Lscott

I think Radioguy7268 pointed out a possible solution. Select one memory slot and program one GMRS channel for TX and another for RX. You can use a mix of analog and digital tones for TX and RX. Then select your next memory slot using the same idea but using different GMRS channels and tones for TX and RX. Setup as many memory slots as you like. All the radios should be programmed identically. During communications you just announce that everyone switch to another preprogrammed memory slot on their radio periodically. Anybody trying to jam or monitor your communications will get frustrated fairly quickly trying to figure out what channels and tones you’re using every time you switch memory slots.

Cool. I’m looking for a basic write-up or how-to for programming a basic NXDN radio. The one in particular is a Kenwood NX-340U-K2. I got the radio very cheap since it turned out to be both read and write password protected. No way to reset back to factory defaults that I could find after a couple of weeks of intensive searching. I finally got a modified version of the programming software that allowed me to blow-by all of the password protections so I could write a blank code plug to the radio which disabled the old passwords. It works on any radio supported by that radio programming software version. I’ve downloaded all of the current NXDN tech docs, radio user manuals and service guides for it. It’s a lot of material to read through, most of which nobody cares about unless you’re writing communications software for NXDN. I’m just looking for an explanation for the typical settings the Kenwood needs, both for simplex and repeater ops. Right now I have the radio stored away until I get more info and time to play with it. I also have the DMR version of the above radio, TK-D340U.

Personally I never put in a RX tone for simplex and repeater use. That eliminates any issue with not hearing a station return a call.

This link has some good tables for coax losses of the different types. http://rfelektronik.se/manuals/Datasheets/3_8_%20LMR400%20Coaxial%20Cbl%20-%20Low%20Loss%20RG8_U%20Cable.pdf

The scanning I do is on the analog channels. I like to monitor the local FRS/GMRS channels, the 5 MURS channels and a collection of business only VHF and UHF frequencies. Most of the public safety stuff has moved to 800 MHz P25 with encryption. There are still a few around that are still on 450 MHz to 470 MHz analog systems. There are a few business that are using DMR, thus the D878UV radio, locally but they are rather few in number currently. The only DMR radios I have are the Anytone D878UV and the Kenwood TH-D340U. The Kenwood I got off eBay for $45 before somebody else saw it and made the purchase. Radios like these don't last long selling that cheap. I guess the seller didn't know exactly what he had. Some of these guys buy surplus equipment in bulk and sell it off for what they can get for a quick buck. I also snagged a Kenwood NX-340U with the rare 400 MHz to 470MHz band split, perfect for Ham Radio, for $50 the same way. Haven't seen deals this good since then. The few I've seen since then sell for $125 and up for the base models. https://comms.kenwood.com/common/pdf/download/DMR_TK-D240V_D340U_K_letter_1124.pdf https://comms.kenwood.com/common/pdf/download/05_nx240v_340u_K_1117_typeD%20added.pdf Both radios will do analog/digital on a per memory channel basis. The brochures say the radios won't do normal FM for the US models. Get the right version of the programming software and license key they will. It's a limitation of the radio programming software, not the radio's hardware or firmware that I can see. There are pockets of NXDN activity. https://ctnxdn.wordpress.com/what-is-nxdn-all-about/ From the little I've read NXDN and DMR both employ similar ideas, talk groups etc., for communication, but use different modulation/signaling formats and narrow bandwidths. I know this thread is about DMR, however NXDN will work in a 6.25KHz bandwidth and DMR using 12.5KHz bandwidth. That has the potential to expand the number of usable "channels" without using more spectrum. Some of the existing 25KHz channels could be split into 2 or more digital only channels. The most intriguing thing about DMR is the SFR, single frequency repeater, mode where one can build a repeater using just one frequency in place of a pair. That eliminates the trouble and cost of a set of tuned cavity filters.

