QTC   Newsletter

Moncton, NB                 June 2010

A regular feature of “QTC Newsletter” is The Prez . . . Sez. Through it, our Club President reports on Club activities, gives an update on the progress of Club projects and outlines Club objectives.  Marcel will be happy to respond to your questions, comments and suggestions.

THE PREZ . . . SEZ

As the month of June begins we look forward to enjoying the warmer weather.  Hopefully, it will extend into Field Day.  Taking advantage of a sunny morning last Saturday, Warren MacKnight, JP LeBlanc, Bill Gillis, and yours truly completed work on the R7 HF vertical antenna that couldn’t be done during winter months. It was also fitted with non-conductive guy wires to stabilize it during high winds and ice loading.

We’d like to express our sincere thanks to Denis Bourque, VE9EMS, for conducting the hands-on Space Station operating instruction at the May meeting.  Our goal is to have the majority of Club members capable of operating VE9MSC. Denis has given much time to assisting the Club and its members to gain proficiency and greater use of the Space Station.  Many thanks, Denis.

This year MAARC will participate in the annual ARRL Field Day from the site of the 2010 Scout Jamboree in St-Antoine NB. The FD operating schedule is from 1800UTC June 26 to 2059UTC June 27.  Antennas, equipment, etc. can be setup prior to operating times.  JP and I have visited the site and it will be relatively easy to erect antennas.  But . . . we need your help.  Even if you are unable to stay for the full schedule, your help in erecting antennas will be greatly appreciated.

MAARC, Inc. will be celebrating its 75^th Anniversary next year.  One of the planned activities is an on-air event with a special call sign. Other special activities are under consideration to suitably mark the occasion.  One plan is to tie-in with our annual flea market.  This is an important milestone for the Club and we need your ideas and assistance.  Let’s see those hands go up!

Our last meeting before the summer break will be on Monday, June 21, 2010 at 18:30hrs L. See you there.

73, Marcel, VE9ML

(In the May column we reported on the first ‘Hamfest’ held in the Maritimes.   We are still bringing together additional details on this event including related photos.  They will appear in the next QTC Newsletter.)

DID YOU KNOW     .      .     .     .     .     .     .     .     ?

The vertical antenna referred to as the ”5/8 whip,” commonly used as a 2-meter mobile antenna was originally developed  to fill a need for an efficient transmitting antenna in the AM broadcast band. The first broadcast antenna designs used a top loaded vertical type of antenna.  Usually this vertical was lower that a ¼ wavelength and was supported from a number of top loading wires strung between two towers. There was no radiation from the horizontal top loading wires because of the canceling effects of opposing current flow.

Besides physical support, the horizontal wires served to electrically lengthen the vertical element as a means to bringing it near a quarter wavelength. This type of antenna structure certainly had its drawbacks. In areas where there was heavy ice loading, the large number of conductors and leverage on the supporting structures frequently caused severe damage. The radiation pattern was distorted by two supporting towers.

A paper published in the proceedings of the IRE, December 1924, “On the Optimum Transmitting Wavelength for a Vertical Antenna Over Perfect Earth” described the findings of Suart Ballantine. He had determined that a vertical radiator of 0.64 wavelength produced maximum radiation horizontally broadside to the antenna. In his paper, Ballantine calculated that in comparison to the zero gain of a quarter-wave vertical, the 0.64 wavelength antenna produced a gain of 3.03 dB.

One problem in the broadcast application became apparent with the first installations. Radiation from the higher angle minor lobe returned to ground from the ionosphere at night, and caused severe fading several miles from the transmitting point by interfering with ground wave major lobe.  The solution was reduction in antenna height to 0.528 wavelength.  Ballantine’s later developments in ground radial systems further improved the efficiency of broadcast vertical type antennas. To this day, despite the widespread shift to the FM band there are still thousands of AM broadcast stations using 190 degree towers.

Stuart Ballantine who was born in 1897, made many important contributions to the science of radio. In 1922 he wrote “Radio Telephone for Amateurs.” Fully indexed, it dealt with basic theory, vacuum tube theory, RF stages, various modulation methods systems and antenna systems.  Published as a hard cover volume, it was a major treatise for its time and set a precedent for comprehensive radio publications that followed, such as ARRL’s “Radio Amateur’s

Charles Stuart Ballantine

Handbook” launched four years later.

The author of this column has a hardback edition of Ballantine’s text that his father purchased in 1924.  It is an intriguing insight into the state of technical advancement in that period, Ballantine’s extensive technical knowledge and his unique manner of presentation.
Ballantine had a very distinguished career.  He was born in 1897 and by 1908 was an Amateur Radio enthusiast. He worked as a ship radio officer during the summers of 1913-15.  After graduation from Drexel University, he began his engineering career with the US Navy and was instrumental in achieving several advancements in direction finding and developments in the loop compass.
After WW1 he attended Harvard and went on to foster many significant advances in the radio and audio field. He held more than thirty patents and was a Fellow of the American Physical Society, the Acoustical Society of America and the IRE.  He received many prestigious awards from major organizations and the Franklin Institute named a medal in his honor. Ballantine died in 1944 at the age of 47.      –VE1WG

Sincere appreciation to Denis Bourque, VE9EMS for conducting a Space Station “hands-on” operating instructional session at our May meeting.

MAARC, Inc. 75^th Anniversary

We want your ideas and assistance in marking this special occasion.  Since many Radio Amateurs travel to Moncton for our annual MAARC Flea Market, it has been suggested that we expand that activity by including special 75^th Anniversary observances.
Let’s have your thoughts and suggestions.

This month’s QTC Newsletter is purposely kept brief with the emphasis on our upcoming 75^th Anniversary in 2011.

We trust all will contribute their ideas and assistance to mark this very special occasion.

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