FlightAware Discussions

Raising antenna

Just wondering if raising my antenna on the roof top another couple of metres would make any difference to the long-range hits.

I’d like to improve my coverage to the East. There are hills to the East of my position and sea to the West.

Thanks :slight_smile:

Have you tried using heywhatsthat.com? It will create a theoretical max range ring (or several), based on your location and antenna altitude. You can play around with the height setting to see what effect it can have.

The site only allows for geographical obstructions, and isn’t aware of trees or buildings.

That said, it seems unlikely that a couple of meters is going to make a measurable difference on the mountains side.

Imagine a line that starts at your antenna, rests on the top of the farthest horizon that you can see in that direction, and continues onward forever. At whatever point that line intersects with 35,000 to 40,000 feet of altitude, that is going to be your max range. Now imagine raising the antenna end of that line by 6 feet. It pivots on the mountain top, and the far end gets lower, so the 35,000 foot altitude intersection moves farther away from you. How far it moves depends entirely on how far you are from the obstruction - the closer it is, the greater the effect.

Thanks for the reply.

Seems like I’ll have little gain to my East however I may have a greater effect to my West??

Sorry, there is a better tool there. I should have been more specific!

Go to heywhatsthat.com and click on the “New Panorama” tab.

On the left side, enter your location, either by street address or latitude/longitude. for #4, enter your antenna’s elevation above ground level or sea level, if you know it… Give your map a name and hit the Submit Request button.

It will take a minute or two to produce your result.

Go to the map at the bottom, and click on the button called Up in the Air at the top right corner of the map. Now, below the map there will be an orange field with 10000 in it, and a blue one with 30000. These are your range rings by altitude. Zoom the map out to see. You can change the altitude values to see your range for different altitudes.

Below is an example of mine, at the default 10k and 30k

I have the Cascade Mountains to my east, which flattens that side of my ring, but they start 80 miles away from me, so raising my antenna a few feet wouldn’t make much difference.

Hmm ok it seems I may already be exceeding my expected range -

There is a discussion somewhere here in the forum. A few meters up or down normally does not change it significantly, especially if the geographical location impacts it.

I tried it the other day to bring the antenna down from 2nd floor to basement. Reception was the same.

Oh wow! Would have thought that would make a massive difference.

What about an AMP, would this help at all?

An LNA can amplify only things which are already there.

So if no signal is coming in, there is nothing which can be amplified.
My setup during the test was a Raspberry 4B with the Flightaware Pro Plus stick which contain already a filter and an LNA.

My geographical location simply prevents from getting things improved. I would need to raise antenna by at least 100 feet to have an impact.
And i am not sure if the authorities would love that :slight_smile:

If it’s easy enough to do, you have nothing to lose by trying it.

I raised mine by 7ft and it made a huge difference.

1 Like

I’ve generally found these are the boundaries you have to break to get improvement with antenna placement.

1: Outside (obviously, getting the antenna anywhere outside helps vs inside usually)
2: Rooftop (removes your immediate building from blocking signals)
3: Above surrounding buildings (takes those buildings out of the equation for interference)
4: Above treeline.

Any movement without crossing one of those boundaries usually doesn’t help much, if at all.

–Chris

3 Likes


This is about the highest I can safely go using 40mm thick-walled PVC, the 10mm coaxial cable is hidden inside the pole to lower the wind load.

1 Like

:+1: :+1: :+1:
Fully Agree

 

Can’t argue with this at all.