Lscott

The antenna needs a ground plane, or the equivalent, to work. I've tested a lot of hand held radio antennas with and without a ground plane. Just about everyone resulted in a crummy match except the 1/2 wave types. I had thought that a good ground plane would yield a good match, nope. Some tested better when stuck on the back of my hand, see sample photo, verses a large sheet metal ground plane. I'm guessing the antennas are specifically tuned to use the small ground represented by the metal body of the radio and coupled into the users arm while hand held. I wouldn't depend on the coax shield either. You get RF on it which feeds back into the radio resulting in "undesirable" operation. For the NA-771G you can try a tiger tail. I'll suspect as the tail moves around the match will change a lot too. If you have a backpack with a good sized metal frame that might work as good if not better than the tiger tail. 483039407_AmateurRadioPedestrianMobileHandbook.pdf

For fiber glass tops a good choice is a 1/2 wave antenna. They typically don't really need a ground plane so you have much more flexibility in mounting locations.

The design of CHIRP only gives you access to a subset of the features in many radios. If you want to use all of the functionality of your radio I advise you use the manufacturers software.

I don’t own any “purposely manufactured” GMRS radios. I use new or used commercial gear, many with Part 95 certification, programmed for GMRS. Generally the commercial gear works better, has more features and more flexibility. A few of the hand held radios I own are 4/5 watts with up to 512 channels, plenty for any uses I need.

The various digital voice modes use variations of FDMA modulation. In the case of DMR it’s also done in 30 milliseconds bursts per time slot. Since the frequency shift is done directly on the carrier, it’s not audio frequency shift keyed, and the bit stream there will likely be very low and high frequency components. The radio’s Discriminator will try to decode it as audio. The high and low frequencies will get filtered out by the audio circuits so when applied to the transmitter there will be high data loss, missing data bits. The loss likely will be too high for the RX radio to perform adequate error recovery so the communications fails.

This is what I read: If you are a licensed amateur in the Philippines, you can use these frequencies legally. 144–146 MHz (all classes) 420–450 MHz (Class A,B, C) ———————————————— In many countries Hams are limited to 430 to 440. I think some of the older Ham gear in the US had the same limitation. In fact checking some of the recent Chinese radios, where you select the “mode”, you’ll see different ranges for VHF and UHF.

You sure about that? To date there are no digital voice modes authorized by the FCC for GMRS. If it’s being done by the city are they operating under a grand fathered license? Checking the FCC database should show what frequencies are licensed and emission mode. The later will be the clue if they have authority to run digital voice.

Except towards the fringe of the coverage area. That's the attraction, better audio when the simple FM signal starts going into the crapper.

I my location there is a general "Net" meeting once a month on the GMRS repeater. It's run similar to what you hear on Ham repeaters simply because the format works. Lately there is a "Prepper's Net" on Tuesday nights each week. I think the current roster has about 177 registered users for the repeater. The repeater is owned by the City of Troy and was their backup machine for the fire department in the beginning.

That likely has more to do with diffraction effects. I've experienced that at audio frequency where I work. When somebody was running a 1/2 hour short circuit test, on an inverter setup for 10KHz, just walking a dozen feet one way or the other the high pitch screaming fades out noticeably, and there was nothing in the way.

Bad advise. The pipe rail material is too soft, doesn't have the mechanical strength to resist anything other than a VERY light wind load without bending, even for modest lengths.

Thanks. That link worked. I down loaded the manual and added it to my on-line electronic library on the computer.

Link doesn't seem to work for me.

There are similar types of plans. Trouble is there are too many of them. https://radiofreeq.wordpress.com/2013/07/15/3-3-3-radio-plan-for-shtf-communications/ https://ovatvc.org/2022/03/the-wilderness-protocol/ https://tcares.net/the-wilderness-protocol/

Sounds counter intuitive. Something I should look into.

The old sat disk mount is most likely in a lump of cement so no real connection to the earth. He would need a good ground rod at the base with a heavy gauge copper wire between it and the antenna base. I don't see the need for a ground radial system.

One of those fiber glass masts might work. Getting one with a larger diameter, which may not need any guy wires, and keeping the height high enough to do the job is worth looking at. You can contact the manufacture and see what they recommend.

You might need bigger U-Bolts. That pipe looks rather larger in diameter. I would consider getting a length of antenna mast to get the antenna up higher. Getting it up higher than the local home roof peaks would be the minimum I would recommend. Don't be tempered to use stuff like water pipe, fence pipe etc. All of those are soft and will bend easily in a modest wind. Antenna mast is manufactured using higher strength material. https://static.dxengineering.com/global/images/technicalarticles/dxe-st300cm-22.pdf https://www.hamuniverse.com/antennamastguying.html https://mgs4u.com/fiberglass-push-up-masts/

Looks like you’ll have no problem clamping a good length of mast to that pipe.

Do you have a photo of it you can post?

The wall thickness doesn't matter for RF performance. It is a factor for the mechanical strength. However the larger diameter of the conductor will make a noticeable difference in the bandwidth of the antenna. The larger diameter will result is a low SWR over a wider range of frequencies.

The problem with high gain antennas is the height. You have to constantly remember it’s up there. No garage parking, fast food and bank drive throughs and low hanging tree branches to name a few of the hazards. The first time you forget is when it gets ripped off the roof. If you’re lucky it’s just the antenna/mount that gets wrecked.

I think linked repeaters serve a purpose, however I just wished the rules were more clear cut. Setting up a system is risky since the FCC could pull the plug on the idea resulting in a waste of time, money and hardware. So long as people understand that they can make their choices accordingly. Then there is the digital voice mode issue. More posters are commenting about hearing increasing digital voice activity in some areas. The FCC will have to do something sooner or later. Either get serious and enforce the rules, or change them to legalize the practice. Personally I’m in favor of the idea if done in a manner that’s not disruptive to the majority of existing FM only operators. I started a thread a while back about possible rules changes. It got derailed by a discussion of an issue that had little to do with the topic. In any case I did attach a paper outlining an idea to one of my posts.

That would be great. You really need a COR contact if you want to build a repeater using a radio. Some have sort of done that on a custom basis by using a simple circuit patched into RX LED circuit.

Some other view points on the matter. There are some specific caveats pertaining to data encryption. It's not a blanket permission either. https://www.rrmediagroup.com/News/NewsDetails/NewsID/17804 https://www.qsl.net/k/kb9mwr/projects/wireless/Data Encryption is Legal.pdf