Lscott

Humm... That makes all the difference. Given the costs you mention it does explain why businesses are jumping on the free radio services. I knew there were some costs but had no idea it was that expensive. Given the numbers above isn’t the likely outcome FRS and MURS will become primarily an unlicensed business radio service?

I should have been more specific. FCC will not issue a new GMRS license to a business. If the owner and his employees have their own that’s OK as you correctly pointed out. Then each person can use the service under their individual license of course. What I was trying to get across if enough businesses end up using MURS that would likely crowd out those who want to use it for personal use. There are only 5 channels after all. If a business really needs radio communications I think there are better choices, such as getting licensed and one or more frequencies assigned for their use by the FCC. Around me there are a significant number of businesses using FRS radios, which seems to be on the increase. Mostly the old 1/2 watts models. Fortunately those don’t travel that far. The newer radios at 2 watts are more of a problem. Given that MURS allows up to 2 watts it won’t take many frequent users to occupy those 5 channels, and for some distance as well. Which gets me back to the topic of just how popular is MURS? From some of the posts, and my monitoring in my area, it hasn’t caught on with that many users yet.

Exactly my point!

Oops pasted in the wrong link for the Kenwood brochure with the radio info. This should be the right one. http://www.lauttamus.com/_pdf/TwoWayRadio/Kenwood/tk-270g-370g.pdf

In the way of hand held radios I've used the TK-370-K, TK-370G-1 and the TK-3160. Generally the 450 MHz to 470 MHz frequency split versions can go outside of the official range by 10 MHz or so. My favorite is the TK-370G-1 model. By the way it's also Part 95 certified so there is no question it's legal to use on GMRS. It's found on Ebay for a reasonable price if you look carefully. Batteries and antennas are readily available if the one you want doesn't have it. It can use the cheap Baofeng type speaker mics, head sets, antennas (yes they use the reverse SMA type on these radios just like the Chinese) and programming cable. https://forums.mygmrs.com/topic/2022-kenwood-lmr-for-ham/ I've also had good luck with the TK-270G-1 VHF version for 2 meters. Both radios are bigger than most of the newer compact radios, heavier but built like a tank. If you get one be sure you get a charger with it if not look for the KSC-16. I've had good luck finding the programming software for it, KPG-56D. Forget using Chirp. I've never had a version of it that didn't mess up trying to enter frequencies in to it for the "G" versions. For the simple TK-370-K it seems to work OK.

IMO business use should be prohibited. That's done for GMRS currently. There should be plenty of UHF business exclusive frequencies available for licensed use. With only 5 MURS channels it won't take much business traffic to make them unattractive for private individual voice communications. If businesses say that UHF is too congested for licensed UHF frequency and that's why they use MURS on VHF perhaps the crap below is one reason. I just can't understand why a business like a shopping mall needs to run a 35 watt repeater. It's only used by the mall security detail. https://wireless2.fcc.gov/UlsApp/UlsSearch/licenseFreqSum.jsp?licKey=3354643 I'm about 5 miles away per Google Maps and I pick them up clear as a bell using a simple HT on a table top in my house. Does everybody in a 5 plus mile radius really needs to hear them chasing shoplifters out the door and through the parking lot?

It seems to be a shame MURS doesn’t get more use by private individuals. You get to run 2 watts, like FRS which also doesn’t require a license, and external antennas which are not allowed on FRS. In fact any legal FRS certified radio the antennas can’t be removed. I’ve run across dual band mobile antennas specifically tuned for MURS and GMRS. Used with a cheap duplexer one can operate a MURS radio and a GMRS radio, if you’re licensed. The radios can be operated one at a time or at the same time with the duplexer providing the isolation between the radios. The duplexers are cheap costing as little as $30 not counting adapters and patch cables.

I'll guess the usual suspects are about as light and cheap you'll find, GMRS-VI and the TR-505G. https://powerwerx.com/tera-tr505-gmrs-recreational-handheld-radio The BTECH you already have. I would suggest you just get anther one, they're fairly cheap. That way all the accessories are interchangeable, external speaker microphones, antennas, battery packs, mobile battery eliminators, programming cable etc. Then you only have to deal with one programming cable and software. You can make one code plug, radio memory file, and use it on both radios unchanged. Trying to keep two different radio's code plugs compatible is a bit of a pain. Been there done that many times. Finally you only need to learn one radio, not two, and the various menu items and settings. You also don't have to worry about which radio you grabbed and trying to remember how to use it later if that's not the usual one you carry around. On the last point I typically keep all my radio manuals in PDF format and loaded on the smart phone. If I need to use a feature I can't remember to access or setup the manual is right there.

