KevinJ

Just remember….. the tower will almost AWLAYS have way better coverage then you can transmit into it.  So just because you are well within the circle and can hear the repeater perfectly fine does not mean it can hear you.  Nothing replaces actual radio checks in the ground from different places.   

You always here that UHF is line of sight.  If you can't see it, you can't talk to it.  My experience has been otherwise.  Granted if you have a 1000' mountain between you and the person you want to talk to it ain't happening simplex.  I just upgraded my repeaters power.  Same antenna at about 40' off the ground and surrounded by trees 270º around me.  Today I took a ride with my 20 watt Wouxun KG-XS20G+ with an MXTA26 Midland magnetically mounted, basically straight north.  I had my phone at my repeater as I called out to it recording with a voice activated app.  My truck was moving on all of these, probably around 40mph +/-
 
3.85 miles out with Line Of Site


Full Quieting Area.wav Going farther out, on a hill but behind one also  6.54 mi


Top of hill past Randal Dr.wav And then down that hill 75 feet below the other peak and still in the shadow of the hill   7.0 mi


Hickory St.wav Getting worse but still very readable  7.2 mi


Entering Agawam.wav Unreadable at Shoemaker Ln  7.9 mi


Shoemaker Ln.wav Sounded much worse on my end and I figured I was done but really it wasn't that bad  9.25 mi


McDonalds.wav  
Cute little experiment.  Shows line of sight doesn't mean you can't be heard.  Obviously you lose quieting and sometime you lose readability.  It was nice to find out I could insert audio.
 
 
 
 

It is my understanding most of them are serviceable. When the inserts start to burn out, you will see a reduction in your Farz. You can stay on top of this by periodically by  checking your coverage footprint. I don't know if the VSWRs would get worst or not because it is mostly a desense issue rather than RF being reflected back.

A large VHF set of tubular aluminum can's might change tune based on how they were sitting when tuned.  Anything built from extruded aluminum is going to have enough rigidity to be mounted in any configuration without it being an issue.
A small 'flatpack' duplexer like the EMR pictured is probably the LEAST prone to it flexing from it's orientation.  But mounting them on an uneven surface MAY cause issues.  But, on the flip side of that, a flatpack duplexer is a NOTCH only type of filter and the bandwidth of the notch is wide enough that even if they were lightly tweaked, I seriously doubt that you would be able to see a difference on a tracking generator or a VNA. 
 

Reduce the power going into the duplexer as the losses caused by the duplexer is turned to heat. The loss in dB remains the same but the amount of heat created is reduced.

You can link them directly with the 'mygmrs' image but you will need to edit some files to do it. 
The way the system worked when it was up had a server that housed the database for the different nodes.  That is the server that made it 'work' without the need to manually edit the files.
The specific file is rpt_extnodes_gmrs. which was in the path /var/lib/asterisk. 
Here is the format of the file.
21700=radio@66.158.37.66/21700,66.158.37.66
21701=radio@67.52.45.142/21701,67.52.45.142
21702=radio@66.158.37.66/21702,66.158.37.66
21703=radio@67.52.45.142/21703,67.52.45.142
The 217XX is the node number, then the public IP address of the node / UDP port number used. Then the IP address again.
You will need to edit that file, or create another file with that information in it so there is a whitelist and connection path to the other node you are trying to link to.  BOTH nodes will need entered into that file on both Raspberry Pi's for it to function and connect.
The reason I bring up creating another file is there is a script that runs every 10 minutes that updates that file.  I don't know if it will blank the file if the server isn't available.  I don't THINK it will but that hasn't been tested.
For more specific instructions on getting it working, you should look up information on AllStar Link.  It's the ham radio software used for lining repeaters that the system was based on.  It's been around for a long time and is well documented on the web.
There is also a different system called GMRSlive that has an image that directly allows you to configure it with this information and has a better interface for getting this going.  The myGMRS image is really meant to be automatic and as such requires a strong understanding of Asterisk and the rpt app within Asterisk to modify it to work correctly. 
Disclaimer:  What I posted here is for academic use.  Choosing to implement a system using this information on a radio service it's not allowed to be used on is YOUR choice.  I am only providing info, not telling you to break the FCC regulations regarding linking or any other FCC regulation.  I don't care what you do.  Just don't tell them I put you up to it.  Because it's your Circus and Your Monkeys.... NOT MINE.
 
EDIT  
BTW: I am waiting on confirmation that I can go into this topic with a full explanation of how to do this.  Once Rich says it's OK I will post it, but not before.    But what has been said here and a bit of google searching and research will get you where you need to go. 

My EMR Corp Duplexer mounted to a backboard. The cables were custom made by me.
If you're going to use a cheap Chinese duplexer I would be more concern about burning out the plastic inserts at each connection port rather than the mounting orientation. The cheap Chinese duplexers have a habit of burning out the plastic inserts in the ports from RF.

I can tell you from experience, you don't want to go down that path. 😱

@KevinJ, as a Property Manager for over 20 years, I would strongly advise against ANY type of attachment to the house, until and unless you get written permission from your landlord (That permission should be explicit regarding exactly how the installation will be made, by whom, and exactly how the property is to be restored when you vacate). You will be in violation of most typical Rental Agreements if you do install or attach anything to the structure, and, more importantly, you will become responsible for any and all damage resulting from the installation or the next strong wind. Failure to properly and regularly maintain any attachment points can allow water intrusion which will, over time, cause extensive damage to the structure, and possibly attract destructive pests such as termites or carpenter ants. Any intrusion will also cause mold to grow, creating a health issue for your own and subsequent families.
I've seen too many Tenants create huge problems for themselves by doing much less...

