VoIP Patch Update

I've done off-air testing of my previously-successful VoIP phone patching using a younger PC (Pentium 4, 2.8 GHz). Here is an annotated screen shot that shows the sound card settings along with Skype audio settings. I'll use the three control panels shown during on-air operations while I verify the best configuration. Previously I have used only the Gmail Call Phone VoIP application. The younger PC has the CPU power needed to run Skype. The older Pentium 3, 600 MHz PC could manage Gmail Call Phone (Google voice) at 76 to 100% CPU utilization.

Click on the image below for a full sized view.

Skype's floating toolbar

Here is a screen shot showing the floating toolbar near upper right side of my desktop.

Test Tone Waveforms

The test tone files shared by Carl can be used to illustrate the capabilities of the free, cross-platform audio editing program Audacity. Below is a screen shot showing the 3 individual tone waveforms and the composite waveform, as displayed in the program. The tones were of 30-second duration, but this display is zoomed in to about .06 second to make the waveform shapes clearly visible. Click on the image to enlarge.

Audacity also has a frequency analysis tool that produces a plot of amplitude vs. frequency for up to 23.8 seconds selected from a waveform. Below is a screen shot showing the analysis of the composite waveform, with the 3 peaks corresponding to the individual notes (C, E, G) or frequencies contained in the composite. Click on the image to enlarge.

This program, like others of its kind, enables a user to record audio entering a PC's sound card, and to perform edits on all or portions of a recording. Such simple edits as copy/cut & paste, and amplitude changes can be done with the same ease as their equivalents in a word processing program. Many other editing functions are included.

Toroid choke for VDSL modem

I noticed that my transmissions on 3740 kHz were often accompanied by a loss of sync on the VDSL modem that provides U-verse service to my home. This is not surprising, given the frequency spectrum used by VDSL and the proximity of my dipole antenna to the aerial service drop that brings phone service and U-verse to my home. I obtained a large diameter ferrite toroid -- FT-240-J from Amidon and installed it on the DSL line cord at the modem. The 'J' material is designed to provide excellent attenuation in the 0.5 to 20 MHz range. Below is a photo showing the installation.

This toroid is large enough to thread multiple turns of the DSL line cord with the RJ-11 plug attached. Since the toroid resolved my interference issue, I could install a smaller toroid with the RJ-11plug temporarily removed, and save the large toroid for future troubleshooting or other problem resolution.

Update 6/20/17: This toroid should be effective on higher frequencies also, up to the 20 MHz top of range quoted by Amidon. At my past QTH I needed this toroid for 75 m only. 40 m and 20 m were not affected. At my present QTH the VDSL modem was replaced due to a lightning surge, and the new modem was not susceptible to interference. 

Hurricane Irene's Track

On 8/22/11 I saved a screen shot of the forecast model tracks for Hurricane Irene. See below, and click on the image to enlarge.

It is interesting to compare this with the actual track of the storm as shown below.

Of the various forecast models, the NGFDL seemed to have a good fit as the storm approached North Carolina, while the GFS had a good fit during the later path of the storm. According to what I saw on TV, the model tracks were all pretty close together as the storm traveled up the east coast. Naturally, small changes in the track's position east or west made a big difference in storm surge at the local communities on the coast.

Note that 8/29/11 was the 6th anniversary of Hurricane Katrina's landing on the coasts of Louisiana and Mississippi.

Lumens per Watt

Lighting technologies on today's consumer market span a wider range of choices than ever. As we migrate toward better energy efficiency, new metrics come to the forefront to help with decisions about what to buy. With the advent of compact fluorescent lamps (CFLs), the actual light output in lumens became an important characteristic for comparisons, since their power consumption in watts is considerably less than the power required by standard incandescent bulbs. Product specs and advertising are now including lumens per watt as a measure of efficacy, to indicate the amount of light produced with the power consumed by the device.

Many web pages now include tables that list this measure along with the actual light output and power required for a given lighting technology or device. For example, see this one from a utility company. A similar table appears in the middle of Home Depot's main page about light bulbs.

A review of such tables shows that incandescent bulbs trail the pack at only 10 to 17 lumens per watt. Fluorescent devices are much better, in the range of 30 to 110 lumens per watt. LED devices are shown in various tables and past web articles as being in the range of 20 to 60 lumens per watt. However, the LED technologies are improving rapidly. One of the companies actively developing this technology has reported achieving 200 lumens per watt. Another company making progress on the price is discussed in the article:
Silicon Is Key to Quest for $5 LED Lightbulb.

As noted in the article LED Lighting: Blue + Yellow = White :
"One of the goals of the U.S. Department of Energy's 2010 solid-state lighting road map calls for more than doubling the lumens per watt in commercial LED products by 2015."


Currently available LED devices are pricey, but moving lower, and are not yet at efficacy levels that surpass linear fluorescent bulbs. It should be noted, however, that linear (tube) fluorescent bulbs diminish in brightness with age and are usually specified with their beginning-of-life brightness. Also, the efficiency of the fluorescent fixture ballast is not necessarily included in the specs for the bulbs. And remember that fluorescent bulbs contain mercury. Be sure to recycle them.

A common application example may provide additional appreciation for the device specs. My friend Larry has a workshop that is illuminated using four twin-tube 48" fluorescent fixtures. Assuming 40-watt T12 bulbs and using the data from Home Depot, these fixtures would produce 8 x 2600 = 20,800 lumens and consume at least 320 W. If the same lumens were to be produced using common 100 W incandescent bulbs (1180 lumens each), there would be 17.63 bulbs, consuming 1763 W. One currently-available LED spotlight could provide 1100 lumens with only 15 W. Power for the 19 needed bulbs would total 285 W, but the cost is prohibitive -- $798. When LED devices are commercially available at 200 lumens per watt, the total power requirement for Larry's workshop would be 104 W.  Clearly it is not economical for Larry to replace his full set of fluorescent bulbs with LED devices at the present time. New construction, especially commercial, should look closely at using LEDs, however. The economics of using currently-available LED bulbs in place of incandescent bulbs and CFLs are discussed in the article: The Lightbulb That Really Is a Better Idea.

Hopefully, as incandescent bulbs vanish into history, LED devices will become more plentiful and less expensive so that we can enjoy better lighting efficiency while avoiding the toxic characteristics of fluorescent bulbs.


John

Updating Vulnerable Software

There is no end in sight to the parade of malware exploits that make use of vulnerabilities in popular Windows-based programs. If you are not sure of your system's vulnerability or don't trust the automatic notifications that you receive from some programs, you should consider running a scan on a regular basis to determine what programs need to be updated. Two facilities that I have used and trust are:

• FileHippo - You can download popular program updates from their home page, or install and run their free Update Checker for a scan of the most popular programs installed on your PC. You can choose to have it run every time you start Windows or just run it on demand. The results are displayed on a convenient web page where you can click and download any updates you need or want. They include beta versions of programs that you may or may not want to use. This scanner identifies version updates for a select group of popular programs, not every program installed on your system. The updates are not all associated with patching security holes. Below is a screen shot fragment that shows the scan results I obtained today. Click on the image for a full-size view.

• Secunia Online Software Inspector - This scanner concentrates on identifying vulnerable programs on your PC. It also provides a web page report with links to the updated program versions. It is a Java applet and so requires Java to run. Below is a screen shot fragment that shows the scan results I obtained today. Click on the image for a full-size view.

Scanning takes only a few minutes on most systems. Downloading and installing the updates may take some time, especially if you have many outdated programs, but all experts in the field of computer security agree that patching vulnerabilities is very important to the overall secure use of your computer.