Leaving aside the little sliderule that I used as a child, the larger ones
latter, and the huge spiral job at University, I started with a desk top
Burrows (sp?) with nixie tubes and lots of RFI (still have it). In 1972
when the HP35 was announced, I bought two. One for my wife to use. They
were so expensive that we had our names engraved into the case. Still have
them and they still work.
The HP25C was nice, the HP15C was near-optimum (and still kept as a
backup), but I find the HP48 series to be the most useful. I keep one at
work and one at home and at least one new-in-the-box. As Roy has indicated,
the HP48 does an excellent job with complex numbers including solving
systems of linear equations with complex coefficients. The HP48 also allows
the easy storage of non-linear equations with many variables and allows one
easily to solve for any one variable. I have not used more than a few % of
the calculator's capability. Only one faculty member in my ECE department
uses other than an HP calculator (a young instructor).

For some time, I used the HP calculator with a built in printer and
magnetic card reader. Cannot remember the number. I did use its
programming capabilities. One program that I wrote - to get in the
obligatory antenna reference - was a program to estimate the bore-site gain
of a rhombic antenna - HP published it in one of their many books.

My students are required to master the use of a calculator in circuits
and electronics. The HP48, and now the HP49, is the best for those
purposes. However, many students limp along with TI calculators. Some of
them do not have ready access to a reciprocal key. Try finding the
impedance of three impedances in parallel without a reciprocal key. With an
HP48/49 the task is trivial.
The ability with one stroke to combine an imaginary part with the real
part of a complex number is an example of how well suited the HP48 is to EE
work.

As part of my syllabus, I give examples of the type of calculations that
the student's calculator must be able to perform. Because discerning
students now purchase HP49 calculators, I also have one of them. Seems not
to be as rugged, but it is much faster.

I can not speak to the programming system of the HP48 as I have not used
same - though the solve scheme of complicated equations gets a regular
workout. Swapping is effected with two key strokes: (0,0 column, row
starting in the lower left) 0,3 and then 6,8.

It was always clear that when the engineer founders of HP left, the
company would flounder. Thank goodness much of the important part was spun
off.

The answer to the original question: buy an HP49 - spend some quality
time learning to use it. In terms of purchasing cost, an HP49 is very low
cost compared to a good slide rule.

73 Mac N8TT
--
J. Mc Laughlin; Michigan U.S.A.
Home:

"Roy Lewallen" wrote in message
...
I also started with an HP35, then 45, and went from there to an HP41CX.
That was the nicest calculator I've ever had, and I flat wore it out. I
was late getting a PC, but put the 41 to use in solving everything from
iterative network problems to antenna patterns, self and mutual
impedance calculations, phased array feed systems, you name it. The
functions I most used were right there on the keyboard, available with a
couple of keystrokes at most. Programming with the assembly-like
language was fast, easy, and to me, intuitive. I ended up with a very
large library of programs of all kinds.

Its replacement, an HP48GX, is a disappointment in every way but one.
The person or people who dreamed up the programming system were totally
indoctrinated, like so many of today's software engineers, that object
oriented programming (OOP) is the best and only solution for every
possible problem. Consequently, creating even a simple program is
terribly time consuming and the result is worse than the worst GWBASIC
spaghetti code I've ever seen. It's horrible! And while it can be highly
customized, the learning curve is steep. Without customizing, just
changing the number of displayed decimal points from 2 to 3 involves 5
keystrokes and waits of several seconds. I still don't know of a quick
and easy way to swap the values in the x and y registers, although I
honestly haven't looked hard and am sure there's a moderately simple way.

Its single redeeming feature, which keeps me using it daily, is the
facility with which it handles complex numbers. I can mix and match real
and complex numbers, add, multiply, take the square root, trig
functions, everything, just as easily as with purely real numbers. I can
swap between viewing in rectangular and polar notation in a second, and
enter complex numbers in either form. For the kind of calculations I do
very frequently, it's terrific. But if I didn't do a lot of calculations
with complex numbers, I'd give it a 0.5 on a scale of 10.

Roy Lewallen, W7EL

Tom Ring wrote:

In order, I like my HP15C, HP11C, and way behind HP48SX. And then there
is my HP25.

I originally purchased an HP35, then an HP45, then an HP25, then finally
an HP11. Which was so tough it got run over by a NY DOT dump truck and
had merely a crease above the LCD display. And is still in use 25+
years later.

I purchased the HP15C as new when I thought the 11C was lost.
Fortunately it was not. So I ended up with both (eventually).

I purchased a 48SX at a hamfest for $75. It seemed a good deal at the
time, although I had to wait about a year for the heavy tobacco smoke it
had absorbed to dissapate.

I still like my 15C the best. And it is still on it's second set of
cells since 1982, impressive.

-----------------------------------------

So, what calculators do you like best?

And, of course, why.

tom
K0TAR