berkinet

Well, first, the old FCC GMRS regulation was Part95-A, that is now Part95-E. But radios approved for Part95-A are grandfathered for Part95-E. Since the radio is also Part-15 approved, it could be used, probably requiring internal re-programming, on other services. Next, the repeater channels. That just means the radio will transmit on a frequency exactly 5mHz higher than the frequency it listens on. Since most repeaters, especially in GMRS, use some type of access control system, audio tone (not audible to you) or digital code you would have to also program or set the right tone or code for the repeater you wanted to access. And, no, there is no such thing as automatically connecting to a repeater. I guess there could be, but I have never actually seen a radio that does that. To make that work, the radio would have to try all 8 repeater input channels, and try all possible access tones/codes and be able to detect if a signal was heard coming back. (See below). Which brings us to your last question... how do you (or a smart radio) know you have "connected" with the repeater. One way is to use another radio to listen. But, that is likely to fail, especially if you are using a cheap toy radio, since its receiver will be overloaded by your transmitter. The other, more common, method is to listen for a short transmission of client carrier. This is called the hang-time and is set by the repeater owner. So, after the incoming transmission ends, the repeater will continue to transmit for a short period, maybe a second or so. But, if the repeater has no hang timer, then to only way to tell you got in is to use a second radio.

Simple question. Complex answer. Basically, any radio that is not Part95E certified is illegal to use on GMRS. But, to go further... First, you have to define "ham radio." There are lots of ham radios that do not operate in the GMRS band, so for those the answer is simple, no. Then, UHF radios that cover the GMRS band and are only Part 15 certified, or not certified at all (hams can build their own radios) and legal to use on the ham band but not on GMRS. And finally, GMRS radios will not get certification if they can be user programmed to operate on non-GMRS bands. However, from a practical standpoint, there are plenty of radios that can transmit on the GMRS band and are not Part95-E certified, and this includes most UHF "ham" radios. Although, in some cases an internal modification is necessary -- usually involving snipping a couple of jumpers or resistors. Not this modification is explicitly prohibited by the FCC rules. So, final answer. Most, if not all, ham UHF radios are capable of operating on the GMRS band, but not legally.

One note... If you do file a petition, it would probably be best to refer to: Rule Part 47 C.F.R, Part 95 Subpart E. The section numbering was changed in 2017. And, before doing that, make sure the rule is still there. It used to be in Part95-A § 95.25 Land station description. But, I do not see any such reference in the new Part95-E.

If you want to save some money, there are GMRS Certified radios available on the used market that are both a lot less expensive than the Midland products, and a lot better. Search through this forum and you will find many recommendations.

Slight correction. No legal mobile rigs on the market. There are plenty of VHF radios that will work. Some even have reasonable quality.

Come on. just look in the wikipedia, or simply google wiki qrp Here is the link to the wikipedia article section you want

Lots of answers available if you google "qrp radios"

If you seriously need to be able to call for help, take a look at: satellite phones ($200 to $1,000+ for the phone and $0.50 to $2 per minute) or Personal Locator Beacons ($200 to $300) Both of these options are reliable and designed for the type of situation you describe. Other solutions, such as that described by @marcspaz, will also work, but will be more difficult to use and will be inherently less reliable. Also, if you know the area where you are going and know that cellular phone service is available from high locations, that may be your best bet. And, as always, keep in mind: P.P.P.P.P.P.

Having the right equipment is only a part of the solution. You have to know who, how and when to call. This means prior research. There is no magic button to press to find a repeater. Prior to leaving your home, you need to know what repeaters, if any, exit, what are the access requirements (frequency, PL, etc.), are there clubs in the area, do the SAR teams use GMRS (or some other service) and if so what channel do they monitor. Also, there is no point on calling for help at 2AM if that is outside of normal operating hours and nobody knows you are in trouble. Even if you cannot find someone to call, what are the park service, forest service, BLM, state, etc frequencies so you can at least monitor if necessary. Too many people buy some radio thinking it will save them one day and then don't touch it again until they are in deep sh*t. That's when they find the batteries have corroded so badly that the internal contacts have disintegrated.

Try: https://hamfiles.co.uk

Couldn't you just remove the PA? On many GR1225s they are already blown out anyway.

Conceptually all well and fine. However, who should provide this support? It isn't, in my view, the responsibility of those already involved in the service, they got involved to meet their particular communications needs and not necessarily promote the service to others. Also, many GMRS users are quite happy with things exactly as they are and see no need or reason to encourage others to get involved. Next, it is not the FCC's job, they regulate the service and, loosely, police it. But, they have neither the funds, means or charter to promote any particular communications service. So, what we have left are the manufacturers and resellers. We certainly cannot mandate that sellers also promote and support GMRS, so it end up being a marketing option for them. Some will provide support to some degree or another, some won't. And, don't forget that any costs associated with training and support will ultimately show up in the price of the product. But, and here is the rub, a huge percentage of radios used in GMRS were either purchased used or were not specifically certified for GMRS, or both. In fact, one very common recommendation on this forum is to buy high quality used equipment instead of new gear. For me, I am willing to help where and however I can. But, I have no interest in making a proactive effort at setting up a support program to encourage and support new users, and the responsibilities that go along with that. Fortunately, there are others around here who are interested in such endeavors and perhaps they will respond here as well.

In fact, antenna systems never have gain, all they have is loss. The goal is to minimize that loss. What is called antenna gain is more properly called apparent gain. That is, the RF energy emitted from the antenna will always be less that that emitted from the transmitter or amp. The apparent gain is achieved by distributing the RF energy in something other than a 360° patten.

