Lscott

You can go to this site and experiment with putting in different heights for the antennas. http://www.hamuniverse.com/lineofsightcalculator.html The resulting range is just an "estimate" of what you're likely to get. There are a number of hard to define factors that also figure into range calculations. So take what you see with a grain of salt.

When looking at an antenna system you need to consider at least two things, coax loss and your antenna gain. At UHF coax loss can be rather high for the typical type most people tend to use. It's a trade off between cost and cable loss. Less cable loss the bigger and more extensive the coax will be. I see many going for LMR-400. The loss at 450 MHz, GMRS is 462 MHz to 468 MHz approximately so we're close enough for this example, is 2.7 db per 100 feet. So if you have a 30 to 40 foot high tower or mast on the house you could easily use 75 feet of cable from the antenna to the radio. That works out to 2.03 db of loss so only 63 percent of your transmit power makes it to the antenna! What you would like to do is pick an antenna that has enough gain to make up, so to speak, for the cable losses at a minimum. A quick note here on gain, or loss, of every 3 db represents an increase by a factor of two, or a loss by 1/2. So a gain, or loss, of 6 db would be an increase by a factor 4, or a loss by a factor of 1/4. Now we have some things to look at very carefully with antennas. You will see antenna gains shown as some gain followed by "dbi" or "dbd". If it isn't shown or mentioned it's most likely in "dbi". The two gain spec's are NOT the same. The gain spec'd as "dbi" is the gain above a theoretical and impossible to build isotropic antenna. The gain spec'd as "dbd" is the gain above a dipole, really amounts to a 1/4 wave antenna on a ground plane. Think a cheap 1/4 wave magnet mount. The gain in "dbd" for a dipole is 0 while using "dbi" it's 2.15. Remember this is exactly the same antenna! Manufactures like to use the "dbi" spec because it inflates the gain by a couple of db. If you're not paying attention a cheap antenna rated in "dbi" may appear to be as good as a more expensive one rated in "dbd". Dishonest, no, but you need to be educated about what the spec's mean to make a good purchasing decision. So for example you might see a 1/4 wave antenna spec'd as 2.1 dbi. Hummm... Now getting back to the issue with cable loss you need a real gain of at least 2 dbd just to break even due to coax losses in the above example. Ideally you would like a lot more. Of course the antenna will be larger, longer, and more expensive. As the gain increases, it's usually at a spec'd center frequency, as you depart from that ideal point the gain tends to drop off. You want one designed and tuned close to center of the band of frequencies you want to operate on. In you case around 467 MHz to 468 MHz which are the repeater input frequencies for GMRS. I'm sure some members here have good recommendations. Also search past posts on the forums here for info.

Just for fun I looked for some info on the Kenwood TK-8180 or TK-8180H radio. It looks nice. What I noticed from the Kenwood brochure there are two band splits depending on model "type". Either one will work for GMRS, however if at some point you have a desire to get your Ham license, the Tech Class is very easy, then the "type 2" is what you want. It will work over the complete Ham 70cm band AND the GMRS frequencies. https://pdfs.kenwoodproducts.com/28/TK-7180&8180MPTBrochure.pdf From some notes elsewhere on the Internet you can program the "type 1" radio down into the upper part of the Ham Band, 430 MHz to 450 MHz, but the VCO has problems locking to those frequencies. Seems like the trouble starts around 441 MHz to 442 MHz. Below those frequencies the radio likely won't work. The "type 2" radio is spec'd from 400 MHz to 470 MHz. GMRS runs from about 462 MHz to just under 468 MHz. So this model could be used for both services when programmed correctly. That saves having two radios. If it was me I would get the "type 2" since I'm dual licensed, if you can find one. I'll guess most are the "type 1" radios. Looking at a few eBay listings the sellers don't make it explicitly clear what model they are selling. Sometimes the description is just plain wrong. Look very carefully at the FCC and nameplate stickers in the photos. The model number may show something like "TK-8180H-K" which doesn't appear in the manufacture's brochure so its a bit questionable which "type" it is. My guess would be a "type 1". Oh, you do want to make sure it has an FCC ID tag. First with the FCC tag, and the certification number on it, you can check to see what parts the radio is certified for. Additionally in the grant the frequency ranges the radio is certified for along with the bandwidth and power are listed. That's serves as a check on whatever the seller claims as the spec's for the radio. Second as an example I ended up getting a hand held radio a while back that was a European model, didn't notice it had no FCC ID tag. The radio needed a hard to find version of the programming software. The radio worked fine once programmed. Further the code plug for the European model and US model I have can't be swapped. There were some feature differences that made the code plugs incompatible so now I have two separate codes plugs instead of one for the two radios.

