Lscott
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Posts posted by Lscott
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I just got my GMRS license a few days ago and would like to purchase a current production handheld with at least a genuine four watts of power and be repeater capable.
You can look at this radio. It is currently being sold by Kenwood. You can find them on eBay for a decent price. The link below is for just one example.
As mentioned by others be sure you get a battery pack, charger and the antenna for it. You can find the programming software and cable online as well. If you buy a used one make sure it is a "Type 1" radio. Also watch out for people selling the European versions, you really don't want one of those since they don't have the FCC certification and requires a hard to find version of the programming software. On UHF most commercial radios cover different sections of the band. You want a radio that covers the 462 MHz to 467 MHz range.
Also if you ever plan on getting your Ham License, the Tech Class is easy to get, this radio will also program down to 440 MHz, the normal Ham 70cm band runs from 430 MHz to 450 MHz, even if the spec's don't mention it. The section from 440 MHz to 450 MHz is where most of the Ham simplex operations and repeaters are located. This way you can have a Ham Band UHF and GMRS radio all in one.
https://www.kenwood.com/usa/com/lmr/tk-2170_3170/ (Kenwood product page)
https://www.ameradio.com/doc/Kenwood_TK-2170_TK-3170.pdf (Brochure)
It has the required FCC Part 95A certification so there is no question if it's legal to use for GMRS.
https://fccid.io/ALH34713110 (FCC info)
I would look for a good commercial quality radio before looking at the cheaper Chinese type radios. Generally the commercial quality radios typically have much better receivers, more selective and don't loose sensitivity in strong RF environments like near large radio and TV stations. You get what you pay for.
Oh, congratulations on getting your GMRS license! 8-)
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The cable I am modifying is a 100 foot LMR400 cable with male N connectors on both ends. Aside from shortening the cable to 35 feet for a better fit, I wanted to install the PL-259 connector to avoid having to use an adapter on my Kenwood 8180 which utilizes the PL-259 connector for cable attachment.
I think you have two things going on here.
1. The connector you installed, PL-259, is not a constant impedance type like the type "N" which will contribute to the higher SWR reading. The connectors calculate out, based on some dimensions on a few I've looked at, of around 25 to 40 ohms. It also depends on what the dialectic material used happens to be as well. The length, connector, of the miss match section also matters but in this case its rather small. This results in an impedance "bump" and a cause for some reflected power. If the radio uses an SO-259 socket there isn't much you can do about that.
2. When you cut the cable length from 100 feet to 35 feet you reduced the losses in the cable. However that applies to not only the forward power but also the reflected power. The formula for calculating SWR based on the power reading is:
SWR = (1 + sqrt(Pref / Pfwd)) / (1 - sqrt(Pref / Pfwd))
Where:
sqrt() - square root function
Pfwd - Forward power
Pref - Reflected power
How this works to increase the SWR reading as measured at the radio end of the cable is as follows. With lower forward losses the reflected power from any antenna mismatch will be higher because the power to the antenna has increased. Additionally the reflected power is attenuated less as well. Both work to increase the ratio (Pref / Pfwd) in the above formula. Remember you're measuring the forward power at the radio end and that hasn't changed. Thus the numerator becomes larger while the denominator smaller in the above formula. The final result is the number calculated becomes larger, the SWR.
I suspect the cable length change has more to do with the increase in SWR than the connector in this case. So as others have pointed out most radios work OK with an SWR up to 2:1, at least that's what I've seen in the spec's for the ones I looked at, without issues. An SWR around 1.5:1 or so is fine. You won't gain much by trying to lower it.
- Riktar and Radioguy7268
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So, checking out facebook when an ad poped up for the PowerTalkieX as a family emergency communications device. Heres the link to it : https://preparedhero.com/products/powertalkiex?utm_source=fb&utm_medium=social&utm_campaign=powertalkiex&fbclid=IwAR3nSv3JEPDBSZxQcoKo1s2gwKoiMBEeNnlrRGFduSrkhv6sTRTcfA63Mlc
I scrolled down the page at the link above and the spec's given were:
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Technical Specs:
License Free FRS Radio
462 - 467 MHz
Exceptional conditions: Approx 20 Miles range
Everyday use: Approx 3.2 Miles range
Rugged city use: 50 floor penetration
One-piece back clip
9-level noise reduction
80 decibel speaker output
16 Memory Channels
8,000 mAh internal battery
Type-C fast charging
Only 1.5CM thick (as thin as an iPhoneX)
Under 5oz weight
15 day standby
LED dot matrix display
Headphone charging interface
Transmitter
Output Power: 2W/0.5W
Modulation: FM (F3E)
Max.Frequency Deviation: ≤5KHz
Sparious Radiation: ≤7.5μW
Receiver
Sensitivity: 0.16μV(12dB SINAD)
Audio Power: ≥300mW
Audio Distortion:
80 decibel speaker output
Receiving Current: <300mA
Standby Current: <200mA
Emission Current: <1800mA
Audio Distortion: <5%
Intermodulation: >60dB
Max Frequency Deviation: <5KHz
Supply Power: DC3.7V
CTCSS/DCS: The transceiver has 50 CTCSS and 208 DCS, also non-standard subaudio can be programmed
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To me it just looks like a cheap DSP based "radio on a chip" type hand-held. This is common in the "Baofeng" type Chinese radios. They use the RDA1846, or a derivative of it.
You can get the datasheet and programming guide for the chip here:
https://github.com/phishman/RDA1846/tree/master/Datasheets
I would like to see the FCC ID, which it should have to be sold in the US. From the FCC web site can you see what parts the radio has certification for by looking at the grant.
- Logan5 and Radioguy7268
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The site below has some good info on various Chinese radios.
Your specific radio may not be there but a closely related one likely is.
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You should contact the vendor and have them check it out. Some antivirus software will flag good software as having a virus. We have an in-house written utility to load a calibration-configuration file to a custom designed microprocessor based board where I work. The IT department used Webroot and it kept erasing the utility exe file after flagging it as virus infected. Really frustrating. Had to get IT to put that file in an exclude list to keep from getting erased every time I tried to install it. 8-/
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If you want the better coax, hard-line, its going to cost you. The site below does sell 1/2" and 7/8" hard-line. It seems they are able to install the connectors too. I'm sure there are other places you can get the cable, likely at around the same cost.
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If you’re going to splice in jumpers be sure to use a constant impedance connector like type “ N”. Every connector has a small insertion loss. Usually a fraction of a db for good quality ones. The small power loss shouldn’t be very noticeable.
Also be VERY sure to weather proof the splice points if outside. It’s also a good idea to do the same at the antenna base where the cable connects.
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Canceling the Hamvention was either going to be voluntary or, I suspect, the governor of Ohio would have ordered it canceled.
One question I posed to some Ham friends is now that the event is canceled will vendors that planed originally to be there now offer discounts on line, the same ones they would have offered at Hamvention for a limited time?
Many of the general equipment vendors do a lot of business during the 2 1/2 day event. Offering the show discounts on line would help increase their business for a bit.
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Hamvention 2020 is officially canceled.
Also the Toledo Ohio swap for Sunday 15, 2020 was also canceled. Both for the same reason, Covid-19. I suspect other swaps around the country will be canceled as well sooner or later. For people looking to pick up radio’s, radio related items at the swaps this could be a poor year.
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In fact since it has a large cross-sectional area, it probably has enough bandwidth to actually be a full quarterwave electrically.
I built a 1/4 wave ground plane antenna using some stiff bus wire and a PCB style BNC connector after doing some simulations with EZNEC to check the bandwidth. The elements were just soldered on. The bandwidth I achieved was 430 to 470 MHz with an SWR of 1.6 or less. The SWR dropped to around 1.1 or so around 450 MHz. I wanted a cheap antenna to use at the Dayton Hamvention good for Ham and GMRS/FRS. I mounted it on top of a baseball cap while keeping the power at 1 watt or less. The elements were only 6 inches long and held it on top using a zip tie through the fabric. Worked far better than the rubber duck antenna with the radio hanging on my belt because the antenna was up in the clear.
I tried several of those clip-on type antennas where you use an HT antenna on them and clipped to a hat etc. I see a lot of people using them. None were worth the effort that I tried. Really poor match when I checked them.
- RCM and Elkhunter521
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If I remember correctly, there was a shakeup with the exact section of Part 95 with the rules change in 2017.
The older radios will show either a "Part 95" certification, or "Part 95A" in the grant for GMRS. The FCC reworked the rules back in 2018 when they became effective. Some of the sub parts, A - B etc., got changed around so they don't match up. The link below high lights the changes
https://www.law.cornell.edu/cfr/text/47/appendix-A_to_part_95
Look at the first entry in the list for GMRS. The rule sub part name change does not invalidate the radio's original FCC certification.
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I've used the Kenwood TK-370G-1 model. It is part 95 certified.
You can read the spec's from the site below. There are other versions of the brochure that show several UHF models:
https://www.ameradio.com/doc/Kenwood_TK-270G.pdf
You can find these at Ham Radio flea markets and on eBay. If you go this route be sure you get the EXACT model above. There are several frequency range versions designated by the "-1", "-2" etc.
Look for one that has the radio with "tested" in the description and with battery, antenna and charger. You can expect to pay $50 to $75 more nor less for one. You can find better deals for less money but you may have to fix it and or missing battery packs etc. I've gotten some very good deals trying to save money that work fine, a few that I had to do some bench repairs and a couple in the junk box.
The programming software is easy to find with some searching and use the cheap Baofeng type USB programming cable. I picked one up for $8 from R and L Electronics in Ohio.
There is a newer radio which is smaller that is also certified. Its the Kenwood TK-3170-K. I have the TK-2170-K VHF model.
The spec's on this radio are located here.
https://www.kenwood.com/usa/com/lmr/tk-2170_3170/
You can find these radios used for $50 to $100 with the same advise above for the TK-370G-1.
There are various Chinese radios made by companies like Btech. By the way this is only a 2 watt radio.
https://baofengtech.com/gmrs-v1
Most of the Chinese radios use a simple internal design, radio-on-a-chip with little output and input filtering, which doesn't perform as good as the commercial radios like the two examples above. You get what you pay for.
The advantage for some of the commercial radios are they can be also programmed for the Ham 70cm band. So if you get your Ham license, if you don't already have it, you can use one radio for both services.
If you plan on using the radio in a mobile setting consider an antenna connector adapter and external antenna at a minimum. While you can use the radio handheld with the small screw on antenna inside of the vehicle the range will be noticeably reduced.
Others here have their favorite recommendations.
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Squelch control on my Baofeng UV-B5 is a joke,
May be you can try this change:
http://www.miklor.com/COM/UV_Squelch.php
It's simple to do using Chirp. I changed a couple of my cheap Chinese radios and they seems to work better.
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At UHF, that's where GMRS operates, antenna height is the BIG issue. While more power may help if there are obstructions between the two stations using a better antenna and high enough to clear local roof tops will pay off.
To give you an idea of how far you may expect to communicate the site below will give you some idea. As you can see from the examples holding two radios by hand, 5 feet, you're lucky to get 6 miles. And that's with no obstructions! I have talked mobile to mobile and got reasonably clear communications using an external magnet mount antenna of around 5 miles at 5 watts on VHF while driving on an open highway. Past that the other station began dropping out. The other station was using a similar setup. I would expect on GMRS, UHF, about the same performance.
http://www.hamuniverse.com/lineofsightcalculator.html
I would also recommend you look into getting a better radio. You will find lots of suggestions here where most people recommend a good quality used commercial grade, Part 90, radio. Some are even FCC certified for Part 95 so there is no question about their legal use on GMRS. While many people buy the inexpensive Baofeng radios they don't have the best performance. I have several Chinese radios I play around with. For not a whole lot more money you can get a much better quality radio. I have several Kenwood TK-370G-1 radios that are FCC part 95 certified, 128 channels, narrow and wide band per memory channel, and 4 watts.
I have near me a DMR station that routinely breaks through on multiple frequencies on the cheap Chinese radios, but doesn't do it on my Kenwoods. That's the difference a good receiver makes.
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How about some how to, or tutorials, on basic topics. GMRS is mainly aimed at non technical people who simply want a good means of communications and don't have much interest in the theory or radio as a hobby. For that there is Ham Radio.
For example one wants a mobile installation. Basic info on how a mobile radio should be wired up for electrical safety, battery connections, fuses etc. What type of coax cable to use, cable connectors, antenna location and antenna mounts. Recommended mobile radios, antenna manufactures and models. Some sample photos of other people's installations for ideas to go along with the written material.
Another would be for portable radios. Recommended manufactures and models. Issues with using a portable radio in a mobile setting, speaker microphones, heat sets, battery types, battery eliminators, cable adapters from the portable radio to mobile antenna. Again some sample photos.
Repeater operation. What are they used for. What specific channels are reserved for them. Explain why there are two frequencies used and in general how this is programed in to the radio. Explain what a "PL" tone is used for and why it's typically required.
The how to's should be kept at a low simple technical level. The idea is to help somebody setup a functional radio installation without getting mired in a lot of theory. After the system is up and running there is plenty of time and people who can provide additional info for those that have the interest.