Other than a few local businesses, seldom heard, I almost never hear the frequencies used for voice communications by private individuals. There are a number of old Part 90 radios that predate the creation of MURS so they could be used, grandfathered in, and a number of new radios that are reasonably priced and Part 95 certified for it. So the question is just how many people really use it other than businesses or for a wireless intercom/data applications?

If you do a lot of bike riding a good mobile bike setup could be in order. https://www.dxzone.com/catalog/Operating_Modes/Mobile/Bicycle/ A lot of examples can be found from simple setups to the complex with batteries, solar panels and power amps.

If it is configurable the Kenwood software will let you change it. I think on some of my portables I have that option in one of the menu tabs. The reason why it is an option is so a user doesn’t accidentally turn the volume control all the way down thus missing messages. Setting a min volume level prevents that from happening. With a radio hanging on a belt its easy twist the volume knob and not realize it. At least for the channel selector it has detents so that’s less likely to happen.

Does the radio programming software help file give any clues? Other radio manufacturers offer a similar feature. It typically works using a proprietary signaling method. For example one manufacturer let’s users program in a multi digit DTMF code, like a touch tone telephone number, and only radios with a matching code will open the squelch so you can hear the audio. All other radios the audio will remain muted. Some others use two-tone or five-tone signaling. I think Motorola uses their own proprietary system MDC. https://en.wikipedia.org/wiki/Selective_calling

I would recommend you use the official Kenwood software to program the radio. I’ve had problems with Chirp and the TK-270G/370G wide/narrow band 128 channel radios, VHF and UHF. For the older TK-370 wide band only 32 channel radio it seems to work OK. Reporting Chirp bugs is fine, just don’t hold your breath waiting for them to get fixed. Seems some never do get addressed. One of the main problems with Chirp is not all of the radio’s features are accessible. That’s why the manufacturers software is necessary. Before I even consider buying a used radio I’ll search for a downloadable version of the programming software. Second is getting the programming cable. If I can’t get both I won’t buy the radio. I don’t know about other people but I’ve had much better luck finding the above for Kenwood radios verses Motorola radios.

Nice article. One needs to understand there are several different Lithium battery chemistries which was not made clear. Some are a bit dangerous and can become unstable under certain conditions. The worse is Lithium-Ion. Lithium-Ion has one of the highest energy densities and why its used in EV battery packs. The protection and monitoring systems built into them is extensive. The other chemistry is Lithium-Polymer which sees use in flying drones where you need the most power and energy storage with the least weight. Those people have to be careful as there have been fires from battery failures. The reason why Lithium Iron Phosphate is the recommended chemistry is due to it's very high stability. The down side is the energy density, watt-hours per unit volume or watt-hours per unit weight, is a bit lower than for the other types but still much higher than for Lead Acid batteries. Over all for portable use its a good trade off.

These guys have solar panels, charge controllers and some batteries too. I got a couple of their 50 watt, one 30 watt and four 10 watt mono-crystalline panels. Prices are OK for new. https://www.renogy.com Example of a nice portable 30 watt panel. Not that large. The 50 watt panels are good but not as easy to carry around. Some people get a couple of panels then bolt them together using a door hinge, with cabinet drawer loop handles on the end, so they can be folded up for easy transport. https://www.renogy.com/30-watt-12-volt-monocrystalline-solar-panel-new-edition/#prd-specs If you're lucky you can find used panels at swap meets. Most of the time people seem to want around $1/watt or more, which is a bit much for used panels. What you quickly notice as the panel power goes up the cost per watt drops, for new panels. If there is no rating for the panel a simple measurement with a meter will give you an idea of approximately how much power you can expect to get out of one. Yeah, I'm one of those guys who at times takes a meter to swap meets. 1. In full direct sun light measure the open circuit voltage of the panel. 2. In full direct sun light measure the short circuit current out of the panel. This will vary depending if the panel is at exactly pointed at the sun or off a bit. 3. Multiply the above two readings then multiply by 0.75 (which is the typical "fill factor" its called, to get the "STC" panel rating. Under typical operating conditions don't expect to get much more than around 75% of the above rating. For the example panel above you get: Voc= 22.9 VDC Isc= 1.7 Amps Panel Rating = 22.9 * 1.7 * 0.75 Panel Rating = 29.2 Watts (Manufacture lists at 30 Watts) Real Max Output Power Expected = 30 * 0.75 Real Max Output Power Expected = 22.5 Watts You can get the Anderson Power Pole connectors at this site, crimping tool as well. I got the big set because I wanted to make a bunch of patch cables. https://powerwerx.com/anderson-power-powerpole-sb-connectors Another handy tool is an in-line DC power meter from them. You can keep track of how much power you're producing out of the panels and the amp hours you use from the battery. I got two of these as well, one for the solar panel array and the other for the battery pack. https://powerwerx.com/watt-meter-analyzer-inline-dc-powerpole For long cable runs forget the expensive red and black zip cord cable, costs too much. I went to Home Depot, or Lowes, and got a big roll of 12 gauge stranded low voltage direct burial lighting wire, black zip cord type. Then just stick the power poles on the ends after making sure you got the polarity right. With the red and black power poles on the ends who cares what the wire colors are? https://harriscountyares.org/training/KNW/KNW-120.pdf You want to use the heavy gauge wire because at low voltage and high current the voltage drop can be significant. The large gauge wire gauge keeps the voltage drop way down even on lower power systems.

