Installing NMO on hood

[KC8UQX]

I'm trying to figure out to install my Larsen 2/70 on my 2015 Subaru Forester. I need to be able to get my car into the garage, so roof mounting it is out of the question. I was thinking of a lip mount on the hood, but there's no good place that can take a lip mount. There aren't any good flat areas around the edge of the hood.

But there is fantastic access to actual hood, near the outboard edges. Mounting an antenna directly in the middle of the hood (directly over the engine) is obviously not a good idea, but what about near the edge? The coax would get wrapped in wire loom to protect it.

Are there any other considerations needed before drilling into the hood?

 

[toastycookies]

a fold-over antenna on the roof?

 

[n5ims]

Since you'll already be mounting it on the edge of your hood, how about using one of these and attach to the quarter panel. No 3/4" hole to patch later (just 2 or 3 small screw holes where nobody will look anyway) and routing the coax along the quarter panel is easy, out of the way, and won't fall into the engine if (well, when) what you attach it gives way.

http://www.theantennafarm.com/catal...-bracket-mounts-268/nmo-l-bracket-mounts-296/

 

[KC8UQX]

Since you'll already be mounting it on the edge of your hood, how about using one of these and attach to the quarter panel. No 3/4" hole to patch later (just 2 or 3 small screw holes where nobody will look anyway) and routing the coax along the quarter panel is easy, out of the way, and won't fall into the engine if (well, when) what you attach it gives way.

http://www.theantennafarm.com/catal...-bracket-mounts-268/nmo-l-bracket-mounts-296/

I bought one of those, planning on mounting the antenna that way. However, there's not enough flat metal to mount an angle bracket.

I don't mind drilling holes. I just want to make sure I'm not considering something when drilling into the hood.

 

[mmckenna]

Make sure the hood is grounded. Don't rely on the hinges/latch. If the hood doesn't already have a ground strap, add one, two, or more.

Make sure you know what is under that part of the hood. Don't rely on the hood shielding the electronics under there. A nearby computer, ABS module, etc. might be negatively affected by having a lot of RF nearby. I'd recommend trying a mag mount first. Make sure you test at the highest power you'll be running and at several different frequencies.

Consider the coax you'll be using. Anything exposed under the hood could get exposed to higher than normal temperatures.

Make sure it doesn't hit the windshield when you open the hood.

Personally, I wouldn't want a transmitting antenna that close to the occupants. The windshield won't supply any RF shielding. Having an antenna running 50 watts or more just a few feet in front of and on the same plane as the occupants wouldn't be ideal. At least on the roof you have some steel between you and the RF.

I'd seriously consider the rooftop again. My wife's Ford Escape has a 1/4 wave VHF whip on the roof that hits every time she pulls in or out of the garage. The antennas are flexible enough that if absorbs the hit. It's been up there for 5 years without any issues. You can also get springs that install at the base of the antennas.

Center of the roof will provide a proper ground plane under the antenna. Corner of the hood might create a lopsided ground plane that can cause some directivity.

On the other hand, I have a co-worker that has a 1953 Jeep CJ with a 10 meter base loaded antenna mounted smack in the center of the hood. Works well.

 

[Voyager]

Is there a place to mount a flat NMO mount? They look like that angled mount, only they are completely flat.

 

[safetypro79]

2014 Outback NMO

I use my HP-2 using a Diamond lip mount with a low profile Laird VHF/UHF on the rear hatch for the last 6 months works perfect comes with RG-174 to male SMA

John

Boise, Idaho

 

[teufler]

the right angle brakets are perfect for mounting in the front. Between the fender and the hood, oposite the car amfm antenna doesn't look bad. Brackets come in stainless steel or you can paint themn the same color as your vehicle.

 

[Voyager]

Many hood designs do not allow for such mounting. Sometimes you have to use a flat mount or bend one into custom shapes.

 

[jiminpgh]

Is the hood made of metal?

My 2011 Forrester's hood is plastic.
While I have no antennas on it, I considered a trunk lid nmo on the rear door.
I could slide it across and in the corner it would allow the hatch to open without interference.
The guy with the coast guard insignia raises enough points to disqualify the hood.
A 1953 jeep probably has zero plastic parts, except maybe ignition parts.
Most of the late model cars have plastic hoods.
Large hood mounted antennas parked at Wal-Mart will make you hamsexy.

 

[mmckenna]

Large hood mounted antennas parked at Wal-Mart will make you hamsexy.

Yeah, that would be a serious red flag....

The plastic hood is a good point. Might be an issue if he's using a ground plane dependent antenna.
Personally, the benefit of having a properly mounted antenna in the right location (full ground plane) makes up for any garage door, tree branch, parking garage strikes. Decent antennas will be flexible enough to absorb that. Steel/aluminum skinned vehicle rooftops should be fine. If the hood is plastic/composite, etc. I'd be cautions, repair/replacement could be costly.

I'd put a low gain antenna with a proper ground plane up against a high gain antenna with an unsuitable ground plane any day. And, I was serious about having a transmitting antenna, especially one with gain, on the same plane and in close proximity of the passengers. For a scanner or CB I could understand, but not a 50 watts +. I don't even feel comfortable with trunk mounted antennas because of that.

 

[popnokick]

Assuming by your ham callsign that you want to transmit with this antenna as well. I had the same problem (low clearance to my garage and other obstacles) and did a center roof mount NMO on my Jeep Liberty. I use the fully flexible Comet SBB-2 2M / 70cm dual band gain antenna (pictured as installed). It flexes easily each time I go in / out of garage. And as a center roof mount works really well to meet all the criteria in this thread (RF safety, good RF ground, good location on car, etc.).

 

[KE5MC]

Not the best location on the vehicle, but it works for me. Does not require much of a lip and mount has 3 axis of adjustment. Antenna is a Comet SBB-5NMO.

 

[popnokick]

One of the great things about the NMO mount is that you can easily change antennas. Normally the Comet SBB-2 is on my center rooftop, but I also have a Comet CA-2x4SRNMO that I can quickly use. However, because it strikes the garage door overhead I do not leave it on. The SBB-2 is the full-time antenna because it's carefree when it comes to hitting low overheads, branches, etc. I found that top center of the roof was a better antenna location.... even for a shorty like the SBB-2... versus having a longer antenna partially obstructed by the car body when mounted on a hood or trunk lip.

 

[safetypro79]

P25/UHF/VHF NMO mobile antenna

P25/UHF/VHF NMO mobile antenna


On my 2014 Subaru Outback

John
Boise, Idaho

 

[safetypro79]

#2 photo

Second photo showing Diamond mount and low profile antenna, works great on out P25 VHF/UHF her in SW Idaho