Comet SBB-244NMO offroad?

[taugust]

Cograts on the call sign, Mark.

A coupla tips: The open coil on the Larsen can cause some wind noise as well. I notice it more in humid conditions for some reason. I have heard people using electrical tape over it to close it down, but the shrink tubing idea is more solid. I wouldn't worry too much about branches snagging in the coil. If a branch is a problem, it will take the antenna off or bend it.

The center contact spring is thin sheet metal and is not a very reliable spring. Make sure you check it periodically and bend it downward to ensure it is making good contact. It can back off contact and you can burn up your finals on the radio with high SWR if it looses contact.

Also, spray some WD-40 inside to keep moisture from building up inside and corroding things.

Hope this helps.

 

[4RunAmok]

Also, spray some WD-40 inside to keep moisture from building up inside and corroding things.

WD-40 dries up, and causes it's own problems. I use a tube of Silicon Gel Lube from Radio Shack, keeps the threads lubed, and keeps water out.

 

[ScoutII]

I'm not so worried about the coil or the antenna. I drilled through the top of my 4runner, and put an NMO mount up there, so I'm worried about the antenna getting caught and bending my roof, or tearing out the mount.

Thats been my issue. The MNO mount getting pulled out. I'm going to beef up the sheet metal, either large fender washers or a plate. We've gone on some trails with low branches and they have taking there toll. I should carry two antennas so I can switch, but sometimes you don't know the trail and then its to late. I have a nice mag mount, but that gets knocked off too, then your looking for a different place to put it. For me middle of the roof is best.

So I hammered the roof sheet metal flat, but the MNO mount got damaged a bit. So I need to find a tougher MNO mount or switch to a SO-239 connector. looking at one of these.

 

[4RunAmok]

With the heat shrink on the coil of the Larsen 2/70, branches skate right over it. Yes it's a tiny bit bent, but it bends back if it goes too far, but I have not had any problems with the actual NMO bending the surface.

This is the one I bought: http://www.hamradio.com/detail.cfm?pid=H0-009384

Uses a 3/8" hole, and with some loc-tite on the threads and some vaseline on the underside of the top of the mount, it's never leaked.

 

[soonenough]

Hopefully a few of you can chime in with some experience here. I'm looking at running said named antenna soon; however, I'm unsure of its offroad durability. Anyone running one, before I pull the trigger?

I've never run that specific antenna, but I did have a Comet SBB-5NMO antenna on a lip mount on the hood of my truck, and I broke the antenna in half the first time I caught it on a tree branch. The branch grabbed it right at the coil and snapped it.

For a replacement I bought a Larsen dual-band antenna. It's similar in size (a little shorter), and almost identical in apperance except that the base is quite a bit wider. Personally, I think the Larsen antenna is a MUCH better solution for off-road use. I can literally take the tip and bend it completely over until it touches the lip mount, and it just springs right back to where it was. I don't think there's any way I could've done that with the Comet (if there was, I don't think it would've broken from getting caught in that tree branch). That's my .02

 

[trump]

Thanks to everyone that helped out.

Just as an update:

Purchased a Larsen NMO 2/70B the other day and I will not be running 220 Mhz anytime soon. I do plan to heatshrink the coil when I get that far.

I'll start another thread with pictures of the whole mobile setup soon.