Amateur Radio Stack Exchange
Amateur Radio Stack Exchange

Questions tagged [feed-line]

Questions about RF feed lines. Also tag with coaxial-cable if the feed line in question is a coaxial cable; also tag with connectors if the question is about connectors for an RF feed line.

Questions on topic in this tag include anything to do with the use of any type of RF feed line, coaxial or otherwise. The selection of cables and connectors; how to route, solder, and splice cables; the use of cables in outdoor and other environments; the use of leaky coaxial cable as an incidental radiator; or the building of a balun or antenna using feed line are all on topic in this tag.

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How to estimate ladder line loss?

There have been a number of questions regarding the issue of feed line loss and ladder line eventually gets discussed. So I am curious, how does one begin to estimate the loss in ladder line? So, for the case of 2 bare wires "somehow" spaced an…
Chris K8NVH
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What are the implications of pulling LMR400 through EMT conduit with several 90 degree conduit body fittings

In order to route my antenna feedlines out of my house, I have to pass through a wall, into the garage and through another wall. All of this involves four 90 degree turns. I am wondering what the possible issues would be with using 2 inch electrical…
ghendricks
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Ladder line vs twisted pair: where do the losses actually occur?

I don't understand why 14 AWG XHHW-2 wire would work fine when used in ladderline for high-power HF transmission, but the same wire would exhibit higher losses when used in a twisted pair configuration. Can anyone explain to me why ladderline has…
Mark K1LSB
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Why isn't some form of twinax commonly used for antenna feed lines?

Twinax (shielded controlled impedance balanced line pairs) is said to be used in 10G ethernet signaling for greater noise immunity that other cabling types. Why isn't twinax (or similar) commonly used for amateur radio antenna feed lines, where…
hotpaw2
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Can I use 14/2 UF-B wire as transmission line?

I'm wanting to build an antenna system utilizing twin lead feedline running to an 80 meter doublet. I'd like to avoid the typical hassles that accompany 450 or 600 ohm ladder line so I'm considering using simple 2 conductor wire as the feedline. I…
Mark K1LSB
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Mix 300 ohm window line with LMR400 for long feedline run to 6m/2m/70cm?

I have about 150 feet of LMR400 going to a tri-band 6m/2m/70cm antenna, and unfortunately the loss is quite high at these high frequencies, at this length. About 70 feet of that run is non-negotiable because that's how high the antenna is up in the…
User5754448
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Is there a lower limit to the usable frequency for PCB 'stripline' feedline?

I'm designing some low loss antenna switches for 160-10 meters, and my current plan is to construct the entire system as continuous 50 ohm microstrip feedlines on 2 sided FR4 PCB. All examples that I've been able to find focus on applications above…
Hamsterdave
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Is using 14 AWG XHHW-2 twisted pair wires for high-power (legal limit) HF TX feedline a bad idea?

My question is specifically regarding using a homemade twisted pair of 14 AWG XHHW-2 wires as twin lead feedline for high-power HF ham transmissions. A somewhat similar question has been posted in the community (and answered) regarding the use of…
Mark K1LSB
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