Batboard

Anyone have any experience installing antennas in a Kenworth T300 chassis? A local vollie dept. bought a brand-new pumper/tanker built on the T300 chassis and they want to get a radio installed (already have a brand-new TK-790, so that's not a problem). Of course, the roof is all fiberglass, presenting antenna issues.

I'm currently thinking about cutting a ground plane from moderate-thickness aluminum then attaching it inside the vehicle, above the headliner, to the roof. I'm assuming a thick NMO mount will be required as well. Anyone see any problems with this plan? Any special considerations in drilling fiberglass?

Thanks!

You would probably need a thick roof mount, but you could always get a plate of aluminum real thin to keep down the weight and ground that. Or you could just use a no ground plane antenna and they work just as well.

See if you can search this group a little bit -- I thought someone had a similar issue with outfitting an ambulance...

Ah ha! ... found it. Maybe this will help: http://batboard.batlabs.com/viewtopic.p ... =ambulance

Gordon

what band

if low band try and install a ball mount on the Business part of the truck same for the other as well

KitN1MCC wrote:what band

if low band try and install a ball mount on the Business part of the truck same for the other as well

VHF-Hi (155MHz). The truck's a tanker/pumper... don't think drilling a big hole in the side would be looked upon favorably! Between the top-mount pump panel and the 2500gal. tank, there's absolutely nowhere to mount anything except the cab itself.

Unfortunately, a no-ground-plane antenna isn't an option. Going to have to run a 1/4-wave as the tanker only has about 12" of clearance when going under the bay door (old station).

I'm probably going to have the city shop cut a disc of aluminum, then mount that to the underside of the fiberglass using some RTV, then drill a hole. Hopefully that should work?

Just make sure you ground the aluminum plate somehow, and I personally would try to find something else to secure to also. The RTV will work, but I would like put a piece of it under the dome light that way if the RTV fails, there is something else holding it also.

maybe mount the antenna on the body with a L bracket and use a real antenna not a cheap 1/4 wave

how is a 1/4 wave not a real antenna?

what about a mirror mount and ground it to the frame ? just a thought
Jhook

apco25 wrote:how is a 1/4 wave not a real antenna?

Haven't you and I sided on this discussion before? I recall you have quite a few 1/4-waves on the roof, like I do.

Kit, a 1/4-wave will work perfectly. There are a total of four receivers across a county that's roughly 25 miles wide and 40 miles long. And this is Texas, nice and flat. I have no problem talking into the fire repeater from 30-40 miles outside the county using a 50-watt Astro Spectra... the high-power version does even better.

Jhook - I've thought about a mirror mount, but there's no easy way to get the coax inside the vehicle besides drilling a hole in the fiberglass and pooky-ing the cable inside. And I still don't think the mirror mount is as secure as an antenna on the roof will be.

Good thoughts, guys. The department and I both appreciate all of them! Looks like we're about 2 weeks from having the radio and having an install party...

I was was questioning Kit's logic on why a 1/4 wave is bad.

As you know, I run exclusively 1/4w antennas on my ride and while I do have gain antennas stowed in the cargo area i've never had a need to use them.

For simplicity get the mirror mount NMO from Maxrad, use a 1/4w VHF whip and be happy.

I'd just verify the mirror has a good ground to the truck body.

I may have not Types it out Correct . I ment get a Real 1/4 Wave not on of the cheap rubber ones

i liek the comtelco heavy Duty 1/4 and the such

I used to work for a KW dealer, advised on "extras" all the time, of course it helped that I also used to run a M shop.

Been down the "clearance" road before too. I think your add on ground plane will work. Outside of that, the aluminum mirror bracket tubes are hollow, if you are real slick you could use a flat chrome mount bracket and mount it to the top of the mirror bracketry, then sneak the coax through the tubes (might have to drill them) and drill the door, behind the bracket foot and grommet the hole thing. This is very similar to what they do when the truck comes with heated or motor mirrors.