How this specification was developed
During the 1995 Baker-to-Vegas (B-2-V) race, we only needed a small number of trackers, and the equipment was provided by a few gracious vendors (Alinco, AEA, and Trimble), either for free, or at a discount. This allowed us to build identical packages (same radio brand & model, same TNC, and same GPS receiver) so our configurations were consistent. Physical packaging involved using nylon wire ties in loops, to suspend the 1995 equipment packages within some 6 gallon tupperware-style tubs. After the race, the radios and TNCs were sold to members of the support group.For the 1996 B-2-V race, we needed to equip more than twice as many vehicles. However, most of the equipment wasn't available to rebuild the original trackers from 1995, so we relied on loaned equipment to make up the bulk. As a result, we lost the consistency of 1995, and had to develop a modular wiring plan, to allow ease of configuration and field-swapping of any failing components. Physical packaging was also inconsistent in 1996. Unfortunately, one radio was physically damaged during the 1996 race, but the cabling allowed for easy field replacement.
For the 1997 B-2-V, we decided we would need to try to create a standard tracker package, including the physical packaging. The concerns were;
- keep packages similar in construction and packaging (easy to identify)
- use the modular wiring diagrams, with a few modifications
- provide a method for folks to easily use their radios and TNCs in their shack as well. (We realize that not everyone is going to want to have their tracker in their vehicle all the time, but would be willing to loan it out as needed, on a temporary basis. Even 'permanent trackers' should be built to these specifications, to increase the available pool for emergency use.)
Randy Foutch (KE6HCI) was the first to find some waterproof containers at a local Wal*Mart store, for less than $10. They are a bit larger than a hanging-file storage box, and bright safety orange, with a gasket and a lockable latch. (Granted, the case IS plastic, so the lock is not going to provide much security, but it is something.) Others have suggested military surplus metal ammo cans, or even newer plastic ammunition boxes from local sporting goods stores. Mark Keiser (N4OGL) built a good tracker in a metal ammo can, including chassis-mount pass-through connectors for data and antennas, and LOTS of sealing compound on the nuts and bolts that penetrated the metal casing! The physical details of the Wal*Mart box are shown below.
Paul Carlin (KE6NVU) made a mounting bracket insert for his plastic Wal*Mart box, to allow for easy mounting of hardware within the box, without puncturing the case. (There should probably be some type of cutout to allow the power and antenna cables to pass through.) This mounting bracket also allows him to quickly and easily remove the gear from the box, for use as a fixed station for packet or voice operations at home or at other locations.
Paul brought his prototype to the CLUES meeting, to discuss the use of this type of bracket. At the meeting, we discused the needs for Baker to Vegas (standardized installation, and the ability to easily use the equipment for other things, without the need to dedicate equipment for a tracker, using standardized connectors to allow for easy swapping of failing components in the field), and the way the bracket was designed. As a result, we made a few suggestion for improvements, but we decided that this insert was just what the doctor ordered! The images below show the view from above, looking down at the closed case (on the left), and with the lid open (on the right).
(Mount your Radio and TNC so that the displays are right-side-up using it on a desktop.)
Paul has ordered 10 sets of these insert kits to be made at a local plastics shop (TAP Plastics). The cost is expected to be less than $20.00. After adding some velcro and wire-tie anchors (see mounting details below), we figure that a standardized APRS mobile tracker package can be built for less than $40.00. Of course, that is for the "package". Radios, TNC, and GPS receiver still need to be added.
We are going to consider ordering more of these insert kits, if there are enough requests for them.
Building a tracker for Baker-to-Vegas 1999
We'll be using a modified version of the 1996 cabling scheme for the 1999 relay.
You can view the changes on the 1999 wiring overview page. The ideas behind
the packaging are to extend the idea of wiring consistency to the package, and
to provide a packaging system that will allow folks to use the radio and TNC
in their shack, on a shelf or desktop, and still be able to
convert it to mobile operation quickly and easily. By incorporating an insert
(physical details shown below) with the orange Wal*Mart box, and using the wiring
diagrams on the cable and wiring overview pages,
the mobile trackers will be easy to work on for the technical team at B-2-V
'97. The inserts we used are made of Poly-Carbonate plastic, but Plexiglas,
or standard sheet Acrylic should also work fine. (Make sure that the bonded
joints are made well!)
The two 1" holes are 'finger holes', to make it easy to install and remove
the insert. The 2" hole is a cable and connector pass-through. The 2"
diameter half-circle is to pass the cables behind the unit when you are using
it on a desktop, instead of in the mobile tracker box.
Mounting devices to the frame should be done using strong velcro. In order to
be interchangeable, this means that the hook-and-loop style fasteners should
be used, as opposed to other styles. (This is so we can swap hardware out in
the field, if needed, and not worry about how to keep the new piece from bouncing
around inside the box.) The "Loop" part goes on the insert, and the
"Hook" part goes on the equipment.
Keep in mind that the temperatures in the boxes could reach the high 90's (farenheit)
or above, so if you use the cheap velcro, it will probably peel away from the
insert during use, leaving your equipment to bounce around inside! The Velcro
folks (The company who patented hook-n-loop fasteners) developed a product designed
to hold up to earthquakes, and it holds up well in warm environments. Try calling
or mailing for a catalog from the sources below;
Quake-grip Velcro stuff -- Q-Safety, 2335 Foothill, Pasadena,
CA 91107
(v) 818-449-1590 (f) 818-449-6866 We've used part # 2801 (9'-roll of quake-tape
velcro)
Thumb Lock Safety Fasteners -- Fastening Solutions, Inc.,Van
Nuys, CA 91411
(v) 818-994-6398 Look at the model TL-100 (small pad) and model LS-36 (36"
long extra strap). They also carry a line of fasteners that are also security
devices...
In addition to the velcro attachments for the equipment, you should use self-adhesive
nylon wire-tie anchors to hold power harnesses, and other cables for your package.
These will keep the cables in place as you move it from box to desktop, and
back to box again. It will also keep your cables from getting tangled with any
other cables you put into the box, like the power harness to the battery, serial
cables for the TNC, and assorted adapters, the external GPS antenna, or mag-mount
antenna.
You should label ALL of your cables and accesories with your
callsign, and with the equipment information (i.e. "PK-12",
"Alinco DR-1200", etc.), so they are easily identified. It will also
help ensure that parts that you loan out seperately will get back to you!
Engraving your name and callsign in the handle of the box is a good idea, since
it's pretty hard to get paint (or anything else, for that matter) to stick to
the box. The plastic material is practically impossible to glue to, which is
why we went to the inserts. (It would have been hard to get the sealant to stick
if we had drilled holes in the case!)
One other modification we came across is the use of a rubberized canvass matting,
available from marine supply stores, between the bottom of the insert and the
bottom of the case. This material is used shipboard to keep plates and things
from sliding around. In the bottom of the box, it not only keeps the insert
from sliding around, it also virtually eliminates rattling between the insert
and the box. It's not too expensive, but is usually sold from 1-foot wide rolls,
so you may wind up with a bit more than you need. (You could always use the
extra in your shack, or the local EOC.)
Other Links: [Wiring Overview] [Tracker Packaging] [the Staffing Mailbox] for questions, fill out a [Volunteers Form], visit the Photo Gallery, or the [Headquarters Page].