What a difference six months makes!

Pumpkin Pie takes in the weather on February 9 and July 28.

Surfin': An Antenna Advantage

 

Sunday afternoon, I added two stations to my AM radio log: WHDD on 1020 kHz in Sharon, Connecticut, and WWRL on 1600 kHz in New York City. The two are numbers 157 and 158 in the log that I started keeping about 18 months ago.

During those 18 months, I have used four different radios with four different external antennas. I added the latest loggings using a Crane CC SW Pocket AM/FM/SW radio and a Terk Advantage indoor AM antenna.

The Terk Advantage can be connected directly to a radio that has external antenna connectors, but may also be inductively coupled to a radio without external antenna connectors. Since the CC SW Pocket has no external antenna connectors, I have been using the inductive coupling option.

Initially, I placed the radio next to the antenna (see first figure). The problem with that configuration was that when I moved the antenna to null out or peak a signal, I then had to move the radio so that it was adjacent to the antenna.

Sometimes the null or peak would change slightly after I repositioned the radio and I would have to tweak the null or peak and reposition the radio again. There had to be a better way.

Since the CC SW Pocket is so small, I tried placing it inside the loop of the antenna (see second figure). It fit perfectly and when I moved the antenna to null or peak a signal, the radio moves with the antenna, thus I usually find the null and peak on the first attempt.

The Advantage is an excellent antenna. It is lightweight and compact with a 9-inch diameter.

It does a great job pulling in signals. Oftentimes, it picks up signals that the radio does not hear with its own internal antenna. Couple the radio with the antenna and suddenly there is a station on frequency that was not detectable sans the antenna.

The dial on the antenna allows you to peak the signal. It is labeled in kilohertz to simplify tuning the peak.

The Advantage also does a fine job of nulling signals. When I logged WWRL, WHNP in East Longmeadow, Massachusetts, was equally as strong on 1600 kHz. Although the two stations were approximately 180 degrees apart at my location, WWRL to my southwest and WHNP to my northeast, I was able to null out WHNP and hear WWRL in the clear.

One more thing: the Terk Advantage is the coolest looking antenna I have ever owned.

Until next time, keep on surfin'.

Virginia is for Radio Lovers

I just received the July-August 2013 issue of AMRAD Newsletter and as usual, it contains an interesting lineup of articles.

• "JT55a - A Minimalist's Error-free Ham Radio Protocol" by Terry McCarty, WA5NTI
• "An Arduino-based DFCW Beacon" by Andre Kesteloot, N4ICK
• "Adventures with the Arduino" by Karl Berger, W4KRL

Join Amateur Radio Research and Development Corporation (AMRAD) to receive the newsletter and be part of a group of ham radio "experimenters specializing in telecommunications technology."

AMRAD is based in McLean, Virginia, just up the road from the antenna farm pictured in the postcard above. Its monthly meetings always feature on-the-cutting-edge presentations.

By the way, here is the description on the back of the postcard:

"THE UNITED STATES NAVAL RADIO STATION AT RADIO, VIRGINIA. Situated at the southwestern end of Fort Meyer Military Reservation opposite Washington, D.C. Built by the United States Navy Department [Bureau of Steam Engineering]. Land ceded to the Navy Department by the War Department. Rated power of station 100 kilowatts. Towers, one 600 feet high 150 feet square at the base, two 450 feet high 120 feet square at the base, located at angles of an isosceles triangle, large tower at the apex base of the triangle 350 feet between centers of towers, perpendicular to base 350 feet. Normal range: day 2,000 miles, night 3,000 miles. Cost about $250,000."

KA6M/R

KA6M/R, the first digipeater (Source: www.pprs.oprg)

Following up on yesterday's blog post, here is what I wrote about KA6M in my first book Your Gateway to Packet Radio in 1987:

"The United States amateurs did not let grass grow under their feet. Once the FCC gave the go-ahead, packet-radio experimentation south of the border forged ahead. The first US packet demonstration was conducted at the 1980 ARRL National Convention in Seattle, Washington. Most of the initial experimentation involved building and tinkering with the VADCG TNC*, but on December 10, 1980, the first "made in the USA" amateur packet development hit the airwaves: Hank Magnuski, KA6M, put a simplex digipeater (KA6M/R) on 2 meters in San Francisco. Hank's system used a home-built TNC based on the Z80 microprocessor and a Western Digital 1933 HDLC IC. Like packet radio north of the border, Hank used a Bell 202 compatible modem on his TNC because the modems were readily available as surplus equipment. As a result of Hank's operations, a group of interested amateurs joined him in the founding of the Pacific Packet Radio Society (PPRS)." 

* Canadian amateurs got the go-ahead to do packet radio in 1978, two years before amateurs in the USA. Vancouver Amateur Digital Communications Group (VADCG) developed the first TNC, which was available as a kit and became known as the "VADCG TNC."   

 

Handie History

Until I saw this 1944 Motorola advertisement, I had no idea that "Handie Talkie" goes back to World War II.

"The first radio receiver/transmitter to be widely nicknamed 'Walkie-Talkie' was the backpacked Motorola SCR-300, created by an engineering team in 1940 at the Galvin Manufacturing Company (fore-runner of Motorola). The team consisted of Dan Noble, who conceived of the design using frequency modulation, Henryk Magnuski who was the principal RF engineer, Marion Bond, Lloyd Morris, and Bill Vogel.

"Motorola also produced the hand-held AM SCR-536 radio during World War II, and it was called the 'Handie-Talkie' (HT). The terms are often confused today, but the original walkie talkie referred to the back mounted model, while the handie talkie was the device which could be held entirely in the hand (but had vastly reduced performance). Both devices ran on vacuum tubes and used high voltage dry cell batteries. (Handie-Talkie became a trademark of Motorola, Inc. on May 22, 1951)." (Source: Wikipedia)

The name Henryk Magnuski, principal RF engineer of the walkie talkie, rang a bell. One of the packet radio pioneers was Hank Magnuski, KA6M; in 1980, his callsign was used for the first packet radio digipeater in the USA, KA6M/R in the San Francisco Bay area.

And it tuns out that Henryk Magnuski is Hank Magnuski's father!