- #1
Jackson Richter
- 43
- 2
When investigating 600 ohm ladder line, a few questions come up that I hope some of you can answer. It appears this type of feedline can operate with significant vswr because of its extreme low loss characteristics. On the other hand, impedance matching between the feedline and antenna feed point become important with coax type feedlines. Basically, I am a firm believer of bench-marking feedlines for future reference. Coax is relatively simple to bench mark. Inserting an inline wattmeter at the source of the 50 ohm feedline with the use of a fixed known load at the other end and record the wattage. Remove the wattmeter and place it at the end of the feedline next to the same load and record the wattage again.
When trying to benchmark open-wire feedline for loss, it becomes a little more difficult.
Since most inline wattmeter's are 50 ohms, placing a wattmeter would have to be placed ahead of an impedance matching network matching 50 ohms to 600 ohms and the another network matching 600 ohms back to 50 ohms again? Correct?
Of course the loss in the matching networks would also have to be known.
The other concern is having the ability to easily verify if the feedline currents in an open-wire feedline are 180 degrees out of phase, minimizing any feedline radiation. Thanks for any help here.
When trying to benchmark open-wire feedline for loss, it becomes a little more difficult.
Since most inline wattmeter's are 50 ohms, placing a wattmeter would have to be placed ahead of an impedance matching network matching 50 ohms to 600 ohms and the another network matching 600 ohms back to 50 ohms again? Correct?
Of course the loss in the matching networks would also have to be known.
The other concern is having the ability to easily verify if the feedline currents in an open-wire feedline are 180 degrees out of phase, minimizing any feedline radiation. Thanks for any help here.