Antennas

[Advanturetrek]

I'm building a van with a fixed, fiberglass "cruiser" top. The headliner hasn't gone in yet, so I have a once-in-a-van-lifetime opportunity to pre-wire for radio antennas. But, it's tough to figure out what I actually will need without having used and experimented with the van. I would appreciate comments and advice on my plans.

1. Cell phone amplifier - I definitely want a cell phone amplifier. I plan on pre-wiring an NMO mount on the roof to the dashboard. I'll use a Larsen NMOC/P3E mini-whip.

2. UHF/VHF Ham - I don't have a ham license yet, but I anticipate getting one for short range communication. I plan on pre-wiring an NMO mount on the roof to a cabinet behind the driver. I'll use an antenna like the Larsen NMO2/70SH with a radio featuring a detachable front panel, and the front panel will go on the dash.

3. CB - If I want a CB radio, I'll use the pre-wire for the UHF/VHF ham with a different whip.

4. HF Ham - I don't have a ham license yet, but I anticipate getting one for long range hobby and emergency communication. I plan on prewiring from a cabinet behind the driver to the rear of the vehicle for possible addition of a portable antenna, such as a Buddipole, or a permanently mounted screwdriver antenna.

5. GPS - I already have a handheld GPS and a phone with GPS, so I may never want an additional, built-in GPS. However, given that antenna mounts are cheap compared to tearing up a headliner, I plan to prewire a spare NMO mount. Larsen sells NMO GPS antennas.

6. 802.11 WiFi - I might want an external Wifi antenna to use free Internet. The small antenna built into my laptop might be sufficient, but, again, given the comparatively low cost of mounts, I plan on putting another spare on the roof.

Most of these antennas require a ground plane, and I plan on lining the underside of the fiberglass top with metal foil grounded to the chassis and roof rack.

I am concerned about height. A fixed top is already tall before adding antennas, so I'm using short (<19"), flexible, removable whips. I might have a temporary bumper or hood mount for those times when height is an issue. Or, should I give up on roof mounted antennas due to height?

Thoughts? Am I missing something or over-thinking this?

Thanks,
-Peter

[cygvan]

interested in the responses to this post as well.

advanturetrek, i found decent info on 3gstore.com. im looking at a number of products on there for cellular and wifi solutions.

one thing i dont understand (and havent researched just yet) is a "groundplane" ive heard the term before in regards to antenna but never had reason to look it up.

[charlie56]

Originally Posted by Advanturetrek

I'm building a van with a fixed, fiberglass "cruiser" top. The headliner hasn't gone in yet, so I have a once-in-a-van-lifetime opportunity to pre-wire for radio antennas. But, it's tough to figure out what I actually will need without having used and experimented with the van. I would appreciate comments and advice on my plans.

2. UHF/VHF Ham - I don't have a ham license yet, but I anticipate getting one for short range communication. I plan on pre-wiring an NMO mount on the roof to a cabinet behind the driver. I'll use an antenna like the Larsen NMO2/70SH with a radio featuring a detachable front panel, and the front panel will go on the dash.

Consider where you will be traveling. If you go into forested areas, a roof mounted antenna may be wiped off the roof by tree limbs. I have to go up and remove or bend over my dual band antenna for limbs. Its not hard with a penthouse, but with a cruiser ??? I also have a short Comet B10 mounted on the drivers side fender primarily for APRS work. It performs quite well.

Originally Posted by Advanturetrek

4. HF Ham - I don't have a ham license yet, but I anticipate getting one for long range hobby and emergency communication. I plan on prewiring from a cabinet behind the driver to the rear of the vehicle for possible addition of a portable antenna, such as a Buddipole, or a permanently mounted screwdriver antenna.

I mounted my High Sierra 1800 screwdriver to a home-brew bracket attached to the Aluminess swing-arm bracket. It works great! This week from S/E California I was hitting Russia, Japan, the East Coast, Canada, etc.

Here is a link to the ultimate ham radio mobile installation guide. Before you do the install, read everything he has to say. Everything is explained including ground plane.
http://www.k0bg.com/

[Advanturetrek]

Thanks for the tips and links.

cygvan: Some antennas require metal beneath the antenna, called the ground plane, to function properly. This is, obviously, a challenge for many of us since we've replaced most of the van's metal roof with fiberglass.

charlie56: Thanks for sharing your setup. I am concerned about height, and I do like forests. It is helpful to have your positive report on a bumper mount -- I may go that way instead of worrying about tearing off a higher antenna.

Anyway, I'll share whatever I end up doing. I'd appreciate other experiences, especially with bumper mount antennas.

Thanks.

[GMAs]

Ahhh the old antenna mounting trick... which allows for two options...

Drill/cut and bend

or

Attach with out changing the sheet metal...

