HP CALCULATORS

> HP11C and HP15C differences.
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> Notice key differences and statistical functions.
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> The 15C has matrix functions.
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> Jerry M. Davis

Yes it had more powerful statistical functions and more program memory.
I knew someone who wrote a traverse program for the 15. It worked but you needed a cheat sheet for data entry.

This brings up some more HP calculators.

The first hand held to program the HP65.

Then of course the HP67 a big improvement. Could use HP65 memory cards.

The office didn't suffer, out came the HP97, did the same thing the HP67 and gave a print out. Same memory cards as the HP67. Sorta had a hard copy, of course the print outs have faded by now unless kept in a dark room. They were blue on white, a big improvement came with the black on white print out.

More later the saga will continue.

Jerry M. Davis

Very nice... thanks for stirring up some great memories.. Bought my 97 at the Colorado School of Mines bookstore for $750. That was a pile of money in 1976 or maybe it was 77, anyway it made me very productive for many years... actually sold it in 1989 for about half what I paid for it.

I got my HP65 mail order from HP. It was in or close to 1973 maybe 1974. It cost if I remember right close to $750. It came in a plastic box, had a black leather(real) belt case and came with the standard programs. I know that was a princely sum back in those days. Probably $2500 or more of today's paper. But it was fantastic. I was based in Kansas City flying for TWA. I met my future wife there and wonder of wonders she was from North Carolina, about 90 or so miles from where I grew up on the family farm. Her dad was a Surveyor, so I had something to show him. He said the results of the HP65 were not right. When I saw the Rectangular to Polar conversion key, I knew I had it made. He had a Rockwell calculator, yes Rockwell made calculators back then. It had Sine, Cosine and Tangent to 8decimal places if my memory is correct. I had programmed a simple traverse program for the H65 and showed it to him. He said it wasn't right. I asked him to get his work sheet out and calculate with his machine. He would take about fifteen minutes to come up with the X & Y coordinates of one leg. I could do it in about 10 seconds. We had exactly the same answer to four decimal places, but he maintained mine were wrong. I think the HP65 calculated to 12 places. I was visiting back here one time shortly thereafter and he came in at lunch time and saw me, he didn't even eat lunch. He asked if I had that figuring machine with me. I played him along and asked him what figuring machine. He said you know that machine you have that does all kind of figuring. I said of course I have it with me. Come with me was his answer, we went back in the field without his lunch meal. Anyhow within about 45 minutes we figured the stakes for a lot in a new subdivision were not right. He remarked that the machine was the best thing he had ever seen. I gained a lot of points with my future father in law. that day, later I bought him a new HP67 for his birthday. Then later my wife and I bought him a HP97 for his birthday. He died in 1983, so I have his office and all kinds of old stuff. An Engineer Surveyor that went to the same church as my Father in law. Said he would act as Surveyor till I got my rear in gear and took the exams. I did and we worked together for a couple of years and he left for a better Engineering job out of State. I'm a HP man through and through.

Jerry M. Davis

It sure stirs up some thoughts and jogs some memories looking at the progression of the HP calculators and thinking about them. I guess HP has sort of got out of calculators, at least like they used to.
Now a feller can get the computing power and memory that took up a room full of computers in a smart phone. Well, really more. Faster, too.

Bought my 97 at about the same time and it kept me going for a couple of years until I got my Apple computer. But the 97 kept chugging along for several years with some special programs that I wrote. Perhaps the most used was a program to reduce taped distances to horizontal correcting for slope and temperature. Still have it down the basement, but the card reader no longer works. And probably the printer no longer works either.

And THEN

Came the HP9815. It had a tape drive to store coordinates (in blocks of 50). When I took the LSIT (1982) we were told "No programmable calculators". I had an old HP (21?) that I used since I couldn't use my HP25. A fellow came in and sat near the wall for an outlet and pulled out his 9815. Nothing was said and he finished the exam. Then about 4 years ago I couldn't even use my 25 year old HP41 for the exam in another state. Dang cheats ruin it for all of us.

Andy

The SAGA continues.

My first HP41C

My first HP41C with extended memory and extended functions modules, made it almost a HP41CX

A rare HP41 notice no function labels and no model number on the lower edge of the calculator.

The rare HP41 with a plastic overlay to make it a 41CX. The overlay was supposed to be for spills and a dust prevention device. I only got one of the overlays, it made the keyboard hard to use, had to press too hard and quite a bit of the time you didn't get the action when you pressed the button. Had to keep a close look at the X register to see if you got what you wanted.

The HP41CX rigged for solar observations. Using the Elgin-Knowles Astro ROM and the Radio Shack Time Cube for hacking the HP41 clock. Ah, a real easy way to have a good bearing reference for the map. Notice the Infra Red module to get a hard copy of the results with the Infra Red printers. I had one of those printers and obtained another one a few years ago from J.T. Stickland in Mississippi. Stopped by his place on one of my trips sometime ago. Still using the printer J.T. With the Black Thermal Paper the hard copy doesn't fade unless exposed to bright light. The Blue thermal paper would fade in a short time light or no light.

The HP41 with the Survey Supply Company SUP-R-ROM, fantastic, 149 coordinate pairs possible if I remember right. Oodles of coordinate geometry routines. Could download to a computer and upload from a computer. With the HPIL module installed you could build up a fantastic operation in the office and in the field. The SUP-R-ROM cost more than the HP41 but it was well worth the cost. I ended up with three SUP-R-ROMs before moving on to a data collector. The HPIL module is a subject of it's own. Survey Supply was a company in Apex, North Carolina that sold surveying and engineering supplies both with a store front and through catalog sales. They were extremely well known in the southeast part of the country, don't know if they penetrated well into the central and western states or not. The owner died of heart attack while mowing his mothers yard. The company continued on for a few more years but eventually closed doors.

