JohnE

Another option would be using an LTR controller ,w/that said all of your radios would have to be LTR capable

have been using these for decades but single band https://d3dqzy9ky05fbv.cloudfront.net/wp-content/uploads/2020/06/ASP-Mosaic-Series.pdf also have been using a Laird B4505 for a few yrs now and I find it comparable to the Mosaic

https://www.rfparts.com/relays/relays-tohtsu.html http://www.advancedreceiver.com/page22.html I' sure there is a way to make one of these for for you found one more https://www.w6pql.com/using_inexpensive_relays.htm and an article https://www.rtl-sdr.com/building-a-transmit-receive-relay-system-for-a-boat-anchor-transmitter-and-sdrplay/

Effort is a gross understatement back story..... not enough room for a fall zone , too much BS to put up a 125' tower. Have ~100' pine trees in strong health condition. Hire tree guy and he thinks I'm nuts but he's getting paid. Put the whole antenna ,pipe and cable attached together on the ground. strain relieved and stressed the cable before having it hoisted and mounted as one piece. My only mistake in the was cheeping out on the antenna. So far it has served me well.

a little lite reading on grounding https://www.blm.gov/sites/blm.gov/files/Lands_ROW_Motorola_R56_2005_manual.pdf as to mast- while I agree EMT is a poor choice I have used 1" aluminum for many yrs on lightweight antennas (sub 6 lbs and <8') pretty much anything that has a bending moment of less than 75 ft/lbs. Most of the antennas that are made for our purposes fit that description.

From personal experience wish I still had the pics LMR 600 long story short the outer casing on the cable becomes porous and water migrates into it. at best in the NE 5-7 yrs and it needs to be changed. As a sub for 400 I sometimes use FSJ 2. Similar size and loss

12 and 20dB sinad is all I care about. Where does it open and where does it close in CSQ or pl

Kenwood TK 805d , 880, 863, 8160, 8180 and NX 5800

variation on Jeep crawler that I have used for decades is self vulcanizing silicone tape, E tape, butyl mastic and more tape. Have used heat shrink w/"glue" inside where tape was not really an option.

hook up the yellow wire to 12V , it's an ignition wire. that is where you need to start before going down the rabbit hole

like a microwave backbone

GPS would be for simulcasting to sync the transmitters timing. Also said transmitters would have to have a high stability XO to lock it on frequency. You are need a comparator or something that works like one. seeing as you are using IP everything should come back to one "computer" and select the site w/best RSSI and as it moves it goes to the next. IIRC there was a HAM that had some you tubes on it. I think it was in relation to a simulcast set up. hope this was some help

Grounding is a double edge sword. most power supplies have a grounded plug(3 prong) that means it is grounded to your AC electrical system. The radio attached to it is in turn grounded as is the antenna connector on the back a chassis ground. You see where this is going. At a minimum I would get a Polyphaser and make sure it has a proper ground that will offer some protection. The pic below is an example of a direct hit. Antenna was completely vaporized, connector too. The Polyphaser had to be removed from the ground bar w/hammer. the equipment (a city agency) was undamaged. The cable will most likely have to be changed as a precaution.

Agreed. From what I have seen they are tuned 462/467 flat there in lies your problem. It's a half Meg out at a minimum and that's not gonna cut it. I have seen some screen shots of properly tuned ones and they seem to be ok but have some power handling issues just an FYI JE