Y’know how a quarter-wave stub of coax feedline has interesting properties? Like, if you attach one end to an antenna analyzer and left the other end open at 1/4λ down, then the open circuit looks like a short on the analyzer; zero Ohms resistance. And if you short the end, it looks like an open; …
Tag Archives: feedline
Visual Mismatch
Sonofabitch. As it turns out, the 60-ish feet of 50ohm RG-8 coax feedline I “rescued” from the disused tower at my last office is actually 75ohm T-1253A. I should’ve looked at the silkscreen more closely. I’m a blind fool. That might explain some of my inability to match my antennas on some bands. The SWR …
Rebalanced
Took out the drill and did repairs to my 1:1 and 4:1 baluns. Made the holes wide enough and at the 3/4″ centers necessary to accept the banana terminal blocks. Sealed the interface between the case and the block with a flattened piece of Coax-Seal(tm) for water protection. Looks better, and now the terminals won’t …
1:0 Balun
Severe storms and winds this weekend prompted me to take down one of my two antennas for safety. I have a 20m inverted-V dipole with 1/4 wave 300Ω twinlead as the feedline from the center insulator to a 1:1 current balun mounted on my wall (the twinlead is transparent at 20m frequencies). The other antenna …
Fat, Thick, and Dirty
I finally did it. I soldered a pair of PL-259 connectors (screw-on type) onto a 28′ (8m) length of scavenged RG-8 cable. And it works. It really, really works. Of course, they’re really, really dirty. And it took me 2 hours to f’n do it. But it works.