Author Topic: The FAN DIPOLE,an EASY, EFFECTIVE HF Antenna  (Read 14482 times)

Offline Carl

  • Mr HamTastic!
  • Forum Veteran
  • *********
  • Posts: 13105
  • Karma: 714
  • COW?...No ,I haven't seen your cow.
The FAN DIPOLE,an EASY, EFFECTIVE HF Antenna
« on: January 06, 2015, 10:26:41 AM »
The Fan Dipole is often way over-built with todays automatic antenna tuners (and manual tuner ,for that matter) a  multi-band antenna need not look like a NASA radio installation. All you need to build a 6 through 40 meter antenna is 110 feet or so of wire ,insulators (made from PVC pipe ) and a 1 to 1 BALUN / Feed Point where it all comes together...Plus a bit of rope (black 550 para cord is my choice).

The balun is a transformer that helps to keep your radio from interfering with other electronics and you will find it worth the $20 to $30 you spend. It also handles the two wire antennas and coax connections. The common feed point should be up 20 feet or so ,hung from a pole,tree or tower,or even rooftop. with the two antennas sloping down to a lower (but still above head level) support at the ends with a bit of rope and insulators to do the job. My antenna has slim 10 ft sticks of conduit stuck in the cyclone fence for it's end supports though I do have a tower finally...the original middle support was an 18 foot aluminum pool cleaner/skimmer pole and I still have it.

A picture is worth a few words here:



and with these TWO dipoles ,I work 80 ,60,40,30,20,17,15,12,10,(whew!) and 6 meters with only a 3 to one tuner in my radio. Though I suggest a better capable range tuner like most any LDG tuner and a 4 to 1 Balun for your widest range of antenna use. My antenna was made from an extension cord that was put to the curb after a neighbors hedge trimmer incident and some PVC with the only real cost being the Balun that cost only $16.95 back in the day.

NOTE that I chose 20 and 40 meters as they are my favorite bands and I see little need to add other wires cut for other bands that my tuner can already deal with...what I give up in efficiency I make up for in ease of install and operating time. If you feel the need to TUNE each band buy cutting(and this can help) PLEASE cut the lowest frequency first (longest wire pair) and remember that there is a bit of inter-action between the wires ,so cut carefully...if you must mess with it.

Happy Hamming!

Offline Smurf Hunter

  • Survival Veteran
  • ********
  • Posts: 7168
  • Karma: 333
Re: The FAN DIPOLE,an EASY, EFFECTIVE HF Antenna
« Reply #1 on: January 06, 2015, 10:54:12 AM »
Regarding the baluns, there are several 1:1 options available in that price range.

What if any functional difference is there between a direct copper wire connection and just using the eye hooks?





Or, can you specifically recommend a balun?

Offline Carl

  • Mr HamTastic!
  • Forum Veteran
  • *********
  • Posts: 13105
  • Karma: 714
  • COW?...No ,I haven't seen your cow.
Re: The FAN DIPOLE,an EASY, EFFECTIVE HF Antenna
« Reply #2 on: January 06, 2015, 11:22:51 AM »
I much prefer HOOKS to tie to and wires to solder to ...The hooks only option tend to loosen in the wind and don't offer much of an electrical connection. Mine is an earlier version of  the MFJ  that used threaded contacts and eyelets and has been in service many years...You tie your wire to the eye hook for strength and solder the wires for good electrical connection . The coax should not hang on the connector and should be weather sealed ( I use self vulcanizing tape AND PVC tape over the SV tape) Also you are welcome to steal my idea of the pulley and para-cord as it has saved a lot of climbing . Photo shot minutes ago and it was 25 feet up and a bit farther from me ,sorry focus is not so good.





Online FreeLancer

  • Global Moderator
  • Survival Veteran
  • ******
  • Posts: 5958
  • Karma: 771
  • Militant Vaxxer
Re: The FAN DIPOLE,an EASY, EFFECTIVE HF Antenna
« Reply #3 on: January 06, 2015, 01:25:24 PM »
How close together can the ends of each band be to each each other?  I'm assuming more distance is better.

