|Monthly Newsletter Dedicated to the Advancement of Amateur Radio March, 1999|
THE PRESIDENT'S CORNER
Thanks to Beryl Adams, Director of the Riley County Red Cross for leading us through the Red Cross Disaster Relief Training. It gave us a good idea about how the Red Cross deals with disasters and how we might help in the future.
Our next meeting will be March 12th, 7:30 P.M. at the Red Cross Building at 1410 Poyntz in Manhattan. Jim Duncan, KUØG, will give a talk on the many aspects of APRS (Automatic Packet Reporting System). Jim will have an APRS system at the meeting. We hope that Daniel Soldan, KBØOTV, can have the KSU Solar Car APRS system to demonstrate. As usual, many of us will meet at the Manhattan Sirloin Stockade for the Eating Meeting at about 5:15 P.M. before the regular meeting. If there is enough interest and time there will be a tour of the KSU Solar Car. It's not done but you can see the progress and get a good idea about how the new car is built.
The next XYL dinner will be on March 18th at 7:00 P.M. We'll go to El Cazador. I hope a lot of XYL's can join us and that you OM's will let your XYL know about it. Hams and non-ham women are welcome.
Norm Dillman, NØJCC
We are about through with the no-code class.
We only have three students but went ahead with the class. Chuck talked about RF safety for the Saturday February 27 class. He will also give us a program at a future club meeting.
SOLAR CAR UPDATE
Good progress has been made recently on the KSU Solar Car, Apollo #11. Qualification is at the end of April in Michigan and the Rayce is at the end of June. If we have time we'll give a tour of the current progress after the next regular MAARS meeting. The team has made a lot of progress on encapsulating and testing the 700+ solar cells on the car. The individual testing is almost done. The prototype of the maximum power tracker to get as much energy possible from the solar cells is being constructed. Most of the data acquisition system had been built and the two-meter packet link is working. We hope to have a 9600 baud/440 MHz system for the race. The motor and controller finally arrived. It's a ($12,000) hub motor that is very efficient. We also have all of the race batteries and extra test batteries. We're using special lead-acid batteries and not the $40,000 NMH battery pack made available by Ovonics. The composite frame is all done and all four wheels should be attached by the meeting. The main part of the composite body has been painted. If you have questions about the car just call "CQ Solar Car Team" on the 145.41- KSUARC repeater and you'll probably get an answer. The team members are required to have a Ham license to go on the race. In addition to the APRS/GPS mapping in the lead car and two support vehicles we also use 2-meter and 440 MHz to communicate with the driver and each other; 440 MHz for data as already mentioned plus we'll be experimenting with SSTV on HF.
FROM THE EDITOR'S DESK
Chuck Carter, AAØRI
Because of illness in John and Lenore's family, there won't be any minutes in this month's Newsletter. We will bring you February and March minutes in the April edition as well as more of the old minutes.
I have an article that should be of interest to all of you as I know how serious some of you are in antenna lore. Please let me know if you are interested in this type of material as well as the serious, as I seem to find it all over the www pages. Most of the authors are willing for us to use their stuff in our Newsletter.
73 de Chuck ..._._
by Al Cake, G3MOV
There are a great many types of antenna and most of them function best when they are erect. This is because of 'standing-waves' which produce energy in a vertical plane. Energy in the horizontal plane requires 'lying-down waves' and this is why most of the radiated and received energy is termed 'ecstatic' rather than 'magnetic'. (Kirchhoff's fourth and fifth laws of self-immolation present a heated argument on this subject.)
One of the most famous aerials is the diamond-shaped 'Ron Bick' aerial, named after its inventor Ron Bick of Watford, England. This aerial is very good but, because of its size, it has two main disadvantages - it is difficult to erect vertically and it is of limited use in fast-flying jet aircraft.
Another aerial that deserves a mention is the Log Periodic - so I have mentioned it.
I will now move quickly onto the three 'pole' antennas, namely the monopole, the dipole and the tripole. The last-mentioned can be disregarded as it is not now in use. The reason for this is fascinating, but I can't remember what that reason is. The monopole is very useful for LF, MF and HF but has limited usefulness at VHF frequencies where one should use the stereopole if maximum enjoyment is required.
At this point the reader may feel that there has been some neglect of the technical aspect of aerials. This is true and the author intends to deal with the dipole in depth technically, but at the same time try to satisfy the natural curiosity of the non-technical reader.
The word 'dipole' is a composite of two Latin words, 'di' meaning 'six' and 'pole' meaning 'sticks'. So it can be easily seen, even by the most ignorant, that a dipole is made from six sticks. As the reader will already know from my in-depth study of the Log Periodic, six sticks will have a much wider aperture than only one stick. Now we come to the technical bit. Pushing these sticks into the ground at regular intervals will give a quasi-omniphysical deltoid stub-matching line-of-sight high incident ground-wave. If three of the 'sticks' are coated with an intensely ionised P material and the other three coated with un-ionised N material then Zowie! - it's instant Receivesville man. (It is hoped that the reader will forgive the author for occasionally lapsing into the vernacular, particularly when excited).
Another thing about aerials that must be remembered is feeder independance. If the feeders of dipoles are spread apart it changes the natural independance of the aerial from 75 Ohms to 250 Megohms. As is commonly known it is impossible to hear anything with that sort of resistance in the aerial feeder. So best not to do it.
Other types of aerial in constant use are the 'Beverage' (called the 'T' aerial in Britain). This is also called a long wire and is 1.5 inches long at 16 Ghz. The Inverted X is also famous but not much in use as no-one can decide which way up it is supposed to be.
Finally, we move on briefly to microwaves where there are special considerations to be taken into account. Microwave and satellite signals can 'bounce around' all over the place and can become what is technically known as 'dirty'. However, fortunately there is one aerial which can be used effectively to 'clean up' these 'dirty' signals. This is, of course, the very well-known Carbolic Dish.
If you would like to become a member of the American Radio Relay League and receive the monthly issue of QST, your treasurer has a form you may use to apply. The club keeps $5 of each new member's dues and $2 of each renewing member, so even if you are renewing, do so through the club. The main thing to remember is that if you join through the club, your check must be made out to MAARS. When the form is sent in, the treasurer writes a new check deducting the amount which the club is permitted to keep. They will not reimburse the club. If you are renewing, bring your notice for renewal along to the meeting or send it to the Treasurer at the MAARS address.
April 17 - Joplin ARC Hamfest - Joplin, Mo.
April 23 - Des Moines ARC Hamfest - Des Moines, Iowa
May 14 - 16 - Dayton Hamvention - Dayton, Ohio