Category Archives: Geek Stuff

Geek Stuff, General

4G, or not 4G – that is the question

Someone asked me this weekend about 4G Wireless; Wikipedia has a good basic description. (Plus I also watched Kenneth Branagh’s Hamlet this weekend (OK, it is Shakespeare’s Hamlet – as interpreted by Branagh) Excellent DVD)

ITU Requirements

This article uses 4G to refer to IMT-Advanced (International Mobile Telecommunications Advanced), as defined by ITU-R. An IMT-Advanced cellular system must fulfill the following requirements:

  • All-IP communications.
  • Peak data rates of up to approximately 100 Mbit/s for high mobility such as mobile access and up to approximately 1 Gbit/s for low mobility such as nomadic/local wireless access, according to the ITU requirements.
  • Scalable channel bandwidth, between 5 and 20 MHz, optionally up to 40 MHz.[6][6][7]
  • Peak link spectral efficiency of 15 bit/s/Hz in the downlink, and 6.75 bit/s/Hz in the uplink (meaning that 1 Gbit/s in the downlink should be possible over less than 67 MHz bandwidth)
  • System spectral efficiency of up to 3 bit/s/Hz/cell in the downlink and 2.25 bit/s/Hz/cell for indoor usage[6]

Confusion has often been caused by some mobile carriers who have launched products advertised as 4G but which are actually current so-called 3.9G technologies, and therefore do not follow the ITU-R defined principles for 4G standards.

Geek Stuff, General

The Equation of Time

I was looking at my calendar and noticed that the Winter Solstice is coming up Dec 21. Then I noticed that the time of sunset on the solstice is not the earliest  amongst the days nearby. And the time of sunrise is not the latest. Indeed, looking over the various sunrise and sunset times, it turns out that the earliest sunset was in the period of December 3-10 – 16:37  in Colorado Springs – and the latest sunrise occurs from December 31 – January 10 – 7:18. But the Solstice is still the shortest day, longest night of the year. (9:26, 14:34 hrs). Most peculiar, one would intuitively think that the shortest day would have the latest sunrise and the earliest sunset.  Something was wrong and I needed to find out.  So I went to Google.  

It turns out that others have noticed this phenomenon before and have an explanation of it. I like this explanation – he said analemma. The US Naval Observatory was not quite as detailed but did summarize it nicely- Declination and The Equation of Time.

I still have a hard time visualizing the spacial relationships. What I need is a picture – no… no…  doesn’t help…

Geek Stuff

Strike Through

I would like to be able to change the strike though character in HTML from ‘-‘ to ‘/’. I have not been able to find any way to do it and it isn’t even offered as a ‘text-decoration’ option.

Does anyone know how you go about getting W3C to consider adding that option to the HTML standards?

Geek Stuff

Cookie Monster

I hadn’t realized how insidious these trackers have become. This WSJ article discusses how cookies have grown since their Netscape days. There is also a link to a tool that tells you who has what installed on a domain site, about half way down the article.

Is there advertising on web pages? I should probably pay more attention and be less oblivious.

Geek Stuff, General

Distance as a matter of perspective

I was doodling around, as I sometimes do, thinking about the differences between East Coast Travel and Western Travel.  What brought this up is an upcoming trip to NYC and I realized I do not know the relationship of the area airports to the city.  When I lived back in the DC area, I would usually drive to NYC, or take a train.  I never really thought about flying unless there were extraordinary circumstances.

But I worked out some charts to compare a drive from DC to Boston with a drive from Albuquerque to Denver. Both routes by Interstate A-D on I-25 and D-B on I-95, I-84,and  I-90 (I could have taken I-95 all the way but the distance would be different.) Both routes are about 445 miles.

To give some context to the routes, I noted the population of the different MSAs (Metro Statistical Area) each route went through or by.

Interstate Distance Cities MSA Pop
DC 446 Washington 5,358,000
I-95 Baltimore 2,667,000
Philadelphia 5,838,000
Trenton 367,000
New York City 19,000,000
I-84 Bridgeport 900,000
I-90 New Haven 845,000
Hartford 1,190,000
BOS Boston 4,523,000
Total 40,688,000

There are more than 40 million people living along the DC-Boston route.That is a mind-numbingly lot of people.

Out here:

Interstate Distance Cities MSA Pop
Albuquerque 448 Albuquerque 846,000
Santa Fe 144,000
I-25 Pueblo 157,000
Colorado Springs 617,000
Denver Denver 2,506,000
Total 4,270,000

The total number of people living along the Albuquerque-Denver route is less that the population of the Boston MSA. More than half of Colorado lives in the Denver MSA.  About half of New Mexico lives in the ABQ and Santa Fe MSAs.

And the Western route is only in 2 states. The Eastern route passes through 7 states and districts.

Geek Stuff

Battery Backup

I was listening to the radio a few days ago and they were talking about the difficulties of building a power grid that is sized to handle the peak load in the middle of the day. For 18 out of the 24 hours the electric needs are relatively low and then in the middle of the business day the load can grow another 80%.  One idea might be to use solar or wind to cover the peak, but they aren’t always reliably available.

My first thought was to build a giant battery, charge it up at night and let it discharge during the day. I imagine that the batteries would have to be immense, multitudes of them, each the size the Pentagon. Might be none too feasible, potentially unsafe and esthetically challenging.

The next day, they were talking about the upcoming future of electric cars. Especially intra-city commuter vehicles. Then I had a vision of parking garages full of batteries. Just sitting there plugged into the grid topping off. They could be the peak power reservoir.  The Utilities would actually have an incentive to distribute recharging stations to every parking slot in every garage in the city.  Drivers could get free electricity in exchange for the use of their batteries for the day.  The report ended with a blurb that some city planners were already thinking of using the car batteries that way. Drat, another idea stolen.