The Larsen Company, manufacturer of quality mobile and other antennas, publishes an antenna location information sheet in their product catalog. They consider ground plane availability, the antenna electrical length and the radiation pattern of each design.
Each antenna type (1/4 wave, 1/2 wave, 5/8, etc.) has a very specific radiating pattern to be considered when selecting a mobile antenna. Larsen notes that "the signal radiating from a 1/4 wave antenna is directed more vertically, thus making it ideal in urban environments where buildings might obstruct the signal. The design of a 5dB collinear mobile antenna is designed to direct the signal more towards the horizon. This type of antenna is ideal for geographically flat regions where the signal coverage is sparse."
Using a standard automobile, there are five possible general locations for mounting and antenna: the roof, front fender, rear fender, trunk and rear (or other) window glass. The center of the roof is always the best location for a mobile antenna. Using it as reference, here is a comparison of the other locations for different antenna mounts:
Roof center (permanent) 0,0dB
Remember: -3.0dB means that half of your antenna gain is lost. As you can see, the placement of your antenna and the way you mount it is critical. You can lose all the benefit of that “super” antenna by putting it in the wrong spot.
Roof center (magnetic mount) -0.2dB
Roof corner (magnetic mount) -0.2dB
Trunk center (permanent) -2.1dB
Trunk center (magnetic mount)-2 .8dB
Trunk lip (center) mount -2.8dB
Trunk corner (magnetic mount) -3.4dB
Hood corner (magnetic mount) -2.4dB
On-Glass (upper window)-0.5dB
On-Glass (midpart window) -1.2dB
On-Glass (lower window) -3.0dB
New Hams in Area
Help! Help! help! Your editor need your help in identifying new hams in area. After you welcome them, please get their call, name, and address. They will be sent a courtesy copy of the newsletter. Also, they will be listed in the “Welcome New Amateurs to Midland” column. Please notify your editor by phone, email, or 2 meters. Your help will really be appreciated.
Thanks in advance. Dewey |
Call PolicyThe local high school has a policy that the parents must call the school if a student is to be absent for the day. Kelly Raines, deciding to skip school and go to the mall with her friends waited until her parents had left for work and called the school herself. This is the actual conversation of the telephone call. Kelly: “Hi, I’m calling to report that Kelly Rains is unable to make it to school today because she is ill.” Secretary at high school: “Oh, I’m sorry to hear that. I’ll note her absence. Who is this calling?” Kelly: “This is my mother.” —ARNS Bul., Jul. ‘99 |
VE Testing Results10 July 1999.Pansy Pearl Loper Big Spring, TX Technician Christopher D. Tatro Andrews, TX Technician Jon P. Calder Monahans, TX Technician |
Hiram Percy Maxim, 130 Year AnniversaryThe ARRL Board also approved a proposal to hold a Hiram Percy Maxim 130-year anniversary on-the-air event in September. The event will mark the 130th anniversary of Maxim's birth, September 2, 1869. It will take place September 2-11. —Board Meeting, The ARRL Newsletter, Vol. 18, No. 29, Jul. 23, ‘99 |
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