That doesn't address the issue of the currently displayed memory channel being scanned even if it isn't in the current scan list. You can't delete what isn't there! I told their tech support guy if I wanted to scan the currently displayed channel I would have added it to the scan list. I don't need the radio to do it for me and not offer the option to exclude it. I told the tech support guy I have dozens of radio models that do scanning and NONE do what the D878UV does. The only work around I've found is to insure that the currently displayed memory channel is one that appears in the selected scan list. It's extremely inconvenient to poke around on the radio to display a memory channel in the current scan list, and I have multiple scan lists so it's even more of a pain, before starting the scan. And not to mention these Chinese radios scan really slow. The fastest radio I have for scanning is my Kenwood Ham tri-band radio, TH-D74A, which does about 30 memory channels in a hair over 1 second from my timing measurements, impressive. https://www.kenwood.com/usa/com/support/pdf/TH-D74A.pdf https://www.va2pv.com/wp-content/uploads/2017/04/QST-Kenwood_TH-D74-Review_VA2PV-April_2017.pdf I would like to see them to bring out a model that does DMR like the above they have for D-Star.

I've pulled my hair out fighting with the radio programming software for the Anytone D878UV DMR radio. The worse part of the radio is the user programming software, it sucks. There are features that plainly don't work as expected. Some they fix in the next revision, then the revision after that it's buggered up again. I've grown tired of sending off bug reports to their tech support guy in China. There has been two updates since the last one I did on the radio and I have little motivation to screw around with to see what is mucked up this time with the current update. The scan lists is one of those that bugs me since I do a lot of scanning with my radios. It just so happens than when you start a scan the currently selected memory channel is included in the scan even if it is NOT in the scan list. I was told by Anytone support this is NOT a bug. They claim people want to revert back to the channel when a scan is stopped, OK, but there is no reason to include it either. If the channel is a very busy one you likely don't want to stop every time there is activity on it. VERY annoying. There is a sort of half a**ed way to work around it but it should be required.

I looked at the web site to see if there are any gain figures published, didn't see any for that Yagi. Have you considered a "corner reflector" type antenna? They look like the old style UHF TV antennas, the ones with a "Vee" shaped reflector. I've done some simulations using EZNEC+ software. If you're into modeling, building or just plain curious about antennas this is a good software package to use. Not too expensive. There is a free demo version. https://www.eznec.com/ A few of the UHF corner reflector models I built show a real gain of 11+ db over a dipole if optimized a bit. The bandwidth seemed wider than the 11 Yagi I modeled from M Squared antennas. The horizontal side lobes seems small and the vertical side lobes were reasonably small. Arrow also sells corner reflectors too. http://www.arrowantennas.com/solid/cr4501.html With a corner reflector you don't have to worry about the metal mast buggering up the match or ruining the gain of the antenna since the mast is always behind the reflector.

On the various Chinese radios I have in my collection there is a setting for the TX power level accessible through the menu system. It should be documented in the user manual.

How many people have damaged their HT from overheating when used at a moderate to high duty cycle transmit condition? I tend to be careful of the small palm sized radios since the aluminum sub chassis doesn’t have enough mass and surface area for heat dissipation compared to older model radios which were significantly larger. At anything more than a very low duty cycle I can feel those tiny radios turning into great hand warmers really quick. The typical manufacturers spec’s are a 5-5-90, 5 percent TX - 5 percent RX (with audio) - 90 percent standby (audio muted), when estimating battery pack operating time. I’m sure it also has something to do with the radio heating issue too.

You get what you pay for, and if you're not careful not even that.

Really that much RG-58 coax! Depending on which table I consult the losses at 450 MHz, just a bit below the GMRS frequencies, for 100 feet of coax is 11db. That translates into a 98 percent power loss! That coax run is about the next best thing to dummy load. I'll also bet the match is darn near 1:1 too since almost all of the reflected power is wasted in the coax. You could disconnect the antenna end of the cable and still see a near perfect match. I've had people tell me they have used a spool of RG-58 coax with nothing on the end as an effective dummy load on UHF for testing transmitter power, power meter on radio output and the coax spool on the load side of the power meter.

If you wait a week or two after XMAS most of those toy FRS radios go silent. The kids loose interest and or the batteries go dead.

