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Below, Copthorne Macdonald—the inventor of slow scan television— a method of amateur radio transmission that allows ham operators to both hear and see each other during shortwave braoadcast.

SOLAR POWER FOR THE HW-8

Wood can always be burned for heat, and an oil or tallow blaze will provide light, but there's no substitute for electricity when it comes to powering a radio. Fortunately, it doesn't take much "juice" to keep a ham rig on the air, though ... and the little bit we do need to run a QRP (low-power) amateur rig — such as the Heathkit HW-8 described in my MOTHER NO. 47 column — can be supplied in a reasonably economical fashion by an array of silicon solar cells.

Other people have also seen this as a natural marriage of components. "Mac" McNaughton (VE3EQQ), for instance, uses a 300-ma (milliamp) panel coupled to two series-connected 6-volt wet-cell nicad batteries to power his HW-8 from Mitchell, Ontario. Also, a fellow by the name of Jack (K7ZR) sent his HW-8 with 180-ma solar array and 12-volt motorcycle battery down to last summer's NDR Workshop at Bob Hickerson's (WA6RRR's) place in Yreka, California.

My own setup is a bit more modest than Mac's or Jack's in terms of solar panel size, battery capacity, and overall cost. The "generator" panel I use-a small (1/2" X 7" X 8") unit called the "model SPM-150-16", made by Solar Systems, Inc., Highway 18 East, Dodgeville, Wis. 53533-consists of 40 series-connected 2-centimeter by 2-centimeter silicon solar cells mounted in a transparent plastic case. The panel produces up to 100 milliamps of output current during the day (depending on the cells' orientation, cloud conditions, and temperature), and is priced in the $80-$100 range.

[As of late November 1977, the SPM-150-16's exact price was $70.75 plus $2.25 postage and handling.—MOTHER.]

Since the SPM-150-16 solar array will interface with most any battery system of 16 volts or less, I decided to use a serieswired string of 12 C-size G.E. ni-cad batteries (mounted in appropriate-sized holders on the inside of my HW-8's top cover) to store my solar panel's output. This setup supplies 14 or 15 volts to the HW-8 and gives me a storage capacity of 1,000 milliampere-hours (maH) ... enough for over five hours of normal operation ' (The average current required by the HW.8 — assuming 50% "listening" time and 50% "sending" time-is about 175 milliamps.)