Tuesday, February 7, 2012

Internet Access by Cell Modem and Router

This is one of the various ways of accessing the internet - wi-fi, cellular and satellite. This article is a subset of the cellular route. For more information about cellular access, see the Internet by Data Card and Internet by Cell Phone Yahoo groups. For more information about other access methods, see Internet Access in your RV

While traveling last summer I was using a Cradlepoint MBR 900 router mounted in the rear of the cabinet above the dinette. The LD factory had installed a 12VDC outlet there for this purpose and a vent cover on the roof above the cabinet for through the roof access for an external antenna. I had a Millenicom Novatel U760 air card plugged in the USB port on the router that was in turn attached to a 12" 5db gain magnetic mount antenna placed on the roof of the LD behind the AC. I bought this antenna from the 3G Store online. I had glued a 5" galvanized sheet steel plate to the roof for the magnet attach.

[Notes 1) Kyocera makes a router competitive with the Cradlepoint. 2) 12v wires can accessed by removing the bin panels. 3) The antenna wire can be lead through a roof vent.

1 antenna
Magnet Antenna attached to sheet steel placed in center (side to side) of roof for best ground plane.

Rear of AC @ top of photo

2 antenna wire entrance

Vent cap to cover wire entry point

I subscribed to the Millenicom "Advanced Plan" ($60/month) system that uses the Verizon digital network for our internet service while traveling extensively in the western states during the Summer/Fall, 2011. We also use Verizon for our cell phones. Since we boondock in remote areas extensively, we didn't always have service. That was OK as these locations were some of the most beautiful. However, we did stay in some places that were quite remote but we did get the internet when the cell phones didn't work. I attribute this to the fact that the cell phone, due to low transmit power, has less range (even standing on the LD roof for elevation) than the Millenicom air card using it's gain antenna/ground plane.

While at the Tampa RV Show I bought an internet/cell system amplifier kit that Wilson Electronics makes from a Florida vendor, CellKicker. Their price at the show was about $400. whereas the 3G online store sells the same kit for $530. The kit consist of the Wilson SOHO 50db amplifier, a Wilson Indoor Directional Antenna, 20' antenna extension wire, and a Trucker 5db gain antenna with a pole mount spring base to attach to the ladder on the LD. Since I already had the 5db mag. mount antenna in place I used it instead of the trucker antenna.

The installation: I mounted the Wilson SOHO amp near the Cradlepoint router and used a 12VDC "Y" adapter for the two power plugs going into the single 12V wall socket. I modified the "Y" adaptor by adding a rocker on/off switch on the output of the adaptor. The switch is on an extension wire below the cabinet above the rear dinette seat for easy access.

3 wilson amp

4 switch

I mounted the Wilson Indoor Directional dual band antenna on the wall where the TV bracket is located above and behind the driver's seat.

5 wilson indoor antenna

I routed the antenna wire from the amplifier along the back of the cabinet up to the shelf above. Access holes were already in place for other TV wiring done by LD. It was recommended by Wilson to get as much distance between the indoor and outside antennas as possible to prevent feedback oscillation at the amplifier. Twenty foot spacing is recommended by Wilson, however due to the full metal roof and sides of the LD the 13' spacing I had was adequate to prevent feedback between the antennas. There are two LEDs on the amplifier that glow red if this is occurring or glow green if all is functioning properly. To test this, I turned on the system with the LD parked inside my metal shop which gave me a red indication. I immediately turned the amplifier off. To complete the testing, I moved the coach outside well away from the shop under a lot of big trees and re-activated the system which then gave a green indication. With the system off, my cell phone showed a signal strength of one bar for both the 3G and cell networks as we are located some distance from the Verizon tower. When switching on the amplifier, both network signal strength indicators went to a full four bars. All worked as advertised! All I have left over is the Wilson trucker antenna still in it's package.

Note on another modification shown in above photo: Last summer I replaced the outside TV antenna amplifier with a Winegard digital antenna amplifier that is shown to the left of the White Wilson antenna. The Winegard was very handy in locating local digital TV station towers.

Mike Coachman

If your Wilson Amp gets hot, here is how to mount it on a heat sink.

First I fabricated a piece of 1/8" aluminum plate (I found in my scrap bin) to mount the amplifier to. The amp was about 6.5" X 4" so I cut the plate to 12" X 7" mainly to fit on the back wall of the cabinet. Using the wire brush on my grinder, I removed the blue paint on the flat aluminum back of the amp housing for better heat transfer. Did the same to the oxidation on the aluminum plate coating both with a thin layer of dielectric grease to prevent future oxidation. I then screwed the amp to the plate and the plate to the wall using some rubber grommets (vibration damping) as stand off for better air circulation around the plate to dissipate the accumulated heat generated by the amplifier. It may be overkill, but it certainly can't hurt anything.

1 Alumunum heat sink plate2 Rubber groment mounting spacers

3 Full setup router, air card, & amplifier

If you really like to be out in the boonies, you might want to consider the installation of a directional yagi antenna on a telescoping mast.

Contributors: Mike Coachman, Larry Wade

Revised: 7 Apr 7