Lscott

Did you look back at some prior posts in this thread? I attached a file outlining most of the points you mentioned to one of my posts. While I think digital voice, not DMR for technical reasons, can be done on GMRS but with certain tight conditions. I would suggest you read that file. I think there is a valid reason to do digital voice that would benefit users while not ruining it for everyone else if the suggestions in that file are followed.

I've fat fingered entries when building a code plug for a radio. Later testing it and noticed it wasn't working. Reloading the code plug in the programming software that's when I spotted the mistake. Who knows who got hammered when I was testing the radio out transmitting on the wrong frequency. I understand the above and still screwed up because I didn't double and triple check the entries. This is why, at least for GMRS, the radio needs to be certified, fixed frequencies, because it's easy to mess up. The more programmable it is the more potential for mistakes. When programming Part 90 radios there is a LOT of room for mistakes, even by people who know what they are doing.

They're just option shopping. Looking for someone to validate what they know is wrong so they don't feel so guilty. Same thing when your kids say everyone else is doing it, until you remind them strongly they're not or else.

It's sort of a bummer when you see your really expensive, $300-$400 plus, HT slip out of your pocket and sink to the bottom of the lake.

Save your money and buy a quality radio.

Of course there is the option to use a belt sander to reduce the height of the screw. Then use a hacksaw to cut a small slot in the top to use a flat blade screwdriver if necessary.

Oh, one other important point that very seldom gets mentioned is the quality of the coax cable. I'm NOT talking about signal loss in the cable. Coax cables are not perfect and will leak a little RF along their length. When your TX and RX cables are in close proximity signal leakage from the TX side coax can get into the repeater's receiver section AFTER the duplexer. That sort of defeats the whole purpose of using one. Smart repeater builders will use multiply shielded coax cable for this exact reason. Yeah, it might be more expensive, but it's the difference between a great performing system verses a poor one.

That's more important than you think. Remember one of the functions of a duplexer is to "isolate" the RX and TX sections since they are both using the same antenna. A receiver can only tolerate a small level of signal before the AGC, automatic gain control, in the radio reduces the internal signal level to keep it within the operating range of the electronics. The gain can be reduced to the point were a weak signal is reduced to a level where the FM detector can't work. That's desense in action. As strange as it sounds some repeater owners discovered that REDUCING transmitter power improved the receiver sensitivity! Why is that? Well consider the duplexer has a FIXED attenuation. Those cheap Chinese duplexers don't have a lot to begin with anyway. So if the transmitter power is increased the signal level feed into the receiver's front end increases too. As I mentioned if it gets too high then the AGC kicks in big time and your receiver goes deaf. That's why higher power repeaters use duplexers with 100db or more isolation. They have to use it to keep the signal level into the receiver below the point were desense occurs. Finally if the repeater is installed at a site with a bunch of other high power transmitters, which are in close proximity, all that power is trying to get into your repeater's receiver too. The duplexer has to keep all that crap out as well.

You get what you pay for. Some find out the hard way why something is so cheap.

Yeah, based on the what I do at work, it’s not hard to do. The last exciting time blew several Silicon Carbide MOSFET’s. They exploded like M-80’s. My boss, who was standing in front of the equipment said his ears were ringing for a while afterwards. I was standing on the back side a few feet away from the power assembly watching the scope and got the full effect. R and D work has its moments.

Some people are deathly afraid of getting on “a perfectly functioning aircraft.” Maybe they are really the smart ones.

That’s why many people come here.

Don’t know but it’s in the rules. https://www.ecfr.gov/current/title-47/chapter-I/subchapter-D/part-95/subpart-J/section-95.2707

This reminds me that from time to time I can see a group launching hot air balloons a few miles north of my folks house. You can hear the roar of the propane heaters. My understanding these are controlled by the FAA. Must have some type of pilot license to fly. If near an airport they are required to have an air band radio. Other than that I understand they use everything from CB, GMRS, commercial frequencies and Ham. However MURS is not allowed.

