My membership in Winnebago County ARES/RACES and my occasional net control duties in public service events with the Fox Cities Amateur Radio Club led me to be interested in building a portable VHF station. Although it isn’t that hard to transport all the necessary parts loose in a toolbox and then assemble the station onsite, there is a big “convenience factor” in having a station pre-assembled and ready for transport.

An article in the August 2000 issue of QST Magazine described such a portable station, built in a toolbox, but the particular approach used involved lots of wiring and switches, which I wanted to avoid. I did a search on the internet and found lots of useful information, particularly at http://home.comcast.net/~buck0/combox.htm where several people contributed ideas, including SATURN operators who had helped following 9/11. Their SATURN stations particularly caught my eye. I then fairly quickly decided on the following design features:

Use a large box with plenty of room for air flow and include a fan for high power running
All power and RF connections go through the open front of the box rather than through the walls
Anderson Powerpoles for all DC connections with a power distribution strip so accessories can easily be plugged in and unplugged (instead of using switches)
An AC power supply and provisions for battery power with a meter for the supply voltage
A cross-needle power and SWR meter
Front-firing external speaker and a jack for headphones

After the initial build I discussed the station with Greg Schneider, W9IEI, and added two more features:

A lamp run off station power
Be able to recharge the battery from the AC power supply

My next step was to find the right box. After a fruitless trek through several hardware and home improvement stores looking for a toolbox sufficiently deep, I finally went back to the website showing the SATURN stations and realized that I had been in the wrong stores. What I needed was an MTM “Case-Gard” sportsman utility dry box, Model SPUD7-35 (the “35” is the orange color). I couldn’t find one locally, but with a Google search I found an ATV outfit in Illinois that sells them.

After getting the right box, the rest was pretty straightforward. The only parts I needed to fabricate were hold-downs for the power supply and meter (fashioned from small aluminum angle, cork strip, and long stainless bolts), a bracket for the fan, and the bracket for the RF output (made from bent aluminum flatstock and a UHF through-bulkhead barrel connector). The items of equipment I purchased were:

Icom IC-2100H/25N 2m transceiver (good eHam reviews, no fancy digital options, just out of production)
Diamond SX-40 cross-needle meter (small)
Astron SS-18 power supply (15 amps continuous, small)
Motorola SSN4020A external speaker (hard to find, but excellent sound, no distortion, small)
West Mountain Radio SuperPWRGate (expensive, but has smart battery charger and seamless transfer)
Military surplus mono headphones

I already had a Saratoga Products 1-in, 3-out power distribution strip, into which I put a 15 amp fuse. I also had on hand a small 12v computer “muffin” fan and a Simpson 15v DC meter that I had previously put in a case with an on/off switch. Finally, I added a Par Electronics pager notch filter. I built a 4 LED station lamp using a circuit from the webpage http://www.solorb.com/elect/solarcirc/4ledlit/ which works fairly well. I put together a DC extension cord to reach a battery on the floor and purchased a 15’ AC extension cord for the power supply.

I used stainless bolts and screws for mounting the equipment to the box, managing to get everything conveniently placed with some spare room on the left side of the box for either a 17 Ah gel cell or items like a logbook. Actually, there is enough extra space that I can fit in the headphones, extension cords, logbook, manuals, etc. while carrying the box. The rig manual and other paperwork is in a ziplock bag. A small compartment on the lid holds the lamp and pens.

The 17 Ah gel cell that fits in the box is OK for short public service events or as an emergency backup to AC power, but I plan on using larger batteries for longer, remote assignments.

I recently acquired some old Radio Shack HTX-202s and HTX-404s and rebuilt their battery packs. It just so happens that the external DC connector for these radios, which is the same for the trickle-charge connection on their battery packs, is the same as the connector used for my Simpson meter (2.5mm coaxial DC plug). Thus, if needed, I can use the station power supply to recharge my HTs’ battery packs or even power them directly if the main radio goes out.

(Click on Images for Larger Image)

Descriptions for Pictures

View 1. This view shows the station without the mic, voltmeter, and lamp, and with the power distribution strip pulled forward (on top of the power supply). The bottom of the fan, which is top-mounted and aimed at the rig, can be seen beneath the speaker. The aluminum angle hold-down brackets are clearly visible over the PS and the meter, and the pager notch filter is behind the RF connector on the right. The RF connector is UHF, but a BNC adapter is installed in this view. In the back right-hand corner is the stored DC extension cord, and a Nifty Ham Accessories quick guide to the transceiver is to the right of the power meter. The 17 Ah gel cell is on the left and fits nicely enough that it doesn’t have to be secured for normal transport. The SuperPWRGate is mounted to the top wall behind the speaker and can’t be seen at this angle.

View 2. In this view the microphone, voltmeter, and station lamp have been installed. The mic is held up with a little suction cup with a hook. The station lamp has a long, thin handle which simply slides through an opening between the lid and the box. The extension speaker is connected to the radio through a 3.5mm stereo Y-connector and extension cord. The other side of the Y is for headphones. If there are two ops at the position and quiet operation is needed (as at a shelter), the speaker can be unplugged and a second set of headphones used. While working noisy public service events it is nice to connect both the headphones (for the operator) and the speaker (for others).

Wisconsin ARES^®/RACES Works Along With