Repeater in a Box
a semi-permanent, moving mobile approach


This is one approach to getting a repeater to easily live in a vehicle with an eye on simple swapping to other vehicles as desired with minimum effort


I decided to box up the repeater so that it was primarily self-contained.  This would simplify moving it from vehicle to vehicle.  I additionally wanted to be able to turn the box on its side to that it could sit on the floor behind the passenger seat in a sedan if not placed in the trunk.  So the mounting of the repeater as well as the rest of the stuff inside the box could be kept intact in either type of "mounting".  The batteries are handled differently.

The repeater is screwed into and completes the forth side of the box.  The box height is abut 3 inches taller than the repeater to accommodate the router, the 12V controller and miscellaneous cabling.  The box has large holes drilled into the sides and back primarily for easy cable penetration as well as ventilation if either the power supply an/or RF power amplifier fans are switched active.

 The UHF duplexer/antenna is optional as I typically use a "leaky" resistor dummy load on the transmitter connector (at 1 watt RF output) and spike on the receiver connector, good for about 1/4 mile.  I use a default 10 Mhz split without a duplexer with no issues.

Use of batteries and the 12V controller enables continuous operation without regard to the vehicles "start" battery.  I have an optional 8 foot cable that I can power pole into the mux with a DPDT switch for router on/off as well as repeater on/off at the driver's finger tips.  I have had  a couple cellular issues that did require a reboot, so this approach is handy while in motion as well as flexible depending on the current "install".

I get about 12-14 hours on a single 22AH SLA battery including the normal TX time (1.1 amps idle and 2.4 amps TX).


Front of the box; Duplexer (drilled and screwed to top cover), Router and 12V controller velcro'ed in place, box cover optional but handy if you need to recover trunk space or further protect the electronics. 

Rear view of box; batteries optional with AGM or gel cells recommended (not SLA's as I have here), Anderson Power Poles used throughout, USB programming cable permanently attached.

Sedan Trunk View from Driver's seat; This still incomplete install shows the repeater facing forward on passenger side of trunk and with back seat down, driver can see the repeater, router and USB modem status while in motion if needed to confirm overall IPSC network connectivity status.  Not shown:  Duplexer, 3G/4G external antenna mounted on roof and a 10A switcher power supply and 110 cables in pocket left of box.  Small flat 110VAC extension "dongle plug" (can hang out the trunk for easy access to longer extension cord).  [ Consider tying down the install to limit a flying object inside the cab in a crash situation ]

Other considerations

  • Consider using the new XPR-5700 repeater; size, weight and wider range of RF power levels

  • Use the handy Parrot talkgroup (or tablet for Netwatch) to confirm IPSC connectivity; great to have while driving

  • Extra CAT5 cables for laptop or plug in a Ubiquiti Loco M2 or M5 for for more powerful WiFi Access Point

  • Carry additional grounded 110VAC extension cords for longer stationary deployments

  • Use larger AGM or Gel batteries for longer standby times, avoid the use SLA's inside the cab or box if possible

  • Use of a 12V/20A controller is very handy to simplify the install, less need for power switch & more flexibility but be aware that it may switch the negative side of 12V circuits; keep battery, PS & vehicle power issolated

  • Access to an inline volt/amp meter (Watts-Up or cheaper GT model) on power poles is exceedingly handy

  • Box weighs 65 lbs fully loaded (36.4 repeater & box, 6.1 cabling, 11.2 per 22AH battery), power poles a must!

Email if you have questions on my approach or you wish to "roll your own".  no7rf@trbo.org

 

Revised: 08/02/2015 10:00

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