I checked and there is more info for a Japanese specific frequency expansion mod for that model, IC-706MKIIG. One guy was nice enough to check the power output on his radio after doing the US version mod. While the radio will transmit way out of band the output filters really roll off the power past a point. There are another mod for the radio to increase power output. IC-706MKIIG Freqequency Mod Power Output.pdf IC-706MKIIG Transmit Power Mod.pdf IC-706MKIIG Japanese Version Frequency Mod.pdf

Even if it didn't doing the MARS/CAP mod will fix that problem. IC-706MKIIG Frequency Expansion.pdf

Also, it's outdated but any how, the equipment is blocked from receiving cell phone frequencies too. If I'm not mistaken I think some countries have finally caned that requirement for their local certification since cell phone service is now gone digital, and encrypted I think too. People should read what is in Part 15. Just about everything electronic has the sticker on it and/or is mentioned in the manual for the device. It has some interesting statements about RF interference susceptibility. The next time the neighbor complains his yard lights flipping on evey time you key up your radio is sort of out of luck.

I've purchased stuff on eBay from some Chinese sellers, a few from Canada and once from Ireland. In all cases the seller took care of the paperwork. The most frustrating thing is when the package sits in the foreign country's export house for days. Then when it arrives here it sits in a custom clearing house for a week or two, if you're lucky, before it clears. So far I haven't had to contact customs or pay any additional import duty on purchases outside of the US. I have seen several IC-706MKIIG's for sale at swaps. Most were really beat up but a few looked OK. If you go that route DON'T buy anything EXCEPT the 706MKIIG model! The older ones had various issues including poor sensitivity. I liked mine and the limited DSP features they had worked well for the era. The disappointing thing is the power on UHF was a max of 20 watts. However I didn't find that a huge issue. I had some mobile power amps, Mirage and RF Concepts, that did 10 watts in and 100 watts out if I ever needed more power. IC-706MKIIg.pdf RF_Concepts_RFC-4-110_RFC-4-310_user.pdf D-1010-N.pdf

https://www.universal-radio.com/catalog/hamhf/ht40.html

There are some decent Chinese PCB houses out there that can manufacture the blank board for a cheap price. This is one we used at work here for making some quick prototype boards. https://www.pcbway.com/ You just need a PCB layout package that can generate standard Gerber files. A number of people have used KiCad to do their own boards. It's used for a number of public domain projects. https://www.kicad.org/ Before that the favorite was Eagle. However it has some significant limitations with the "free" version that KiCad doesn't. https://learn.sparkfun.com/tutorials/how-to-install-and-setup-eagle/all Were I work we use Altium Designer for schematic capture and PCB layout work. The projects and part libraries are cloud based. All you need is the software loaded on your PC and Internet access for the license server and the cloud server. Then you can work from anywhere as a team partner.

I’m going to hang on to it. It’s one of the smallest DC to daylight multi mode radios I’ve seen that can do 100 watts PEP on HF through 6M. It also has a remote face plate option too. It also has the optional high stability reference oscillator installed and I think the 1.8KHz SSB filter too. I’ve been thinking about just setting it up as a base radio

The commercial digital radios have better frequency stability spec’s. It’s necessary due to the quad frequency modulation, 4 discrete frequency shifts, used. If the frequency drifts too far off the radio can’t detect the particular dibit, two bits encoded per frequency shift, being sent resulting in a higher bit error rate. That’s by the way why people have to tweak their hotspot frequency. The other reason if the frequency drifts too much the RX radio will loose sync with the data stream if the transmission lasts too long, mismatch between TX and RX data rates. Then the communication fails. The same frequency reference use for TX and RX is also used for the data stream bit timing. The various digital modes standards have spec’s for the above. I wouldn’t be surprised that the cheap Chinese digital radios have a tendency to experience drop outs due to the above. Some of those radios have crummy frequency stability specs to save money on a better reference oscillator. For amateur use the dropouts aren’t critical. However for first responders it could be life threatening.

There is a difference between “occupied” bandwidth and channel spacing. People tend to get the two confused. 25KHz channel spacing - typical 16KHz bandwidth (5KHz deviation) 20KHz channel spacing - typical 14KHz bandwidth (4KHz deviation) 12.5KHz channel spacing - typical 11KHz bandwidth (2.5KHz deviation)

People get distracted yacking on their mobile radio too. Sometimes that doesn't end well either.

I ran an Icom IC706GMKII mobile for a number of years in a van. That worked rather well. When the van got destroyed in a rear end accident I got another new one. It's never been used and still in the box. It has the MARS/CAP mod I believe. The FT-817 hasn't been used in a few years. I need to program up the AT- D578UV III Plus with the Bluetooth remote speaker microphone and stick it in the new ride. Just been too lazy to do it.