The HP41C was truly a fantastic item, then and even now. One still goes into the field with me and one is always in the office along with the HP15C

> The HP41CX rigged for solar observations. Using the Elgin-Knowles Astro ROM and the Radio Shack Time Cube for hacking the HP41 clock.

A cool feature of the HP41CX was the "Correct" function where you set the clock to UTC, waited a few weeks or so, then hacked the clock against UTC using the "Correct" function. It would calculate and store a Delta correction which continuously added or subtracted clock cycles from the crystal frequency, effectively calibrating the crystal itself. If the temperature didn't change much it was then accurate to +- 1/10 of a second per month.

The "no label" model was an OEM unit for use as a controller for some 3rd party electronic device. We nicknamed them the "Stealth".
I think they came with a flimsy plastic cover over the Prgm/Alpha toggle.
I ran across a surplus dealer that had bought a crap load of them.
I bought from him and resold hundreds to surveyors around SoCal.
Probably upwards of 700.
They came in bulk boxes of 50 bubble wrap units with no accessories of any kind.
Still have a couple. Sold them for $55 ea. This was in 1991.

Where I worked we got into the Solar Shot thing. As a way to detect bad traverse angles.
I remember the individual who was promoting the whole thing was very adamant about timing with the WWV signal and making sure time was recorded to the nearest tenth of a second.
Then I explained that the broadcast minute beep tone had to be further corrected using the "embedded double click" correction. Broadcast beep could be up to 0.7 second off.
(then they would do a "Leap Second" adjustment)

Of course he told me I didn't know what I was talking about.

I made a copy of the official documentation.

Of course he was then telling everyone to make sure they corrected the time signal using the double click correction.

That SOB never said a bleeping word to me about it. Ever.
Never a word about all the goofed Sun Shots.
Bad time record was probably the least of their problems.

It reminded me of General Mapache warning his troops to "use the tripod" on the big machine gun in the movie The Wild Bunch.
Exactly. Classic.

General Mapache knows about machine guns

Well, I sure geeked it up good and proper when I got my first HP-48. I compared the clock of the HP-48 against a time standard a week or so after I synchronised it. I Noted the drift and scheduled an alarm to run a program every day or so that put the clock back whatever fraction of a second was required to keep pace. I even somehow figured out how long the program took to execute and subtracted that time from the correction. Ahhhhhhhh... good times!

Great thread Jerry. Thank you for sharing. My affinity to HP calculators came much later. Dad has an 11C and 42S. The build quality of the 11 and its predecessors is outstanding. I doubt that very many electronic devices of today will be functional 40 years from now.

HPIL MODULE

The HPIL Module would allow you to put several items on the HP41CX. The module had two wires attached, you had to have cables for each device you wanted to loop. The devices came with two cables and in and out, so your just in and outed the devices. The first device on the loop would be attached to the HP41 by one of the wires from the HPIL module in the HP41 and the last device would use the other cable from the HPIL module in the HP41CX. I had two printers, two mini tape drive, two floppy drives that were HPIL capable. All devices were battery powered. The tape drive, floppy drives used the same batteries that the HP97 calculator used. I also had a RS232 device that would use the HPIL module. So I could have quite a few things on the loop. I usually took one printer in the field and the other stuff was in place on the drafting cable. The RS232 device drove a small CRT display, it was black and white. It would show the calculations as the HP41CX did the calculations and sent the results out on the loop to the Printer and the CRT display. With this display I could see the calculations and have a hard copy on the printer. The display rolled down the same as the printer, it would show about three calculations before the first one would roll off the screen. With the Survey Supply Sup-R-Rom in the HP41CX on the drafting table, I could have real time results while drafting. My drafting arm was easy on the surveyor, it had a vernier on the angle part, could set it to a minute. I usually drafted the line work on paper then put the mylar on and traced, the labeling was done with a Linex Scriber it was made in Sweden I think. The scriber would attach to the drafting arm, so it was possible to line the text up with a line on the Mylar. I had several fonts with the scriber, so I could pretty the plats up rather nice. It could be set with the Leroy sizes. The outline and fill module made real nice looking title blocks. I had an Old English font, I made one map with that in the Title Block, looked real fancy but I was ashamed of the results, so I never used that font on another Plat. With the HPIL module I could save the coordinate file on tape and on diskette. Could load the HP41C from the diskette or the tapes. The tapes were rather slow but the diskettes were kinda fast. Of course with two of each device I could copy from diskette to diskette, tape to tape and from diskette to tape and reverse. Somewhere about 1986 or 1987 I got my first IMB computer, it was an IBM 286 with 512 K or ram, with a 40 Meg Hard Drive, it was upgraded to 640 Meg memory so I could install Autocad Version 9. I was uptown then. Had a Houston Instrument pen plotter. Didn't do any computer mapping for delivery till 1992 when I got a HP Design Jet 600, I was on Autocad version 12 with Softdesk. By then the HP41CX, had given way to the TOPCON HA2 data collector for field work. It was powered by a HP71B inside a TOPCON box.

Below is a couple of shots of the HP41CX with the HPIL module and tape drive with cassette drive.