Antennas
- Thread starter lcat06
- Start date
mmckenna
I ♥ Ø
Avoid the Chinese crap. One of the Tram mounts I disassembled had a very poorly installed connector.
You can't go wrong with one of these:
theantennafarm.com
You can't go wrong with one of these:
Larsen NMOMMR - NMO Magnet Mounts with PL-259
High frequency 0 – 3000 MHz magnet mount. NMO antennas, PL-259 connector installed includes 12ft of RG-58A/U cable.
theantennafarm.com
BadManBro
Newbie
McKenna,Permanent NMO mounts:
For your ham radio with a UHF connector:
3/4" NMO Hole Mount 17' RG58/U with PL-259 connector TE Connectivity MB8PS
Manufacturer: TE Connectivity; Description: The Laird MB8PS vehicle roof mount antenna installation hardware kit is for Motorola-style mobile antennas, 0 –
For your scanner with an SMA connector:
Laird TE Connectivity MB195SMI14 - NMO 3/4" Hole Mounts SMA
Manufacturer: Laird External Antennas TE; Model #: MB195SMI14; 3/4 in Mnt 14ft LMR195 crimp SMA plug; LAIRD's MB195SMI14 all brass 0 – 1000 MHz permanent
Doing your first permanent antenna install isn't easy. It's a big step. But once you do the first one, you'll never go back. None of the nonsense with compromise mounts, routing cable through doors/windows, etc. Will not leak if installed per the directions, and the directions are pretty easy to follow. Only challenge is that you'll need a 3/4" hole saw, but that's not a big deal:
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For the amateur radio, I'm guessing you have a dual band radio?
Kind of the gold standard is this one:
Larsen NMO2/70B Premium Larsen 2m 70cm 144 440 Amateur Ham Radio Antenna Dual Band
Larsen NMO2/70B 2m 70cm 144 440 Amateur Ham Radio Antenna Dual Band Larsen
If clearance is an issue and you want something a bit shorter, this is a good antenna:
Larsen NMO2/70SH Premium Larsen 2m/70cm Amateur Ham Radio Antenna Short Dual Band
Larsen NMO2/70SH Premium Larsen 2m/70cm Amateur Ham Radio Antenna Short Dual Band
Larsen makes commercial/public safety antennas and these two amateur radio models will outlast your vehicle, the one after that, and you'll likely pass these down to your grandkids. I've got 30+ year old Larsen antennas. They are much more durable than the consumer/hobby grade stuff you'll find.
For your scanner, I'd recommend this antenna:
or this one:Larsen NMO150/450/758SF Tri-band Mobile Antenna covers 150-174, 430-520 & 750-870, 100 Watts, Length 16.5 in, NMO Mount, Spring Base
Larsen NMO150/450/758SF Tri-band Mobile Antenna covers 150-174, 430-520 & 750-870, 100 Watts, Length 16.5 in, NMO Mount, Spring Base
EM Wave EM-M43002 Tri-Band 150-162/450-490/763-870 MHz Mobile Antenna - 17.7 in - NMO - Spring Base
EM Wave EM-M43002 Tri-Band 150-162/450-490/763-870 MHz Mobile Antenna - 17.7 in - NMO - Spring Base
I've used both of those extensively on top of full size trucks. They've hit a lot of low tree branches and are doing just fine. They'll cover VHF, UHF, 700 and 800MHz, so pretty much all the good stuff your scanner needs.
Spacing depends on how much you have available. For both of these antennas, they'll want about 18" of ground plane in all directions under them. Doesn't necessarily mean they have to be dead center on the roof, they can be offset if that's what your installation requires.
They also need to be separated by a few feet to prevent the transmitted energy from your dual band antenna from overloading the front end of your scanner.
I wouldn't worry about spacing too much from a 4 watt CB radio antenna. 4 watts isn't enough to be a problem for your radios. Keep 2 feet or so away and you'll be just fine.
Not sure exactly where on your vehicle they should go since you have the top rack to deal with. You'd want to keep a bit of spacing from that. If you don't have a sun roof, that's good. Working around those can be a challenge.
If you really wanted to go all the way, you could replace that firestick with an NMO mount CB antenna:
Larsen NMO27C CB & 10 Meter Amateur Radio Antenna NMO Mount 27-30 MHz Ham
Larsen NMO27C CB & 10 Meter Amateur Radio Antenna NMO Mount 27-30 MHz Ham
I read through a lot and enjoyed your prolific and thorough posts - thank you!
I too am looking to install my first permanent antenna. No or low gain 1/4 wave for gmrs in hilly/ mountain areas with an NMO mount so I can swap to 5/8 when Imout in the open.
My vehicle is a bronco with a hard plastic top and a permanent roof rack over the entire roof - about 4" above the plastic. The plan is to get a 24" aluminum disk or 24x24 square as a ground plane with the NMO in the center.
Questions for you / the community
Should I worry about mounting the plane on the rack? Will it matter if on top or underside of crossrails? Insulate it with some rubber? Mount directly on plastic roof just under the (aluminum) roof rack?
Is it better to run the coax along the rack edge, under the hood and through the firewall to the radio or hole saw through the roof and route coax in the cabin?
Thanks in advance for any suggestions.
Badlands Manual Bronco
mmckenna
I ♥ Ø
For GMRS/UHF only use, your ground plane only needs to be 12x12. That might make this a little easier. 12x12 with a 3/4" hole, or a 12" diameter circle will work fine.
You want the ground plane directly under the antenna mount. Not spaced under it.
