12el DL6WU Yagi 12dB gain – lightweight boom construction using a folded dipole.My 23cm portable antenna collection includes: I can see the lights from the Norfolk skyline at night but darned if I can hear 'em using a discone at 35' unless I drive about 6 miles toward the city.I’m enjoying the challenge of 23cm 1296 MHz homebrew antenna construction for SOTA purposes. Been following this topic and want to build one of the antennas, put it on my tower at about the 90' level and feed it with CATV hardline. Heck, I'm working on trying to hear 800 mHz transmission from VA Beach and Norfolk from my home in Chesapeake, VA. Yes, the earth is actually pear shaped but those calculations would include location based operators, factoring path azimuth and calculated using a much more involved formula the results would minimially affect the outcome, especially on a purely latitudinal transmission path. The formula posted earlier also factors radio waves extending slightly beyond the visual horizon though how far is frequency dependent. The visual horizon uses slightly a different constant in the formula (if memory serves, the USCG teaches that to be something on the order of 1.213). Trees, buildings, hills, etc means YMMV hence the use of the (~) symbol on the mileage outcome. The post simply demonstrates the relationship between antenna height and the pure distance to the radio horizon. This makes commercial antennas more attractive. Unfortunately, the price of copper has made it economically unfeasible to build many types of antennas. A multi-element yagi would be a better choice. My feeling is that if you need to receive distant 855Mhz signals something with higher gain than a biquad would be a better way to go. Your receiver will not care if the impedance of the antenna is not exactly 50 ohms.Ī friend once held a competition for new hams to design a 1.2Ghz antenna. Also, you will use the antenna for receiving and not transmitting. The only way to know for sure is if you have the necessary test equipment to measure the performance of the antenna. The significance of this is not worth worrying about where the difference between the theory and practice is only a few mm. Or, you can assume that the calculator produces only theoretical values. In the present case, you might assume that the person who wrote the design software had some practical experience in antenna design and, therefore, took these considerations into account. For example, a half wave dipole wire antenna will end up shorter than the theoretical calculation due to end effect. The bottom line is that any calculated dimension of an antenna will be slightly different in a real antenna. In any antenna design there is the theory and then there is the real world.
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