Those mounts will work fine. You can often find them free/cheap if you look around. Look for them at metal recyclers, flea markets, etc.
I think I’m going to need about 75ft of cable was thinking about LMR400 what kind of connection will I need?
LMR-400 is about the lowest level cable I'd use on a 75' run, and I'd encourage you to use something better.
-Yes- it'll work.
1/2" Heliax is a good option, but it's stiff and can be very difficult to run in a residential application. It's got a fairly large bend radius, so routing it through walls can be challenging. I've done it, it's possible, but it may very well kick your butt in the process.
LMR-600 might be a good middle ground. It's more flexible and has a tighter bend radius. It'll be a bit cheaper than the 1/2" Heliax, and will perform better than the LMR400 over that sort of length.
If you've never installed your own connectors, you may want to consider having them pre-installed for you. It'll save you some headaches.
I'd recommend doing an N male connector at the antenna end and an N male at the radio end. But do not connect it directly to the radio. It's heavy cable (same for LMR-400, heliax, etc) and you'll put a lot of strain on the connector. Instead use a short jumper for something like RG-58 with a female N connector on one end and the other end to match your radio. This short jumper won't have any noticeable loss, and will take the strain off the radio's antenna jack. That'll save you a repair down the road.
At the antenna end, you can do the same thing, or you can carefully support the cable where it attaches to the antenna to make sure it doesn't strain the antenna base. On the professional side, it's common to use a short jumper of more flexible cable to make the final connection.
Also do I need to ground it?
National Electric Code says yes, you do need to ground it. Common sense says yes. Doing the right thing says yes. Doing the job safely says yes.
An inexperienced hobbyist/ham will tell you "no".
You decide, but hopefully you'll do the job right.
The antenna mounting bracket needs to be grounded.
You need to ground the coax shield and you need to provide lightning protection (yes, even if you don't get much lightning in your area, or your buddy tells you it will never get hit, or if someone tries to convince you that a wrap of electrical tape will magically stop a several million volt surge that has traveled thousands of feet through the atmosphere…)
Use a Polyphaser installed at the point where the coaxial cable enters your home.
So, you'll need an LMR-600 jumper from the antenna with a male N connector long enough to reach from the antenna to where the coaxial cable enters the house. Leave a drip loop (google that, keeps water from running down the cable into the house).
The Polyphaser will provide the lightning arrestor function to help protect what's in the house, and it will ground the outer shield of the jacket. From the Polyphaser, you'd run your cable from there to the radio.
Grounding may be best left to a professional electrician if you have concerns, but here's what you'd need:
Ground wire (6 gauge is what I would run) from the mounting bracket straight down to a ground rod directly below the antenna. Keep any bends/turns in the cable gentle and sweeping, lightning likes to jump off sharp points and sharp bends in wire.
You'll also need a ground wire (6 gauge again) from the Polyphaser direct to the ground rod.
On the professional side, it's not uncommon to install a ground bar near the Polyphaser and ground the mounting bracket/Polyphaser to that and then run a single wire down to the ground rod.
If you can use an existing ground rod at your homes electrical panel, if it's near the antenna mount, that's acceptable.
If that's not possible, then you'll need to install a new ground rod (at least one) and bond that to the house ground rod. No exceptions.
So any suggestions thoughts or idea will be very appreciated I have a guy from the fire Dept that’s kind enough to put it up for me but he’s not a radio guy and I can’t do much due to a spinal injury.....
Thanks in advance
Mark M.
Done right, this should work just fine. Just make sure he's aware of the NEC requirements for grounding. If unsure, get an electrician to do that part for you.
And as others said,
DO NOT(!!!!) ignore proper waterproofing on ALL the exterior coaxial cable connections. Quickest way to destroy all this work is to skimp on the waterproofing.