Hummm... "CCR" -> Ceedence Clearwater Revival. Remember them? https://en.wikipedia.org/wiki/Creedence_Clearwater_Revival

You likely can use the panels you have now. However you do need a charge controller specific for LFP batteries. I got a couple of the 5 amp ones from the company below, Genasun. They’re good for up to maybe a 50 watt panel more or less. I think you can parallel the controllers. These are the good MPPT, max power point tracking, type, not the crappy PWM ones you typically find on many systems. https://sunforgellc.com/

Try looking at battery packs from this company. They do a lot of business with Hams for portable operations. They have pretty good prices considering. https://www.bioennopower.com/collections/12v-series-lifepo4-batteries Personally I have the 6AH pack ($80) for portable work with HT's. I have the 40AH ($360) for home use when the power dies. If you get the batteries make sure to buy the charger too. The 6AH LFP weights a lot less than the old 5AH Lead Acid Gell Cell, and with much more usable capacity too. I don't recommend anybody use a Lead Acid battery unless cost is an extreme concern. Personally I've wreck too many Gell Cell and AGM batteries to want to fool around with them anymore. If you don't maintain them at full charge when not in use they will sulfate and fail. And if you do they still don't last that long. The other disadvantage is the terminal voltage falls fairly quickly to the point where you're lucky to get maybe 50 some percent of the rated capacity out of them. Most mobile equipment wants to see a nominal 13.8 VDC (+/- 15 %) and when it drops to around 11.75 VDC the equipment misbehaves or shuts down. Then there is the weight. Using LFP, Lithium Iron Phosphate (LiFePO4), batteries have a nominal terminal voltage of around 13.3/13.4 VDC over most of the full discharge range, which is a good match for mobile equipment. By the time they drop to 12.8 VDC you have used around 90 percent of the rated capacity. The batteries will routinely allow you to discharge them to 80 to 90 percent without damage. Under this kind of use expect to get around 2000 charge/discharge cycles out of the pack. Lead Acid is only good for a few hundred when using just 50 percent, using more the cycle life drops even more. You can charge up a LFP battery and let it sit for weeks to months without it hardly self discharging. Further for very long term storage you only partially charge them. Sitting around for very long periods doesn't seem to hurt the batteries at all.

It could end up being a rather long list. Here are a few examples. >8-| http://www.ominous-valve.com/acronyms.txt https://rsgb.org/main/publications-archives/radcom/supplementary-information/abbreviations-and-acronyms/ https://www.electronics-notes.com/articles/ham_radio/abbreviations_codes/abbreviations.php

I agree. For the most part it did what his intended purpose was, a very basic explanation of antenna tuning and gain. Since it wasn't meant as a highly technical article minor errors can slide by without a major loss in the concepts. Great effort.

This is a valid point. The antenna impedance is not a simple resistance when off resonance. Combine that with some capacitive coupling in series I’m sure will also generate some weird SWR characteristics.

For a quarter wave antenna it has some rather odd behavior. There seems to be several peaks and dips in the SWR over the range. I would have expected to see just one dip at the resonate frequency and smoothly rising to either side, which is what I saw with the antenna I built. Also the EZNEC+ antenna simulation I ran for it showed the same thing. I'm wondering if part of what you're seeing is caused by the UHF (SO-239 to PL-259) adapter used on the antenna analyzer. Of course those adapters are nowhere near a 50 ohm impedance. The simple 1/4 wave i made used BNC adapters which are 50 ohms. Have to be careful because there are 75 ohm versions too and hard to tell apart since the size is very similar. The interface between the two adapters is likely around 1/2 inch, however due to the velocity factor of that part electrically it looks longer. Teflon has a dialectic constant or 2.1 and the velocity factor is the square root of the reciprocal of the dialectic constant. So for Teflon that works out to 0.69. At 462/467 MHz the RF travels through the connector interface at 69 percent the speed of light, or you can consider the connector looks longer by the factor of 1/0.69, or 1.45 times longer. For a straight barrel adapter, female to female SO-239, I measured the center OD and the shell's ID and using a basic formula to calculate the impedance I got around 28 to 29 ohms. https://www.electronics-notes.com/articles/antennas-propagation/rf-feeders-transmission-lines/coaxial-cable-characteristic-impedance.php So if we consider the adapter interface is around 0.72 inches long at 28 to 29 ohms we could use the lossless transmission line equations to figure out what the impedance will be with a given load on the other end. I did that for various frequencies for my own education and the results were "interesting." At the frequencies we are using for GMRS that impedance bump is rather large. I have a PDF of some calculations a while back along those lines just to see how it affected the SWR. If somebody wants them I would have to PM the file. I can't seem to attached anything to my messages in a long while, I keep getting an error that says I only have 666 some bytes left to attach a file. If I could I would. I know this might be getting a bit deep for some people, but what really counts is the results.

