I was cleaning out my stuff (trying to keep from being classified as a hoarder), and found my old HP-41CX, as well as all the stuff I had to go along with it. Cassette drive, printer, HP-IL loop, 300 baud modem, modules, and a bag full of faded printouts with all the programs I wrote. That is where I got started writing programs to make my survey life easier. Lots of reduction programs, SPC, UTM, solar and star shots, etc.
Put 4 new N batteries in, and it works! A lot of memories (no pun intended).
One program in particular I remember-we had to run 130 miles of second order levels and bluebook it, in the days before digital levels, using dual scale rods and a micrometer. I setup the HP41 for data entry, it would check all the readings, make sure distances were within tolerance, check the three wire readings, and that the high scale/low scale all agreed, then store in a binary format that I created. At the end of each day, the crew would use the 300 baud modem to send me the data. I then processed the data on a PC to create the bluebook files.
What a great machine it was for its time. I bought an HP48, never liked it. I now use an HP 33S, but I don't like it near as much as the old HP41CX. I especially liked to programmable keypad, you could assign functions to keys. I miss the old HMS+ and HMS- keys that I had back then.
Curious as to how many surveyors like/use/prefer RPN? I still think it is the best way to go, but that is how I started out.
I still prefer RPN, and use an HP-48 emulator on my PC.
How did you get the 41 to store the level data as binary?
I still use one or more of my HP-41s EVERY DAY!
When the last 41 goes TU, so will I!
Loyal
Best HP ever made..... IMHO I too used mine for custom problem solving. I remember writing a program that accepted the output from my Geodimeter 140 total station and calculated a running "slope chainage" for a pipeline survey. There was actually a HPIL loop box that Geodimeter sold for the purpose of making that connection. I still have my HP IL printer card reader, etc somewhere around here. Another program I wrote involved solving for the cantenary curve for various sized transmission line conductors for checking the sag and installed tension on EHV transmission lines. My 41CX is right next to me as I type this. Wish I could buy a brand new one just to have on hand. I have a 48gx with the TDS card and extra memory I used as a data collector with my Topcon total station but I never pick it up any more.
Boy, Jim, it's been a long time...As I recall, I converted each two digits to a character, and then stored all the observations from one setup as a string of characters. It may have been a little more complex than that. I was trying to use memory in the most efficient way possible, as it was at a premium.
I think it was like BS rod low(4 decimals), FS rod low, BS rod high, FS rod high, then BS low intercept (stadia), BS high intercept, FS low intercept, FS high intercept. It also stored the date/time of each reading.
The way I had it setup, I could store a week's worth of data on the calculator.
I also used the HP41 when we were turning 8 sets of T-2 angles for traverse, it checked everything, told which if any needed to be reobserved, and then stored all the data along with the EDM obs and temp/pressure. Back in the office it would transfer to a PC for calc's over the HP-IL loop and printout. Sort of like an early poor man's data collector.
I have trouble trying to use a standard calculator (non RPN). I keep messing up, trying to move things up the stack. Fortunately there are HP41 emulators for my android phone.
Although I didn't have one, I remember a Kern total station that the HP-41 would attach to via the HP-IL loop, I think.
I also found a copy of "Survey Calculations Journal" (SJC) from 1983. One article was "ASTRONOMY including COMPUTER SOLAR" by Jerry Wahl. It would be interesting to see the whole set of this journal. I did a quick google search but couldn't find anything online.
I also have one working daily - one which has off days when it will not switch on and a pair in the office which need stripping down to clean whatever muck has collected behind the keys.
The only failing of the 41s was that the on-off keys are "press" rather than slide, so the contacts are not self cleaning.
The first Geodimeter 440 instruments didn't have an internal memory and relied on a HP41 hidden away in an external box and labelled Geodat 126. These were linked up by a cable which was effectively an HP-IL. After a few months Geodimeter sorted out their own internal memories, but all their internal systems were based on the HP OS.
My 41cx finally died a few months ago. In my search for a possible source to get it repaired, i found an app for my Iphone that emulates identically the 41cx and included all the possible programs that were available at the time. Unbelievable app for $9.95. I have been using HP calculators since 1972, starting with the HP 35, actually took my exam with the 35. Although the company had some 48's, i stayed with the 41cx. Lover the RPN.
Still have my 41CX with the survey pack, assigned DMS +/- to run with that pack, liked my 67 better as a calculator and did a bunch of comps with the 35 using the routines published by HP. That book showed the order and what to input to keep the re entry of data to a minimum, still have the book but the calculator got away from me. I like RPN along with the stack.
jud
RPN had me baffled until I forced myself to use it, now algebraic messes me up, like another person mentioned I find myself trying to use the stack. HP35s.
I have a pretty complete set of SCJ, got some back issues at the beginning and was with it til the end. I think the issue with my solar program in it was one in which Joe Bell declared that if he didn't get x number of subscriptions by such and such a deadline he would cease publication and refund subscriptions. He stopped and didn't refund anything.
My program was pretty neat at the time, but totally obsolete now since it used the Almanac for computers which ceased being published long long ago.
- jlw
My HP-41CX just died 2 weeks ago 🙁 Just got a HP 35s to replace it but I don't think anything will ever be able to truly replace it.
My 41 died on it's 17th± birthday. Sent it off to fixthatcalc.com, for $79 got it back like new. Since I simply cannot use an algebraic calculator, I was glad to find them, and happy to pay the price.
I remember when my old employer bought a couple of Sup-r-Rom chips. We were in tall cotton when we could recall points by number, rather than having to type in N & E for 'bout every computation when using the HP Survey chip. We always photocopied the printouts from the thermal printer for safekeeping.
Wish I could find a new charger & nicad pack for it, although the N cells last a year or better.
SS
Randy Sloyer is "The Man" here http://www.fixthatcalc.com/index.php
I've never been disappointed with his help.
Cheers,
Derek
I supported a wife and 6 kids for a couple years selling geodetic software for the HP-41CX. I have the emulator on my iPhone now, and it blows my students' minds when I do State Plane transformations on my iPhone.
I programmed a system for geodetic levelling on the HP-41CX also, but I had an HP-IL floppy disk drive that would record the day's observations in MS-DOS readable Text files. In the field, every observation was printed out on paper and also recorded onto a magnetic cassette, then transferred to the floppy disk in the office. The two projects involved about 500 benchmarks, and all were BlueBooked and accepted by NGS in the middle 1980s.
I used the company's HP41 with survey module and it was top shelf.
Did all computations for a 3 crew office with it and had to write and plot all the points and coords on blue grid Clearprint paper with Koh-I-Noor pen.
The largest project was a 2K acre subdivision with a 250 acre in the middle with lots from 1 ac to 10 acres.
They never would upgrade to anything that would store point numbers so I got an apple version of Surveyor 1 by Carlson.
41cx was the best.
Very user and surveyor friendly for functions, applications and programming.
My brother forced me into the RPN world. I was baffled for a while but he kept after me. He just told me the buttons to push. Eventually I learned what I was doing. Been using RPN ever since.
We have the 41, the 48 the 35 and even had an HP-85 back in the day. Big desktop unit with a screen and a tape drive. What a monster.
I don't know how anyone even uses those other calculators.
John:
I have quite a few copies of the SCJ which I would be glad to pass along. Just
e-mail me your mailing address and I will get them out. [email protected]
T.W.