radio

Communications

July 2nd, 2010, 21:31 hours

Given the limited space, low dash, and stadium-style seating in the Discovery, the best solution for mounting additional displays and controls turned out to be a custom dash pod. This position on the dash allows for easy viewing on the road, no obstruction of the road from the driver’s seat, and minimal permanent changes to the vehicle.

The pod is built out of 1/8th-inch aluminum plate assembled and ground smooth to match the contour of the dash. On the top of the box, two small speakers provide better sound quality from the radios and conceal access to the only two bolts required for secure mounting. An internal frame holds the CB radio, power wiring, phone charger body (USB based), and the data/audio splitter for the phone (routed to the stereo for music playback). Surface-mounted on the face is a Pro-Clip cradle for my phone, microphones for the CB and amateur radios, the display/GPSr of the amateur radio, dual 12-volt power ports, and dual Anderson power poles.

Underneath the passenger seat, a 1/4th-inch aluminum plate holds the guts of the amateur radio and other wiring where the original CD changer used to reside. An APO-3 cuts power to the aftermarket equipment before the battery’s charge drops too low to start the vehicle, and a RIGrunner 4005 distribution block provides clean wiring and the ease of Anderson power poles.

A slight trimming at the bottom of the “B” pillar allows antenna cable in protective conduit to slip in and up to the roof. The power cabling follows a similar route forward under the foot plate and passes through a factory-provided grommet in the firewall to the engine bay.

Once through the firewall, the 8 AWG wire heads through a 40-amp circuit breaker for fuseless protection, and has ample capacity remaining for a planned carputer setup. The primary battery has also been upgraded to an Odyssey 2150.

Tags: amateur, Anderson, cb, Discovery, Fuze, HAM, Land Rover, phone, power, power pole, radio, radios, stereo
Posted in LR Discovery | 1 Comment

OAUSA SummerFest (Field Day) – Big Bear, CA

June 29th, 2010, 08:57 hours

4×4s, camping with friends, great food and wine, and amateur radio – what a great weekend. Here’s the contact map (and a link to the forum) from OAUSA’s first Field Day…

Dani finally got a chance to tinker with HF, and managed to log a few contacts herself (including Guam). She has been bugging me for new radios and equipment ever since. I’ll have to admit, while I’ve appreciated the capabilities of HAM radio for some time now, I never fully understood it’s potential for practical application until we used the repeater to co-ordinate dinner plans between 4 different groups on the road with 35-miles of mountains between us on Saturday night. Doing so was actually easier to accomplish under those conditions than it would have been with all of us sitting at home on a conference call.

While our primary purpose on the mountain this weekend was participation in ARRL’s Field Day, several groups did get out for some wheeling. On Saturday morning we headed over by Arrowhead Lake to run Willow Creek trail, a scenic route I’ve never been on before.

After Willow Creek, we continued up Dishpan Springs, a trail I haven’t seen in 10 years. The fire a few years back has left the place in a barren, almost desert-like state. The forestry service has also removed the best part of the trail, the T-6 water crossing, and replaced it with a concrete bridge and a parking lot. The first picture is pre-fire and pre-bridge back in 2001…

Despite being short a water crossing and a rock garden, Dishpan is easily twice as difficult as it was 10 years ago. About half way up the trail we ran into a six-foot-tall wall of rock where once there had been fire road (courtesy of fire damage and a harsh winter). We considered our options while watching the Jeeps tackle the newly improved “waterfall”, and bumped into a couple fellow ExPo‘ers visiting California to pick up a Flip-Pac. Ultimately, our new friends and us decided we were better off heading back to camp for chili and cornbread. Maybe next time… after I get my rock sliders installed.

Back at camp and resupplied with firewood we enjoyed a small potluck of chili, steak, cornbread, various wines, and of course… cake! I also had a chance to try out some low-light, long-exposure photography with the tiny Canon SD940is.

On Sunday a few of us ran up Gold Mountain before Dani and I headed back to the desert. It has also been torn up pretty bad since I was last here (a mere 3 weeks ago). The trail looks as if someone sat in all the difficult spots and spun their tires for a few hours, and many of the bypasses have been blocked off. Still, we all made it through and even managed to bring a stock Xterra with us unharmed.

As always, the rest of the pics are in the Flickr set…

Tags: amateur, Big Bear, California, camp, camping, Field Day, OAUSA, Outdoor Adventure USA, radio, San Bernardino Mountains, San Bernardino National Forest, SummerFest
Posted in Trips & Travels | 1 Comment

Antenna/Light Bar OTC

March 8th, 2010, 18:26 hours

I wasn’t originally going to post this, but the ~~end~~ intermediate result turned out so well as to deem it worthwhile. In setting up the forward mount for the roof rack I had planned to pick up, I found out just how easy (and inexpensive) it is on a Discovery to add mounting space for antennas, lights, or whatever else you may want to add up on the roof. To make the bar, you’ll need:

1/4-inch x 3″ x 48″ aluminum flat bar is more than enough for antennas, consider 3/8 or 1/2-inch thick if you are going to add lights (or tweak as necessary for your needs)
four 8mm-1.25 bolts with matching flat washers (double-check this if you have a pre-2004 Discovery)
tape measure, a marker, a 4mm allen wrench, a drill with a 9mm (or 5/16ths) metal bit, a chop saw or even a hacksaw (aluminum is easy to cut), medium file (for rounding edges), fine-grit sandpaper
mineral spirits, bedliner and appropriate brushes (I’ve had good luck with Rustoleum, Duplicolor came out awful)

Home Depot carries the bolts and washers, Metals Depot has great prices on the aluminum.

