Impedance of Each Element on Telewave ANT Folded-Dipoles

[rescue161]

From my research, DB Products and others are using ~100 Ohm impedance elements and I have had success in making new phasing harnesses using a combination of 35, 50 and 75 Ohm coax. I need to repair a phasing harness on a Telewave ANT1506-9. Below is a brief description of the damage.

Our club has a Telewave ANT1506-9 antenna for one of their repeaters and it was shifted on the tower by Hurricane Florence. From the ground, the antenna looked like it was bent at about 75 degrees. I climbed the tower, loosened the clamps and straightened the antenna, but the phasing harness got cut/crushed by the mounting clamps when the wind shifted the antenna mast. The crushed area is about 3 feet from the feed-point. The coax on the bad section is 50 Ohm RG213 (Belden 8267). From my research, it appears that I should be able to just cut out the bad section and put a new N-Type on the now shorter feed-point. Being 50 Ohm coax, I would imagine that I can cut it to any length and be okay. If I'm wrong, please let me know now as it'll be another climb and a repair on the top of the tower.

My main question is what is the impedance of each element on this type of antenna? The construction is not like the DB Products and is a complete loop. I have two single-element antennas (ANT150 & ANT450) and am tempted to cut away the element to see what they used as a matching network. If someone already has this info and can share, it would help me save the destruction of a good antenna.

 

[kf8yk]

The antenna feedpoint impedance is about 280 ohms. At the feedpoint a 1/4 wavelength section of 125 Ohm RG-63B coax transforms the feedpoint to 50 Ohms, where it's spliced to the 50 Ohm RG213 coax.

The quarter wave coaxial transformer & splice is located inside the tubing for the folded dipole element on the end opposite of the drip hole. The element is not a continuous loop, there's a gap opposite the mounting pipe hidden under adhesive lined heat shrink tubing. This gap is the feedpoint.

The phasing harness for multiple dipoles is a power divider using 50 Ohm coax & Tees. Past the first T the coax lengths are critical, before the first T you shouldn't have an issue shortening this section of coax.

 

[rescue161]

Yes, I knew the gap at the feed-point was there. I was just going to cut away the heat-shrink to see what type of coax was inside the tubing. Thank you very much for the answer!