- Felixdacat, sifert and WRQL315
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Around by me there seems to be more business use of the frequencies than anything else. Mainly what I hear are the cheap "bubble pack" FRS radios. They're easy to identify due to the funny "Roger Beeps" you hear. FRS is legal for business use as far as I know.
Some local retail and manufacturing business, and typically during the day the cleaning crews at the nearby hotels use them.
I hear very little personal or family use however. When I do it's mostly after Xmas with kids and lasts for a few days until the novelty wears off and or the batteries die.
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I picked up 4 Kenwood TK-370G-1 radios off of eBay and some Ham swaps for a decent price if you look around. I've paid as little as $15 to around $40. You will need a charger and battery for most of the used radios. Most of the radios come with the antenna. Make sure you get the type 1 radio! There are several different versions covering sections of the 400 to 470 MHz range. The link below is the PDF version of the Kenwood brochure with the details for the radios and accessories.
https://5.imimg.com/data5/TT/AN/AB/SELLER-3451103/kenwood-tk-270g.pdf
Note the radio will do wide and narrow band. By removing a diode inside of the radio, covered in the service manual, then checking the option in the programming software you can enable front panel programming. It's a pain to program the radio this way but possible. I haven't mod'ed my radios since I would rather do the programming through the computer anyway.
The radio has Part 95A certification so you're legal on GMRS.
The stated range for the radio is 450 to 470 Mhz. However the radio will function down to about 440 MHz which covers the Ham simplex and repeater sections of the band that you're most likely interested in using anyway. I have one sitting on my desk here at work right now scanning the GMRS/FRS - local mall security and some Ham repeaters frequencies. In fact I was monitoring a couple of Hams talking about the snow we're getting, on the GMARC repeater on top of the Renascence Center on the river front here in Detroit. That's about 14 to 15 miles from where I'm at. As others have pointed out it is legal to use Part 90 radios on the Ham bands.
To simulate a VFO I programmed a bunch of channels with 25KHz spacing. The channel names were things like 445-200, 445-225 etc. With 128 channels I had enough for the GMRS/FRS, some Ham repeaters and 20 to 30 Ham band simplex frequencies. The ARRL band plans shows the simplex section frequencies over the 442 - 445 MHz range. The repeater sections are 442-445 and 447-450 MHz.
The software to program the radio isn't hard to find and you can use the cheap "Baofeng" type USB to serial programming cable. The software will complain if you enter a frequency outside of the stated range but will accept it if you click OK.
Good luck with passing your Tech Class license test!!!
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The other advantage is the radio can run at high power to give the best signal strength at the receiver, but TDMA means the radio is only transmitting for half the time. That means the radio should be running an average of half of the continuous transmit power, cooler operation and longer battery life.
Here pretty much hoping DMR wins due to the dual timeslot tdma, which allows for two concurrent voice calls without requiring additional frequency space... -
If you look around on the Internet you can find PDF copies of the radio user guide and service manuals. Useful to have.
Have done this for all 3 radios. And have actually read a lot
Also if you get the FCC ID off the back of the radio you can search the FCC database where you will find the test reports and the FCC grant, Part 90, 95 etc. for example, the radio is certified.
Did this as well, before ordering a used radio.
Will be interesting to see on the cable and software. Supposedly the ebay seller is the best (recommended here). Will have to keep playing but it can get frustrating when things do go as advertised.
Thank you.
Great. The service manual came in handy for me. I got two identical dead hand held radios off eBay. Swapped parts around and got one functional. Used the service manual with the diagrams to identify the failed parts and their Kenwood part numbers. Now I can order them and get the second radio fixed. You never know what you may need the documentation for at some point.
One other thing I do myself is look for the radio programming software. If I can't get it then the radio would be nothing more than a paper weight and not buy it. I wouldn't send it to a shop to have it programmed. I end up modifying the code plugs from time to time and have different ones depending on what I plan to do with the radio at the moment.
I hear too much about Motorola radios and how they handle the programming from a friend who is a radio tech for a local city transportation department. Then the licensing costs for the radio programming software from another friend and his Mototurbo digital radio. I have another friend looking at some used Motorola P25 radios on eBay to use simply as a scanner for public safety monitoring. He says its cheaper than some scanners he looked at.
I at least have had good luck getting the Kenwood stuff.
