 7.2 VDC to 7.4 VDC. It will be a bit higher right after you take the radio/battery pack out of the charger, maybe as high as 8 VDC or so. Even fresh batteries will show a voltage drop under load. Different battery chemistries have different internal resistance characteristics. Some of the worst ones for heavy loads are your common carbon-zinc types.

I picked up one of those simple full duplex repeater controllers where you plug in two HT's with the antenna ports cabled into a dual band diplexer. The controller has a built in battery but no ID function. I got a diplexer from MFJ that claims 60db of isolation between the VHF/UHF ports. Most do no more to 40 to 50 db. You really need to read the spec's on these things before spending your money on one. The cheap Chinese cavity notchplexers only claim 70+ db isolation between the TX and RX ports as it is for an in-band repeater. The less isolation you have the lower the TX power allowed to reduce desense. Some cases I've read where there was desense the TX power was reduced, not an intuitive thing to do without understanding how the system works.

I’m just looking for something quick, easy and cheap to experiment with. The power isn’t an issue at VHF/UHF as much as antenna height. People work some of the LEO FM sats with an HT working into a small Yagi for example.

Interesting. I have a KG-UVD1P somebody at a swap gave me for free. I never looked at it. I’ll have to see by any chance it has x-band repeat.

That's what I tried with my FT847. I used it in the satellite mode half duplex. The HT would TX to the base radio which x-banded to the local repeater. The HT would then RX the repeater's output directly. No issue with worrying about the ID requirement since I always went from the HT to the base so when I ID'd the base would of course be ID'd as well. The part with the HT which has to operate split band, TX on one band then RX on the other. My big disappointment was the Kenwood TH-D74A. You can't program any of the memory channels that way. The TX and RX frequencies have to be on the same band. Since it does have two VFOs, RX sections, it can still be setup to sort of work that way but it's a lot more of a hassle. It's one of the reasons I still keep my ancient TH-G71A around and several CCR's. That radio is very easy to program for split band operation.

This one claims it has the function if it really works. https://www.retevis.com/RT23-Cross-band-Repeater-HAM-Radio

That's the other issue with cross band repeat operation, the ID problem. I don't know of any radios that have the ability to TX the call sign as required when TX'ing from the repeater to the user's radio. The repeater's TX has to self ID on the Ham bands. My interest is something I can slap together quick. For example using a x-band radio on a balloon or kite for field day.

I just picked up an old Kenwood TH-79A really cheap at a local swap the other weekend. After getting the documentation in pdf format off the Internet I saw it has a cross band repeater function built in. This is NOT the same as cross band operation, but a true repeater operating V/U or U/V. I've experimented a bit using a cheap controller, 2 HT's and a diplexer but was looking for maybe something a bit more simplistic. What current production hand held, not mobile, radios have this feature? I found the Retevis RT23 claims to have it and is fairly cheap as CCR's go. I'm not interested in issues concerning duty cycle. Just whether the radio has the basic functionality and how well it works.

So if there are experimental GMRS repeaters running digital modes under a special FCC license authorization there must be users too. While not currently authorized by the FCC for general use some of us have multimode radios that can receive one or more of these digital modes. If we knew where these repeaters were located it would be fun just to monitor the testing.

One of the first FCC Part 95 certified radios I got was a used Kenwood TK-370G-1. https://mra-raycom.com/wp-content/uploads/simple-file-list/Specifications/portables/TK-270G-370G-Product-Brochure.pdf

I was talking to some buddies at a weekly coffee break I go to which are all Hams. Some think the Monroe Michigan swap in June is going to be really popular. I tend to agree. It normally is but this year I think it’s going to get mobbed.

Right now only in Oregon State, otherwise you have to keep it in the original shipping plastic bag it came in when using it. 8-)

Glad you had success getting the out of band frequencies to work on your Motorola radios. The Kenwood software works about the same. If you enter a frequency outside the of the official range you get a warning message that pops up. If you click to dismiss it the software will accept the entry. It gets tedious when you have a lot of them to enter, but at least it works. I suggested to a fellow Ham to build a test code plug for a radio he wanted to push petty far out of the official range. Put in frequencies, starting at the boundary of the official range edge, about every 1 MHz apart in successive memories. Then try each one out to see where the radio’s PLL fails to lock, you get a warning tone out of the radio in that case. No guarantee the same range works on another radio of the same model due to component tolerances. Once you know the limits the next question is power output and sensitivity as you mentioned. That depends on the power amplifier’s output filter band pass characteristics, and the RX section’s filter. On some radios the power amp filters can be “tweaked” a bit provided the components used have adjustments. The RX section maybe. Many of the Kenwood radios I’ve looked at use some type of electronically tuned band pass filters. Those I doubt are easy, if at all, possible to tweak. The tuning voltage is likely non linear with the precise value generated by the radio’s micro using an internal formula or look up table.

The important point is paying attention to the amp rating of the fuse. Too low and the fuse will fail. If the fuse is rated close to the max current the radio will draw the heat buildup will eventually fail the fuse. Remember that a fuse is a thermal device, an element has to melt to open the circuit. Fuses operating at elevated temperatures may also fail at current levels below their rating. The voltage rating on the fuse is the max system voltage where the fuse is guaranteed to clear the fault without excessive arcing. Using a higher voltage rated fuse should not be an issue.

Did anybody consider trying the Kenwood TK-3360, or the older model TK-3160 radios? They have about the same feature set as the basic VX-261 units. https://www.motorolasolutions.com/content/dam/msi/docs/EA_Collaterals/ENGLISH/commercial/portables/vx260_series_spec_sheet_ea.pdf The Kenwood radios will do wide and narrow band FM, use various battery pack types including Lithium Ion, plus all you need is a cheap Baofeng type cable to program them. In fact many of the cheap Chinese radio accessories, like speaker mics, work on the Kenwood radios. The software I found on line to down load fairly easy. The VHF models work nice as MURS radios, make sure the power is set to low, with enough channels left over for NOAA weather monitoring. https://www.kenwood.com/usa/Support/pdf/TK-2360_3360.pdf http://astralcommunications.com/site/wp-content/uploads/2013/01/TK-2160_3160.pdf I see the UHF version radios selling on eBay frequently in various states of condition, some are the full package, radio charger, battery pack and antenna. As I've mention before Kenwood radios will program outside of the stated band split. So if necessary even a few Ham 70cm frequencies can be used.