Ads-b calculated range vs real range


#1

hello, i’ve just made a simple calculation of my ideal ADS-B range based on my height and location… and i made a comparison with my actual range with the feeder. I noticed (pls see attached photos) that i see very very few aircrafts in the zone where teorically i should have the better range!! I also noticed that in that direction i have the house wall, maybe i need to change the antenna location? i actually can’t mount my small antenna on the roof of my house…


#2

hi

check this out :smiley:
[What is the Maximum Range I can Get?]

Evangel


#3

When checking theoretical range, take note that not only man made obstructions may reduce actual coverage, but also that trees can have a significant effect.


#4

I used this guide. I think is the position of the antenna the problem (there is my house wall in the direction where I should achieve the maximum range). But I didn’t believe that a house can decrease significantly the range. Now I’ll try to put it in the garden to see if I can have some improvements


#5

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#6

There doesn’t seem to be any calculation factor for tree density. :slight_smile:


#7

abcd567 rulez :smiley:


#8

For further reading, look at “Fresnel Zone”
Fresnel_zones

For ‘better’ range prediction, try Radio Mobile
Radio Mobile


#9

Here is range plot by “Radio Mobile” technique at my location. It was not done by me. It was done by someone else (Martin) for me in Nov 2015.

https://discussions.flightaware.com/t/built-my-first-antenna-and-doubled-my-coverage/15770/746


#10

That eHam thread is excellent. It can keep a person busy for a very long time.:grinning:

I was under the impression that a CoCo would be much better than a Cantenna. Not so, discarding all my CoCo files.:wink:

I once build a Jpole antenna for the 2M band using 300 Ohms twin lead TV cable. It worked great. Anybody tried it for ADS-B?

Looks like you have been at this for a very long time. A fantastic journey.


#11

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My bitter experiance with both the coaxial colliner, and wire collinears

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November 2016

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IMAGE 1 OF 4: J-Pole


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IMAGE 2 OF 4: Super J-Pole


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IMAGE 3 OF 4: Quick Spider

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IMAGE 4 OF 4: Message Rate Graph
J-Pole%20vs%20Spider


#12

Thank you!!

I use a Flightaware and a ‘trimmed’ RTL dongle antenna.

I’ll try a spider and a cantenna.


#13

very very useful reply. i think that my big problem is the house wall. I need to find a better position :frowning: