Lscott

I would think very carefully about doing this. Besides going to aluminum to save weight the sheet metal gauge is likely reduced too. With an NMO mount there isn't that much metal area to resist the bending moment of the antenna. I've read more than one account where the roof was damaged, roof area bent or the mount just plain ripped out, when the antenna hit a small tree branch or driving at highway speeds. At least with a magnet mount it will just knock it off the roof most likely with little to no damaged being caused. If you do go with a NMO mount research first for a good way to reinforce the roof are around it before doing the install. Many mobile antennas are fairly stiff and don't give much if they are flexed so an antenna strike goes straight to the mount. Some antennas are available with a spring located at the antenna base. These will reduce the chance your vehicle roof and or antenna will suffer damage from a low tree branch strike or other low obstruction contact.

You want to look at something like the following: https://transition.fcc.gov/bureaus/oet/info/documents/bulletins/oet65/oet65b.pdf https://www.osha.gov/SLTC/radiofrequencyradiation/evaluation.html

That might be a good thing, no fires and little criminal activity. 8-) I hear some interesting stuff every once in a while by monitoring the local mall security frequencies. A lot of them are still on analog narrow band FM with their UHF radios. Some have switched to DMR, P25 or NXDN. It gets better around XMAS. I've heard about hookers by the mall doors drumming up business, chasing shoplifters through the parking lot, fights in the food court you get the idea. A couple of times I heard them kick the local TV news crews off the property if they didn't get prior permission. Once the parking lot patrol spotted a couple doing their thing in a car. The mall security supervisor told the mobile security dude don't bother them.

There are various web sites where you can look up this kind of info. One example is below. https://www.radioreference.com/apps/db/ In the programing mode, I assume one could find the frequencies of government channels like the park service or local police channels. Some may be listen only. Does anyone know how to find out what frequencies are used?

If the repeater is listed as "open" that would be true. If it isn't then you do need to ask first. Ignoring the argument about the repeater being private property is the one about identification. As along as the owner, and their immediate family, use the repeater it will be properly identified every time a family member uses it and ID's per the FCC rules since everyone is using the same call sign. That may not be the case when others are allowed to use it. For instant if a simple controller is used with no builtin ID function. There are a number of cheap repeater controllers out there that do not have an ID function. A lot of these get sold where everything from a couple of handheld radios to high power mobile radios are used with them along with cheap Chinese duplexers to build a repeater. https://radio-tone.com/product/rt-crc1-repater-controller-full-duplex/ https://www.surecom.com.hk/surecom01_product.php?id=114919 If the repeater owner allows users outside of his immediate family to use the machine it needs to ID with the owner's call sign. This by the way is the same problem with Ham full duplex cross band repeaters, getting the machine's transmitter to ID when relaying the signal back to the owner's radio. So if you don't ask first you have no idea how the repeater is setup. The owner may not want people to use it since it lacks the ability to self identify and if the owner allows others to use it they could end up with a problem with the FCC.

Using an old computer switching power supply likely won't work. First they are electrically noisy and will kill your receiver sensitivity. Second the designs use one of the low voltage outputs for regulation, 5 VDC - 3.3 VDC - ???, while the rest float around a bit. If the regulated output isn't loaded down enough it may not even start. We use a number of off the shelf switching power supplies where I work for some industrial controls. I have one right now in my office loaded down with a fat power resistor on the 5 VDC rail just to get the thing to turn on so I can use the other outputs for testing a project. About using it to charge a lead acid battery may not work well, if at all, since the high voltage outputs are a "nominal" 12 VDC on the computer power supply. You need around 13.5 VDC to 13.8 VDC to charge a "12 VDC" lead acid battery. Then there is the different charge stages to keep from damaging the battery, bulk - absorption - float, which is normally done by a smart charger. There is a bit of a difference between liquid filled, gell cell and AGM lead acid types on the charge and float voltages to content with.

Nope. You’re never too old to try. It’s only complex if you really want to drill down into the technical details. Fortunately you don’t really need to in order to get licensed. The whole idea with licensing is to understand the rules, avoid causing interference and not hurt yourself or someone else. The learning comes at your own pace once you’re licensed and where your interests take you.

I was doing some searching for anybody that may have tried the idea and stumbled across this gem. Got me a bit interested in the idea. https://az276019.vo.msecnd.net/valmontstaging/vsna-resources/microflect-passive-repeater-catalog.pdf?sfvrsn=6 While not exactly a water tower the idea is along the same direction, a passive reflector repeater.

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.

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. https://www.ebay.com/itm/Kenwood-TK-3170-UHF-HH-Radio-DTMF-Keypad-Battery-Charger-Free-Programming/153889511911?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649 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-)

Yup. I have some friends that have either the Ham Tech or GMRS license and are looking at getting the other one. For the $70 and good or 10 years why not get the GMRS license IMHO.

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.

I scrolled down the page at the link above and the spec's given were: ------------------------------------------------------------------------------------------- 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 ---------------------------------------------------------------------------------------------------------------------------------------------------- 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.

The site below has some good info on various Chinese radios. http://www.miklor.com/ Your specific radio may not be there but a closely related one likely is.

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-/

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. http://www.davisrf.com/heliax.php

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.

Some items they do. I have actually contacted vendors in the past if they are going to offer a discount on an item I wanted. It might not be much, around 5 percent, but on a $500 radio for example it adds up. Plus you may save the shipping costs too.

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.

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.

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.

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.

I've used the Kenwood TK-370G-1 model. It is part 95 certified. https://fccid.io/ALH29473110 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. http://www.randl.com/shop/catalog/product_info.php?products_id=71426&osCsid=b0beekg0h744pcdf1jhbq8ebo2 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. https://fccid.io/ALH34713110/ 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.

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.

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.