Fan Dipoles (#450)

Bob Carver, KB0XT, wants to know how close he can put his dipoles or if he can even combine them? Yes! He can. Watch to learn all about Fan Dipoles


Edited by Callum Jakeman.


Theme music is "Sour Tennessee Red," by John Deley and the 41 Players, courtesy YouTube Music Library.



Twitter: @dcasler

[acae]

You always have great explanations. Thank you very much!

[PelenTan]

Just a quick presentation suggestion. For your whiteboard, try taking a Sharpie and marking an "X" on the top and one side of the aluminum edges. This will help the camera to stay focused when you wipe it clean.

[popsmorris]

I built a fan antenna right after I got my general. It has 10, 20 and 40M elements. I have it in the attic since Live an an antenna restricted neighbor hood and the antenna work really well. Lot's of fun to build too. This antenna, along with end fed antenna I built, also in the attic, let's me do about anything I want using my antenna tuner.

[iamhis]

Excellent Dave!! Keeping us sharp! "NOT house wire currently in use"

[KevinMaxson]

I use 16 gauge landscaping wire for my wire antennas. I successfully built one for 5MHz for my military detachment for tactical deployment.

For home use, I built a dipole center with an SO-239 connected to a 1:1 choke and split into two terminals. I can put whatever length wire(s) I want on it, whenever I like.

[KTRAM]

My fan dipole is my very first homebrew antenna and I still use it to this day. I made my own balun/choke and used 14g THHN wire. I have the 75m stretched flat/horizontal and the 40 & 20 meter in an inverted V.
I can tell you that through experience do not be afraid to bring those legs down.

You would be surprised at where you can contact on 100w with it. I have worked all continents including Japan on 100w with my fan dipole. I tuned my 75m first then trimmed my 40 & 20. I found that just by bringing the legs down on 20 & 40 did bring the SWR down rather than trimming them further. I still prefer my fan over my Hexbeam in some instances. Best of luck. Thanks Dave. 73

[jwerp]

I have a fan dipole in my attic at our FL QTH with elements for 40, 30, 20, and 17 meters. It is in an inverted V configuration and the 40m element resonates on 15m and the 30m element resonates on 6m so with 4 elements I get 6 bands. It works surprisingly well. I worked 85 countries that past winter with my Icom 7300 and 100 watts on CW. We are in an HOA so no outside antennas are allowed. The condo is a single story so the antenna at the center is probably only about 30 feet high. Fortunately no foil backed insulation is in the attic and the roof is tile.

[glenmartin]

Thank you, Dave. Have a great week and take care of yourself.

[mattsgarageshop]

Nice video as always Dave. I'm a bit puzzled by the fan dipole I just built. It was originally a 40m (not quite but close) dipole, feedpoint up high off a 1:1 balun I built in one of those 4x4 Cantex boxes from HD. So each leg around 32-33 ft. Worked great. I then added two legs for 10m, each around 8'2" or so. When I checked the SWR on this new configuration, resonance hadn't changed on the 40m band, but it was also way off on the 10m band, as in, unusable. Not sure what's going on, so it's my current radio Sherlock Holmes adventure.

[davemitchell]

When you pull the legs of the dipoles "at odd angles" as you say, and pull the legs down to inverted VEE configuration, you get what is called a "Maypole Antenna." I have run these for over 30 years with excellent results.

[jedidiahstockton]

Just finished my fan dipole home brew! Excited to use it next week. It’ll be mounted pretty low. Using steal and copper wire. 40m 60m and 75m band half wavelength. It will only be mounted 7feet above ground. Funny you say to not use house wire in use. A co worker was trying to build an antenna using the “grounding port in buildings” I didn’t think it was the best idea.

[KjellSvendsen]

I'm about to be building an even bigger and more multibanded version now, of My Vertical Multiband Fan Dipole Antenna for 10 to 20 meter DX'ing: No loss of gain!

[raulcrudele]

Excellent description! Some combinations do not work; for example, a fan dipole, one for 60 m (5.3 Mhz) and 40 m (7 Mhz) the 40 m dipole does not work.

[seantran]

Thanks much David, Iam kind a person slow in doing things. I'm glad that I found you. following step by step to help me completed registered FCC number. Just wonder, do you have video how to apply The GMRS License.?

[grumpy_ken]

I have a couple questions regarding fan dipoles, if someone could point me in the right direction. What is the input impedance? Does it stay at 50 ohms (I guess it's actually 73 for a dipole) as you continue to add elements? which brings me to- is there an upper limit to the number of dipoles that can be combined? and finally, does the power half with every element? thank you for these videos, they are very helpful

[BigRedLC]

Okay, question. Since 40M length seem to work well on 15M, does the inverse apply? In other words, if I put a 15M element on a fan dipole, will it cover 40M as well or will it be too short? 73 KG9PN.

[NStooges]

Hi Dave. I have an existing 20m dipole that is perfectly tuned for 20m digital. If I add a pair of new wires to the existing dipole in fan dipole manner to add 6m capability, will that significantly de-tune my 20m dipole?

[mjktrash]

NOTE: Question duplicated from another (incorrect) video

If I wanted to build an antenna (a fan dipole, or possibly a fan-"dublet" with 450ohm feeder similar to a G5RV???) for my IC-7300 that covered ALL of the bands from 160m down to 6m, how many legs would I need to do? (Do any of the bands double up on any of the fan legs?)

I have an attic space that is ~48' long at the ridgeline that is ~28-30' in the air.

For the longer legs, can I wrap them back around (with spacing) and/or possibly use chokes? If I wrap them back around, how many times can I do that? (effectively ending up with multiple"Zs" in each of the longer legs"

If I use the 450ohm ladder line, how long can it be or should it be before I switch it over to co-ax?

Finally, I can't seem to find consistent data on whether the internal ATU on the IC-7300 can actually tune this type of antenna, how do I determine (specifically) what my SWR is on this antenna (and know that it is below the 7300's 3:1 SWR limit?)

[tomw]

Hello again Dave. Love your videos. I am thinking about a 40, 20, 10 and maybe 6 fanned dipole. I would imagine there is a bad, better and best pattern to use to adjust the wire length to achieve the best results. I know to wrap the wire instead of cutting until the proper length is obtained. Is there one band that it is best to adjust first. And would you think adjusting one would make a big difference to the others. And I would add a choke, most likely a coax choke to prevent rf from coming down the shield. Any thoughts would be appreciated.

[davidhodgson]

Thank you Dave, you just gave me a great idea, make a fan dipole.
You see I am short of coax, and as you know you can feed a fan dipole with a single feeder, job sorted.
HS0ZQA David