Wish you luck and hope the project works out well. On occasions I've felt a radio would work better if it bounced off the wall a few times. 8-\
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Everybody has their favorite digital mode. There are enough of them, D-Start, DMR, P25, NXDN and Yeasu's System Fusion to name a few. The fly in the ointment is which "standard" will be the majority of people end up using? Bet wrong and you end up with a radio with dwindling support. So far I haven't seen, or know about, a small hand held radio that offers more that one digital mode. Thus if you use more that one mode you end up with a separate radio just for it.
The next issue depends on the digital mode. While radio to radio contacts are basically straight forward going through a repeater is not. The problem is some digital modes may not be compatible with old analog repeaters. The old analog repeater has to be replace at the owners expense with digital compatible equipment.
One of the attractions of digital modes is the ability to link repeaters together over the Internet using various VOIP protocols. That requires access to a high speed Internet connection and a sizable infrastructure to handle the VOIP packet routing etc. like routers and gateways, Then there is the need to register to get you own unique ID so your radio can be identified within the digital network and the VOIP traffic routed to it.
Digital modes are a lot of fun and have their advantages. One just has to understand what maybe involved and plan accordingly. 8-))
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Many USB to serial cables use a chip manufactured by a company called "Prolific" inside. The chip is a popular one so it didn't take long for it to get cloned. The cloned chips were cheaper than the official one. To combat the spread of the cloned chips the company wrote code into their driver to detect the clones and refuse to work with them.
The fix to get cables using the cloned chips to work required finding an older version of the driver before the detection code was added. Your other choice is to get a cable using a real Prolific USB to serial chip or the other type using a FTDI type chip in it.
https://www.ftdichip.com/USB.html
Trying to use a cable with the cloned chip the driver appears to install OK but you get error messages when you use it with the newer drivers.
Note that some Chinese radios use the USB to Baofeng type plug, but it's a pass through cable only. The USB to serial chip is built into the radio. My D878UV is like this. Using the Baofeng type USB to serial cable results in connection fail and other error messages. I have to use the specific cable the radio shipped with so its packed away and labeled for use with that radio only.
You can buy the USB to serial cables online. The one I have was sold by R and L Electronics in Ohio. I've used it several times to test a code plug for for my TK-2170, the VHF version of your UHF TK-3170 radio. It works fine on that radio and some other ones I have. Used it on both Windows 7 and Windows 10. I didn't do anything special, just plugged it in and let Windows install the driver.
As long as its the same manufacture as the one I got, didn't switch suppliers, it should work. Mine has "Baofeng" on the fat end that plugs into the computer's USB port.
If you look around on the Internet you can find PDF copies of the radio user guide and service manuals. Useful to have.
Also if you get the FCC ID off the back of the radio you can search the FCC database where you will find the test reports and the FCC grant, Part 90, 95 etc. for example, the radio is certified.
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You can down load the Kenwood programming software for your radio from the location below:
http://www.radioscanner.ru/files/kenwood/file8416/
The download link is near the top of the page. The file you want is "kpg101d.zip"
The zip file should also have the license key you need to enable the software install. I have it running on Win 10 Home. I used this software to load a test code plug in to a used TK-2170 I picked up.
The radio uses the Baofeng type programming cables. If you buy one make sure it doesn't have a fake "Prolific" serial to USB chip in it. This site has the info about the cables:
http://www.miklor.com/COM/UV_GettingStarted.php
Sooner or later you are going to want to make changes or load the code plug up into another TK-3170. No point in paying somebody when you can do it yourself.
Just ordered a 3170 and having it programmed.
Over a hill question.
in Technical Discussion
Posted
Maybe. It would be like reflecting a light beam off a mirror. It all depends on where the two antennas are located relative to the water tower. I know this could work because years ago I was talking to my brother on the Ham 70cm band which is just below the frequencies used by GMRS. He lived several miles from the airport. When a plane was at just the right point and orientation his signal jumped from an S0/S1 to over S9 for several seconds. He was using a base antenna and all I had was a simple magnet mount about 10 miles away.
As a matter of fact back in WWII some of the early radars ran around 150 MHz, some used up to 300 MHz, and used a flat reflector with a number of dipole antennas mounted in front in such a way to get a directional beam to bounce off aircraft.
https://en.wikipedia.org/wiki/Mammut_radar
That was before Britain invented the cavity magnetron.
https://spectrum.ieee.org/tech-history/dawn-of-electronics/from-world-war-ii-radar-to-microwave-popcorn-the-cavity-magnetron-was-there
Other Hams bounce signals off the ionized trails left by meteors as they enter the Earth's atmosphere. It's called meter scatter.