Private Line covers what has occurred, is occurring, and will ocurr in telecommunications. Since communication technology constantly changes, you can expect new content posted regularly.
Consider this site an authoritative resource. Its moderators have successful careers in the telecommunications industry. Utilize the content and send comments. As a site about communicating, conversation is encouraged.
Thomas Farely
Tom has produced privateline.com since 1995. He is now a freelance technology writer who contributes regularly to the site.
His knowledge of telecommunications has served, most notably, the American Heritage Invention and Technology Magazine and The History Channel.
His interview on Alexander Graham Bell will air on the History Channel the end of 2006.
Ken Schmidt
Ken is a licensed attorney who has worked in the tower industry for seven years. He has managed the development of broadcast towers nationwide and developed and built cell towers.
He has been quoted in newspapers and magazines on issues regarding cell towers and has spoke at industry and non-industry conferences on cell tower related issues.
He is recognized as an expert on cell tower leases and due diligence processes for tower acquisitions.
« January 2006 | | April 2006 »
Here's my latest writing on mobile telephone history. 9,000 words, concentrating on developments after World War II. You can download it in .pdf format (internal link) or as a Word document (internal link). The .pdf is illustrated. Both versions have dozens of references. Comments are always welcome.
With thanks, privateline.com reader Mark Jonson e-mails this kind and thoughtful message:
"I've been reading your notes on telecommunications and wireless for several years. Now having a job in the cellular industry I've found the information you provide on this website seems to be more accurate and detailed than almost any other source I've encountered on the Internet. I'd consider it a must-read for anybody working in this field.
However, I'm e-mailing you today because I just read the IEEE Interview of Joel Engel posted March 7. You give a link to it below. Among Engel's comments, I found his prediction in which he stated "[i]t won’t surprise me if one of the Bell companies merges with AT&T" almost prophetic considering this interview appears to have taken place in 2001. This is clearly an indication of someone who has not only worked in telecommunications for many years, but also understands how the industry works from a greater perspective than most people realize. As he said in the following paragraph, we need to be able to "step back and see the big picture." After reading this interview I felt his prediction should not go unnoticed. I definitely look forward to more of your postings in the future.
Thanks,
Mark
The editorial cartoon above is by Rex Babin, copyright 2006 by the Sacramento Bee, all rights reserved.
Q. Why are cell sites often represented by hexes?
A. This shape dates back to the original cellular radio memorandum written by Young and Ring of Bell Labs. Among other things it discusses in print for the first time, the idea of frequency reuse in a small zone system. You can download a copy of this important 1947 paper by clicking here.
Take a look a the graphic below, from that paper. In this example there are nine sets of frequencies. See how the center of each cell site lines up to form a hex? It was then a natural thing to depict smaller areas as hexes. Also note how the same frequency set is never used in an adjacent cell. This idea applied to all cellular radio schemes until Qualcomm's CDMA based system (IS-95) allowed all frequencies to be used in all cells, greatly increasing capacity.
Be cautioned! Cell sites do not lie at the center of each cell, as you might think from this illustration. Read the excerpt from this IEEE interview (external link) below to see why cell sites transmitt to the inside of a cell, not the outside:
Hochfelder: Going back to your work at Bell Labs, you mentioned Phil Porter and Dick Frenkiel as two people you worked with to develop the idea for first generation mobile telephones. Would you tell me a ittle about them? I’d also like to hear about any other talented engineers that you worked with at Bell Labs.
Engel: There were very many talented engineers, and I’ll only be able to mention a few. . . Phil Porter never got the credit he deserved. Many of the features in system we developed were his brainchild. In most radio systems, the transmitter is at the center of the coverage area, radiating in all directions, and when people thought of cellular systems with hexagons they thought of the same thing. Phil came up with the concept of putting the base stations at the corners of the cells with directional antennas aiming inward. That gives further isolation from the other antennas, the other cells further away, and that’s the way they’re all built these days. That is only one of his innovations.
Hochfelder: Simple, yet brilliant.