Questions tagged [folded-dipole]
8 questions
19
votes
5 answers
Why do folded dipoles have greater bandwidth than ordinary resonant dipoles?
This is something I've read in passing, but never encountered an explanation of why. For example, Wikipedia says:
Another common place one can see dipoles is as antennas for the FM band; these are folded dipoles. The tips of the antenna are folded…
Phil Frost - W8II
- 51,321
- 5
- 84
- 209
14
votes
5 answers
How does a folded dipole work?
A folded dipole is like an ordinary dipole, but with the ends extended and folded back, until they meet. Although it looks like a loop, I'm told it behaves similarly to a dipole.
How does this thing work? If I could see the voltages and currents in…
Phil Frost - W8II
- 51,321
- 5
- 84
- 209
8
votes
3 answers
What sort of radiation efficiency can one expect from a folded dipole?
It is pretty well established that folded dipoles have much greater acceptable-SWR bandwidth than ordinary dipoles.
Radiation efficiency is simply the quotient of radiated power to the antenna feedpoint input power.
Seeing that folded dipoles are…
user
- 4,828
- 2
- 29
- 59
5
votes
2 answers
What happens if I “open” a folded dipole so that the two wires are not connected anymore?
A folded half wave dipole consists of two wires in parallel with only one of the wires driven, but the ends of the two wires electrically connected. As I understand it (and I may well be wrong there) the folded dipole still behaves similarly to a…
anyfoo
- 153
- 4
4
votes
2 answers
Coaxial Folded Dipole Antenna Matching Impedance
In http://www.nsw.wicen.org.au/technical/projects/coaxial-folded-dipole-antenna, the guy is using a 50 ohm coax cable to build a folded dipole antenna and claims that this will enable use at 50 ohm (I assume the required matching impedance).
Now,…
user4575
- 51
- 1
- 3
2
votes
2 answers
How to estimate a dipole feedpoint impedance?
An ideal dipole, at resonance, will have an impedance around 73 ohms. A folded dipole, around 280 ohms.
How can I calculate the impedances when not at resonance? Let's assume I have a span of 15M in my property where I can hang a dipole. Ideally,…
hjf
- 1,199
- 9
- 23
0
votes
1 answer
How should I stack these folded dipoles?
Looking to stack these 8 folded dipoles on my 100ft tower.
I can not find any information whatsoever on these. I have 4 consecutive serial numbered boxes.
Bluewave Marathon
BME139FN1H0
138 - 174 MHz
Gain 5.5dBd
Looking for information on an…
VE6RSO
- 3
- 3
0
votes
3 answers
To folded dipole, or not to folded dipole?
I currently operate a 20M half-wave dipole with a balun. It's a little lower than ideal, but it gets me on the air.
I've read about folded dipoles. But I've found contradicting information about them. So here are a few questions:
Does a folded…
hjf
- 1,199
- 9
- 23