Offline Carl

  • Mr HamTastic!
  • Forum Veteran
  • *********
  • Posts: 13105
  • Karma: 714
  • COW?...No ,I haven't seen your cow.
Re: The FAN DIPOLE,an EASY, EFFECTIVE HF Antenna
« Reply #4 on: January 06, 2015, 01:53:21 PM »
How close together can the ends of each band be to each each other?  I'm assuming more distance is better.

I have had different wires within 18 inches of each other and needed wires about 5% longer than for single wire/band due to interaction. But you tune the longest wire(lowest band) FIRST and work your way higher...if it matters to you that all is perfect.
In building one at a friends place we just cut all wires to the proper length and 'let 'er rip' with no real difference in performance. Many designs use as little as 8 inches separation( I even made a dual band with ladder line as the two bands) Remember that many HF bands are multiples of each other and you don't need 5 wires (like I started) I have just a 40 meter cut for 7.300 and a 20 meter cut for 14.070 (I love PSK) and work all the other bands (even 80 meters at a tad lower than max power) on those TWO WIRES. I know there are more efficient (like a wire for each band) options ,but that is for the folks who try to find that last percentage ,and I just want to have fun and operate.

Online FreeLancer

  • Global Moderator
  • Survival Veteran
  • ******
  • Posts: 5958
  • Karma: 771
  • Militant Vaxxer
Re: The FAN DIPOLE,an EASY, EFFECTIVE HF Antenna
« Reply #5 on: January 06, 2015, 02:42:03 PM »
Would you expect it to perform better than a G5RV with tuner in an attic installation?

Offline Carl

  • Mr HamTastic!
  • Forum Veteran
  • *********
  • Posts: 13105
  • Karma: 714
  • COW?...No ,I haven't seen your cow.
Re: The FAN DIPOLE,an EASY, EFFECTIVE HF Antenna
« Reply #6 on: January 06, 2015, 02:55:44 PM »
Would you expect it to perform better than a G5RV with tuner in an attic installation?

The G5RV could have a slight edge due to the SWR factor and how ladder line does not have the loss that coax does when high SWR is in the mix. Do you plan to work all bands ? If not you will be better with a fan dipole with each element tuned to your favorite bands.

The typical G5RV is a 20 meter antenna that can be tuned ,with an antenna tuner, to work on other bands.
The fan dipole is a two or more band antenna that can be tuned to other bands.
This 20/40 I have actually IS tuned on 40/20/15/10 meters due to 40 being a multiple length of 15 and 10 being a multiple of 20 meter wire.

One plus with attic install though is that your automatic tuner does not have to be by the radio and will run just fine off a simple pack of AA cells or a small 12 volt supply like a wall wart and with that type install you regain what coax loss would be incurred.

Decisions ,decisions.....

Online FreeLancer

  • Global Moderator
  • Survival Veteran
  • ******
  • Posts: 5958
  • Karma: 771
  • Militant Vaxxer
Re: The FAN DIPOLE,an EASY, EFFECTIVE HF Antenna
« Reply #7 on: January 06, 2015, 03:15:44 PM »

Offline Smurf Hunter

  • Survival Veteran
  • ********
  • Posts: 7168
  • Karma: 333
Re: The FAN DIPOLE,an EASY, EFFECTIVE HF Antenna
« Reply #8 on: January 06, 2015, 03:41:36 PM »
I have some automatic tuner questions:

1) why are so many brand/model specific?  I understand they have vendor specific wiring, but aren't they AUTOMATIC?

2) with an integrated tuner in some nicer HF radios, if there was a long run of coax into an attic like FreeLancer was asking, would there be any advantage in a second automatic tuner very near the antenna itself? 

