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[Articles Home]  [Add Article]  

Fan Dipole

Alan Applegate (K0BG) on December 26, 2003
View comments about this article!


Fan Dipole

There seems to be a difference of opinion on what is or isn't a fan dipole. It is the intention of this article to set a base line for the description and thus not mislead a newcomer to our hobby.

The single element dipole is by far the cheapest and easiest antenna to erect. Since it can be made from a variety of materials it remains the most ubiquitous of sky hooks. It consists of two 1/4 wave length sections fed in the center with coax and configured in an inverted V, flat V; in straight, bent or dog legged fashion; and one which can be strung horizontally or vertically. The use of a balun is optional, but recommended. The center support and end insulators can be made from just about any non-conducting material you can name. Literally thousands of articles have been written about them, and just about anything you need to know about building one can be found in the ARRL Antenna handbook.

Just for the record, a multiband, open wire (or ladder) line center fed, single element dipole antenna is more correctly called a doublet as the antenna is only a resonant dipole on one frequency. A manner of semantics perhaps, but like I said we need to differentiate between the various types.

As the old clich goes, there is no free lunch and the bane of a dipole is limited bandwidth especially on the lower bands. Over the years a lot of experimenting has been done to increase the bandwidth of a dipole. As evidenced by the proliferation of antenna couplers (incorrectly called antenna tuners) in recent years, most increased bandwidth schemes add to the complexity in terms of supports, tuning, and real estate. This didn't (and doesn't) stop a lot of folks from giving it a try.

An article appeared in Radio News just after WWII describing an 80-meter "Fan Dipole" which had multiple legs, each of a different length. The antenna was fed with home brewed ladder line, which was connected to an adjustable link tank on the transmitter end. Bandwidth was touted to be the whole band and this is certainly true considering the broad range of matching capability an adjustable link tank has.

Circa 1948 brought several more articles describing other techniques to increase bandwidth on 160, 80, and 40, the "in" bands in those days. One used five separate dipoles all cut to the same length and spread apart in a fan, and another with five dipoles all cut to slightly different lengths and arranged in a fan. Both delivered on their boast of increased bandwidth at the expense of complexity.

Latter-day "Fan Dipoles" have not stayed the course with respect to single-band operation. Raytheon for example makes one which is essentially a log periodical set of dipoles and intended to cover a large part of the HF spectrum. Because the elements are arranged in an hour glass shape, its resemblance to a "Fan" is a hard to fathom and a misnomer.

So if we intend to use the term "Fan" to describe an enhanced bandwidth dipole, then its use to describe a multiband dipole is erroneous and misleading. For the record, a multiband dipole is one that has two or more dipoles cut for different bands and fed from just one coax. The fact that it may be arranged in a fanned out pattern doesn't change the basic premise.

Whether you agree with the basic premise or not, describing the same antenna by several different and misleading names is confusing for all. Let's all endeavor to keep the aforementioned in perspective and skip the misleading nomenclature, which is all too prevalent in our hobby.

Alan Applegate, KBG

Member Comments:
This article has expired. No more comments may be added.
 
Fan Dipole  
by K0RGR on December 26, 2003 Mail this to a friend!
Possibly the most effective 80 meter antenna I ever used was something of a 'fan dipole'. It was erected between two tall towers atop the Engineering Building at San Jose State University, and belonged to the club station, W6YL.

There were two dipoles cut for opposite ends of the bands. These were fed with an open wire section between the two dipoles, and open feeders to a fixed-tuned matching network that was fed with coax. I don't believe we needed to use any sort of tuner - the SWR was reasonable over the whole band. I wish I knew the details of the feed system - no doubt some engineering student spent a lot of time on it.

I remember the stories about full-sized yagis and Delta Loops for 80 meters, but the W6YL skyhook was a real contender. The DXers in the club were very pleased with it.
 
Fan Dipole  
by VE7NGR on December 26, 2003 Mail this to a friend!
Let's see...