Check the link below for a better eliminator. http://store.batteriesamerica.com/cbe-26batteryeliminatorforkenwoodtk-2160217031603170radiosetc.aspx

Yes. There are 12 year old kids that take and pass the exam.

You could also look at a somewhat older Kenwood radio model. I have used the TK-370G-1. You can find these radios with a full numeric keypad fairly often. Following the instructions in the service manual, removing a diode I believe, and selecting the self programming option in the software the radio can be field programmed through the front panel. http://www.dannel.co.za/vertel/TK-270G-370G_5-Tone.pdf

What gets old is when the kids in the nearby local neighborhood take up residence on your favorite repeater’s output frequency causing interference just when you want to use it. While FRS radios can’t access repeater input frequencies they all have the output frequencies in them.

I also have both. I use a cheap Baofeng USB programming cable on this radio and a bunch of other Kenwood radios that have the two-pin port on the side. I got my programing cable at the link below. I’ve used both the software and cable with Windows 10. http://www.randl.com/shop/catalog/product_info.php?products_id=71426

Looks like I can't paste the FCC search results link with the search results. 8-( One would need to go to the link below, FCC's "License Search" page. https://wireless2.fcc.gov/UlsApp/UlsSearch/searchLicense.jsp Then do a search by FRN number, click on the button to the left of the edit window and select "By FRN". The FRN number to use is this one. 0002748242 This shows all current and past licenses held by the mall.

You might be right about that! Many of the shop fronts are closed up and the space is cleaned out. The foot traffic in the mall during the week is almost nonexistent. I think half the people you see are called "Mall Walkers" who are there just for the exorcise. Its is a large mall. It beats freezing your nuts off outside and slipping on the snow and ice.

I've run down the source of traffic on an unidentified repeater, at the time, on the same frequency pair used by a local GMRS repeater, with currently 54 confirmed users. It seems to be used by the housekeeping staff at a local mall which is operating a repeater but with a different PL tone. I verified this by catching a member of the mall's security staff talking on their licensed frequency, WQOX482, then talking on the GMRS unidentified repeater a few seconds later to the mall's housekeeping staff about the same topic. The housekeeping repeater never ID's nor does anybody else I've monitored using it. From what I can find the repeater appears to be operating illegally since 10/12/2015. https://wireless2.fcc.gov/UlsApp/UlsSearch/results.jsp The license has long since expired, KAB1523, and was not renewed thus their is no "grandfather" exception to consider. The following link clearly shows the repeater frequencies used under the "Special Conditions" section of the now expired license. https://wireless2.fcc.gov/UlsApp/UlsSearch/licenseAdminSum.jsp?licKey=194751 Our repeater administrator has decided not to make an issue of it since the "illegal business repeater" is seldom used. It's his choice and machine so the following question is just for general information. Has anybody else run across a known verifiable illegal use of GMRS frequencies, this does NOT include legal use of FRS radios, by a business and what if anything was done about it? Does the FCC really care to get involved?

I know of people who won't turn on their CB radio if the kids are in the car because of what goes on there. Nice to hear people are behaving themselves on GMRS and hope it stays that way.

That one you linked to looks good. I purchased a couple of these for solar power applications. Monitor panel output and the charge going in/out of a battery bank, usually a 12 VDC to 13.3 VDC. https://powerwerx.com/watt-meter-analyzer-inline-dc-powerpole I tried to use one for battery capacity testing unfortunately when the battery voltage drops a bit the meter quits working. The typical HT pack I use is 7.4VDC and they didn't work well at that low voltage. There is a separate port for external power but it still leaves me with making up a load for the battery pack and for a check against the pack's name plate rating the test needs to duplicate the manufacture's test conditions. That's hard to do without the specialized test gear.

I guess none of mine have that technology. It sounds like a very good feature to have. I just purchased two new NiMH 1800mAh packs because the two I thought were good tested at greatly reduced capacity. Sort of surprised me.

I would recommend keeping it about 12 inches away from large metal objects. The top part of the antenna, about 75 percent of it, is where the RF mainly radiates from. If you don’t need to use the antenna often you can try hanging it from an eye-hook screwed into the ceiling.