Transmission1

Hi all.

I am thinking of making an HF Fan/Multi band Dipole for 80, 40, 20, 15, 10 and 6m.

My question is this.

How cryticle is the spacing between each element?
Is 1/2cm (that's half a centimeter) ok? Or does it need to be wider.

If wider then second question is how cryticle is the spacing of the center gap?

Thanks

nay27uk wrote: ↑28 Jan 2018, 15:03 Hi all.

I am thinking of making an HF Fan/Multi band Dipole for 80, 40, 20, 15, 10 and 6m.

My question is this.

How cryticle is the spacing between each element?
Is 1/2cm (that's half a centimeter) ok? Or does it need to be wider.

If wider then second question is how cryticle is the spacing of the center gap?

Thanks

I don't believe there is a hard and fast rule, so spacing is not that critical other than to ensure they do not physically touch each other.
The commercial antennas generally use 3-4 inches of spacing between the elements. Do you intend having the guying points for all of the dipoles in the same place I.E parallel, or are you going to select different guying/mounting points?

Thanks kilimax.

It will be mounted in an attic so inverted V, was hoping to run the longest across a full rafter so all others elements just dangling on small spacers below the first longest.

Reason I asked is I have found a small bit of left over double sided PCB I wanted to use as the feed point and mount (cheaper than buying a pre made center feed mount) that is approx 4 inch by 2 inch, I could turn it the other way and have more space between elements. Just wanted a bit of insite on spacing of elements before I draw out the board and etch it

It must be big attic for 80m dipole xD
For wire distance I wouldn't go lower than 50cm. Tested in free air.
40m will tune also in 15, so 1 less wire.
Since 10m will be dead for a few years, especially on wire I wouldn't bother, as well as 6m.
Chris

Hi ch25.

Yeah that idea has been turned on its head now, I was going to bend the 80 and 40 sections back on themselves a few times as from reading this does not affect the electrical length of a dipole that the radio sees, Anyway been in the attic today (first time since moving in 13 years ago NEW BUILD) but the attic is only a half attic with a big bloody breeze block wall blocking the other side off from about 3 feet from the peek of the roof, so we have one full side of a roof plus 3 feet.

I have had the idea of trying one of these W3EDP antennas instead but does anyone know if these can be bent back on themselves like a dipole can, would need to be something like the below configuration for the driven element then the counterpoise would only need a small bend.

It is a small comunal attic that is only 7 feet wide with only one full side of roof slope then 3 feet extra space from the peek of the roof along the other side roof slope then a solid wall.

can you lay a wire the full length of the building in the gutter?

Nope it's a 3 story block of flats and I cant get a ladder long enough, thought of trying the attic idea because my 2 and 70 collinear on the wall outside is now bent to hell from that bad wind we had the other week all because I cant get a bracket near enough to the top of the roof so 20 foot of mast is unsupported the other 10 foot bottom end is supported by 2 wall brackets.

Got an end fed longwire I use for HF 135 foot through a 9:1 Un-Un to a tree 140' away feed into house with RG8 Mini un-un runs down the wall to a 4 foot earthing rod I put this antenna out and take back in as and when I need to use it due to HA rules on antennas but cant get it to tune up, every time I get a tune below 2.5 SWR the radio cuts off, if only on 5 watts its OK for about 1-3 mins before cutting off the radio, not sure if it is something wrong with my homemade Un-Un or if it is the fact that the only tuner I have is for SWL cant afford the price of a proper HAM tuner at them prices unless someone has one for about £30. Thinkit is the tuner causing the problem probably arching over when the SWR gets below a certain point.

Just fed up now sick of trying to get solutions, dont help when the housing say NO ANTENNAS not even a SKY DISH lucky for me I know all my neighbours and get on with them so they didn't mind me sticking the collinear up but dread to think what will happen when the HA finally see it.

Think I might just sell up as cant even use HF without a proper tuner and they are simply to expensive.