Lscott

Yup. The typical automotive alternator is a 3-phase device. They usually embed a 3-phase full wave rectifier on the frame on the back, 6 diodes. The output is DC with a small AC ripple at 6 times the AC frequency of one phase. The reason 3-phase is used is due to the low AC ripple after rectification. In many applications it can be used directly without filtering. The attached file goes into the electrical theory behind the above. Rectifiers.pdf

Not likely to happen in any form. https://www.arrl.org/news/fcc-turns-down-petition-to-create-a-4-meter-band-in-the-us

I was at a local Ham swap about a year ago. A local radio dealer was there. They weren't selling anything, but looking to hire a radio tech to do radio programming. They had some sample radios there as example what what one would be working on. One was a multi-mode EF Johnson - Kenwood, drool. https://www.efjohnson.com/viking-vp8000-portable-radio These are a bit outside of my budget range, even used. https://www.ebay.com/itm/156479419419?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=tvRZDxRVQp2&sssrc=2047675&ssuid=j_t98fioS_6&widget_ver=artemis&media=COPY

He would think it was a free peanut butter sample.

OK, Then he can't say he never got $hit for mail.

I looked at the group's Articles Of Incorporation in "Article III - Purpose" is to promote Amateur Radio. Nothing specifically about getting involved with GMRS. http://flscg.org/wp-content/uploads/2014/11/Articles-of-Incorporation-FSGinc.pdf I can't find whose license the GMRS repeater would be operating under. It has to be someone. Does it ID itself? All the Ham gear can belong to a club however.

Send me your mail address and I'll send you the proof in the bottle.

Don't know until it's tried.

If it's operating illegally I guess they would be very unlikely to complain if ordinary legal users hijack it for their own use. That might be enough to convince them to shut it down or get a legit business frequency and move off the GMRS channels.

https://apps.fcc.gov/els/GetAtt.html?id=234790&x=

Now this is a bit of an off beat question. Lets "assume" for the moment those repeaters are operating under a grandfathered license before the rules were changed in 2017. The owners could have been licensed for business use and their authorization might have allowed digital voice. I'm not sure if that last part was allowed under the old rules. In that case those repeaters might be operating legally.

Apparently because they can. They seem to think those repeaters are useful. It cost money to build, install and maintain/operate them. No. It's sad if they don't have a special FCC experimental license to test them. Otherwise it just shows the total lack of FCC enforcement activity.

Do you have the link for those?

........

Just one more thing. There is nothing wrong programming in non GMRS frequencies if all you want to do is “monitor” them. You just need the correct license to transmit on those. Some specifically designed GMRS radios allow out of band frequencies, but those will only work on receiving.

This is a technical question. The answer is a very qualified “maybe” and it will be specific to a particular model radio. Now for the technical dive into why it might be an issue. Some of the more expensive radios, commercial grade, use a type of electronically tuned filter on the radio’s receiver section for better selectivity. That could be a variable capacitance diode fed with a variable DC voltage output by the microprocessor. That’s how the filter is tuned when the RX frequency is changed. That component would be OK. However I have spotted what appears to be a variable inductor, again using a variable voltage/current, to adjust the filter frequency. If it has a magnetic core the inductance could be affected by a very strong magnetic field in close proximity to the radio. That would bugger up the filter frequency and thus the receiver performance. I think for the vast majority of radios people use a strong magnet isn’t an issue. It’s usually the high end commercial radios that use the tunable receiver input filters. And just about all of them typically use the variable capacitance diode in that circuit. Which are not affected.

Yeah. The line was almost 1.5 miles long from the later news reports! The photo was looking ahead. We must have been at least 6 to 8 blocks away from the arena. It was a constant flow of people walking by the entire time we were in line.

I have a buddy who wrote to the airline he was flying on. He got permission to use his Ham HT “on the plane!” Wow. I don’t know the particulars but he’s done it more than once.

Before you start moving the antenna around and swapping it out for a different model I would do a simple experiment first. Have a buddy a mile or so distance monitor your transmission. Rotate you vehicle in a circle relative to your buddy. If the quality of the transmission, and watch the signal strength, doesn't vary too much then I would just leave it alone. The only really good reason for playing with a different antenna, or it's location, would be for a really poor SWR, something over 2:1. If it's under 2:1 I wouldn't worry about it much.

Absolutely. Yes. There are other people using frequencies outside of the ones officially allocated for GMRS. That's why the FCC exists. It's their job to make sure various groups of users don't interfere with each other. This should give you an idea just how packed the radio spectrum is. The FCC has to keep track of this mess. https://www.ntia.doc.gov/files/ntia/publications/2003-allochrt.pdf

Generally not good. 1. Transistors are not great for linearity. As the amplitude increases for more power the waveform likely deviates further from the ideal sine wave shape. Any departure indicates harmonics of the base frequency are present. That's why there is a band pass filter on the output stage of the radio. The UV-5R's, particularly the older models, were known for having poor filtering on the output. If the radio meets FCC emission standards before the mod it might not afterwards. 2. All power transistors have a power dissipation rating, and thermal resistance from the transistor's junction to the heat sink. The power amp stage, transistor, in the radio is no exception. Whatever power is going into the final amplifier stage and not coming out as RF is turned into heat. It's not unusual for the efficiency to be around 50 percent. So if you get 10 watts out that means you're dumping 10 watts of heat into the radio's case. That can turn the radio in to an instant hand warmer. Maybe even too hot to hold and likely fail the output power transistor. The junction is going to be very significantly hotter than the case due to the thermal resistance. This is why I'm not a fan of tiny radios. Not enough case size to dissipate the waste heat generated during transmit. 3. In the case of number 2 above for lets say 10 watts out, 50 percent efficiency, the drain on the battery pack is 20 watts. Just how long do you think that tiny battery pack is going to last? You'll likely will need to carry around extra battery packs if you transmit at high power a lot, and don't manage to kill the radio from excessive heat before then.

Remember people put up repeaters and the cost comes out of their own pockets. A few are more civic minded and operate open repeaters. However even if the repeater is listed as "closed" many times the owner will allow you to use if once they have your info and confirmation that you will adhere to whatever rules and restrictions they place on it's operation. All you need to do is try and contact the repeater owner and ask polity for permission to use it.

IF it ever comes to be that would be the most likely result. Also the one the FCC would be more inclined to consider. If you look back through the prior posts to this thread you'll find a file attached to one of mine that goes into a bit more detail on the subject.

I think that's the way it's likely to get done. The best idea I read was using the nearly unless FRS 0.5 watt interstitial channels. Using a digital voice mode narrow enough, there are a couple that would work, it would fit between the GMRS repeater channels without causing interference, and likely can be done at higher power like 5 watts. That would give GMRS effectively 7 more useful channels without begging the FCC to allocate more scarce UHF spectrum to the service. It also would keep the existing higher power frequencies free of digital so it won't disrupt FM operations there.

The list is longer. There are more digital voice modes than the above if you count several more like NXDN, P25 and dPMR. Then there is the new one M17 too. Your waist line is going to look like Batman's utility belt with all the radios hanging on it for the various digital modes in use. The problem is finding a place to hang all the speaker mics.