Some options to consider:
You could mount that 12x12 plate/12" diameter circle of metal on to the rack and mount the antenna in the center.
If you had a place on the plastic roof that was a foot more away from the rack and at least 6" in from the roof edge, you could place the ground plane on the underside of the roof with the NMO mount in the center. You'd likely need a thick mount NMO, rather than the standard ones used through a vehicle metal roof. I've done this similar installation of transit buses that have fiberglass or composite roof material.
Or, you could mount a 1/2 wave UHF antenna on the rack. Not ideal, but it would work. The 1/2 wave antennas do not require a ground plane under them, but they'll work better with one.
But your plan to mount some sort of ground plane under the antenna with an NMO mount will give you more flexibility to swap out different types of antennas as your needs dictate.
Shorter run is better. All coax cable has some amount of loss, so reducing the amount you use is beneficial. Routing through the engine compartment needs to be done carefully.
Not sure how big the rack is, but if it covers the entire roof of your Bronco, then what I would do, if it was me:
Like you suggested, mount a 12" square or round plate to the roof rack with an NMO mount in the center. Make sure the antenna is up clear of the rack and anything metal that you carry on it.
If the rack doesn't cover the entire roof, I'd drill a hole in the roof of the Bronco, put a 12" diameter disk of thin sheet material on the underside with an NMO mount through the center.
The other thing you need to pay attention to is the type of NMO mount you use.
Most of them are designed to be mounted through the roof skin of a vehicle and the underside of the NMO mount is not designed to be exposed to the elements. If the underside is exposed, you need to use one of these style mounts:
Larsen NMOKHFUD - NMO 3/4 Hole Mount Other
Manufacturer: Radiall Larsen; Description: High Frequency, Dual Shielded. 3/4" Permanent Hole Mount. For standard vehicle roof mount antenna installation.For
theantennafarm.com
BadManBro
Newbie
McKenna,For GMRS/UHF only use, your ground plane only needs to be 12x12. That might make this a little easier. 12x12 with a 3/4" hole, or a 12" diameter circle will work fine.
You want the ground plane directly under the antenna mount. Not spaced under it.
Some options to consider:
You could mount that 12x12 plate/12" diameter circle of metal on to the rack and mount the antenna in the center.
If you had a place on the plastic roof that was a foot more away from the rack and at least 6" in from the roof edge, you could place the ground plane on the underside of the roof with the NMO mount in the center. You'd likely need a thick mount NMO, rather than the standard ones used through a vehicle metal roof. I've done this similar installation of transit buses that have fiberglass or composite roof material.
Or, you could mount a 1/2 wave UHF antenna on the rack. Not ideal, but it would work. The 1/2 wave antennas do not require a ground plane under them, but they'll work better with one.
But your plan to mount some sort of ground plane under the antenna with an NMO mount will give you more flexibility to swap out different types of antennas as your needs dictate.
Shorter run is better. All coax cable has some amount of loss, so reducing the amount you use is beneficial. Routing through the engine compartment needs to be done carefully.
Not sure how big the rack is, but if it covers the entire roof of your Bronco, then what I would do, if it was me:
Like you suggested, mount a 12" square or round plate to the roof rack with an NMO mount in the center. Make sure the antenna is up clear of the rack and anything metal that you carry on it.
If the rack doesn't cover the entire roof, I'd drill a hole in the roof of the Bronco, put a 12" diameter disk of thin sheet material on the underside with an NMO mount through the center.
The other thing you need to pay attention to is the type of NMO mount you use.
Most of them are designed to be mounted through the roof skin of a vehicle and the underside of the NMO mount is not designed to be exposed to the elements. If the underside is exposed, you need to use one of these style mounts:
And then get yourself some marine grade heat shrink tubing. Cut a piece about 3" long and slide it over the coax to cover the point where the coax enters the NMO mount. Then shrink it. The marine grade tubing has a hot melt adhesive that will flow when heated and seal everything. That'll keep water out of the mount.Larsen NMOKHFUD - NMO 3/4 Hole Mount Other
Manufacturer: Radiall Larsen; Description: High Frequency, Dual Shielded. 3/4" Permanent Hole Mount. For standard vehicle roof mount antenna installation.For
Thank you that is great advice re the NMO mount - had not considered that. Sounds like the plane goes atop the rack - no rubber isolation needed - with mount in center and then shortest route possible to radio.
I was thinking 24" instead of 12 just to give future options without starting over and from what I understand with g-planes there is a min but no max.
I will also ask the Antenna Farm folks or ? about grommets for running the coax through the roof. From what you said - running through engine compartment is suboptimal - interference or just routing?
Best,
BadManBro!
mmckenna
I ♥ Ø
Well, next useable band down the spectrum is VHF, and you'd need 36" to be ideal there. That's going to look pretty goofy. I'd stick with the 12" circle or square.
I'd avoid running it through the roof. If you do, use a packing gland type feed through, like one of these:
My concern with the engine bay is heat, but if you route carefully, it'll be fine. Don't bundle the coax with other existing wiring, keep it separate. Make sure it doesn't rub against any sharp metal. If the rack had vertical parts that come down in front of the windshield, then that might be a good way to do this.
BadManBro
Newbie
McKenna,
Thank you - all good points. The size of the plane - there is already a black rack covering the black roof. I will prime and. paint then plane black or dark grey - just not the part rhat makes contact. Just figured it couldn't hurt. I will send a pic when I can.
Thanks again.
BMB
mmckenna
I ♥ Ø
Nice. Looking forward to seeing it. I really like those new Broncos.
