The aerial wire is switched between the ATUs. CO ATU used solely for top band on the other transceiver. Centre, Vectronics ATU for general coverage on one transceiver. Top left left, SWR meter (rebuilt to cover top band). ATU set up for end fed wire and two transceivers:īelow is my set up for an end fed wire and two HF transceivers. What is frightening is the misconception, the myths, surrounding this impedance matching device. A poor aerial is a poor aerial, no matter what you do at the feed point. Remember, an AMU does NOT improve the performance of an aerial. That remains at 240 volts no matter what you do. It doesn’t somehow alter the mains supply voltage. A mains transformer transforms 240 volts to, say, 12volts. In other words: two-thousand ohms in, and fifty ohms out. The AMU transforms the impedance from two-thousand ohms to fifty ohms. Neither does it change the fifty ohm output impedance of the radio to two-thousand ohms. The matching unit doesn’t miraculously change the aerial feed impedance to fifty ohms. If the impedance of your end-fed aerial is two-thousand ohms, it doesn’t change. The impedance of an end-fed wire could be anything between twenty and several thousand ohms. The output impedance of most amateur transmitters is fifty ohms. It’s a matching device, matching one impedance to another. But this device is not an aerial tuning unit. The term ATU has become extremely popular over the years. Correctly termed, the AMU is an aerial matching unit.
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |