[Elecraft] Solar Power for KX3

[Edward R Cole]

Up here in Alaska I had a few experiences using solar powered remote 
communication systems.  I worked a couple years for the BLM Wildfire 
Center (Fairbanks) radio shop and we had some 5w GE repeaters 
installed in big fiberglass boxes with a square solar panel attached 
to the cover.  We would just take them out to a location (usually a 
hill or mountain top) and set them on the tundra with the panel 
facing straight up.  The panels never got direct sun but averaged 
about 70% of peak all thru the long arctic summer (20+ hours).  I'm 
guessing the panel was about 20-30w.

One summer/fall I worked for a bush PBS TV station (KYUK Bethel, AK) 
maintaining remote TV translators.  Many ran on solar panels which 
were installed vertical on the side of plywood sheds that housed the 
equipment.  The theory was the max solar power was needed in winter 
with short daylight near the horizon;' during the summer the sun was 
high but days were long so average power was much more.  These were 
2-3 30w panels for running 10w TV translators 100% transmitting an AM 
video carrier.

My last work involved remote repeater sites only accessible by air 
*helo*.  They ran on huge alkaline battery banks (10,800 AH) but had 
200AH batteries with 60w panels recharging them in summer.  Automatic 
voltage sensed switching changed over from solar to the alkaline 
plant.  These panel were faced south at the optimum solar angle 
between noon and sunrise/sunset.

For a portable "backpack" system one will have to rely on frequent 
repointing to keep the panel in optimum sun.  Interestingly an 
overcast summer day has 70% of the sun's power on a clear day.  A 
flexible solar panel can be rolled and carried in a tube.

73, Ed - KL7UW