Single band version: multiple elements tuned to different frequencies, fed in parrallel

Multi band version: multiple elements tuned to different frequencies, fed in parrallel

Sounds like the same thing to me!

If we had one really wide band extending from 3.5 MHz to 29.7 MHz, and I used this technique to build an antenna that could operate across the whole band, would it then be a fan dipole, since it covers only one band?

The fact that we are only interested in operating on several arbitrarily selected bands is irrelevant - the two antennas you discuss are one and the same.
 
RE: Fan Dipole  
by AC5E on December 26, 2003 Mail this to a friend!
Alan's too young to remember that Radio News article. I wasn't the oldest kid in the club either but if my normally accurate memory serves, it came out in 1948, along with a review of the brand spanking new RCA TS630 TV chassis, and between an ad for Sarkes Tarzian selenium rectifiers and an article on service and alignment of the classic Echophone EC1.

An issue or two before that Art Collins' version of the fan dipole was published with two pairs of dipoles connected at the feedpoint, with graduated spreaders leading to around 12 feet of separation at the closed ends. Essentiallly, this was what evidently would now be considered a "butterfly dipole." It makes a good full coverage antenna.

And the moral is that both names and styles change.

73 Pete Allen AC5E
 
RE: Fan Dipole  
by KB9YZL on December 26, 2003 Mail this to a friend!
From the treatment the Fan Dipole has gotten in its incidental mention in literally hundreds of posts, I clicked on this topic anticipating a humorous offering. Instead, I found a technically interesting article!

Thanks Alan!

Kent Carroll
KB9YZL

 
Fan Dipole  
by W4LGH on December 26, 2003 Mail this to a friend!
This particular line caught my attention...
"Over the years a lot of experimenting has been done to increase the bandwidth of a dipole. As evidenced by the proliferation of antenna couplers (incorrectly called antenna tuners) in recent years, most increased bandwidth schemes add to the complexity in terms of supports, tuning, and real estate."

As I have had this argument for years. An internal antenna "tuner" can not tune a dipole antenna fed with an un-balanced line (ie:coax) These devices really should be refered to as "Radio Tuners" as the best they can do is match the coax imp. to the radios imp., thus looking like a lower reflected power or a broader bandwidth of the antenna. When in fact, the mis-match still exists @ the antenna.

I do agree that with todays newer solid-state radios, that it will allow the radio to put out a little more power, as it fools the crowbar (fold-back) circuit of the radio. The older tube type radios had a much broader and tunable tank circuit, to match this mis-match, but again, the mis-match still existed at the antenna.

This is not totally true if feeding the antenna with a balanced feed line (ie: ladder line) as the entire length is being matched. An antenna "tuner" needs to be @ the antenna end, to tune the antenna.

73 de W4LGH - Alan
www.w4lgh.com
 
RE: Fan Dipole  
by K0BG on December 26, 2003 Mail this to a friend!
Brian, VE7NGR, the difference is that one example is cut for ONE band, where as the other is cut for MULTIPLE bands.

And Pete, AC5E, thank you so much for the kinds words, but I actually do remember the article in Radio News. The age incidentally is 63.

Alan, KBG
 
RE: Fan Dipole Police  
by W9WHE on December 26, 2003 Mail this to a friend!
I guess we must also stop calling those MFJ boxes "antenna tuners". After all...they don't really "tune" the antenna, just "couple" the load to the radio.

Does that mean my steppIR controller really is an antenna tuner?

What about so-called "tank" circuits in amplifiers? There really is no "tank" (Abrams M1, Tiger, Panzer, or otherwise) in your amplifier.

What about the button on my microphone? Shouldn't it be called a "keyer" because it "keys" my transmitter?

And those W5IHY boxes, since NOBODY uses them to "equalize" all frequencies (they are actually used to accentuate one "band" or another) shouldn't they be called "un-equalizers"?

 
RE: Fan Dipole Police II  
by W9WHE on December 26, 2003 Mail this to a friend!
Why call it the "international Morse Code"? Did an "international" invent it or did Samuel Morse?

Stop calling that black cable going to your antenna "feedline". Does your antenna really "eat" and does your coax really bring it food?

And those gizmos made by Polyphaser. They don't really "arrest lightning", they they divert it to ground. Shouldn't we be calling them "lightning diverters"?

Why call your Amateur Radio License a "ticket"? I thought a ticket is something you got when you violated the terms of your license.





 
RE: Fan Dipole  
by W9SN on December 26, 2003 Mail this to a friend!
My last qth employed a "FAN" dipole with 160/80/40/20 meters on it. I used a 1:1 balun into 50 ohm coax ran 200 ft back to my shack. It worked surprisingly well, however it was mounted at 90 ft high. I did have a time adjusting each elements and the size of this monster didn't help any either. It was also very heavy, thank goodness for #770 dacron to hold it up. I used dacron to hold each element instead of using insulating spacers like you find on the commercially built ones. I found it easier to tune this way. The SWR was virtually non-exsistant for the areas on the bands I operate (CW). 20/40 meters covered the entire bands. On 40 I worked dx like the big guns with it. On 80 I worked 150 countries.
But I learned something along time ago....anything up 100 ft works pretty well! Have fun, it is a great back up antennna.
 
Fan Dipole  
by W8AD on December 26, 2003 Mail this to a friend!
Hello Alan, and a happy day after Christmas to you! Well now I'm surprised! Normally your articles bring out the flamers who deny the existance of physics, Mother Nature or Cinderella!

An article about fan dipoles isn't controversial enough to get the guys frothing at the mouth or peeing their pants like code vs no-code, incentive licensing, dumbing up or dumbing down, and on and on ad nauseum. You must be "mellowing" out around the holidays.

Anyway, lots of fun--and Happy New Year to you!!! I always look forward to the "Flame Site".

Don, W8AD
 
Fan Dipole  
by K7VO on December 26, 2003 Mail this to a friend!
Alan,

Interesting article, and I am certainly not going to disagree with you. I am, however, going to raise a question. I use a multiband dipole fed with coax from a common point arranged like a fan. You say this does not meet the definition of a fan dipole and I accept that. What simple term would you use to describe it. I have called it a "fanned multiband dipole". Is that acceptable?

BTW, for those thinking of building such a thing, my dipoles are for 80, 40, and 20 meters. With an antenna coupler the 40m one works brilliantly for 15m, of course, since that's close to the third harmonic. The 80m one also works FB on 17m with or without a coupler (5th harmonic) and on 12m (7th harmonic). I effectively have three dipoles that work well on six bands. Oh, and I use it on 10m as well with an antenna coupler, and I haven't the foggiest idea which dipole(s) are radiating on that band. It might be the whole mess of wires. It does work, though, probably like a set of long wires.

Happy New Year!

73,
Caity
K7VO/4
 
Fan Dipole  
by KC0LBZ on December 26, 2003 Mail this to a friend!
The ARRL Antenna Handbook describes a "fan dipole" as consisting of two identical dipoles that angle apart and are shorted at the end. The overall length is shorter than a simple dipole for the same frequency, but the bandwidth is increased. The effect is similar to using a (very!) thick radiator conductor, such as a large-diameter aluminum tube or a wire cage, but is much less complicated than the latter. FWIW, this is also sometimes called a "butterfly dipole" because of the shape. The so-called "bowtie antenna" is very similar, but resembles two diamonds instead of two triangles.

KBG's description is of a single-feed, multiple-frequency dipole array. As long as the individual dipole frequencies are not too close together and are not closely harmonically related, they should have little effect on each other, and tuning of each element is largely independent of the others (though from all I've read, it should typically proceed from the longest to the shortest element and is an iterative process, since they *do* have some effect on each other). That doesn't mean that the selected dipole frequencies cannot be harmonically related; just that tuning becomes much more finicky if they are.