You can do that. The two antennas need to be separated by around 5 to 10 wave lengths to keep the interaction to a minimum. That would be around 10 to 20 feet approximately. You can't connect the two antennas to the radio electrically at the same time. One the impedance match will be all wrong. Second with both antennas radiating the "pattern" will be all messed up. You will have strange max signals in some directions and very low in other directions. The Yagi is designed with the extra elements on the boom, and no others close by, positioned and cut to a specific length to generate the maximum signal strength in a direction along the length of the antenna. You can connect the two antennas, one at a time to the radio of course. The easiest way would be using a two position coax switch. You have one port that goes to the radio while the other two, one each, goes to the separate antennas. All you need to do is flip the switch to select one or the other thus no cable swapping required. If you do use a coax switch be sure to get one rated up to UHF. The cheap HF ones using the SO-239 solid filed connectors ones will cause elevated SWR. The best type are the ones using "N" type connectors. https://mfjenterprises.com/collections/switch/products/mfj-2702 You would be looking for the model "MFJ-2702N". https://store2.rlham.com/shop/catalog/advanced_search_result.php?keywords=MFJ-2702N&osCsid=mi2iq1vl96t07d35go4eai6e32&x=0&y=0&search_in_description=1 If possible all your antennas and cables should be using "N" type connectors where you can. The SO-239/PL-259 types can lead to higher SWR than expected. The "N" type will minimize this. Sometimes you can't help it if there are SO-239 types, typically on mobile or base radios. In those cases you will need to use adapters. Some will claim that adapters have high losses, power. Good quality ones don't. One or two in line and you'll hardly even notice the difference. If you mount everything in your attic you really don't have to worry about water ingress into the cables or adapters. A word about attic mount antennas. If you have foil back isolation and or asphalt shingles this could cause high SWR in the first case, metal in close proximity to the antenna, and lower radiated power and received signal strength in the second from absorption by the asphalt. A Yagi used for FM needs to be mounted so all the elements are vertical NOT horizontal. Almost all communication on the GMRS band uses antennas vertically mounted. If you mount the antenna the wrong way the signal at the receiving station can be significantly reduced. Also your received will be much lower as well. To mount the Yagi vertically you should use a nonmetallic mast. A metal one could seriously degrade any benefit you get from using a Yagi.

Generally I would go with good used commercial UHF radios for base, mobile and handheld use. Some maybe even Part 95 certified. From various comments even people using Part 90 radios have had no issues with the FCC when using them. In fact they are used for building GMRS repeater systems. Look over past posts for lots of good recommendations and reviews of what's out there. Personally I like Kenwood. The commercial UHF radios have far better receivers than the Chinese radios, and their derivatives, and that can make or break a communication setup. You may save some money in the short run but end up disappointed later with the performance. It pays to start off with good equipment. While a repeater may sound like a good idea I would get a basic system operational first to evaluate if you even need one. Building a repeater takes a bit of expertise and some expense to do it right. If it proves you really need one you can always work on procuring the necessary equipment later. As far as antennas again look through past posts. Lots of opinions and some good recommendations can be found there. Besides the antenna you also have to consider the cable run between the base radio, or repeater if that's what you need, and the antenna. A poor choice in cable will result in high losses, negating the higher power output from a base radio and lower signals levels on receive. Low loss coax cable isn't cheap. Also make sure you use "N" type connectors everywhere you can. The common PL-239/SO-259 type will cause you problems with higher reflected power, high SWR. In some cases you just can't get away from them like on the mobile radios so you just have to live with it. You'll also need to ensure the antenna is well grounded and use a high quality in-line lighting arrester to protect your equipment and house. A few people even disconnect the coax from the radio, placing the end in a glass jar, during bad thunder storms. Paranoid, yes, but its additional protection. The antenna should be a type that has a "DC ground". This means the antenna can be grounded for DC current. With a base antenna up in the air they can accumulate a substantial static electric charge just from wind. A few people have been knocked for a loop when they touched the end of the coax when it wasn't connected to anything on a clear day. You also don't need the static charge doing bad things to your radio either.

I have a buddy who got one like this, not your exact model because his had a PL-259 type base, to use on his Jeep. I ran an SWR scan test on it using a RigExpert AA-1000 antenna analyzer. https://pncengineering.com/rigexpert/328-aa-1000.html Looking back over the test results I got the following SWR measurements: VHF 144 MHz - 1.52:1 145.5 MHz - 2.10:1 UHF 430 MHz to 456 MHz - under 1.6:1 462 MHz - 2.3: 467 MHz - 1.8:1 The last two cover the GMRS band. As you can see the measurements are not that good. On VHF, well unless you're operating on a fixed frequency in the range above, forget it. The antenna he got was most likely some Chinese design he purchased from an Amazon source. So from a quality point who knows. Yours might work better. I would most definitely test it before running any significant power out of a connected radio.

The mess on the Ham Bands is due to Hams trying out every digital mode out there. At least there is enough spectrum to allow that. If somebody is running digital either switch to a different repeater or spin the VFO knob to find an open frequency for analog. On GMRS there is a VERY LIMITED number of channels available. Once you start mixing in analog and digital is where you'll see the real mess. People with an investment in analog radios are not going to trash them so the mix with be with us for a long time if digital is allowed. The solution is to change the rules to allow only digital on one or more channels where the balance is analog only. Adding in another one or more channels reserved for digital only wouldn't require existing users to reprogram their radios. However I doubt the FCC is going to add additional channels unless there is a huge demand and or the manufactures lobby for it. That's how we ended up with the FRS mess. Don't forget for digital you will likely need at least one channel for digital simplex and another "frequency pair" for digital repeaters. Without additional channels that has to come out of the exiting 22 simplex ones now, which 8 also being used as repeater output frequencies, and the 8 exclusive repeater input frequencies. That's a big bite out of the current spectrum. If a digital mode were to be selected DMR makes sense. Even one NB analog channel converted to digital can handle two digital voice channels. That would improve the spectrum efficiency so you may not need that many digital only channels. Allowing linked GMRS DMR repeaters? That's a whole other can of worms. You need a registration authority, a network of high level routers etc. Just look at the Ham Bands to see the work required to setup and maintain a digital network. With GMRS being primarily for personal and family communications you need to find some very dedicated people to do the work, know what they are doing and have the money. As it is now there don't seem to be even that many linked analog systems on GMRS. Now you want to add in digital? Last thing, somebody will get the "bright idea" to link a GMRS DMR repeater into other services or outside of the US. Remember GMRS is prohibited from communicating with stations outside of the US or other services. People have setup illegal cross-band analog repeaters between GMRS/FRS and typically MURS so the idea that won't happen with digital isn't realistic. If digital is ever allowed the FCC could simply prohibit any linking of digital repeaters to discourage people from doing it.

From what I can see checking the Canadian frequency allocation at least two of the excluded frequencies are not allocated to the Canadian FRS/GMRS service. Those would be for the US 467 MHz repeater inputs. Excluding those would make some sense. So I would assume that still applies. The other two are listed for the Canadian FRS/GMRS service. It would appear those two could be used and allowed by the FCC. I agree that something likely is messed up with the license restrictions. As you pointed out it might have gotten missed. It won't be the first time the FCC messed things up.

My license was issued on 8-3-2018 and it still has the frequency exclusions listed at the bottom. Until the FCC changes the rules we are stuck with it. Have a look here. These are the Canadian FRS/GMRS rules that I found. https://www.ic.gc.ca/eic/site/smt-gst.nsf/eng/sf01320.html You need to scroll down to where it shows "Annex E" then click on the link to expand it. Then look for section "E.1.2 Channel Frequencies". You'll notice the allowed frequencies are not the same as for the US GMRS service. What's missing are the repeater 467 MHz input frequencies. Specifically 467.650 MHz and 467.700 MHz. The 462.650 MHz and 462.700 MHz are listed however. Now look at section "E.1.5 Transmitter output power and effective radiated power (e.r.p)". What you notice are the bandwidth and power are the same as the rules for the US FRS only radios but they also apply to the Canadian GMRS radios. So for all practical purposes the Canadian "FRS/GMRS" radios are the same as the new rules for the US "FRS" only radios. On a side note. The US has five frequencies listed for the license free VHF MURS service. Canada was looking at doing the same thing back around 2014 I think. It never happened. If you have any MURS radios don't use them there.

Oops that should have been 16 mile road, not 15 mile. The road name I got right at least.

Seems you're in the same metro area, around Detroit, as me. This a bit off topic but if you're within about 20 miles of interstate 75 and 15 mile road, Big Beaver, in the city of Troy is where a nice repeater is located you can use for GMRS. It's a closed machine but all you need to do is email the owner and ask permission. Several friends have done the same and he doesn't have a problem letting the public use it. He just wants to know who is accessing it. I think all you need to do is ask for permission and give your FCC assigned call sign. The listing is in the "myGMRS.com" site's repeater database. Look for the state of Michigan. The repeater is listed as Troy575. There are two shown. You want the second one in the list. The first one is an older listing for the same machine but the data and contact info is wrong or out of date. That's the topic of another thread elsewhere, bad, out of date repeater info in the database. This should be the correct link below. https://mygmrs.com/view?id=3562 You will need to register on this site and login to get the input, output frequencies and access tones or ask for it in your email from the owner. There is another one listed in the Westland/Canton area which is an open repeater, no permission required, but the coverage map shows a smaller area. I haven't accessed it yet from my location and I don't know if it's currently in operation. I think the owner is still in the process of setting things up and this is a fairly new listing. This is the link: https://mygmrs.com/view?id=3808 The owner of the Troy575 machine sent an email out, to the people requesting access permission, about a week or so back asking if there was any interest in setting up an informal "net". The idea was the various users can get together to chit-chat for a while. The repeater doesn't see much use and I monitor it frequently along with several Ham UHF machines near me. I haven't heard anything further about the net from the owner. Congratulations on getting licensed!

Yea, some say you're not a real radio guy until you drill holes in your ride to mount the antennas. Can't do that with company stuff, rentals or lease.

Makes you wonder how their customer service is like if you have a problem.

Unless you're really desperate to get rid of them my offer would likely be too low for you. I'm really looking for super bargains when buying radio stuff.

Don't worry about it. Switch to another repeater or use the VFO to find somebody else to talk to. The crappy attitude was at its height around the time the FCC dropped the CW requirement for all license classes. There were endless debates, some still going on, about the merits of dropping or not dropping the CW requirements. Some of the old timers hated that change, and likely will never get over it. I guess they though of it as a some kind of exclusive club. If that was what they valued most then they got into Ham radio for the wrong reason. Go out, make contacts and have fun.

Does it have the ID function available in the controller? Without that it really isn’t useful outside a single license use operation.

Most antennas I see are gain type and the height gets up there. The link below has a selection of 1/4 wave types. https://www.pctel.com/wp-content/uploads/2018/11/Product-Datasheet-25.pdf (catalog page) https://www.pctel.com/ (Main site) The above is a suggestion for reference. The model PCTCN4347 I think will work and about 6.2 inches tall. This is pre-tuned for 430 MHz to 470 MHz. You will also have to get the magnet mount which is an extra cost. It looks like they require an NMO type mount. I don't known what the cost is for the antenna and mount. You can contact the company. This company seems to carry the antenna series but I don't see anything mentioned about selling a pre-tuned one. I think you have to cut the element to length for the frequency you need. The manufacture may have that data or the antenna comes with a chart you reference for the recommended length. Again I would contact them for details. https://www.theantennafarm.com/catalog/pctel-maxrad-pctcnmft-5913

One thing you need to be sure of is the TX frequency is not harmonically related to the RX frequency. For example if the TX frequency is 146 MHz you don't want your RX frequency anywhere close to 438 MHz for example, which is the third harmonic. The tiny amount of harmonics generated, all radios have some, could be enough to break the squelch on the RX and cause interference. This is a common error most people make setting up a cross band repeater. You could have some other unrelated problem but this issue should be addressed none the less.

A 1/4 wave whip maybe your best bet for the moment, and not just for technical reasons. It seems you want to put the antenna on the roof of a pickup truck at some point. A 1/4 wave antenna will only be around 6 to 8 inches tall. You'll soon discover that's an asset when you find it necessary to go through a "drive through" window at a bank, fast food joint, parking garage all with a low overhead limit. The truck, or most SUV's, roof is already taller that a typical car decreasing your head room. A higher gain antenna is going to be taller. I have a high gain dual band on my Jeep that's about 60 inches tall. I have to think all the time about where I need to drive to avoid damaging it. Sometimes I have to get out and unscrew the thing from the roof rack mount. One other point a 1/4 whip, when tuned right, has a very wide bandwidth. I've built a few for inside and temporary use out of a male BNC PCB socket and stiff bus wire. I can get the SWR down to under 1.5:1 from 430 MHz to 470 MHz with 3 feet of small gauge coax measured using an AA-1000 antenna analyzer. That covers all of the usable Ham 70 cm band and all of the FRS/GMRS channels. You'll find that advantageous when you get your Ham license.

Just a note about antenna restricted areas. I read some time back a Ham had a problem with is HOA with wanting to put up some antennas. Well he researched the bylaws and came up with the following solution. He installed a small crank up tower on a trailer and parked it in his back yard where you couldn't see the trailer part. Cranked it up when he operated. Since the bylaws didn't prohibit antennas on vehicles, which you could reasonably argue applies to trailers. He moved the trailer every once in a while so they couldn't claim it was permanently parked in one spot either to qualify as a vehicle. The HOA couldn't say much. Another Ham did something similar by installing a telescoping mast on his truck parked in the driveway. He then snaked the coax across the ground to the truck from the house. The HOA wasn't very happy but he wasn't breaking any of the rules either. 8-))

I you down load the TK-360G/TK-370G Service Manual from the link in my last post then look at page 11. That's section 8, Self Programming Mode. There it shows you where D17 is located, which has to be removed, and also the front panel/self programming mode enabled in the software has to be selected. The sequence for entering the various parameters through the front panel is covered in the service manual section. As you can see from the tables and flow charts it's really a pain. I've never modified my radios since it's far easier to use the programming software. 8-/ The radios don't have a real "VFO" so any programming done has to be to a particular memory slot. So field programming is not that useful IMHO. Oh, to "simulate" a VFO I did program one memory bank in the 370G with a sequence of frequencies every 25KHz. The memory names were like 440-000, 440-025, 440-050 etc. for example. So skipping to the simplex bank and adjusting the big top side channel selector nob simulates the operation of an adjustable VFO with the frequency step size set at 25KHz. That covered most, depending on how many memory channels you have left, of the simplex section of the band outlined in the ARRL recommended layout for 70cm. Better than nothing I guess. Another good radio that is still currently manufactured by Kenwood is the TK-3170. Also Part 95 certified. If you find them used they tend to sell for more than the TK-370G's do. I've only seen one with a full keypad however. Most just have the top row of function keys. https://5.imimg.com/data5/LH/CE/FE/SELLER-3451103/kenwood-tk-3170-uhf-two-way-radio.pdf You'll notice the band split is spec'd at 440 MHz to 480 MHz for the type one. No question this will cover part of the Ham 70cm band. If you want a mono band radio for VHF look at the TK-2170's band spilt in the same brochure. It will cover the complete 2 meter band up past where the NOAA weather channels are around 162 MHz. These radios are hard to find and people want way too much for them. I think you can guess why. I have both types and they are good radios. 73 KC8LDO WRBZ532

