Doublet feeder & operation
Antennas, Band Pass Filters, Low Noise Yagi, Preamplifiers, Splitters
The antenna tuning unit used should be able to match impedances over a wide range, and it must also have a balanced output connection. It should also be a current balun, NOT a voltage balun. Also the length of the feeder can be cut meet the requirements of the installation. Wide bandwidth, less harmonics transmitted, reduced rfi, lightweight, no tuner required Cons: The feeder can be either open wire or what is termed ladder line. As open wire feeder is able to operate with levels of standing waves and effectively becomes part of the antenna, it is able to operate over a wide band of frequencies.
Mosley Electronics | Manufacturer of World Famous Communication Antennas!
The goal in tackling these frequently asked questions is to help newer hams erect a successful antenna system. AMS detects the operating mode of the received signal as C4FM digital or analog FM, and then automatically and instantly switches the receiver to the appropriate mode. Conversationally, the term "dipole" often refers to any antenna that looks like a dipole, that is, a center-fed wire antenna with a feedline going to the shack. You could probably fit one for 30 meters or higher in an attic or beneath an eave on the house. The present approach to the all-band problem is to use a multiplicity of half-wave-length antennas based on the old formula' and feed them with a common transmission line, or to use a single antenna with "traps" in it.
First off I should mention that I live in the city where there is a lot of electrical noise from local businesses and such. Needs to be hung in the right space so off-center feed point is in the right spot for getting it to the shack and high enough so the vertical matching stub is, truly, vertical. Now, though, with the development of top-band for DX and the addition of WARC and post-WARC bands, I count a total of ten swaths of radio frequency we can use just in the high-frequency bands, and six meters is not that far off. However trying to use one antenna for multiple bands, my favorite has been a version of no. This is explained in any good textbook on antennas; briefly it means that every antenna has an "image" directly beneath it in the ground, and it is the combination of the effect of the antenna plus the effect of the image that gives the antenna most of its directional properties. Band-switching transmitters made compact by the techniques outlined in the first paragraph have increased the demand for suitable all-band antennas, preferably fed with coaxial line, but up to the present time the approaches to a solution to the problem have been rather primitive, to say the least. The H is a broad-band, compact, rotatable dipole designed to offer excellent performance even when mounted at only ft above ground in a V or horizontal configuration.
2 months ago