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.
84 questions
2
votes
2
answers
277
views
Chokes for Multiband Quarter Wave Vertical
I have a Quarter Wave vertical with multiple elements similar to the DX Commander antenna. It's mounted on a metal roof which is acting as my ground plane. I have a run of about 15m of cable back to ...
- 171
0
votes
1
answer
139
views
Sleeve balun issue
Trying to make one of these for 434 MHz. The coax is RG-174 of some 3 mm diameter. I have calibrated the VNA (with 2 x 100 ohm resistors) right where the 47 ohm resistor can be seen, before sliding ...
- 327
0
votes
1
answer
105
views
Tap-feeding for helicals
Does anyone know how to properly do the displaced feed - fig 4.1.b at page 19 ?
I have put the sleeve balun over my coax, but what to do with the coax shield near the feedpoint - leave it unconnected, ...
- 327
4
votes
1
answer
730
views
Antenna - vertical & beam antenna transmit at the same time?
Is it possible to use a vertical antenna and a vertical polarized beam antenna at the same time?
I have a friend that lives about 7 miles away & I can talk to him on 220MHz FM just fine on a ...
- 41
1
vote
1
answer
205
views
Can an isolation transformer be considered a balun / Can you feed dipole with isolation transformer
I'm trying to wrap my head around a concept of unbalanced and balanced transmission lines, baluns, ununs etc. to properly understand how to feed symmetrical (e.g. dipole) antennas.
Currently, i'm ...
- 121
1
vote
3
answers
3k
views
450-ohm ladder line fact vs fiction
I am considering many possible doublet antenna scenarios for a multi-band antenna (80 meters to hopefully, 6 meters) customized to my specific home situation.
Everything is a compromise. I will be ...
- 13
0
votes
3
answers
543
views
longest practical feed line length
So for a HF vertical antenna (DX commander Rapide), what is the longest feed line that that I can practically use using high-quality coax? I realize shorter is better, but my HOA (my wife) is raising ...
- 11
0
votes
3
answers
2k
views
QRP operation SOTA, what coax cable feed-line for HF?
I've done outdoor activities, POTA and WWFF, with a coax RG58 feed line with PL conectors, around 3 meters (9.8 feets), for wire EFHW antennas working HF bands (40m, 20m and 10m).
Now I want to do ...
- 103
3
votes
2
answers
531
views
Can I run my antenna coax near a gas line?
I just moved to a new place and would like to put an antenna up in the attic. My shack location is in the basement with the furnace and water heater. In my explorations, I've discovered that there is ...
- 161
4
votes
2
answers
593
views
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 ...
- 63
0
votes
0
answers
99
views
Is using 14 AWG XHHW-2 twisted pair wires for high-power (legal limit) HF TX feedline a bad idea? [duplicate]
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 ...
- 63
2
votes
4
answers
244
views
Wave bounce inside a resonant antenna
Let's assume we have a transmitter, a feed line, and a standing wave antenna (dipole, etc.). The transmitter is matched with the feed line, and the feed line is matched with the antenna, which is why ...
- 47
4
votes
2
answers
1k
views
Coax in the wall, or around the house?
I am mounting a hex-beam antenna to the peak of my house (assuming that I can find someone with a cherry-picker or a scissor-lift that can help me get it up there). Right at that end of the house is ...
- 51
2
votes
1
answer
230
views
Is a 1/2-wave coax cable shorter or longer than the full-speed 1/2-wavelength?
If I want to cut a half wavelength segment of coax for the two-meter band and the velocity factor is 85%, is my cable going to be shorter or longer than a meter?
I'm trying to figure out if the ...
- 939
2
votes
1
answer
202
views
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 ...
- 63