I have both types. I agree the radios are great, particularly the TK-370G-1's. They are also both Part 95 certified too. I use the official Kenwood software to program the 370G's and Chrip for the 370's. I had issues with Chirp and the 370G's. When trying to organize the frequencies using the "Memory Group" feature Chirp would fail to add frequencies in, some would get deleted and other odd things. It seems to work fine for the 370's which is good because the official software for that model is DOS based. The down side is you don't have access to all of the features in the radio. For the 370G you want the "KPG-56Dv422.zip" file. This works with Windows 10 by the way. You will need some kind of serial number to install the software which should be included in a text file in the download. This software gives you full access to ALL of the radio's features. http://rsws.zapto.org/RadioSoftware/Kenwood/Kenwood.htm As far as I know both models are in fact field programmable. However two things must be done to enable that. First the option must be enabled in the programing software and second a small component must be removed from one of the circuit boards inside. Enabling the feature in software is not sufficient. Also if the radios don't have a full keyboard self programming isn't going to do you much good. http://www.repeater-builder.com/kenwood/pdfs/tk-360g-tk-370g-svc-man.pdf http://yo3hjv.blogspot.com/2010/05/field-programming-for-kenwood-tk-370.html http://rsws.zapto.org/radiosoftware/kenwood/Field Programming the Kenwood Tk-270 370.pdf https://www.manasrekha.com/pdf/TK-270G-370G.pdf https://www.manualslib.com/products/Kenwood-Tk-370g-3058542.html While the radio spec's don't show it you can program in frequencies outside of the official band spread for both models. I have the 370G programed for GMRS wide band and narrow band plus a number of Ham UHF repeaters and some simplex frequencies. The Ham repeater section of the band and simplex section are mostly between 440 MHz to 450 MHz which the radio will TX and RX on it seems OK. The official Kenwood programming software will throw up a warning about those frequencies being out of range but you can click OK and the software will accept it. Its just a bit annoying when building the code plug.

The results look pretty good for a quick test. Some people say they get better range when they add a “rat tail”, “tiger tail” or more correctly a counterpoise to the radio. https://hackaday.com/2014/02/08/improve-your-ht-ham-radio-by-adding-a-counterpoise-antenna-wire/

I hope at some point these guys will get to the beta phase of development then it might be stable enough to do something with it. I've been watching this project for a while. It's an open source clone of MS Windows. https://reactos.org

I'm not sure about the software he has but I've run across some that still use 16 bit installers. Those don't work on Win 10 at all. Setting the compatibility mode is useless. The solution he used is a good one, running Win XP in a VM. https://www.virtualbox.org You can get a Win XP VM in Win 10 but you have to pay for the much more expensive Pro version to get the VM subsystem, "Hyper-V". https://www.download3k.com/articles/How-to-add-an-XP-Mode-Virtual-Machine-to-Windows-10-or-8-using-Hyper-V-00770 VirtualBox does about the same thing for zero cost. However you're left with finding a copy of the Win XP on your own. Virtual Box is a good opensource VM package. I've even run Windows 3.1 in it. Even managed to find a copy of IBM's OS2 Warp 4 and got that to install and run too. If IBM and Microsoft had their act together we would all be running OS2 instead of Windows. https://en.wikipedia.org/wiki/OS/2 Remember "Windows is a pane in the glass".