![]() The "skin effect" describes how RF currents flow in a thin layer on the surface of a conductor, proportional in depth to the wavelength of the signal. This is due to what's called the "skin effect". When we connect the coaxial transmission line to our transmitter, the RF current flows on the center wire and on the inside surface of the pipe. To understand this problem, think of a coaxial transmission line as a wire centered inside a metal pipe. Otherwise, RF currents will flow on the outer conductor of the coax, compromising the effectiveness of the antenna. However, when coax is used to feed a balanced load, such as a dipole antenna, some provision should be made for converting from the unbalanced transmission line to the balanced load. This arrangements works well with an unbalanced load, such as a vertical monopole antenna fed against a ground plane or radials. At the transceiver, the center conductor is connected to the transmitter output (or receiver input), and the shield is connected to the chassis. Coax is weatherproof and may be buried underground, run inside a metal mast or taped to a tower without harmful effects. The sheathing is covered with a flexible outer jacket. It consists of an inner conductor with an insulated covering (dielectric), which is then covered with a braided wire sheathing (shield). Coax comes in several sizes and types for different applications. In the real world, we use a balun to couple a coaxial transmission to a balanced antenna, such as a dipole.Ĭoaxial transmission lines are commonly used to connect our transceivers to antennas. It refers to a device used to couple an Unbalanced transmission line to a Balanced load. I will let you know what I learn and more importantly what I build.Bal-Un is a term formed from the words balanced and unbalanced. I have my reading set out for me the next couple of nights. So for $19.95 plus shipping you can purchase a brand new copy of it here. ![]() I went to their website and lo and behold, they just got in a new printing of the book. ![]() It was originally available from CQ magazine. I checked Amazon and several people had copies, but most started at $150.00 or more. ![]() So I went back on Ebay and no copies were listed this time. Well long story short, I never did receive the copy and after about 3 or 4 weeks Ebay refunded my money since the seller wouldn’t respond to my or their messages. I went on Ebay and found a copy for 49.00 and purchased it using Buy Now. I did a little research and found that many ham’s reccomended Understanding, Building, and Using Baluns and Ununs by Jerry Sevick, W2FMI. The manual tuner has a built in balun that allows me to use my loop with dual rg-6 coax. I am trying to do more remote operation, and obviously with a manual tuner it makes it difficult. A couple of weeks ago, I had a post about needing to build a balun to use with my loop. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |