CAP Talk

Operations => Tools of the trade => Topic started by: BigMojo on February 22, 2008, 03:09:33 PM

Title: Antenna for EF-Johnson 5317
Post by: BigMojo on February 22, 2008, 03:09:33 PM
Looks like I'm getting issued a mobile to mount in my truck, EFJ 5317...one issue, no antenna, supposedly there's an old magnet mount around, but think I may as well just get something. Any recommendations as to what to get? (Through glass would be nice, I'm not a big fan of magnets, and really don't want to drill my truck.

Thanks in advance....
Title: Re: Antenna for EF-Johnson 5317
Post by: KC0IEA on February 22, 2008, 03:37:10 PM
Do not get a glass mount!!
I appreciate that you do not want to drill a hole, but that is the best route.
The closer to the center of the ground plane (conductive roof) the better.
Mounting in order of preference and in general order of effectiveness.
1) Drill hole in the center of the roof.
2) Mag Mount in center of Roof.
3) Pickup stake bed mount. Trunk Lip for car.
4) Gutter Mount.

There are many other options and if you ask 3 hams you will get at least 6 opinions all different.
Title: Re: Antenna for EF-Johnson 5317
Post by: BigMojo on February 22, 2008, 04:13:11 PM
Thanks...Drilling the roof is out. This truck has about 2 years before it gets traded in, and trying to trade-in with a hole in the roof isn't cost-effective! My truck bed is covered by a hard folding cover, so that's probably out too. Guess a magnet mount on the roof...any idea how tall they are? I do have to get in and out of a parking structure every day.
Title: Re: Antenna for EF-Johnson 5317
Post by: brasda91 on February 22, 2008, 05:15:13 PM
You're going have several opinions.  I've used a glass-mount antenna on a vehicle when I had my mobile installed for the fire dept.  It worked great.  But that was my situation.  The other question is, is this radio being issued to you or the squadron?  Our Wing has installed our radios themselves, in our corporate van.  Just make sure the radio is for your use in your POV and is not to be installed in your corporate van.
Title: Re: Antenna for EF-Johnson 5317
Post by: BigMojo on February 22, 2008, 05:29:21 PM
Nope. It's being assigned to me for my POV. Our van already has one in it. I'm our "first responder" for UDF missions, so Group thought I should have a radio in my truck.
Title: Re: Antenna for EF-Johnson 5317
Post by: Major Lord on February 22, 2008, 05:48:09 PM
Actually, you have lots of options, besides the best option cutting a 3/4 hole in your roof top for an NMO mount. There are numerous stsyles of disguised antenna, including the film antennas that go on the inside of car windows, AM/FM look alike VHF antennae, and duplexers that allow you to use your car radios AM/FM whip antenna with your VHF or UHF radio. Check out: http://www.licenseplateantenna.com/ They have a cool undercover license plate antenna, STI makes a good disguise antenna for cars, or just go to E-Bay and type "disguise antenna" to find a whole wide world of suspicious asian antenna products!

I kind of like the Radio Shack product that has a flange that goes over your operating windows, and has a BNC connector outside your car for a whip. You just hang it out there when you need it. Its really made for hand-helds, but with the right whip, should handle 25 Watts okay.

You will find it strangely liberating the first time you cut a hole in the family car with a hole saw....

Major Lord
Title: Re: Antenna for EF-Johnson 5317
Post by: BigMojo on February 22, 2008, 06:24:24 PM
Quote from: Major Lord on February 22, 2008, 05:48:09 PM

You will find it strangely liberating the first time you cut a hole in the family car with a hole saw....

Major Lord

(http://img116.exs.cx/img116/1231/z7shysterical.gif) Thanks for the insight...I already have one "through glass" scanner antenna, that works GREAT when attached to my Mk4 Sniffer for pulling in EPIRB/ELT signals. So I was hoping I could just get something similar for the opposite side of my back glass. Not a big fan of looking like a porcupine driving down the road...but, we'll see.
Title: Re: Antenna for EF-Johnson 5317
Post by: SarDragon on February 22, 2008, 07:17:53 PM
The antenna will add about 2' to the height of your vehicle. My suggestion for dealing with the parking structure hassle is to get a mag mount with an NMO mount on it. Leave the mount on the roof all the time, with antenna off until you need it, then screw it on and do whatcha gotta do. There are caps available to keep the connector from corroding.

YMMV.
Title: Re: Antenna for EF-Johnson 5317
Post by: tribalelder on February 22, 2008, 10:54:54 PM
Truck got gutters ? Get a gutter clamp w/NMO mount. A 1/4 wave whip is about 19 inches and is less likely to have height problem in parking structure; a gain antenna is about 40 inches and is your choice for 'the road'. One mount, 2 antennas is one choice.

A disguise antenna doesn't advertise you have a radio aboard, but its performance, whether it's 'patch on the glass' or 'looks like regular antenna on vehicle cowl' has highly compromised performance.  I can't speak for the mystery license plate, but it's mounted lower that the 'patch on glass' or 'looks like regular antenna on vehicle cowl'.  If you use a disguise antenna 'in town', get a mag mount gain antenna for road.

Gain and tallness are your best friends on VHF.
Title: Re: Antenna for EF-Johnson 5317
Post by: BigMojo on February 23, 2008, 01:28:36 PM
Because of the folding hard top over the bed, my only options are on top of the cab roof, or the rear glass....I guess I'll go with the mag mount with the removable antenna.

Thanks for the insights guys...I appreciate it.
Title: Re: Antenna for EF-Johnson 5317
Post by: JTodd on February 26, 2008, 05:53:14 AM
Quote from: BigMojo on February 23, 2008, 01:28:36 PM
Because of the folding hard top over the bed, my only options are on top of the cab roof, or the rear glass....I guess I'll go with the mag mount with the removable antenna.

Thanks for the insights guys...I appreciate it.

My first antenna was mounted by an "L" bracket under the hood on the front fender.  It worked as well as any others that I've had. My current antennas are mounted on the corners of my headache rack. Works great there also.

Title: Re: Antenna for EF-Johnson 5317
Post by: JoeTomasone on March 03, 2008, 03:45:18 AM

I am currently using a Diamond low-profile mag-mount (http://www.rfparts.com/diamond/k702m.html) along with a Comet SBB-1 dual-band antenna for both CAP and ham use.   The reason is similar - I wanted an antenna that required no drilling and would clear parking garages on top of my tall (8') vehicle.

Works pretty darned well, considering.