I guess I don't understand why there are dozens of model specific tuners when there are a few that seen to be generic like this:  http://www.aesham.com/automatic/ldg-z-100plus/


Offline Carl

  • Mr HamTastic!
  • Forum Veteran
  • *********
  • Posts: 13105
  • Karma: 714
  • COW?...No ,I haven't seen your cow.
Re: The FAN DIPOLE,an EASY, EFFECTIVE HF Antenna
« Reply #9 on: January 06, 2015, 04:08:51 PM »
I have some automatic tuner questions:

1) why are so many brand/model specific?  I understand they have vendor specific wiring, but aren't they AUTOMATIC?

2) with an integrated tuner in some nicer HF radios, if there was a long run of coax into an attic like FreeLancer was asking, would there be any advantage in a second automatic tuner very near the antenna itself? 

I guess I don't understand why there are dozens of model specific tuners when there are a few that seen to be generic like this:  http://www.aesham.com/automatic/ldg-z-100plus/

The model specific tuners have cables and controls ,methods of attaching to the radio or size/form factor that makes the fit and look better with the radio , but they will still tune for any radio that puts out the minimum required RF( 5 watts on most ,except the QRP models)

Most LDG ,and many others have the cables as options to fit most radios that have a TUNE button etc and ALL the automatic tuners I know of will tune with RF applied (a carrier or CW tone is fastest or I use RTTY mode to get RF for tuning ) SSB will work,but often too slow. The TUNE BUTTON on radios basically puts the radio in AM or CW mode at lower than full power to speed tuning.You can build your own button to do the same with model specific tuners with a push button,a resistor,and a mating plug for the tuner.

The long run of coax ,combined with high SWR (even if tuner at radio tunes SWR to low level) brings in LOSS of output power and some people just can't accept that to happen...does it save much...a few watts ...when losing HALF of you power amounts to 1/2 of a S unit ...I just don't see it as a problem (unless running an amplifier)

On the SOAP BOX:

Over 90 percent of all of my HF contacts are made at 20 watts or LESS and I just don't floorboard my car just because I can...there is so little to gain and this is my HOBBY...I don't let the DX chasers who often don't remember who they talked to yesterday set the way I should talk to and befriend others . Talking to others is what I enjoy ,not spending hours yelling in the face of a pileup just to say "you're 5 X 9 " and nothing more...what a truly meaningless pastime.

Stepping down from soap box....

Online armymars

  • Survivalist Mentor
  • *****
  • Posts: 810
  • Karma: 23
  • New TSP Forum member
Re: The FAN DIPOLE,an EASY, EFFECTIVE HF Antenna
« Reply #10 on: January 09, 2015, 06:32:44 PM »
  The antenna specific tuners for a certain radio works with the radio to speed up tuning. As I tune up and down the band the tuner adjusts the coils and caps even before I transmit. This is because it knows where my radio is listening and it goes through it's memory to look for a previous match. When you transmit your right there.
  I've used fan dipoles for years. The best all band one was from Germany. The wires were 49 feet and 51 feet long I think. It gave you about 200 ohms on the 5 HF bands 80 - 10 meters. I found it in a copy of 73 magazine. I like it for Field Day. With a 4 to 1 balun my impedance is 25 to 50 ohms. 

Online armymars

  • Survivalist Mentor
  • *****
  • Posts: 810
  • Karma: 23
  • New TSP Forum member
Re: The FAN DIPOLE,an EASY, EFFECTIVE HF Antenna
« Reply #11 on: February 25, 2015, 04:40:41 PM »
 I want to up date the fan dipole I wrote about. I found it again in the March 1975 issue of 73 Magazine. Pages 126 and 127. The wire length is 55 feet for one dipole and 40.5 feet for the other. This is as a flat top. You will have to change the length a bit as an inverted V antenna. Remember you need to use a 4 to 1 balun on this one. 73.

Offline Smurf Hunter

  • Survival Veteran
  • ********
  • Posts: 7168
  • Karma: 333
Re: The FAN DIPOLE,an EASY, EFFECTIVE HF Antenna
« Reply #12 on: March 01, 2015, 09:57:55 AM »
A related video I found helpful:

https://www.youtube.com/watch?v=8KHzsKYsZL0