3 element yagi @ 25' or 6 element monster @ 15' for 10meters

[towerdog]

I am planning on building a yagi for 10m DX. I cant put up a tower because I rent the place but I can pretty much get away with any kind of temporary pole I can rig up and take down when not in use.

I am thinking a section of pipe with a yoke on the end to swivel in one direction, attached to a block of concrete sunk just below grade level with a pipe sticking up out of it, but that part I pretty much got figured out.

The question is, would there be any benifit to an extremely high gain and directive antenna, over a less gain and directive antenna if I could only get the antenna 10 or 15 feet off the ground.

I have saved enough materials over the years to make a gamma matched monster, I am thinking something along the lines of 5 or 6 elements, 40 feet long, made of uni-strut, 8' x 7/8" lightning rods cut to length for elements with 3/8" allthread and commercial type ceramic insulators threaded at each end for the driven element.

Would being less than 1/2 wave off the ground defeat the purpose or would I be better off buying the materials to make something small, 2 or 3 element out of small dia aluminum rod to put it up higher?

 

[Captain Kilowatt]

Go smaller and higher. Directivity or a bit more gain is not as important as angle of radiation and that comes from height. I would far rather have a three element at 30 feet is better than a six element at 10 feet.

 

[wavrider]

As CK said, height is might on HF.

Three element should give you around 6 DB of gain and anywhere from 18 to 30 DB rejection depending on element spacing.

The three element will have a broader use able band width than the six element does.

 

[Mudfoot]

Can you hang (suspend) the beam from a high tree? I have done such a thing before. I could even turn it. Took some doing, but it worked and worked well. I've even tuned beams this way, both vertical and horizontal. Takes plenty of paracord and some rigging knowledge. Raise, check SWR, lower and adjust and raise back up.

 

[Captain Kilowatt]

Can you hang (suspend) the beam from a high tree? I have done such a thing before. I could even turn it. Took some doing, but it worked and worked well. I've even tuned beams this way, both vertical and horizontal. Takes plenty of paracord and some rigging knowledge. Raise, check SWR, lower and adjust and raise back up.

Oh jeesh. I thought I was the only one desperate (or crazy) enough to do that stunt. My first year in the new house I had a tribander on 24 feet of guyed tower which was the top three sections of my freestanding tower in a temporary installation and a pair of 2m four element quads hanging from a tall oak tree.

 

[n0zna]

CK is right,go 3elm at 30ft...beats a 6elm at 10ft...73 de JW