Shack in the Box

Shack in the Box by Ki4MPZ, Paul

At several club-supported events, I’ve seen the need to have a cross-band repeater to boost the power of my HT to reach the Net Control Station via a distant repeater. The objective: Assemble components for cross-banding 2-Meter & 70 cm in a compact, portable frame that can be quickly set up in the field. The assembly must have a 120 VAC power supply (for use when shore power or generator is available), an on-board 12V battery, and be able to accept a 12V feed from a solar panel controller. With a 15A battery and power supply, the final assembly weighs in at 22 pounds, so it’s portable but not very pack-able.
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The rig shown sets up in minutes by opening the lid, attaching an antenna cable to the SWR meter, attaching the battery to the low-loss power gate, turning the radio on and programming the correct channels. Extended operation requires connecting to a solar panel or the on-board power supply with 120 VAC shore power (or a generator).
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Typical set up times: Antenna & Mast 20-30 minutes, Generator or Solar 10-15 minutes 

Other components that I have for a field set-up

POWER

Ryobi 2200W gasoline-powered inverter-generator
Renogy 50W monocrystalline solar panel (22” x 24”) with controller and adjustable pedestal mount on a 5-gallon bucket with 50 lbs. of concrete.
Optional, other 12V batteries charging from the solar or power supply for additional storage.
 
RF

Tram 1480 2M/70cm vertical antenna; 6db; 8’ tall.
28’ Aluminum Mast/Tripod kit with eight 42” mast sections to assemble from 7’ to 28’ high.
UHF HT for two-way cross-banding, or
Dual-Band HT for either one-way or two-way cross-banding               
 
SHELTER

Folding table to keep the “Shack in the Box” off the ground. Folding frame & cover that sets up over the “Shack in the Box” to provide shade. 

Components and Sources
  1. Kenwood TM-V71 Dual Band radio (2M/70 cm) with 50W output; has 1000 memory channel capability; remote head; simple field programming “on the fly” and handles one-way & two-way cross-banding.
  2. Roadpro RP-160 flat 3.5” dual speakers (re-wired for separate left/right channels.) www.ebay.com
  3. MFJ 4230MVP compact switching power supply (30A) with Anderson Power Pole connectors on rear.
  4. Universal UB-12150 12V (15A) Sealed Lead Acid battery. www.amazon.com
  5. Bat-Pac (model M4) battery adaptor that allows battery connections via Anderson Power Poles, has digital battery meter and dual USB 5VDC outlets. One Anderson P-Pole connector feeds LL-Power Gate (below) and second connector accepts feed from a solar panel controller. www.portableuniversalpower.com
  6. Ki0BK’s Low-Loss Power Gate automatically switches from power supply to battery without interruption of operation in case of power failure; trickle charges the 12V battery; and has 3 sets of Anderson Power Pole connectors for 3 components (25A max).
  7. Ki0BK’s Battery Status Monitor – gives visual status of battery’s charge condition. Both the LLPG & Battery Monitor are from http://ki0bk.no-ip.com/~PWRgate/LLPG/Site/Welcome.html
  8. Workman model 104 SWR & RF Power Meter www.amazon.com
  9. Thermostat-controlled cooling fan mounted to cross-band repeater – uses SMAKN 12V controller with dip-switch settings for on/off threshold, and common 12V 4” cooling fan www.amazon.com
  10. Aluminum frame (home-built) 16” x 8” x 8” constructed of ¾” square tubing (hardware store) and nylon 3-way frame connectors found on Ebay (from seller flourishco). Brackets homemade from aluminum flat stock and angle (hardware store); hinged lid is remnant from plastic cutting board.  
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