I think it’s Rohn makes a mount that angles over the roof ridge and is weighted down. 

I wanted to thank all who replied or even viewed this thread, due to the fact I rent and all other things considered, I am more than likely going to use a non-penetrating type roof mount. They are not expensive, I can easily get one onto the garage roof, and I'm certain I am resourceful enough to build my own and maybe even improve upon the simpler designs I have seen. I will keep all the information I have been privy to hear today! Thanks again to all! God bless and have a wonderful day!

I wanted to thank all who replied or even viewed this thread, due to the fact I rent and all other things considered, I am more than likely going to use a non-penetrating type roof mount. They are not expensive, I can easily get one onto the garage roof, and I'm certain I am resourceful enough to build my own and maybe even improve upon the simpler designs I have seen. I will keep all the information I have been privy to hear today! Thanks again to all! God bless and have a wonderful day!

@KevinJ, Be SURE the chimney is sound before you go mounting anything to it. It looks pretty sketchy in your original pic. Also, regards to gable mounting, ASSUMING  those are electrical wires that are very close (not just cable tv or phone lines), not only do you absolutely NOT want to mount on the gable, you do not want whatever you put up to be able to fall onto the wires in the event of strong winds, so consider your overall mast/antenna height, and fortify appropriately.

You should have various components grounded. But it’s not simple. Read this:
https://reeve.com/Documents/Articles Papers/Reeve_AntennaSystemGroundingRequirements.pdf
 

Always use a lightning arrestor on the antenna feed line. The point is to always try and keep that killer outside the house.

Didn’t even catch the radio type.  So get new antennas and then upgrade the radios to match. 

J-Poles have no gain, therefore whatever power makes it to the antenna is what goes out as your signal. Some antennas by companies like Tram and Comet have gain which increases your signal toward the horizon with the same power going to the antenna. Gain won't increase the distance you can reach; it just provides more signal in the same area.

I use several satellite dish mounts. The j mounts make good mounts for light weight radio antennas. Another nice thing is that most j mounts use a 1 5/8' diameter pipe which is the same size as 1 5/8" fence posts. You can find 1 5/8" fence post couplers on amazon to extend the mast higher. I will suggest that you use UV resistant guy rope if you extend it though.
I can't get above the trees in my yard without going with a 40 foot or taller tower. My Comet CA-712EFC is actually under a big tree branch. I am using a j mount at the peak of my roof with the Comet and have no problems getting out.

same here, requested 4 nearest me when I joined, but only 1 has responded at all, basically just use it if it's listed as open and the tones are there to access it, just announce yourself and thank them for the use, it usually goes well.

same here, requested 4 nearest me when I joined, but only 1 has responded at all, basically just use it if it's listed as open and the tones are there to access it, just announce yourself and thank them for the use, it usually goes well.

same here, requested 4 nearest me when I joined, but only 1 has responded at all, basically just use it if it's listed as open and the tones are there to access it, just announce yourself and thank them for the use, it usually goes well.

THIS! 
It's a bit cliche, but the old saying "you get out of it what you put into it" really applies here. Are you looking to explore what the service, as an adjunct to other services you may also be using or as a stand alone, can do for you in reaching out for contacts? Are you looking to keep in touch with family, friends, fellow travelers?  Are you looking to explore how the equipment works and assembling the best working station?  All this can be part of GMRS. 
I can't speak for them, but my gut feeling is the FCC won't change, or at least not in a radical sense, the Regs. for the service. The explosion is licenses being granted may reach a peak and level or fall off, but those $35 fess coming in don't hurt them in the least.

I was thinking about a good response to the original post, but I don't know that there is one. Radio is so diverse in it's use that I think any answer would be anecdotal at best. For example, it seems very much like a hobby where I live, but in other areas I travel to, it is very much utilitarian in nature. Which one represents the majority trend? No idea.
 
When I look at the purpose of the service, at its core, it is "for facilitating activities of individual licensees and their family", whatever that may be. If it seems to trend in one direction or another, I don't know that it really matters. That fact that it is a somewhat basic service that doesn't require a vast knowledge of radio is really not a factor. There are plenty of other services that have been established for us to use that don't require any more skill than what is required of GMRS. So I don't believe that is relevant. 
 
Bottom line, if some people make a hobby of it, then it's fulfilling the need of the licensee. If it's a utility for others, same thing, it's fulfilling the need of the licensee.  As the service grows, use patterns will change, but ultimately it doesn't matter what is happening around the country. The only thing that matters is if it does what you need it to do.

Anytime someone cites “The Law” it makes me want to send them a Junior Trooper badge. Their next assigned mission is to get over to the left lane and drive 3-8 mph under the posted speed limit. Never, under any circumstance, should the they exceed the posted limit or move to the right.

Still waiting to find out what your source is for these "stacks of complaints" or what, exactly the FCCs actions of "waking up" to it are, and what that source is.  Because otherwise, you're just telling fairy tales whilst everyone laughs ...