• Perm. mobile RR scanner Ant.

  • Discussion related to railroad radio frequencies, railroad communication practices, equipment, and more.
Discussion related to railroad radio frequencies, railroad communication practices, equipment, and more.

Moderator: Aa3rt

  by Trickcooley
I have looked all thru this topic and cant really figure out (or understand lol) what kind of permanant railroad scanner ant. I need. I use an older Bearcat..BC55XLT which works great seeing that I have had it since I was a kid. I have a CB ant. with the BNC attachment and from what I read, that is why I cant recieve anything from a significant distance. I know I need something around 17.5 " high....

Can I get an ant. that looks like a cell phone ant.?

What is gain?

Thanks, I know all this has probably been covered so I apologize in advance. Thanks again!

  by danco
You can find scanner antennas, but I get very good results with my ham radio antenna. An added bonus is that ham antennas are relatively inexpensive.

Two that I can personally recommend are the Larsen NMOQ2/70B and the Comet SBB-1NMO. Both are dual-band VHF/UHF antennas. Both are NMO mount antennas, which requires drilling a 3/4" hole in the middle of your roof. (But you did say you were looking for a permanent installation...)

The NMOQ2/70B looks like the standard cell phone antenna, complete with an open coil mid-height. It's about 19" tall. Cost is about $28.

Here's the manufacturer's catalog showing the The NMOQ2/70B (it's in the middle on page 4):
http://www.radialllarsen.com/docfiles/A ... VHFUHF.pdf

Currently I use the SBB-1NMO on my 4Runner, as it clears my garage door (the NMOQ2/70B whacks the door frame and the door overhead). The SBB-1NMO has a 3" high coil at the base and a flexible rubber-coated whip above, and stands 16.5" tall. It sells for about $43.

Here's the manufacturer's web page (the SBB-1 is near the bottom of the page):
http://www.cometantenna.com/products.ph ... &childID=4

Both antennas are in stock at Ham Radio Outlet:

The NMO mount hardware is dirt cheap--about $13. (search the HRO site for "NMO-K").

You'll also want to use a hole saw to drill the 3/4" hole. Use the proper radio-installation one--it has a depth setting to cut through the metal roof without overpenetrating and destroying your headliner below. Borrow one from your friendly neighborhood Ham, or buy one if you can't get a hold of one (they go for about $50--steep, but well worth it in the long run...)

Edit: You asked about gain. Both of those antennas are unity gain. But a unity gain antenna on the roof of your vehicle is 6dB (or more) better than a rubber-duckie antenna inside the car. You won't be disappointed...

Good luck and 73,

Reno, NV

  by Trickcooley
thanks for the info.

So when ( and if, I can see me wife now..lol)I go thru the roof of my Envoy, what do I do with the headliner? Justr poke a little hole? I doubt I'd be able to take it down and put it back up when I am done running the wire.

How bout a permantant window ant? Or does the metal on the roof actually help pick up signals?

  by clearblock
The window mount antennas are inefficient. You are correct that the "ground plane" effect of the metal roof is essential to good antenna performance.

You do not need to take the headliner down but you do need to remove the trim over the door and get access under the headliner to run the cable.
The headliner should be pulled slightly away from the roof at the point you will drill the hole.

Special 3/4" hole saws are made by Antennex and others with small teeth that only penetrate the roof but it is still a good idea to protect the headliner.

I use the trick of sliding a small metal plate (I use a 4x4 electrical box cover) under the headliner at the point where I am drilling as extra insurance I don't wreck the headliner.

If you don't want to drill the roof, a good magnet mount on the roof is a better alternative than an on glass antenna.

  by Trickcooley
Maybe I should just go with a magnet mount......

Ok, how bout a good mag.mount ant?

  by clearblock
Larsen makes a good mag mount for their NMO series antennas.

Their NMO-MM-R-PL has a 12' cable with a PL259 connector.


  by danco
Trickcooley wrote:So when ( and if, I can see me wife now..lol)I go thru the roof of my Envoy, what do I do with the headliner? Justr poke a little hole? I doubt I'd be able to take it down and put it back up when I am done running the wire.
On my 4Runner, removing the dome light (it's just spring-clipped in place) between the front and rear seats provided access to the roof. I drilled the hole just forward of where the dome light is (drilling a small pilot hole upward from inside the vehicle) and installed the mount there.

I removed the door trim on the passenger side pillar between the front and back doors and removed the plastic trim pieces. This gave me access to the edge of the headliner, where I was able to fish a stiff wire from the side to the dome light hole in the headliner. From there, I used electrical tape to attach the end of the coax to the fish line and pulled it back.