There are two threaded holes near the rear of each factory roof bar on a Discovery, these are intended for the OEM cross-bar accessory for which Land Rover charges ~$300. These holes are weight-bearing and designed to handle things like canoes, roof racks, and other cargo. They also make for quick-and-easy attachment points for home-built accessories. With the 4mm allen wrench, remove the two protective caps currently occupying these holes. Then grab your aluminum bar and start measuring. I suggest adding a curve to the aluminum bar as this will add strength and rigidity, and provide additional clearance for your antenna/light mounts.

The pictures are pretty self-explanatory. Measure twice and drill the holes in your aluminum bar, including the holes you’ll need for your accessories. Once that is done, test fit the bar with your lowest-hanging accessory and bolt it down so you can make sure nothing touches. At 48-inches, the aluminum flat bar will be within a couple inches of where it should be so you’ll only need to trim a little off the end. Measure and mark for the amount you wish to trim, then take the bar down and trim it. Double-check the fit, then use your file to round the corners and the leading edge of the bar (for aerodynamics). Sand it down all over with the fine-grit sandpaper, then rinse the bar well with mineral spirits and allow it to dry. Follow the instructions that came with your bedliner, and give it an extra day of dry time before attaching the bar. When the bar is completely dry and hardened, attach it and your accessories to the roof. Once everything is in place you can use a little extra bedliner to cover up the shiny bolts.

A Note on Wiring

There is only one clean way to run wires down off the roof, and that is to drill a hole. Despite the horror stories regarding such things, if done right there is no reason for this to cause any leaks or rattles. Where you place the hole is really a personal preference thing, but the location of the new antenna/light bar does happen to be right above a spot in the headliner that has ample room for wiring and an access panel to get at the roof. This panel can be found by sitting in the rear seats and looking up… it serves double-duty as a dome light. Pop the lens off of the light, then carefully pry the light housing out of the surrounding plastic. With the assembly out you are looking up at the bottom of the roof metal, right where the new roof bar is located. A little careful planning and some fish tape and you can finish up wiring your new accessories without even dropping the headliner.

Tags: aluminum, amateur, antenna, cb, cb radio, Discovery, HAM radio, Land Rover, light, lights, radio
Posted in LR Discovery | 1 Comment

Elk Antennas 2m/70cm Log-Periodic Dipole

February 19th, 2010, 15:00 hours

I’ve had nothing but trouble trying to get on the not-so-local Keller Peak repeater. At first, I figured this was just due to my limited equipment (a handheld radio with the stock rubber ducky at the time) and had all but accepted the fact that I would have to either drive up the mountain, or live with EchoLink delays and drops (which are really bad on Time Warner’s horrible service). Later, after getting a decent mobile radio and antenna set up in Dani’s truck (and verifying it was installed right by testing on simplex), I realized equipment might not be the whole problem after all. I did several trial runs by sitting on EchoLink to verify there was, in fact, traffic and listening in on the mobile with the squelch turned off – still nothing but sleep-inducing white noise (not even the occasional garbled static).

I mentioned this to a friend not long ago, and with his help was able to get this elevation profile:

So, I’m just over 55 miles from the Keller Peak repeater… and half of that distance is through solid rock.

Enter the Elk

On his recommendation I ordered an Elk Antennas 2-meter/70-cm antenna, along with their carry bag since I figured this would end up becoming part of my standard kit in the truck. The antenna packs down small in the bag (about 24 x 6 x 1.5 inches) and is very light and easy to assemble. All of the individual rods are color-coded so there is no confusion getting them in the right order, and everything goes together without tools. The mount fits snug onto 1-inch PVC conduit readily available at any hardware store, which I have since cut to the length of my roof rack for easy transport.

I was able to test it out for the first time under less than ideal conditions (mostly my fault), and I am very impressed. Despite my hastily assembled “pile of firewood and a ratchet strap” mounting bracket, only knowing generally what direction the repeater was in, using the only very poor coax I had on hand, and with strong winds blowing the entire assembly around I was able to hear the repeater crystal clear, and transmit to the repeater with a scratchy-but-useable signal, which would impress everyone from ADT security experts to communication tech-wizards.

(Keller is behind the mountains in the distance on the right)

I think with a proper mount and an accurate bearing from here to the repeater I’ll be in business. I also think I’m going to order a second Elk to leave in Dani’s truck – something so useful and so easy to carry, it almost seems silly to be traveling the back country without it.

Tags: amateur, antenna, dipole, Elk Antennas, HAM, portable, radio
Posted in Geek & Technology | No Comments