Very good! We could use more real world info like this. Far better than saying “I can hit such and such repeater x miles away.” I see questions always coming up asking if such and such antenna can be tuned for Ham and GMRS. Nothing like having the measurements which speak for themselves.

For a really high gain antenna that is likely true. For a modest gain one the answer isn't so clear cut. I recommended a Comet CA-2x4SR dual band antenna for a friend at work, who got his GMRS license, and looks forward to getting his Ham license as soon as local clubs open up for testing again. You can get it in either a UHF or NMO type mount. http://www.cometantenna.com/wp-content/uploads/2013/09/CA-2x4SR.pdf He mounted the antenna on the fender of his pickup truck. It would have been better on the roof but at 40 inches tall it made things difficult going into parking garages, drive thru windows at banks and fast food joints. I used a Rigexpert AA-1000 antenna analyzer to do an SWR sweep of the operating range. https://rigexpert.com/products/antenna-analyzers/aa-1000/ On UHF the SWR was OK. As long as the SWR is under 2:1 most radios should have no issues and work OK. 432 MHz - 2:1 438 MHz - <1.1:1 454 MHz - 1.9:1 464 MHz - 1.2:1 467 MHz - 1.6:1 469 MHz - 2:1 The SWR on VHF was even better. 140 MHz - 1.5:1 152 MHz - <1.1:1 160 MHz - 1.6:1 This is close to what the published spec's from Comet are for the antenna. While the UHF band has some notable dips and peaks in the sweep it is still very usable. The antenna was mounted close to the roof pillar. I would guess if it was mounted further away the SWR sweep would have looked a bit better. You're right about a 1/4 wave having a large bandwidth. I built a couple out of PCB mount type female BNC sockets and some 1/16 inch stiff buss wire for the elements soldered to the center pin and the flange, bent down at 45 degrees for the ground plane. All about 6 inches long. Sitting on a table top the SWR scan showed a max SWR of 1.4:1 at 430 MHZ and 470 MHz after some slight trimming. The minimum of almost 1:1 was at 445 MHz.. I'm using this on top of a bookcase at the office with a handheld UHF radio. It works better than the typical rubber dummy load, called a rubber duck antenna, that the radios ship with from the manufacture.

That depends. The range on UHF is 3 to 5 miles between mobile radios. You can get more range if you can access a repeater. However you will likely drive out of range of the repeater in 15 to 30 or so miles, if the repeater antenna is located high enough. As an example there is a Ham Radio UHF repeater by me with the antenna at 800 feet. The usable range is about 40 miles more or less. The problem with repeaters used on a long trip are two fold. First you need to know where they are and the channel used. Second most use an access tone, without it you won’t even activate it. Trying to input a tone as you’re driving down the road isn’t recommended. Many of the real GMRS mobile radios require some measure of screwing around to set the tone, that is if it’s even possible. Some you have to use the programming software. If you’re lucky you may get a contact with a base station, in which case you don’t need to normally worry about access tones. If the base station has their antenna up 30 feet or more you could get 10 to 20 mile range. Some of the other people here have pointed out in other posts that running a 40 to 50 watt radio mobile didn’t really increase their range much. I would recommend just using a hand held radio, typically 4 to 5 watt output, connected to a good magnet mount antenna on the vehicle roof. You can buy a hand held GMRS radio for under a $100, some are even less. While you can get a cheap mobile radio for about the same price the output power is about the same. Also the hand held you can use the stubby antenna while out walking around and keep the radio in your pocket when not in use. Don’t even think about trying to use a hand held with the stubby antenna inside the vehicle, you’ll be VERY disappointed. Your most likely contacts are a few others operating mobile GMRS, some base stations and likely a fair number of people using FRS radios mobile. Remember FRS and GMRS share the same exact frequencies exclusive of the repeater ones. My experience with people using FRS radios mobile inside of a vehicle is the range seems to be no more than 1/2 to 1 mile. In fact the FRS users are likely to hear you well past the point where you will hear them.