Fan Dipole Spacing

[HomerBB]

I have read where the spacing on a fan dipole can influence the tunability of the individual bands.
One claim is that if the feed point connections of each wire antenna are separated from the next set of wires by 5.5" and the tails of each dipole wire are 36" away from the wire above it that there will be no need to use the cut and try method of tubing usually needed. Using standard formula dipole measurements are virtually guaranteed to achieve a tune..
Anyone tried this? Did it prove out?

 

[Crawdad]

Bump this.
No one answered Homer? WTH?

 

[DoctorAudio]

@HomerBB is pretty industrious, he's probably experimented and answered his own question already..

 

[HomerBB]

@HomerBB is pretty industrious, he's probably experimented and answered his own question already..

Thanks for the vote of confidence, however, I did not build but two fan dipoles since that question. They were both mounted vertically, and one cut for the 2m, 1.25m, and 70cm bands, the other for 1.25m, 70cm, and GMRS bands. I just cut them to standard length, put them together, tried them to see if I could hear and be heard with them. I don't know what the swr is on them, and don't care, as I was talking to other l operators and not to SWR.
The first one, pictured below, blew apart in severe weather last Spring, although I did not know that until I saw some of it laying on the ground. I was still talking with it although it then only had two downward elements and one upward element. The second one is still in the attic doing well.
So, I don't know whether anyone has tried the original questions or not. I didn't.

 

[Crawdad]

@HomerBB is pretty industrious, he's probably experimented and answered his own question already..

Homer is the King of industrious antenna homebrew, IMHO, and I'm sure he answered his own question, but still...........

 

[Crawdad]

I just cobbed this together today since a new radio gets me on 6m:

I added the 6m horizontal at the feedpoint of my existing 10m Inverted V. Thought I'd give it a try and see what happens. It needs a bit more tuning but doesn't look bad at all on the analyzer. Only slightly changed the numbers on the V.
Does it work?? Hell, I don't know, both bands are dead here.

 

[HomerBB]

I just cobbed this together today since a new radio gets me on 6m:
View attachment 63721
I added the 6m horizontal at the feedpoint of my existing 10m Inverted V. Thought I'd give it a try and see what happens. It needs a bit more tuning but doesn't look bad at all on the analyzer. Only slightly changed the numbers on the V.
Does it work?? Hell, I don't know, both bands are dead here.

It certainly looks good, and that counts for something. Who knows, you might can sell them for $159 each on eBay.

 

[Crawdad]

It certainly looks good, and that counts for something. Who knows, you might can sell them for $159 each on eBay.

Plus shipping.
I'll call it the Cobb-a-fan 2000

 

[Captain Kilowatt]

My experience with fan dipoles is that no matter what, there is a certain amount of cut-and-try or changing the spacing of the elements to achieve best SWR. Every installation is different and as such every tuning situation is going to be different.

 

[HomerBB]

My first HF antenna after getting my ticket was a fan dipole. Due to my lot size it barely fit the 80m lowest band wire with a bent shape. I got it working, but it was an ugly beast that looked like the back yard had experienced a giant spider invasion. I took it down, put up a nonresonant skywire loop and had all bands from 160m through 6m with a tuner. Other than four poles/masts at the four corners of the back yard it was less an eyesore and more useful. But, being me, it came down and I continued playing with other options, with usually less good results than the loop. Currently, it's a nonresonant doublet that is getting no mileage due to the dead bands for this past week it's been up.
So much for this solar cycle 25. . . I'll be glad when the teasing stops and real conditions arrive. Making antennas and hearing only crackles, space ghosts, and snakes hissing or dead silence just ain't as much fun.

 

[Crawdad]

So much for this solar cycle 25. . . I'll be glad when the teasing stops and real conditions arrive.

Amen to that Homer

73

 

[w9cll]

My experience with fan dipoles is that no matter what, there is a certain amount of cut-and-try or changing the spacing of the elements to achieve best SWR. Every installation is different and as such every tuning situation is going to be different.

I have found the same. I have built several fans over the years and currently have one up. For spacing I have found eight inch spacers work great, for years I made my own out of PVC pipe but now I use electric fence spacers. I like those because they have the wire channel molded in.

 

[Crawdad]

Question for you experienced folks: Should I tune this with all 4 elements connected or should I remove the 10m wires while I tune the 6m elements?
Or is this thing a joke and not worth the trouble? I have no experience with fans.

 

[Captain Kilowatt]

Question for you experienced folks: Should I tune this with all 4 elements connected or should I remove the 10m wires while I tune the 6m elements?
Or is this thing a joke and not worth the trouble? I have no experience with fans.

Put all wire elements in place and start tuning the higher bands first and work your way down in frequency ie. tune 6m first then 10m etc.

 

[Crawdad]

Put all wire elements in place and start tuning the higher bands first and work your way down in frequency ie. tune 6m first then 10m etc.

Roger that.Thanks CK

73