Mt. Eldridge Repeater
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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
Mt. Eldridge 07 Mt. Eldridge 08 Mt. Eldridge 09 Left: Installation Jan 22, 1997 

Center: Arial view of site 

Right: Helicopter standing by 

Eldridge 12 Eldridge 10 Eldridge 11
May 1988
Eldridge Repair Trip
Mt. Eldridge 01
Mt. Eldridge 02
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.

Mt. Eldridge 03
Mt. Eldridge 04 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.

Mt. Eldridge 05 Mt. Eldridge 06 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. 

this page revised 31 October 1998 by:
Web Site Provided by: AL7FG
Web Page writen and maintained by: KL7XO