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What is the impedance of a long wire antenna?
If the antenna were to be a single band antenna with the wire cut to a ¼ wave length at the desire frequency this would produce a feed impedance somewhere between about 30 ohms to 80 ohms and would therefore be relatively easy to achieve a useful match.
Does a random wire need a counterpoise?
The shorter the wire, the fewer bands you’ll be able to use. (A random-wire antenna needs a good ground regardless of how much power you’re running.) If your radio room is in the basement or on the first floor, you may be able to use a cold water pipe or utility ground. On higher floors you’ll need a counterpoise.
How high can my antenna be?
For antennas not more than 45 feet in overall height as measured from the ground level, not including vertical and whip antennas more than 25 feet above the height of the main building, shall be permitted with a special use and development permit. 2.
How high does a beam antenna need to be?
A beam type of antenna at a height of 70 feet or more will provide greatly superior performance over the same antenna at 35 feet, all other factors being equal. A height of 120 feet or even higher will provide even more advantages for long-distance communications.
How big of an antenna do I need for 40m?
want the antenna to be at least 1/4 wavelength long for each band you plan to use. For instance, to work 40m be sure the antenna is at least 10m or 33′ long. Use only the white gaps for your antenna lengths, and if you’re using different ham bands than in these examples, modify and rerun
Can a long wire be used as an antenna?
The long wire or end fed wire provides an ideal solution for many radio communication stations, but it is not the best option for many instances. Before settling on the use of a long wire or end fed wire antenna, it is wise to consider both its advantages and its disadvantages.
What’s the average length of an antenna in a rig?
rig, often with no feedline, and the other end in the air attached to It is important to use a counterpoise. Antenna”) is an 84′ long end fed and a 17′ long counterpoise (6.5′ for 20m). While these lengths have been shown to work well on many bands, which is helpful if you’re in a hurry to get on the air, read up on the topic
How long should a random wire antenna be?
The graph below shows lengths to avoid for different collections of bands. The fewer bands, the fewer high impedance regions to avoid. You also want the antenna to be at least 1/4 wavelength long for each band you plan to use. For instance, to work 40m be sure the antenna is at least 10m or 33′ long.