Ham Radio Mod, Antenna Coax Route

[Sarge61]

I'm a ham radio operator and I am installing an ICON IC-2370A into my 2019 4R. I already installed the Rago Fabrication dash shelf (and it's great) which is where I'm going to mount the remote control panel and microphone.

I'm going to install an SO239 antenna mount through the roof. Yes, that means I have to drop the headliner, but my real concern is routing the coax down the driver's side pillar (behind the driver's window). I know there's an air bag in there and I'm concerned that any residual RF around the coax could activate the air bag. I'd like to keep the coaxial cable run as short as possible, but if there's the possibility of setting of the airbag, I'll go around the back window and over the driver's side rear wheel well and under the carpet and door trim.

Are my concerns warranted? Is there room in that pillar to run a coax cable? The radio can put out up to 50 Watts of RF on 144MHz to 148Mhz as well as 430 to 440 MHz. Please advise.

 

[Humble Leader]

I just installed an icom 2730a in my rig this winter. great radio. I did not drill a hole in my roof as I use my roof and have a couple boxes up there. I know "real hams" drill holes but I don't like the idea of introducing possible water intrusion if I don't have to

I would stay away from airbags, that's just my preference. going down the rear and through the carpet/along the floor is an idea but it's a long cable run

are you 100% set on mounting the antenna on the roof? larsen makes a 2/70 NMO mount antenna that doesn't need a ground plane. this is one of the best antennas if not the best for ham frequencies when considering its size. I have the 2/70 as well as the shorter version. I have a hood mount and have no issues with ground plane for the short version. I was able to get a cable run of only a few feet with a hood mount

in terms of your specific question on room - there is some room, I know people run wires down that pillar but they aren't as thick as coax

 

[NorthernSailor]

With my Yaesu FTM-350R in my last vehicle, I mounted the power unit as close to the rear of the vehicle as I could to avoid running the coax near airbags. Luckily, it was a pickup truck with a big, aluminum Diamondback 360 bed cover, and I put an NMO right in the center of it. I had great readings with that install; not sure how I'm going to install it in the 4Runner yet, but likely the same avoidance of the bags.

I don't know if the myths are true, but I don't want to find out with one going off into the side of my head.

 

[PrettyGoodSam]

Replying just for the answers because I will be doing this eventually as well.

 

[Humble Leader]

I just installed an icom 2730a in my rig this winter. great radio. I did not drill a hole in my roof as I use my roof and have a couple boxes up there. I know "real hams" drill holes but I don't like the idea of introducing possible water intrusion if I don't have to

I would stay away from airbags, that's just my preference. going down the rear and through the carpet/along the floor is an idea but it's a long cable run

are you 100% set on mounting the antenna on the roof? larsen makes a 2/70 NMO mount antenna that doesn't need a ground plane. this is one of the best antennas if not the best for ham frequencies when considering its size. I have the 2/70 as well as the shorter version. I have a hood mount and have no issues with ground plane for the short version. I was able to get a cable run of only a few feet with a hood mount

in terms of your specific question on room - there is some room, I know people run wires down that pillar but they aren't as thick as coax

I actually wanted to clarify my comment . the larsen I mentioned is a half wave on 2m which does not require a ground plane (short and regular length version). the 70cm band does require a ground plane for both of those antennas. the 2m band is generally regarded as the most popular ham frequency though

that being said I have a third antenna which is ground plane independent on 2m and 70cm bands. I plan to test that and see how much my imperfect hood ground plane impacts performance but I digress. for those that aren't installing on the roof pay attention to whether your setup requires a ground plane. if you're a ham then this comes down to the antenna selection. this is not the same as electrical ground. hood is second best to roof but the ground plane isn't optimal since in the corner you only get maybe 90 to 110 degrees of ground plane vs 360 so performance will suffer outside that angle. and mounting dead centre in the hood looks goofy (no offense and is RIGHT above the loud engine). if you wanna project far out and hit far out repeaters ground plane becomes more important which is why comet's most popular mobile antenna is a ground independent one on both 2m and 70cm. diamond makes basically the same one. short distance simplex you're likely fine regardless of ground plane. very few people are willing to drill holes in a perfect roof and install a 40" antenna up there. some use short versions with good success but the 4runner is already tall and you'd be smacking even a short 19" antenna off of everything. antennas smaller than that offer not much gain. so it's a tradeoff

when it comes to radio it's impossible to get the perfect set up, there are too many variables both in the atmosphere and physical set up of your radio that are not textbook perfect. it's about getting a setup that's good enough or can work the best given your constraints

 

[mrblah]

i ran my GMRS coaxle out of passenger side firewall into engine bay, up the passenger side windshield gutter and on to the roof. Easy peaky.. To get coaxle to fit in the windshield gutter, you have to use a plastic tool and a plastic mallet and you pound it into the gutter...lol..

Should be similar for HAM also.

 

[comtn4x4]

i ran my GMRS coaxle out of passenger side firewall into engine bay, up the passenger side windshield gutter and on to the roof. Easy peaky.. To get coaxle to fit in the windshield gutter, you have to use a plastic tool and a plastic mallet and you pound it into the gutter...lol..

Should be similar for HAM also.

This is probably a bit less risky than hammering the windshield... although I've done the same. I use one of these now and it works great


Universal Wire Hider

 

[mrblah]

This is probably a bit less risky than hammering the windshield... although I've done the same. I use one of these know and it works great


Universal Wire Hider

lol gentle taps with a hobby mallet....

Yeah i run the KC wire hider also, but i thinking of using just office wire hider to run wires down the rear hatch for chase and license plate lights, etc.

 

[4RunnerAquasport]

I have a 2730 I made a base unit out of, great radio. I have a Yaesu 8900 in my 4 Runner that is OK, but not as user friendly as the ICOM imo.
If you do any trails with low hanging trees, roof mount is quite vulnerable.

I have had pretty good range on both freqs with a ditch light bracket and an NMO.
One time on a trip to AZ, I was hitting mountain top repeaters 30 to 40 miles away.

Simplex was hitting 20 miles out to ham with a 40' tower. It was a pretty good propagation night here in Florida. So the ground plane must decent.

 

[DK327]

I have a 10 meter mag mount right behind the sunroof and a 2m/70cm mag mount towards the back of the roof on my 3rd gen, both are 16-18ft cables that came with the antennas running down the side of the trunk and go inside via trunk lip and run down the carpet towards the front where the radios are. Yes it's a long cable run but it's the easiest way to get on the air. I intended to use this setup temporarily but since it worked, didn't touch it for years. The signal loss is negligible on 10m and a bit more on 2m/70cm but I don't mind it. For 10m I'm using a Wilson short load antenna and it's able to handle power like a champ (with SWR tuner) for the 2m/70cm Im using Nagoya UT-72 and it's alight, gets the job done.