by WD0GPS

When I first got my license, friends acknowledged that while it might be a nice hobby (for you old retired guys), the question always asked was – “but what is it good for”?  When I gave the standard EMCOM answer and got the standard “thats what cell phones are for” answer, I knew that I was not going to be satisfied with just an HT and a base station.  YouTube provided some ideas, and being a good HAM I didn’t want to get a ‘canned’ solution since building something would be more than half the fun.  (Plus, I got to buy several new tools)

My wish list included the following:

  • Greater than 15Ah battery
  • Solar panel for field charging
  • At least 25W VHF/UHF radio (DMR would be nice)
  • 100W HF
  • Laptop PC for digital modes, logging, software updates/codeplugs.
  • Ability to charge my AnyTone HT from main battery
  • Voltmeter
  • Headphone/Speaker jacks
  • DC power ports (USB, powerpole, 12v cigar)
  • Light for night ops
  • Self contained except for antennas and feed lines

We are gonna need a bigger box.

Looking around in the garage I remembered that I had what looked like an overgrown (17” x 8” & 13.5” deep) .50 cal ammo box.  That ought to be rugged enough.  The next big question was whether I could build an ‘insert’ for the box that could fit all of the components required to meet the above wish list.  In order to determine that, I needed to know the exact sizes of the major/large components.  Fortunately the laptop I have was 13.5” wide and fit nicely even with the lid on the can.  The real issue was going to be the solar charging system since it would require a charge controller specific to the type of battery.

Power System

My research led me to explore LiFePO4 battery options, which are maintenance  free, rechargeable, lighter than lead acid, and available in an 18Ah size.  I got the ML18-12LI 12 volt, which met the size requirements.  Bioenno Power offers both a 12v LiFePO4 charge controller (SC-122420JUD) and a 28W folding solar panel (BSP-28) which when folded has a smaller form factor than the laptop.

Wanting to be as flexible as possible, I want to be not only able to charge the battery with solar and a grid charger, but also power the whole box with a 25 amp power supply when that makes sense.  Using power poles to connect the battery to the main wiring harness makes this a simple setup.

Radios

While there are many VHF/UHF mobile units available, I wanted to leverage the experience and available code plugs we use with the AnyTone HTs.  The new AnyTone AT-uv578III pro offered all that, and included DMR,APRS,GPS, and the 1.25 meter band in a 50W radio.  Another nice feature is that it has a crossband repeater function, which could be very useful in certain ARES scenarios.

Selecting the HF radio was also straight forward, since the wish list included 100W and space is at a premium the Yaesu FT891 popped to the top of the list.

Building the insert

Fitting everything in and making it useable required building a cardboard model to determine the orientation and placement of the major components.  Keeping all the wiring out of the way and having room for airflow to reduce excess heating problems was also a goal in the modeling process.  After trying ½ inch plywood for the main structure, I was forced to change to ¼” due to space requirements.  I also used ⅛” mason board for the shelves and faceplates.  In order to save on current draw I used separate switches for the radios and the DC outlets.

Overall I’m very pleased with the result and look forward to using this unit for years to come.  Coming in at a bit over 50 pounds (without antennas or feed line), it is not likely to wind up on many summits, but this Solar Generator/Go Box, should more than meet most requirements I’ll run into.

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