[Coco] [OT] Analog computer from Radio Shack

[Kevin Diggs]

Gene Heskett wrote:
> 
> One of the real ones could be quite a bit more accurate than than you 
> folks have estimated them to be.  When I first went to work for KOTA-TV 
> in Rapid City, circa 1964, the Chief, Elmer Nelson, had made himself one 
> of them, ISTR it had an output meter and 8 input dials plus 
> a .1,.2,.5,1,2,5 style of range switches over about 5 decades for the 
> input dials.  Using the then magic and expensive op-amps, and .1% 
> precision resistors and 10 turn .1% Beckman pots for input, he estimated 
> the overall accuracy at maybe .25%.  He used it to design all the tuned 
> circuits in his microwave equipment he was building, and which worked 
> quite well.
> 
> They had tried several makes of microwave gear for their dual channel, 
> bi-directional back to Hays Springs/Alliance (KDUH-TV), 6 hops to Lookout 
> Mountain (KLZ-TV then) in Colorado for their network microwave, but none 
> of it could have the door slammed on the mountaintop shacks for more than 
> 30 days, a rather important consideration when you might have to hire a 
> helicopter to get you there in the wintertime.  So he built one using all 
> millspec tubes, mostly 6922's that could go a year between visits to the 
> shacks.  And that was his computer at the time, but he eventually 
> graduated to an HP-85 in about 1965 or 66.  That HP-85 used a spark 
> discharge printer, and that's the first time I ever saw a smith chart 
> actually plotted.  I hope Elmer still lives, the last time I was in Rapid 
> City was in 1994, and I stopped at his shop, "Tepco Inc" and shot the 
> breeze for an hour or so.  But, he was in his mid 70's then, not as spry 
> but still as sharp as ever, so I've no idea if he is still working or has 
> sold it to the help, one of which had been with him for at least 30 years 
> then.  Tepco's main product is tv translators at the 10 watt power level, 
> good for shadow fills & such. See at <http://www.rapidnet.com/~tepco/>
> 
> 
> I had fun with Elmer, he was a 'papered' engineer, and was always amazed 
> at just how much this 8th graduate knew about electronics.
> 

Gene,

	I'll bet you could tell us all kinds of interesting TV station stories. 
Anything on digital tv (aka ATSC)?

					kevin