Click on each picture to get the full graphic image.
(they should have already loaded and should display very quickly)
Mt. Eldridge
Installed 22 January 1997 by NL7WO and VY1CB
Repaired 5 February and May 1998 by NL7XH and VY1CB
Repaired 24 October by NL7XH
First QSO from Eagle 12 Feburary 1998 by NL7HU
Left: Installation Jan 22, 1997
Center: Arial view of site
Right: Helicopter standing by
May 1988
Eldridge Repair Trip
Left: Two identical repeater systems are under construction.
One for Mt. Eldridge, the other for Porcupine Dome. They are powered by
a 6 ampere, 12 V BP Solar pannels and eight 6TL lead-acid surplus reconditioned
Hum-vee batteries.
Right: WL7TP, Brian is wiring the power system at the Geophysical Institute's
Electronics Shop.
Left: With the back panel removed. The radio is in the
box on the shelf. The battery on the bottom. And the power distribution
in the center.
Right: The battery bank. Only six are shown. Two additional batteries
will be place on top of these. The 6TL batteries are used surplus which
were cleaned and reconditioned by Alaska Battery. They have a reserve capicity
of 200 minutes @ 80F and a high discharge capicity of 600 AMPS at 0F and
350 amps @ -40F. This implies a capacity of (200 minutes) 3.33 hours *
25 amps = 83 amp-hours. Times eight batteries is 664 amp-hours at 80F.
Left: The radio is in the cast aluminium box at the top.
The power distribution is specially designed as shown on the schematic.
Each battery is charged thru a Schotsky (0.3 v drop) diode and a 1 amp
fuse. If the battery should short the fuse will blow and take the battery
out of the circuit. The discharge is also thru a Schotsky diode to isolate
each battery should one fail. The solar pannel is capable of supplying
6 amps. So if more than two batteries short the remaing batteries will
each be able to charge at more than one amp. If this happens all the fuses
will blow. So a 50 ohm resistor is across each fuse. This allows continued
fail-safe operation at a reduced charging rate.
Right: NL7XH, Benny is programming the Kenwood TR77A to cross-band repeat
mode.