Discussion in 'General Technical Questions and Answers' started by KE7ENC, Aug 7, 2005.
What is the difference between a dipole and a doublet in physical mechanical configuration?
The difference between a dipole and a doublet is just about the same as between a condenser and a capacitor.
That is to say it is all in the spelling!!
Wait a minute, Orv. I thought a dipole was a wire split in the middle to attach the feedpoint, while a doublet was 2 wires, one extending from each side of the feed point.
A dipole is usually fed with coax, while a doublet is fed with ladder line.
That's the usual definition here at radio WG7X anyways!
73 Gary WG7X
Doublet is ALSO a term used by some people to pretend they know something more than they do.....
In actual use I have heard the term 'doublet' MOST often used as stated, wire fed with ladder line.
MOST hams refer to a simple coax fed dipole as a Dipole. It is USUALLY 1/2 wave for the band they are working on, OTHERWISE they will name the band.
If they are working 15 meters with a 40 meter dipole, they will say "I'm using a 40 meter dipole"...If they are on 15 and using a 15 meter dipole, they will just say "I'm using a dipole".
If they are on 15 and using a two meter dipole, they will just say "Ain't the new licensing requirments GREAT?"
Just don't fall off the "ladder".
If you saw upon the street a man who walked with dipole feet...
I thought it was a person with dual personalities ! Oh, wait, that is a "bi-polar" person!
about 75 years
About the same difference between a condenser and a capacitor.
I had thought a dipole referred to an antenna that was 1/2 wavelength long on the band you intended to operate; e.g. 66 feet for 40 meters (ladder-line or not). If you used the same antenna on 30 meters it would be a doublet.
So the G5RV is a dipole on 60 meters but a doublet on all other bands. At least that is what I thought.
Nice guess, Paul, but I've always wondered why verticals were not called "monopoles"
It really is a confusing subject. But even the ARRL handbook and other antenna references refer to resonant and non-resonant dipoles, so resonance has nothing to do with being a dipole.
One dictionary defines a "dipole" as "Electronics: An antenna, usually fed from the center, consisting of two equal rods extending outward in a straight line."
So maybe a "doublet" is a) not usually fed from the center, or b) consisting of 2 unequal rods, or c) not extending outward in a straight line?
I think that as Orv originally said, they are essentially synonymns.
Dipole vs Doublet is like ECO vs VFO. One and the same. Some may claim a difference, but they are both electron coupled and change the frequency.
Since this is the internet there is no provision for facts being true to form.
When I first got bitten by the Ham Radio bug in about 47 or 48 the old timers were calling what we term a "Dipole" a "Doublet." I guess I never questioned it then,we were not as smart in those days as the new modern Amateur,we didn't know it all when the calls were assigned.
Remembering back I would guess the term "Doublet" was to differentiate between a dipole antenna and a long wire antenna.
It was not untill the late 60's that I saw the terms dipole and monopole used for a half wave centerfed,and a 1/4 wave end fed.
As I said we as neophytes to amateur radio wanted to learn,so we kept our mouths shut and our ears open,and accepted what we were told from the old timers who had been there before,totally different protocol than what is used today.
Lets not get into "is it an antenna , or an aerial" ? Do we send waves through the Ether or the Ionosphere - - or neither
Actually Jim, we send them through the ether and bounce them off the ionosphere.
I've always known doublet and dipole to be interchangeable terms. Remember that in 47 or 48, feedlines were much more likely to be open wire (also called open feeders, ladder line, even twinlead.) So the idea that the difference could be the feedline has some possible merit.
When I used a wire fed in the center that was not necessarily resonant on that particular frequency, I called it what it was: "a center fed flattop of so many feet fed with open wire."
Moving a tad upscale:
Is it a Quad, or is it a Loop?
Bill in my terminology,if it is a vertical one lambda loop and it is a 1/4 wave on a side it can also be called a "QUAD".
However not all loops are vertical,nor are all loops a one lambda loop.
A loop is loop but some times it is a quad.
If it is a loop and is one lambda total but has only 3 sides it is no longer a Quad,but is instead a "Delta".
Deltas are usually in the vertical plane,but can have the Vertex pointed up or down, The Vertex pointed down is more effecient of the two positions.
Since we are on loops,the most effecient configuration is a circle,although a mechanical nightmare,the next in line is the Quad, then the Delta (vertex down) ,then Delta(V. UP ).
The loop in the vertical plane is the most effecient of the horizontal vs vertical plane.
Most loops can be fed in the vertial polarization or Horizontal depending where the feed point is placed.
Most generally speaking a point 1/4 wave down either side from the top dead center,will supply vertical polarization.
Now are you not sorry you asked ??
Post Script: I am of the group that believes from experience in the Quad VS the Yagi the Quad is superior,and has the advantage of good performance at lower heights,compared to the Yagi.
A folded dipole has double the amount of wire, maybe it is really a doublet