At this point, I was out of the roof, without having to pull down the headliner. I ran the coax the down the door pillar, and under the carpet over to where I mounted the radio under the passenger seat (the radio has a seperable control head that I mounted in the dash console, but that's another story).

I reinstalled the pillar trim, refastened the door seal, and reinstalled the dome light. You can't tell anything was ever done.

Here is the SBB-1 on my 4Runner:

This is the NMO mount from the underside (view through the dome light area):

I understand agonizing over doing this to your expensive vehicle--I sweated over it for 3 weeks before I worked up the nerve to do it to mine. Once I decided "what the heck," it turned out to be a two-hour job and wasn't hard at all. Once you've done it once, you'll never be afraid to do it again!

If you just can't see yourself doing it, you can always have a local two-way radio shop (not Best-Buy or The Good Guys) install it for you...or you can go the mag-mount route.

73 de Dan, KE7HLR

  by Trickcooley
I have no dome light in the middle....lol

By the time I figure out if I wanna do this..its gonna be winter out with no garage and I can tell ya Its not gonna happen till spring.

Mag Mount here I come (least for the winter)

  by danco
No dome light? :(

Well, use the mag mount in the meantime, and this winter, search long and hard on the Internet for antenna/radio/stereo/CarPC/etc. installation tips for your Envoy. Odds are somebody has done this and has a write-up on it.

You might also find info on EnvoyForums.com...

Good luck and 73,


  by keeper1616
try searching over at batboard.batlabs.com - its a forum dedicated to Radio installs and radio equipment.

  by dummy
i have the radio shack magnet mount scanner antenna and it works just fine. its in the bed of my pickup under the tonneu cover. i think it was 30$. it has three sections. i used the top piece only. its about 17 inches long.

  by Trickcooley
I ended up getting a mag.mount for the time being. Went to some small shop near my house and that guy was pretty well informed about anything I could throw at him.

I got a mag. mound and he cut me an ant. at 17"s long.

I can pick up stuff that I have never been able to Before so I guess its working...cant wait to make a day trip and see some trains (and foamers :( )

Thanks everyone for the help!!!!

  by jmp883
I will NOT cut a hole in the exterior surface of any vehicle I own. It's not worth the aggravation.

I will NOT use a magnet-mount on any vehicle I own. I will NOT tolerate what it does to the finish of the vehicle and I DO NOT want the cable running for any distance across the top of the vehicle.

As you can tell I'm extremely picky about my vehicle. It killed me to install the ham radio and antenna I did put in....and it took me several months before I finally came up with a way to do it so that I could remove everything and not leave a trace behind that there was ever anything there.

Those things being said, here's 2 solutions you may want to look into..... :-D

Since an Envoy has a rear hatch you might want to look into a lip-mount. The majority of lip-mounts are made for trunks but there are hatchback styles as well. They slide over the edge of the hatch/trunk and are held in place with set screws from underneath. There are no holes to drill and the cable is hidden inside the vehicle. As for security I had one on an earlier vehicle I owned and it stayed on the car at all speeds.

Another option is an antenna mount that drills into the door jamb of your hatch. The bracket then angles out to a horizontal pad where your antenna mounts. This is the mount I'm currently using on my 1996 Ford Explorer.

Both of these antenna mounts allow you to take the antenna itself off for carwashes or low garages while leaving the mount in place. Most mounts that allow the antenna to be taken off come with a screw-on cap that protects the antenna mount threads from weather and dirt.

The included link are pictures of the antenna mount on my truck.
http://pg.photos.yahoo.com/ph/jmpwpd29/ ... pg&.src=ph
This antenna is connected to a Kenwood TM-V708A dual-band ham radio. This is essentially two radios in one chassis. I monitor my local 2m/70cm amateur repeaters on one side of the radio and the local railroads on the other side.

By the way...go to a radio shop that specializes in amateur radio. Your local Radio Shack doesn't have squat anymore compared to what a 'real' radio shop will have. Try these links:


I think you'll probably find something there you'll be able to use.

Good luck in whatever you finally decide to go with! :-D

  by ColonyLine
I use a Antenna Specialist Commercial 150-170mhz Mag Mount. You can use any type of mount you want with it. It works better than my commercial base antenna. A ham antenna would need to be cut down probably, to long for 160mhz. I was thinking of getting a second Antenna Specialist mobile for my base.

  by Clean Cab
Don't believe all the hype and pay a lot of money for "speciaslized" antennas. A simple VHF 1/4 wave 12" whip antenna will work as well as any other type of antenna. Or, you could try a gain antenna, but my experience with gain antennas is they don't improve reception that much. Keep it simple, keep it cheap.