Archive for July, 2007

GAP Titan vs. Reference Monopole

Gap Titan

Here is a good example of a comparison between the Gap Titan antenna and a simple mono-band dipole. While this is yet another A/B test, the author does follow reasonable engineering practices.

Static Electricity Explained

sparkmovie.jpg

For you beginners wondering about what static electricity is or for you folks who already do know, take a ride in the way back machine and watch this old government video. While a little long in the tooth it does a terrific job explaining and demonstrating various examples of static electricity.

The Amazing Power of Static Electricity

This video was made back when the English language was spoken good… ah I mean well.

This is well worth the twenty minute length.

Vertical Antenna Project

Vertical Antenna Gain Plot

I have embarked on a vertical antenna project and will be covering the steps in several articles starting here…

http://www.cosjwt.com/index.php?a=7

This will be treated a bit like an engineering project with the following steps:

Vertical Antenna Anti-Gain

There was a humerous response in this discusson on the DX Engineering web site concerning the need for radials. The web page is here…

DX Engineering

It is in the pop-up link “how just a few radials can do wonders for your signal by WB2WIK/6.”

Computer Modeling and Measurements of BPL

One example of BPL emissions in this report.

Here is a report from NTIA to the FCC of some very interesting modeling and real measurements.

It illustrates the many ways BPL signals can move about and certainly suggests BPL over medium voltage power lines are not the way to go.

Kenwood TM-G707 2M/440 Radio

Kenwood FM 2 Meter and 70cm Mobile Transceiver with AM Air Band Receive

I have had this radio for about two years now. It really is very nice. I immediately purchased the display remote cables and have the display attached to my center drink holder with Velcro.

FCC’s 40dB loss per decade vs. 20dB

Near and Far Field Attenuation for electrically small antenna.

The above graphic is from this article about the near field affects.

Far Field RF Link Budgets all have one thing in common. They assume a signal weakens as the square of distance. Double the distance and you loose 6dB. This makes sense when you consider the intensity of radiated electro-magnetic fields drops as the square of distance. 3dB is half the power and 6dB is half again or 1/4 the power or 6dB.