KD5RFT
05-22-2009, 11:23 AM
WHY is this miserable transformer worth that kind of money? But, more importantly, WHY are bidders willing to pay this kind of money for it????
Perhaps that's the difference between an amateur and a collector -- we're digging for old stuff to actually use it.
I was sniped many times looking for an all-purpose slide rule at a usable price. I settled on the compliment of the N600-ES (http://sliderulemuseum.com/Pickett/P079_Pickett_N600-ES_LogLog_SetWithS187.jpg) (6" slide rule -- used in the Apollo missions) and the N4-ES (http://sliderulemuseum.com/Pickett/S090_Pickett_N4-ES.jpg) (12" 34 synchro-scales).
Both of these can be had today at a reasonable price. A new N600-ES (without box/manual) runs for $30 new in plastic with soft leather case. A used N4-ES with hard leather case (no box/manual) runs $40 - $60 depending on condition and what day of the week the close lands on. I recommend either of these, even for a beginner as you start with the base scales and work your way up to doing different types of problems and your own creative ways to work even more.
The 6" N600-ES has the most functionality to both price and size/weight ratio (the latter is probably why it went to the moon). I consider the N4-ES to be the most functional 12" general-purpose slide rule and especially like that it features four base-10 log-log scales and a second base scale to use them as base-e.
A general purpose slide rule performs a variety of calculations such as multiplication, division, exponents / arbitrary roots, trigonometry, and features constants such as pi or e and more specialized calculations depending on the rule. Combinations of two to three of these calculations can often be performed in a single step. The slide rule does this by converting the numbers into a logarithmic base which can then be manipulated by additive or subtractive distances.
With a little finesse, you can also work addition and subtraction on a slide rule, but precision is often too low to be practical. A slide rule is best used in combination with pen-paper for solving equations, addition/subtraction, and as a decimal counter when performing a series of calculations. An addiator or decimal counter were also used in the past.
A logarithmic based calculator is naturally well suited for amateur radio calculations. (among many others)
Curious? -- try a virtual slide (http://www.antiquark.com/sliderule/sim/) rule and some basic instruction (http://www.antiquark.com/sliderule/sim/sr-calcs-by-example.html).
Why a slide rule instead of a calculator? A modern calculator is high precision.. anywhere from 8 to 32 significant figures and beyond with arbitrary precision. A slide rule has a general accuracy of 3-4 significant figures or better as you're interpolating the remaining figures. This often translates into tenths of a percent. This is accurate enough for most applications. A slide rule also won't crash if the result is extremely large or small unless you drop it, requires no batteries, and is resistant to EMP (http://en.wikipedia.org/wiki/Electromagnetic_pulse).
It's also fun and has some advantages over a calculator in certain problems where higher precision is not a concern. Because you're actively looking for reasonable answers when performing calculations at each step, you're less prone to certain types of errors that could go undetected when examining a single result. You're focused not only on what steps to perform and in what order, but also the interaction between the numbers and what's a reasonable result at each step. I consider this a great teaching tool. Your result is also not only a single figure, but a graph all of the other possible results if you were to manipulate one of the last variables.
As an example, if you solved for what interest rate would be required to double a quantity of money in 20 years, you could view at a glance how long it would take similar interest rates to reach the same goal. The same could be done with a calculator by plugging in different values, it could be graphed on a graphing calculator, and you could also make a spreadsheet.
A slide rule is a unique and simple device suitable for working a variety of problems. I also enjoy spreadsheets.
73,
Nick KD5RFT
RF Turkey
Perhaps that's the difference between an amateur and a collector -- we're digging for old stuff to actually use it.
I was sniped many times looking for an all-purpose slide rule at a usable price. I settled on the compliment of the N600-ES (http://sliderulemuseum.com/Pickett/P079_Pickett_N600-ES_LogLog_SetWithS187.jpg) (6" slide rule -- used in the Apollo missions) and the N4-ES (http://sliderulemuseum.com/Pickett/S090_Pickett_N4-ES.jpg) (12" 34 synchro-scales).
Both of these can be had today at a reasonable price. A new N600-ES (without box/manual) runs for $30 new in plastic with soft leather case. A used N4-ES with hard leather case (no box/manual) runs $40 - $60 depending on condition and what day of the week the close lands on. I recommend either of these, even for a beginner as you start with the base scales and work your way up to doing different types of problems and your own creative ways to work even more.
The 6" N600-ES has the most functionality to both price and size/weight ratio (the latter is probably why it went to the moon). I consider the N4-ES to be the most functional 12" general-purpose slide rule and especially like that it features four base-10 log-log scales and a second base scale to use them as base-e.
A general purpose slide rule performs a variety of calculations such as multiplication, division, exponents / arbitrary roots, trigonometry, and features constants such as pi or e and more specialized calculations depending on the rule. Combinations of two to three of these calculations can often be performed in a single step. The slide rule does this by converting the numbers into a logarithmic base which can then be manipulated by additive or subtractive distances.
With a little finesse, you can also work addition and subtraction on a slide rule, but precision is often too low to be practical. A slide rule is best used in combination with pen-paper for solving equations, addition/subtraction, and as a decimal counter when performing a series of calculations. An addiator or decimal counter were also used in the past.
A logarithmic based calculator is naturally well suited for amateur radio calculations. (among many others)
Curious? -- try a virtual slide (http://www.antiquark.com/sliderule/sim/) rule and some basic instruction (http://www.antiquark.com/sliderule/sim/sr-calcs-by-example.html).
Why a slide rule instead of a calculator? A modern calculator is high precision.. anywhere from 8 to 32 significant figures and beyond with arbitrary precision. A slide rule has a general accuracy of 3-4 significant figures or better as you're interpolating the remaining figures. This often translates into tenths of a percent. This is accurate enough for most applications. A slide rule also won't crash if the result is extremely large or small unless you drop it, requires no batteries, and is resistant to EMP (http://en.wikipedia.org/wiki/Electromagnetic_pulse).
It's also fun and has some advantages over a calculator in certain problems where higher precision is not a concern. Because you're actively looking for reasonable answers when performing calculations at each step, you're less prone to certain types of errors that could go undetected when examining a single result. You're focused not only on what steps to perform and in what order, but also the interaction between the numbers and what's a reasonable result at each step. I consider this a great teaching tool. Your result is also not only a single figure, but a graph all of the other possible results if you were to manipulate one of the last variables.
As an example, if you solved for what interest rate would be required to double a quantity of money in 20 years, you could view at a glance how long it would take similar interest rates to reach the same goal. The same could be done with a calculator by plugging in different values, it could be graphed on a graphing calculator, and you could also make a spreadsheet.
A slide rule is a unique and simple device suitable for working a variety of problems. I also enjoy spreadsheets.
73,
Nick KD5RFT
RF Turkey
