Lscott

I don't know about the other person but I'll update radio firmware just so I don't experience weird radio behavior at an inconvenient time. I've also had to do it on occasion when the radio programming software says some of it's features are NOT supported by the firmware revision in the radio. I get that message when trying to write a code plug to the offending radio.

I'm glad I don't have anything really pressing at the office to do today so I can spend my productive time reading this stuff.

I found this on-line and had my sister print it up for me. https://www.thingiverse.com/thing:2884874/files

Yup. Good enough!

The best way is anyway that works, doesn't damage the coax cable and doesn't let water leak into the vehicle. You can look at other installations to get some ideas. The links below are for my CX-5. https://forums.mygmrs.com/gallery/image/471-mobile-mount-with-antenna-rear-view/?context=new https://forums.mygmrs.com/gallery/image/473-close-up-of-mobile-mount/?context=new https://forums.mygmrs.com/gallery/image/474-mobile-mount-coax-routing/?context=new https://forums.mygmrs.com/gallery/image/472-mobile-antenna-install-side-view/?context=new https://forums.mygmrs.com/gallery/image/476-mobile-mount-drip-loop/?context=new Some people will tell you that RG-58 has high losses at UHF, it does, but one has to look at the total system and make a judgement call to see what works the best. In my case I ended up using two types of coax, a very thin type to get inside and a lower loss type, better than RG-58, for the rest of the run. This might be over the top but I did the analysis for several installation cases. https://forums.mygmrs.com/gallery/image/483-cx-5-antenna-system-analysisjpg/?context=new

You don’t need a fancy antenna for HF just to get on the bands. A lot of Hams just build simple horizontal dipoles.

Just think about what the INSIDE of that car must look like!

This guy has a few more.

Modern vehicles use thinner sheet metal to save weight for improved fuel economy. What might have been in the past a minor adrenaline surge when the antenna whacked a tree branch now may result in some real damage to body sheet around the antenna mount. I would think a bit more about the usual advise to "just drill the hole" and mount the antenna.

That's really the whole issue most of the time.

I did some quick screen captures of a Ham 70cm J-Pole simulation I had done some time back to show what people can expect. The radiation pattern of most interest is the azimuth one, perpendicular to the vertical element. As seen in the attached images there is some asymmetrical gain variation. The vertical, elevation, pattern is more complex and only of interest if the other station is at high angles , above or below, the perpendicular point.

They are real antennas, and they do work.

Some of the frequencies are in consecutive steps of exactly 100KHz too, so it's not even based on some standard channel spacing either. My first guess is these were "test" frequencies used to "tune" the radio's PLL circuits. I know my commercial radios have a special bank of frequencies just for that purpose. The attached photo is from my NX-1300 for example.

Ah, that's a very useful link for this! The take-a-way is there are such grandfathered GMRS business users out there.

What did you use to test the SWR? I've done some testing myself using a Rigexpert AA-1000 and didn't get great results with the 7500. The comet CA-2xSR did reasonably well. My old Comet dual band CA-2x4MB is the best one I've had, but it's not manufactured anymore. These antennas are sensitive to the type and location of the mount being used. Particularly the CA-2xSR. I currently have the CA-2x4MB on my Mazda. The fold-over spring is weak so I have the antenna permanently taped so it doesn't flip over while driving. I have a spare brand new one still in the green plastic packaging. The antenna is about 60 inches tall so I have to be EXTRA careful where I drive. https://forums.mygmrs.com/gallery/image/471-mobile-mount-with-antenna-rear-view/?context=new https://forums.mygmrs.com/gallery/image/473-close-up-of-mobile-mount/ And this is when I had it on the old Jeep. https://forums.mygmrs.com/gallery/image/259-ca-2x4mb-jeepjpg/?context=new Antenna Scan Results (CA-2x4MB VHF Jeep).pdf Antenna Scan Results (CA-2x4MB UHF Jeep).pdf Antenna Scan Results (CA-2x4MB MURS Jeep).pdf Antenna Scan Results (CA-2x4MB FRS_GMRS Jeep).pdf CA-2x4SR VHF TRI MAG MNT.pdf CA-2x4SR UHF TRI MAG MNT.pdf SG7500A VHF Scan GND Radials.pdf SG7500A UHF Scan GND Radials.pdf

I think before that question it's important to understand what it is, and isn't. There is a good write-up at this link. https://en.wikipedia.org/wiki/J-pole_antenna Most of the issues with the antenna stems from it's radiation pattern. Depending on construction and installation the antenna may present some noticeable asymmetric gain characteristics. One other important point is the antenna requires some kind of "decoupling" network for the connecting coax cable. That's typically done using some snap on ferrite cores very close to the feed point, or a coiled up section of the coax cable. If this isn't done then all sorts of weird highly asymmetric gain characteristics may occur along with high SWR readings, and even RF getting back into the radio causing distorted audio.

Likely they would complain anyway if it was just FM and some real chatty users had the other repeater keyed up for long periods.

One other course is if the repeater is located on a commercial, for rent, tower the owner of the tower may not want that repeater there if it's operating illegally. If nothing else works then likely you may need to hijack the repeater unless it's locked down by the SU's, subscriber unit, electronic serial number or other access restriction method. It might not matter if the unauthorized traffic is encrypted or not from the hijacker. If it has to run encrypted chances are it's RC4, which is compatible with Motorola's enhanced privacy and other manufacture's 40 bit encryption. I have my Kenwood NX-1300's enabled for it if I really need the feature. https://forums.mygmrs.com/gallery/image/290-nx-1300duk5/?context=new Some of the older Motorola radios have it enabled as a freebie on the HT's. https://forums.mygmrs.com/gallery/image/261-motorola-xpr6550jpeg/?context=new The idea is to use it enough to annoy the owner(s) to shut it down and move it. If the FCC isn't interested enough to do something about it they likely won't bother the people hijacking it either. While not ethical, and not legal to use DMR by the business or hijacking users, the FCC has invited the activity by their lack of rules enforcement. Your choices and options are rather limited.

Hum.... If it's operating illegally then I suppose they really couldn't complain if it got hijacked by local GMRS users. If they did the FCC might take more of an interest in it and ask a lot of questions they would rather not answer. Their other choice is to shut it down and apply for a legitimate business frequency and move it there. And SDR dongle with the decoding software, or one of those D878UV's using the digital monitor function, will show you all the color codes, slot numbers, talk groups and user ID's on the repeater. While the D878UV might not be that great of a radio the digital monitor feature is one of it's very useful one's for getting info on unknown DMR traffic.

You sure it's really operating illegally? Remember before the 2017 rule changes business could get a GMRS license. So long as the business has maintained their license, didn't let it expire, they can continue to renew it and operate LEGALLY. The only way to find out is locate the business in the FCC's database, assuming it exists, and if so is their license still active.

The resistivity of platinum is far worse than copper. At UHF frequencies the skin depth of the RF is so shallow the underlying material doesn’t really affect things. https://www.thoughtco.com/table-of-electrical-resistivity-conductivity-608499 https://en.wikipedia.org/wiki/Skin_effect

The few who had too many beers before hand likely didn’t make it to the prom I’m guessing. It’s hard to leave the house when you can’t find the door.