Monthly Archives: July 2015

Stadiametric Rangefinding Approaches

Recently, I was reading about stadiametric range finding methods being used by hunters and their telescopic sights – I was surprised to find a lot of writing on the topic. As I researched the topic, I saw that there are three common approaches used in telescopic sights: milliradian (mil), Minute Of Angle (MOA), and Inch Of Angle (IOA). I will review these methods here. Continue reading

 
Posted in Ballistics, General Mathematics | 2 Comments

Passive Optical Network Fiber Length

I recently was asked to explain how a Fiber-To-The-Premises (FTTP) system measures the length of fiber between the central office and each residence in the network (Figure 1). This is an interesting question and I thought it would be worthwhile to the describe the measurement process here. Continue reading

 
Posted in Fiber Optics | Leave a comment

Sherman Tank Myths

When I was a boy, most of the fathers in my neighborhood had served in WW2. One of these neighbors, Alvin Weese, was an Army veteran who was very specific about his WW2 service by saying that he had "served under Patton" and you could clearly see his pride in having served in Patton's 3rd Army. Continue reading

 
Posted in History of Science and Technology | 60 Comments

Greece GDP Versus State GDPs

I have been trying to understand the economic situation with Greece and its creditors, but it has been difficult because I do not have an intuitive feel for the size of the Greek economy. To understand a number, I need to relate it to something that I know. Continue reading

 
Posted in Financial | 2 Comments

Circuit Worst-Case and Extreme Value Analysis

Electrical engineers design their circuits to work under "worst case" conditions. This means that the circuits will meet their operational requirements when built with any possible mix of components and environmental conditions (Figure 1). Determining the worst case conditions for a complex system can be difficult, especially for analog systems. There are numerous approaches to worst-case circuit analysis. One approach that I use is called Extreme Value Analysis (EVA). Continue reading

 
Posted in Electronics | 1 Comment

Generating Pejsa's F Function

I have had several people ask me to review how Pejsa generated his F function. Recall that Pejsa's approach is based on using a parameter called the ballistic coefficient (BC) to scale the performance of a reference projectile – Pejsa used the US military's 30 caliber M2 bullet, which dates back to the Springfield rifle. This effort involves basic curve fitting, and I will illustrate the process for the velocity interval from 1400 feet per second (fps) to 4000 fps. This velocity range is the most important to most folks and it illustrates the basic curve fitting process well. Continue reading

 
Posted in Ballistics | 3 Comments