Articles by Phil Karras


Balun Use and Antenna Updates

To Balun or Not to Balun That TV antenna? When should it be done? In an article of mine published in Popular Communications, January 2013, “An Omnidirectional DTV Antenna – With Gain,” I included a little…


How to Estimate your Signals

I said I wasn’t going to give you equations for calculating gain, loss, and Noise Figure/margin but I will explain how I estimate the Noise margin (NM) of the antenna system. I’ve worked in a…


USB Power Bank Ah Rating Evaluation

I have been given or purchased a number of various USB power banks. These power banks are designed to replace the AC outlet with a USB power supply so that when you’re in the field and…



Bow Tie Antenna Angle Tests

This is the last article in the series of bow tie (BT) antenna tests. In this test, the angle used, or put another way, the separation distance between the two ends of the BT “V,”…



The Free Radio Frequencies

Recently I learned that the FCC is proposing to change a few things in the personal radio service. Some History: At one time, the only free personal radio service was the CB (Citizen Band) radio…


Virtual vs. Real Channels

With the change to DTV we ended up with “Virtual” Channels what are these? The “real” channels are the channels the TV stations are using to transmit on. Back before HDTV, the channel number told us…