An example in the Antenna Handbook using two dipoles tuned for different frequencies in the same band (specifically, 3.6 and 3.9 MHz) is referred to as "stagger-tuned dipoles". In this case, tuning is tricky due to increased mutual coupling caused by the proximity of the resonant frequencies.

- Sam
 
RE: Fan Dipole  
by AB8IG on December 26, 2003 Mail this to a friend!
From QST Lab Notes November, 1996:

"The other multiresonant dipole is known by many names: multiple dipole, multi-element dipole, parallel-wire or fan dipole. It can be constructed a variety of ways, but Figure 2B shows the technique I used to build my first antenna. Each element is individually tuned to one of the desired bands."

I prefer my wife's more esoteric appellation. "All those stupid wires you've got hanging in the yard!"

Happy new year,
Jim
 
RE: Fan Dipole  
by K0BG on December 26, 2003 Mail this to a friend!
Well Caity, K7VO/4, it is a matter of semantics I guess. I've always thought that whom ever came up with an idea first, and chose a name for it aught not to have their idea truncated. Multiband dipole sounds good to me whether it be trapped or seperate hunks of wire.

Alan, KBG
 
RE: Fan Dipole  
by KD7NVJ on December 26, 2003 Mail this to a friend!
Nice, informative article, Dude !
Thanks and Gd Dx'ing
 
RE: Fan Dipole  
by KA4KOE on December 26, 2003 Mail this to a friend!
I'll bet fan dipoles work really "cool" in the summer months.

Har Har! Hardy, har har! (say in Bugs Bunny voice)

P
 
RE: Fan Dipole  
by W4KEN on December 26, 2003 Mail this to a friend!
Spoken in Curley Howards voice (3 stooges)

Ah , a wise guy ... why I outta..
 
RE: Fan Dipole  
by W4KEN on December 26, 2003 Mail this to a friend!


BTW, I did not even read the article, I never do.

I just like to sit back and watch everyone try to one up each other... nothing like a good pissing contest, don't ya think ?

KA4KOE's response was the best one yet,keep up the good work

73
 
RE: Fan Dipole  
by VE7NGR on December 26, 2003 Mail this to a friend!
K0BG says: "Brian, VE7NGR, the difference is that one example is cut for ONE band, where as the other is cut for MULTIPLE bands."

Same design, different design parameters.
 
Fan Dipole  
by KD7EFQ on December 26, 2003 Mail this to a friend!
Well, following on the logic of that wise....sage W9WHE, Why do we call 160 meters "Top Band" when it's at the bottom of the spectrum with the lowest rate of cycles. "Top band" should be the highest band in the gigahertz or terrahertz or wherever the highest currently recognized band is, in which case, a "Fan Dipole" would be very very small....:-) 73.
 
RE: Fan Dipole  
by KG5JJ on December 26, 2003 Mail this to a friend!
I'm not a "fan" of fan dipoles.

(ducking and running)

73 KG5JJ (Mike)
 
RE: Fan Dipole  
by KB8ELK on December 27, 2003 Mail this to a friend!
look out ...


Would this be a good no-code,qrp,dx,cw,dsp,contest,dual-filament antenna ?

Does it require a ground plane ?

Where can I buy antenna wax ?

How long should the green hose be ?
 
Fan Dipole  
by VE2DC on December 27, 2003 Mail this to a friend!
I would only question the need for a balun... They are one more thing to go wrong... and add nothing to the performance.
 
RE: Fan Dipole  
by KC8VWM on December 27, 2003 Mail this to a friend!

>>>>Why call it the "international Morse Code"? Did an "international" invent it or did Samuel Morse? >>>>

Now read what you said very carefully and answer your own question...

Charles - KC8VMM
 
RE: Fan Dipole  
by KC8VWM on December 27, 2003 Mail this to a friend!
>>>>I'll bet fan dipoles work really "cool" in the summer months.

Har Har! Hardy, har har! (say in Bugs Bunny voice) >>>>

Yes! it's a fact that fan dipoles may better in summer months. The wires expand to different lengths. Seasonal temperatures would in fact change the antennas frequency resonace.

Charles - KC8VWM
 
Where's Tom?  
by G7HEU on December 27, 2003 Mail this to a friend!
Tom / N6AJR

I'm worried about you. All this fan dipole talk and no comment from you. Please just give a brief response so that we all know you are o.k.!

Steve
M0HEU / G7HEU
 
Fan Dipole  
by W6EZ on December 27, 2003 Mail this to a friend!
160 is called the top band because, as we all know, one should always strive to have each antenna at least one half wave length above ground. That puts 160 at the top of the tower, hence "top band."
All the other bands sort of 'fan' out below 160 at the feed point.
 
RE: Fan Dipole  
by N6AJR on December 28, 2003 Mail this to a friend!
OK Im Here, and I have stated many times that what I am trying new ( and old) hams to try is actually a multiband dipole fed with a single coax.

But most folks know that its easier to type in Fan dipole than "a multiband dipole fed with a single coax" and I only type with 2 fingers so It is now officially renamed the Fan Dipole Ver. 2.0.

ok folks, what ever you call it and whether you put it up in a fan, one under the other, in a inverted V, or in the star ( or umbrella ) pattern. it works like a big gun and cost next to nothing.

Or you can go to alpha delta and buy one for $100. ( you can make one for $10..) 73 you'all and have a wonderful new year.

tom, N6AJR, a fan dipole (ver 2.0 ) fan!!
 
RE: Fan Dipole  
by G7HEU on December 28, 2003 Mail this to a friend!
Hey Tom

Hope you didn't think I was being rude. I was honestly V surprised that you hadn't 'popped up' on this one.

Glad to hear that your o.k!

Have a happy new year,

Steve
M0HEU / G7HEU.
 
RE: Fan Dipole  
by BUCK on December 28, 2003 Mail this to a friend!
Someone mentioned that there weren't any flames in this thread, so I thought I would tell about some.

I first started hamming in 1978 and have used a variety of HF antennas including mono-band dipoles, trap multi-band dipoles and what I have always known as the "fan dipole" which consisted of one feedline feeding dipole elements for multiple bands.

Over the years I have had occasion where "flames" were introduced as I tuned my Swan 350 transmitters to some of these antennas. If two different band elements get too close together, or perhaps the wind blows them into each other when I am tuning the rig, I wind up with sparks and flames and a pair of copper wires welded together. I only use insulated electrical wire so the insulation is burned off where the wires make contact.

Nowadays, I use a slightly different version of the antenna. Instead of a full-length 20 meter element, for example, I start with the lowest frequency wire, usually 80 meters and then add a one-foot "tap-wire" for the next lowest band spaced about four inches below the main wire with pvc pipe. Then I tune each tap-wire to its band until I get an acceptable swr for each band I am using. I think the spacers keep the wires far enough apart to prevent arcing.

that's my $.02 worth.

Buck
 
Fan Dipole  
by K0IZ on December 28, 2003 Mail this to a friend!
Here are some references:
QST, Aug 82, A Broadband 80 meter Inverted V
QST, Dec 80, Broad Band 80 meter antenna
Excellent article in Ham Radio magazine, May 83, "Stagger-tuned dipoles Increase Bandwidth". Described equivalent circuits of two stagger-tuned crossed dipoles, SWR's. John
 
RE: Fan Dipole  
by N6AJR on December 28, 2003 Mail this to a friend!
No problem steve.. I appreciate the concern.. but I really like to put the "fan dipole ..ver 2.0" out there for the new hams to play with.

it gives you a good ( better than you would think for what it is) antenna, for next to nothing in cost and gets a new general ( or even tech) on the air today, and some folks juse these and nuttin else..

the best kept secret in ham radio.

73 to all and have a prosperous new year

tom N6AJR ( ver 1.3)
 
RE: Fan Dipole  
by AMATEUR2OO3 on December 28, 2003 Mail this to a friend!
Where can I buy one of these fan dipoles that would cover 10, 11 and 12 meters?
 
Fan Dipole  
by KB7RGT on December 29, 2003 Mail this to a friend!
I am among the first to assert that word choice is important. In my opinion, this topic belongs at most in the category of semantic convention. However, it is probably better described as being in the category of pet peeve.

If it is a matter of semantic convention, I would say the convention is obviously still developing, evidenced by the author's need to try to establish his perspective.

Calling one dipole a fan because its elements are all within one amateur band, and another something else because its are not, is just trying to elevate one's own preference to the level of linguistic law. There is no degradation of accuracy in communication calling both intra- and inter-band fan dipoles, fan dipoles. They both clearly look alike, operate on the same principle, and achieve the same goal.

I also see no problem calling an antenna coupler a "tuner" either. Everyone knows what is being communicated. And what does "coupling" mean anyway? The word is usually used with reference to a physical connection, which obviously only weakly applies to the principles of capacitance or inductance. Tuning however clearly does. But that's just me. I know what is meant whether it is called it an antenna coupler or a tuner. So it won't bother me what you call it.

Facility in communication should be the goal of word choice.
 
RE: Fan Dipole  
by WB2WIK on December 29, 2003 Mail this to a friend!
I'm a fan of dipoles.

I once used a ball-and-brush rotating coaxial joint to facilitate feeding a rotary beam antenna without using a "cable loop" to do so. That wasn't exactly innovative, since I read about it in a very old Handbook (from the 1940's, I believe), but it was innovative for me.

Now, if I built crossed dipoles, aka a "turnstile" antenna (a turnstile is two straight 1/2-wave dipoles crossed at 90 degree angles with a common center point and fed so one has a 1/4-wavelength phase delay line to use a common feedline), and then attached that to my rotating coaxial joint, I could spin the turnstile around at any speed I desired, until it flew apart.

Then, I'd have a real and true "fan dipole," since it would make wind as it's spinning.
 
RE: Fan Dipole  
by W9WHE on December 29, 2003 Mail this to a friend!
tod, W7EFQ writes:

"Why do we call 160 meters "Top Band" when it's at the bottom of the spectrum with the lowest rate of cycles".

Just who is this "we"?. Have a mouse in your pocket? Not all of "us" call it "top band".
 
RE: Fan Dipole  
by W9WHE on December 29, 2003 Mail this to a friend!
tod, KD7EFQ writes:

"Why do we call 160 meters "Top Band" when it's at the bottom of the spectrum with the lowest rate of cycles".

Just who is this "we"?. Have a mouse in your pocket? Not all of "us" call it "top band".
 
RE: Fan Dipole  
by W6TH on December 29, 2003 Mail this to a friend!
--------------------Fan Dipole-------------------------

A half wave resonant piece of wire fed with a single wire should be noted.

A resonant half wave wire fed with a single feed wire is just what it says.

The off center fed resonant wire fed with a single wire is now called: "The Off Center Fed Antenna", Or, "The Windom Antenna". The feed system changes the antennas name. These are still half wave resonant antennas.

A half wave antenna for 80 meters fed in the center with balanced line becomes, "Two Half Waves Fed In Phase", with a gain of 1.8 decibels for the 40 meter band.

A "Yagi Antenna" is a dipole or half wave antenna fed with coax line and has parasitic elements.

A half wave antenna fed with single wire feed ia still a half wave antenna, the same with the Off Center fed half wave and the Windom half wave antenna.

Looks like the feed system changes the name of the antenna. The Center Fed Zepp and G5RV are the same antennas with one exception: The G5RV antenna is shortened on the flat top, but the length is made up in the ladder feedline to accommodate in between frequencies as to the 30 meter band.

Antenna, dipole, aerial, who cares as long as they work.
.:
 
RE: Fan Dipole  
by KL7IPV on December 30, 2003 Mail this to a friend!
Hey, how come no one said anything about the "Cage" antenna? Is that discrimination? Happy new year to all eHammers.
73
Frank
KL7IPV
 
RE: Fan Dipole  
by K7VO on December 30, 2003 Mail this to a friend!
AMATEUR2003: You don't buy fan dipoles. YOU BUILD THEM. Oh, and 10, 11, and 12 meters? Are you a licensed ham? If so, why 11 meters? If not, why 10 and 12? If not, why no callsign?
 
RE: Fan Dipole  
by N7KKR on December 31, 2003 Mail this to a friend!
Nice trip down memory lane. I use an Alpha-Delta DX-LB Plus in somewhat of an inverted Vee configuration with a dogleg to avoid a tree. One set of legs covers 160/80/40/15 and there are two other sets of legs for 20 and 10 respectively. I guess that fits the mold of "Multiband Fan". Glad to be back from "FARPAC" to enjoy it. Best to all!

Kevin N7KKR
 
RE: Fan Dipole  
by N7MJW on December 31, 2003 Mail this to a friend!
I didnt want to put this on the discussion about "fan" dipoles because its off topic, but its seems the conversation is going there.

Some responses are arguing the differnce in nomenclature between a Antenna Tuner and Antenna Coupler are the same thing. This is not so.

There actually is a difference between antenna tuners and antenna couplers. "Antenna Tuner" is a word commonly used in Amateur Radio circles. "Antenna Coupler" and "Line Flattner" are terms commonly used in commercial circles. They are different animals.

"Antenna Tuner" - what comes to mind is a box attached by a short piece of coax to a transmitter sitting on a desk next to the transmitter. There is transmisison line to the antenna, either ballanced or not. People will argue what this box is really doing and how effective it is, but when hams talk about "Antenna Tuners" this is what is generally meant.

"Line Flatner" is a box, between the transmitter and the transmission line. It is intended to "flatten" slight elevations in SWR that may exist on the transmission line so the transmitter sees no SWR. Sounds a lot like a "Antenna Tuner".

"Antenna Coupler" is a different animal. This is a box, usually outside at the end of the transmission line, either run by remote control or automatically. On one side there is the transmission line, the other the antenna. When the coupler is tuned, there is no swr on the transmission line. The antenna is "coupled" or "tuned" or whatever to the transmission line. At any rate, this is significantly different than what hams think of as an "Antenna Tuner".


Dave
 
Fan Dipole  
by AD6KB on December 31, 2003 Mail this to a friend!
I used to be a Coast Guard Radioman, and on board the 378 ft High Endurance cutters (like the Morgenthau) we had a fan antenna that ran from the "Star Deck" just aft of the bridge to the aft mast. Man, would that thing radiate! While on patrol in the Bering Sea/Gulf of Alaska it was not uncommon to work CG Commstas in Portsmouth VA and Guam using RTTY/Voice with the standard URT23 with output limited to 500w by the ET types (didn't trust RM's with 1kw). Very impressive. I guess the length of each element was 100' or so and was coupled by a heavy duty antenna coupler. It was good from about 4mhz up to 25mhz for sure. Below 4mhz it was kind of dicy.
Thanks for the note. I had forgotten all about fan antennae, may be doable!

Tim
 
Fan Dipole  
by K4JRB on December 31, 2003 Mail this to a friend!
I agree that beyond the plain dipole there is much confusion in terms. The normal fan dipole uses two or more wires to broaden the response or allow one to operate both the CW and phone portion of the band. WB4GNT and others have called a multi fan dipole the cage dipole. In any xase there is no gain and no way to provide gain as you get the figure 8 pattern unless its low and then you get an oval pattern with a slight null on the ends. The dipole (any version) can have improved DX angle by sloping or making the dipole vertical. Again there is no gain just the right angle or improved angle for DX (1200 miles or more on low bands).

