Site updated 7/05/2018 What's new?
New Antenna Links,
New Hamfests on Calendar page
| HF Mobile Antenna Efficiency The power radiated by any antenna is equal to the current flowing through its radiation resistance squared, times its radiation resistance. Therefore, increasing the current at a given radiation resistance or the radiation resistance at a given current increases radiated power. All antennas with a size in the longest dimension that is a small fraction of a wavelength have low radiation resistance. Practical considerations generally limit automobile antenna sizes to small fractions of a wavelength throughout the HF spectrum, but especially in the lower frequency portion, so HF mobile antennas generally have low radiation resistance. To maximize mobile antenna and radiation efficiency: 1) Maximize the radiation resistance, which generally means, make the antenna as large as possible. 2) Minimize all series loss resistances to maximize current, which generally means use a large antenna conductor size, a high-Q loading coil, and the lowest-resistance ground connection to the automobile possible. 3) Minimize shunt currents which bypass the radiation resistance by minimizing shunt capacitances and leakage currents through mechanical support insulators. ©2005 Martek International All rights reserved. |
| Add This to Your Site |
Breakfast first Saturday of the month, 8:30 am at TJ's Country Place 4048 West Broad Street
The Southwest Columbus Ham Radio Club operates a different kind of repeater and you’re invited! While this repeater has been on the air for over 30 years, its home to a small and friendly group of hams. Activity in the Club is as varied as the hobby of Amateur Radio itself and it doesn’t matter if your new to amateur radio or an old timer, you will find others that share the same interest as you. We encourage you to be active and perhaps you will learn something new as well. We meet the first Saturday of the month for breakfast and talk about ham radio. Later in the month, we have a family night. This fall, we will be restarting our net (Thursdays at 8:30pm) as a way to encourage the exchange of ideas. The past few summers, we got together for field day and we are looking to do more. We also encourage members to get together and help other hams who may need help with installing antennas or with setting up their home stations. Or, if you are studying for your license, please feel free to ask us any questions that you may have.
Thursday Night Nets
145.23- on the WB8MMR Repeater, check in with us at 8:30 p.m. You do not need to be a member to check in on the net. Club members are encouraged to be net control operators. We have a informal 10 meter net Thursdays at 8:00 p.m. on 28.405, shortly before the start of the 2 meter net, drop in and introduce yourself. John, K8BAT runs the net.