I strongly disagree with this sentiment. Ham radio is much more than talking over radios. It is about experimentation, design, building, fixing, operating radios and related equipment. It is about casual conversations, emergency communications, rag-chews, community and support. It is about voice, data, telemetry, video, mesh-networking and satellite and moon bounce communications. And more. Part of what makes ham radio different from CB, MURS, GMRS, and FRS is the barrier to entry. If that barrier were to be removed, ham radio would quickly devolve into a cesspool. And keep in mind, electric theory is just part of what is tested. There is also wave propagation, proper equipment operation and practices, safety, rules and regulations, and more. I have no objection to remote testing per-se, as long as the same standard of honesty and avoidance of cheating can be preserved. But, for those who see remote testing as a way to avoid a little work and study that is, in my opinion, an extremely poor idea. And honestly, if someone is a complete null, they can just memorize the answers to all 424 questions in the pool - and you only are tested on 35 of those questions and you only need to get 26 (75%) right.

And there is the problem. There is usually no clear answer as to what the best, or even at times, a good, decision is. There are far too many variables involved. It might be that one excellent solution requires someone with a service monitor to configure, or the ability (and courage) to climb a tower, or deep pockets, a machine shop, and so on. Some users here are computer gurus while others can’t even connect a cable between a radio and their computer. Etc, etc, etc. I for one, have no interest in becoming a leader in this field. On the one hand, the more I know the more I realize what I don’t know. On the other hand, I am completely uninterested is accepting responsibility for someone who blindly trusts in whatever I might opine. At best, I am willing to be a guide or counselor to someone else’s journey into self discovery. YMMV. And that is a good thing.

Note. I obviously know nothing about your furnace. But, with modern high-efficiency furnaces, the exhaust gases are not very hot. In fact, a fan is usually required to use the exhaust fumes out the vent. So, if you do have a modern furnace, heat damage to the PVC is not likely to be an issue.

Well, kt seems you have actually answered your own question. Since rooftop antennas are allowed where you live, the real issue is getting the antenna mounted on the roof. It is understandable you do not want to go climbing around up there, so why not hire someone to do it for you? Mounting the antenna is the simple part. There are all kind of antenna mounts that might work. But, there is one very simple approach you can try just to test: Mount your candidate antenna, I'd start with a simple ground plane 1/4 wave, on one end of a 10 ft piece of 1" PVC (Sched 40 is good). Then, about 3 or 4 feet up from the base of the PVC pipe, attach something to the pipe to increase its diameter so it won't fall in to a plumbing pipe vent. Then, just drop the pipe into a vent pipe. Done. Sort of like this (I think they actually drilled a hole through the mast and one side off the vent pipe and used a bolt. But, you could use a pipe-clamp and some pieces of bent coat hanger just as well)....

If you only want to connect to the repeater, I.e. unidirectional, go for a good quality, high gain, yagi, or, if you can find one, a parabolic reflector. Because you will mount the antenna in an attic, you may not need an antenna that can survive -40° and hurricane force winds. But, beware of low-priced antennas.

While marcspaz's response if mostly accurate, signal reflection, while difficult to achieve, is possible. In the days when microwave was in common use for long haul links, mountain top reflectors were fairly common (see photo below). The same principal will work on UHF, IF the antenna is properly positioned at the right angle between the two transmitter locations. It is possible, though not likely, the water tower could act as a reflector. But, the transmitters would have to be well positioned and the antennas would have to be very high gain, probably a dish, and well aimed. So, I'd say if you can borrow two nice dish antennas, give it a try. But, don't expect too much. http://www.rfcafe.com/references/electronics-world/images2/radio-mirrors-communications-electronics-world-may-1969-2.jpg

... and remember, google is your friend.

I think it was Voltaire who observed Perfect is the enemy of Good.

Conceptually, that seems reasonable. But, a) I have no idea where to place such code, and isn't that essentially vox?

UPDATE: After various failed attempts, I think I have finally found the right approach. HAMVoIP using IAX to communicate between my remote device (phone, laptop, etc.) and the HAMVoIP server (Asterisk+Allstar). I am using a direct connection between client and server, so there was no need to register my node with Allstar. For the client software, I am using Zoiper5. At the moment I am only using a test connection in sort of an intercom mode. But, it works. Next step is to modify my USB sound-card to add COS (Carrier detection) and PTT support. I had some fairly restrictive requirements which made this harder than it might have needed to be. First, I wanted to use a simple, inexpensive, single-board computer, like a Raspberry-Pi, at the remote radio site. This pretty much ruled out Zello, which only runs in Windows, or Wine on a i386 Linux board. I spend two days trying to get i386 emulation and Wine working on the Pi, and finally gave up. It just won't work on Debian/Raspian Buster. The next step was Asterisk with Allstar. I first tried using a special Raspian (RasPBX) image that came with Asterisk and FreePBX. That installed, but getting Allstar (apt_rpt) to work was pretty much hopeless. There is almost nothing on the net on how to do that. And then, finally, I found HAMVoIP, this is a special setup of Arch Linux with Asterisk+Allstar installed, and a simple config system. That worked. On the other end, I want to use my Macintosh as the client. There seem to have been a number of soft phones for OS-X around 10 years ago, but almost nothing now. And, I needed IAX support as well to talk to the HAMVoIP server. But, Zoiper5 solved that problem. Anyway, now that I have a working core system, I will take the next step to actually controlling a radio. Stay tuned...

Was the original connector also a PL–259?

I have been looking for a way to do RoIP between some arbitrary computer/phone and a GMRS radio and your project seems like it might employ the technology I am looking for. I have found your new web page (https://central625.wixsite.com/gmrs/) and see you have switched from the DingoTel to using a SignalLink and Zello. Given the low cost of the DingoTel (I found one for $12 on eBay) and the very simple needs of my project, that would seem to be the way to go. So, I would love to hear about your experiences and any advice you might have. Thanks