VHF/UHF Go-Box in Detail

Last week I posted a few pictures of my completed VHF/UHF Go-Box so now I’d like to explain more about it and the reasoning behind my choices. My design requirements for the go-box have developed over that past 6 to 9 months and have changed many times since it’s initial conception. I originally wanted to build something that would contain much more equipment including a second VHF/UHF system, 1-2 scanners, and an HF rig with meters and tuner. I quickly decided that something this size would either never leave my bench or it would never be used due to it’s size and weight. This is a post I made a while back showing the initial enclosure system I planned to use which tailored for ARES/RACES and Field Day type operations before I considered daily use and portability.

Design Requirements

Skip forward a few months and after much more research, planning, and seeing KB4RMA’s completed go-box I finally settled on what I required out of this project (in order of importance):

1. Must be built for regular daily use.
   — The decision was made to make this my home base VHF/UHF until a later date when it will likely move to my office at work.
2. Must be self contained for basic use.
   — Box must house all components for basic use including radio, power systems, cords, cables, etc. This does not include extended battery operation, antennas, and digital mode equipment.
3. Total size must be small enough to be used for mobile operation.
   — KB4RMA had the idea for this utilizing the RAM mounting platform. Swapping to a RAM suction cup mount and extended remote head and audio cables allows for the go-box to sit behind the front seats of most vehicles out of the way while the remote head and speaker is mounted to the windshield or dash. Space is tight with everything in the go-box for transporting but it fits.

Along with those initial requirements I had a few more add-on requirements that would go along with the go-box:

1. Additional external battery pack for extended battery operation.
   — Using a box very similar to the one the go-box was built from I have 8, 7Ah batteries salvaged from a UPS system. This provides me with an external 56Ah source that can be connected to the go-box if needed. Following with my philosophy of everything needing to serve more than a single purpose or use I regularly use this battery pack to charge HTs, charge my phone and tablets, run a 120v inverter, and power other 12v equipment.
2. Accessories including digital mode gear.
   — I am currently refining the box and what is in it but at time of writing I have another box that carries all of my radio programming cables, extra adapters such as Powerpole to T-connector, HT chargers for my EDC HT, Signalink and accompanying cables for digital modes, and my Yaesu FT-1900R VHF transceiver which I use when running digital or during ARES activations.

General  Design

I’ll have to be honest in that this is actually the second box. The first box suffered a critical design flaw when it came time to mount the controls and wire everything up…… I did no planning and just went straight to installing components. This resulted in a layout I didn’t like, switches I didn’t like, and a general dissatisfaction with the entire project. A few days later I salvaged what components I could and began the planning and design of the new box. This was a lesson learned since I had to re-order several items like the LCD voltmeter, switches, and Powerpole connectors. When the planning started here’s what I considered:

Control and Monitoring

• Switched control of main power – Power Supply Unit and Battery
• Switched control of fans – Fans may not be needed if using batteries to power an external device
• Voltage display
• Switched voltmeter selection – PSU voltage and battery voltage
• Ability to charge internal (or external) batteries with internal PSU

Power Systems and Availability

• Internal PSU – 120V AC supply / 12VDC 30A Output
• Internal Battery – (2) 7Ah SLA batteries (originally planned for a third but needed that space to meet design requirement #2, self contained
• External Connections for anything in the field – Anderson Powerpoles, 12v Cigarette Lighter style socket, and universal banana/wire jacks
• 120V AC input accepts standard extension cords – No specialty cord needed if it should be damaged or lost

RF and Internal Components

• Dual-band VHF/UHF radio with remote head capable of 5w or less – Currently using a TYT TH-9800 Quad Band Transceiver (2m/70cm/6m/10m)
• Temperature control – Push/Pull fans mounted in lid
• (Future) Voltage Booster – To supply 13.8V to the radio even when operating on batteries
• (Future) Temperature and Low Voltage Alarm – Currently designing these circuits to be as small and compact as possible while remaining adjustable

Other Connections and Wiring

• SO-239 Panel Mount for standard PL-259 antenna connection
• 1/8″ mono audio – Required for external speaker
• RJ-45 passthru – For remote head connection
• Wiring sized for calculated load – 30A Powerpoles and 12V socket requires larger wire than other control functions like fans and meter

Conclusion

I am extremely happy with the final result. Everything works as I expected and there have been no issues with noise or any component failures. The fans are very quiet, the PSU works well, and everything fits inside the box for transport albeit a bit tight. My go-box is serving as my home VHF/UHF setup while being very easily transportable when needed. Just last weekend I used it during a presentation on digital modes at my local HAM Club meeting and had no issues at all. I’ll be using it with a mag mount antenna in my work vehicles when I’ll be out on the road a lot and also using it during an upcoming SET exercise. Future plans involve adding the voltage booster which will be a large space issue inside the box. The booster may end up a separate system so it can be used with my go-box or the external 56Ah battery system. More info on the battery box will be coming in the near future.

Until then, thanks for reading!