Antenna and tower height question.

[9C1Driver]

So my summer project has been get a hole dug and a concrete pad poured with a tilt base. I am ready for the final install here in the next several weeks. I am putting up an IMAX 2000 with a ground plane kit. I plan on using this for 10 and 11m. Right now with three ten foot sections of American tower and ten feet of mast pipe (3 feet inside the top section on a plate) i'm at 37 feet to the feed point. I can add an additional 6-10 feet of mast pipe if need be. My question would be is there an optimal wavelength height that I am close to that I should shoot for? Right now I have been running the IMAX 2000 no ground plane kit on 20 feet of mast pipe since 2008. This has worked well but my plan was always to get a tower put up. Thanks for any input

I was messing around with this chart and for my needs it appears 36-37 feet might be right where I should be.

Frequency Wavelength Calculator

 

[Wire Weasel]

You should be fine at that height. Otherwise a bit sorry to hear that you have to go to so much trouble, work and expense just to put a vertical on it. Most guys save the tower headache for a big beam.

 

[fourstringburn]

I agree with the post above.

With a tower at 36 ft, your 1 full wavelength above the ground at 11 meters which is a good optimum height at that frequency.

A 3 element horizontal Beam (a 4 element would be better if you prefer to mount it vertically for better local use due to the even distance from mast to center elements) aren't that expensive, around $300. It's the tower that costs more and you're doing that anyway.

Of course with a Beam comes extra expenses like a rotor kit and thrust bearing which can add another $400.

If you live on either coast, you can get away with a stationary beam and point it towards the other coast so no rotor is really needed. Of course half the fun with a Beam antenna is using a rotor to "swing the Beam" .

With a Beam you get true forward gain over a vertical but you lose the convienence of a verticals omni directional pattern but too many, the Beam's gain justifies itself.

If neighborhood astetics is a concern, a vertical has a smaller footprint but will be around 55 ft high to the tip.

A Beam will be lower at 36ft but a 3 element horizontal at that height looks much smaller than you would think. When you put a beam together at ground level it seems huge but it shrinks considerably once it's up in the air.

So as long as your doing the expense and labor of putting up a tower, I would suggest putting up a Beam antenna!

Good luck with your tower!

 

[9C1Driver]

Thanks guys. Actually a beam was my first choice but for now I’m going to run the imax and then 12 feet away run a 2m on the 20 foot mast where the imax is now. Should work well until next summer. I’m in Indiana, my lot is 390 feet deep so neighborhood is not a problem for a tower.

 

[BJ radionut]

I’m in Indiana

Not another one!!!!

 

[Tucker442]

So my summer project has been get a hole dug and a concrete pad poured with a tilt base. I am ready for the final install here in the next several weeks. I am putting up an IMAX 2000 with a ground plane kit. I plan on using this for 10 and 11m. Right now with three ten foot sections of American tower and ten feet of mast pipe (3 feet inside the top section on a plate) i'm at 37 feet to the feed point. I can add an additional 6-10 feet of mast pipe if need be. My question would be is there an optimal wavelength height that I am close to that I should shoot for? Right now I have been running the IMAX 2000 no ground plane kit on 20 feet of mast pipe since 2008. This has worked well but my plan was always to get a tower put up. Thanks for any input

I was messing around with this chart and for my needs it appears 36-37 feet might be right where I should be.

Frequency Wavelength Calculator

 

[Tucker442]

Well, I know there’s some kind of formula for a full wavelength or something like that but in my experience height is might if I was you I buy another 10 foot section for the tower. Don’t use any more pipe because that’ll be a weak point if you get a windstorm. I have a three-story house with a small landing up by the third floor exit door and I have 20 feet of pipe with an IMAX on it with 9913 coax and I can talk anywhere any skip I hear I can contact them with less than 100 W.

 

[Tucker442]

Well, I know there’s some kind of formula for a full wavelength or something like that but in my experience height is might if I was you I buy another 10 foot section for the tower. Don’t use any more pipe because that’ll be a weak point if you get a windstorm. I have a three-story house with a small landing up by the third floor exit door and I have 20 feet of pipe with an IMAX on it with 9913 coax and I can talk anywhere any skip I hear I can contact them with less than 100 W.

I have a ground plank kit on mine too, and I think it makes a difference