Gain is only achieved by phasing or adding a parasitic reflector that forces the signal into a pattern.

The dipole is the easiest antenna to use and is a very efficient antenna. Put one up and have fun!

Dave K4JRB
 
Fan Dipole  
by WA0EAJ on December 31, 2003 Mail this to a friend!
Hey Alan,

'Tis been a long time - we worked together at CW Electronics back in '78. Good article with good poop; I must say however, use tall trees. What does that mean? All of my single band dipoles (balun fed if not with ladderline) demonstrate exceptional bandwidth. Typically 1.11 at bottom of 75m to 1.17 or so at top, and the higher the band, the greater the bandwidth. Maybe it's the left-over Copperweld from B-A -or- the fact that I hang 'em high! Remember also folks - dipoles are 72 ohms NOT 50! Don't feed your dipoles with RG-8 or RG-58, just RG-59 or RG-11 (RG-6 worx too!)... and we won't even mention G5RV's (not resonant ANYWHERE) - after all, tuners are only Final-Foolers.

T C Dailey
WA0EAJ
Denver
 
RE: Fan Dipole  
by K0BG on January 2, 2004 Mail this to a friend!
Electric Apple Juice! You should email me and give me yours.

Alan, KBG
k0bg@aol.com
 
RE: Fan Dipole  
by K4JSR on January 3, 2004 Mail this to a friend!
I think everyone is getting Fan Dipolar disorder!
What about perverted vee antlertennas?
Didn't the Yagis lose the World Series?
Uda thought the Marlins would have won?
My favorite beverage antenna is the beer can vertical.
I think a slot antenna would be very niche!
I was going to put up a stealth antenna, but I just
could not see it.
I was going to make a 160 Meter directional antenna
and call it Quadzilla.
With that I am going to fold my dipole and steal away.
73, Cal K4JSR
 
Fan Dipole  
by WA2JJH on January 4, 2004 Mail this to a friend!
Glad I read the artical. I thought somebody built a dipole in a ceiling fan. Used slip rings for a rotating feed.

Faster the fan went, the more centrifical force gain you would get. Put the fan on a Variac. You would then have a variable gain antenna!(HI-HI) Fan off, unity gain. ERP=1.7 x TX out x R x RPM! hi-hi!

Had to make up my own fan dipole joke.

If it is not to painfull to any one person, what was the original joke?
The original FAN DIPOLE JOKE.

73 and laughs MIKE
 
RE: Fan Dipole  
by KA4KOE on January 7, 2004 Mail this to a friend!
Great googly moogly!! Our fave troll ain't in this one!
Ooops. Now that I said it he'll probably pay this lil thread a visit.

I'm a fan of discussions such as these.
 
Fan Dipole  
by WA2JJH on January 24, 2004 Mail this to a friend!
AMATEUR2OO3 happy new year! Why are you not AMATEUR2004
NOW!

cannot recommend a FAN DIPOLE for 11M.
However if you put you finger across the SO-239 connector on 11M, you will have an 11 meter dummy load!
(Hi-Hi)
 
RE: Fan Dipole  
by N6AJR on March 10, 2004 Mail this to a friend!
Bye the way.. way back ( in the 23 channel days) I did put up a dipole on 11 meters for a friend who had $0 cash.

we took a piece of coax, with a connector on 1 end , and measured 8 feet 6 inches from the other end, stripped of the black cover, pulled the center conductor ( with insulation) through a little hole in the shield wire at the 8 1/2 foot mark, and put it up[ on his appartment wall in a big V. (up stairs appartment.) had an swr of about 1.3 :1 and got out pretty good... and the price was right $ 0

73 tom N6AJR
 
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