Lets take the last one first...

You can go with magnetic mounts for the UHF/VHF / CB antenna. If you look at Accessy Unlimited... you can find the Stainless Steel Van mount which goes on the left hand side of the van between the hood and the fender. I use the Model # AUVAN... but, I have to modify it so as to make a 3/4 inch hole instead of the 1/2 inch one that comes with it... remove the 1/2 inch stuff... for the cb whip antenna... and put the NMO mount on it instead... remember SS is tough stuff to cut.. so I went to a EDM water cutter shop and they did it for a couple of bux... otherwise... hand grind it to the 3/4 inch ROUND hole... fileing is not a option. Now this works for the left hand side of the van (drivers side)... and you can get another for the right hand side to mount the same way .. so as to have CB and Ham... as the NMO mount will accomidate the 2 mtr and 440 dual band antenna. You have to drill two more holes... along with the fender hold down bolt... that already is their... but, when you remove it.. no one is the wiser... and no big gap'n holes are to be seen... coax is routed inside through the firewall... and you can unscrew the antenna.. leaving only the nmo mount exposed... so no one will steal you antenna when your gone... kinda thing...

Otherwise...

You can go up top side... and use a magnetic mount... stick on... which then is removable.. howver, the coax feed wire is always going to hang out... some use duct tape to hold the wire in place.. but, others just let 'er flop in the breeze and run it in through the door seal... either way.. its not a perm mount... where as the fender /hood mount is semi perm...

the other way...

Go look on Utube and see how to drill a 3/4 in hole in the roof of a PU and put a NMO mount up top side... remove the headliner.. and go at it... as this is kinda perm... but the NMO mount has a O ring so that water leaks are not ... If you don't like the idea of cutting up your 80,000 bux van.. you can always take it to a mobile 2 way radio shop .. and they will do it for you... with cost... and yep if you hit low hanging branches.. its going to give the antenna a different look... in the zoom dept. No need to worry about someone stealing the antenna.. as you will also find it hard to get up top side to get at it...

As to which works best.. of course the higher up the better range... kinda thing.. but either works good enough to get the program done...

the third option is to attach 'em to the light bar.. or roof rack.. if you have 'em...

and the forth option is to have someone attach them to the brush/hd bumper on the front of the van... This either requires that you strap it to one of the bars... or have someone weld a tab on the bumper guard... which make it kinda perm... of course if you also put driving lights on the new HD bumper... one can have them put the same kind of tab with the 3/4 in hole on it too...

As to the HF ham antenna...

One can look at the trailer hitch... either front or rear and make a reciever bar to go into it... however, that then takes up the hitch... and if you want to pull a trailer.. ops... other option is to get out the metal working tools and make up a side reciever... to mount it on.. either way.. this requires some heavy cutting and welding to make one stout enough to stand up to the off road environment... We usually use the left side due to the better road clearance above... so we are not whacking the tree limbs going down the road... and you can see it better with the rear view mirror... if mounted on the left rear out the side. Now the down under AU blokes mount their HF antennas on the front of the vehicle... which allows one to view it.. as well but, I perfer mine at the rear... so the pattern is to the right front forward.. and not the right rear backwards... like the AU's do.

By the way... the High Sierria and other screwdriver antennas... will work from 3.5mc to 30 mc.. so indeed you can also use them for CB... and as we do.. with the icom 7000 ... broadcast bands at night for entertainment when fully extended.

Good luck on your ham ticket... C U on the band..

WA6CDE

[macmcintire]

I am joining this discussion merely because it is an area of interest and I want to follow the discussion. However, I do have a cell phone booster in my rig. I've been able to receive cell coverage when I've been out in the boonies where there was no normal coverage. It's great. This is the cell phone booster I use:

http://www.amazon.com/Wilson-Electronic ... 856&sr=8-4

[loren85022]

Mac, one of the Amazon comments regarding the Wilson booster was that you and the phone had to be quite close to the booster. What is your experience?

[macmcintire]

Originally Posted by loren85022

Mac, one of the Amazon comments regarding the Wilson booster was that you and the phone had to be quite close to the booster. What is your experience?

Yes, that is true. Sometimes I literally have to sit in the seat where the receiver is located. At other times I just need to be near the van, with near meaning within a few feet.

[geoffff]

I have the ~4 ft CB antenna Sportsmobile put on the van. It's taken quite a beating hitting tree branches -- I don't really hold back. It also sways (whips) quite a bit when the van is rocking. After 50,000 miles or so, the roof mount is cracked and almost broken, and the antenna itself recently snapped about 2 inches from the bottom.

-- Geoff

[loren85022]

If my antenna is ever whipping whilst my van is rocking, please wait 10-15 mins before you come talk to us about the situation.