Half Wave 10 Meter Dipole Height off the Ground

[Peter Wolczko]

Currently my 10 Meter 1/2 wave Dipole is about 18-20 feet above ground ( approximately on both ends). I would like to increase the height of the far end from the house to about 25-30 feet to get that end away from the lower branches of that tree. My transmission and reception is poor to fair.

Will that help with signal strength?

Thanks and 73,

Peter Wolczko KC1FNF

 

[Nashua Area Radio Society]

Hi Peter, From my experience,  getting your antenna feedpoint up closer to 33 feet (~1 wavelength on 10M) will likely improve both reception and transmission (all things being equal). If you can only raise one end, but the feedpoint height remains static, you may not see that much of an improvement though.  However, experimentation is the key to having fun and finding out what really works for your situation (or not).  Now that we have a foot of snow on the ground, it is the perfect time to be doing antenna work!

Let us know how you make out!

73,

Matt, WE1H

[Anonymous]

I agree with the “higher is better, especially for the feedpoint” idea.

The theory suggests the feedpoint should be at 0.5 wavelengths above ground (or odd multiples such as 1.5 wavelengths) but the theory is done in free air (no nearby obstructions) and with an ideal ground plane underneath.  This article https://ham.stackexchange.com/questions/5470/horizontal-dipole-radiation-gaps makes the same points.

I agree with Matt, experimentation is the way to go.

[Peter Wolczko]

Matt and Dave,

Appreciate your help on this. In the spring I will see about getting the end near the roof further up on the steel pipe near the peak of the roof. The end out in the back yard I can launch it a lot higher in the trees.

Many thanks,

73,

Peter   KC1FNF

[Jeff Millar]

The idea behind looking at elevation plots is to figure out if there is significant energy directed low for DX or high for local communication.  The higher the dipole, the lower the first lobe.  Also, a high antenna is typically able to look over nearby obstructions.  Some people place two or more antenna spaced vertically and switch them with an upper/lower/both switch.  This has the effect of moving the peaks and nulls around and upper or lower can work better depending on propagation.

Some sort of elevation pattern effect occurs with any terrain slope around the antenna, but the peaks move around for each installation…hard to predict.

Another way to think of it…the ground is a mirror and a mirror image virtual antenna acts to beamform the signals.  An incoming ray is received by both real and virtual antenna and the signals are summed.  This is the same as the real antenna receives both the direct path and the reflected path from the ground.

On average, antenna works better at higher elevations.  You don’t really perceive he nulls when operating, it just seems hard to work some stations.  But the next day, the ionosphere is at a different height, the bounces change and the the null moves to make a different location harder to work.

[Peter Wolczko]

Jeff,

I do have a little bit of sloping toward the back of my property and will make sure that I make the best of it.

Thank you and 73,

Peter  KC1FNF

[Author]

Posts