Is a 6 foot height increase worth the effort?


#1

Hi there.
I have read various posts in this forum, and absorbed the information provided. However, I have a simple question, and hope that the “wise and experienced old one’s” out there could offer some advice or opinion.

I am running a FlightFeeder (v7.8.8) and the antenna is on a mast mounted to the chimney on my roof. The device is in my living room. At the moment, the antenna is about 6 foot higher than the apex of my roof, with a clear line-of-sight to the horizon. I regularly achieve very close to, and rarely but occasionally above, 200nm. My typical time-out range is around 185nm. (I am on the coast, and the flight paths are to and from inland).

My question - I have an opportunity to raise the antenna a further 6 - 7 foot approximately, while keeping the same 10m ( 33 foot ) cable length, but this will require a new mounting bracket, longer mast, drilling of holes through the wall, re-routing, etc.

I would like to know if the 6 foot height increase of the antenna will give any “significant” increase in distance achieved, along the same clear line-of-sight to the horizon. Basically, will my “normal” 185-190 nm range increase to in excess of 200 - 215 nm on a given day? (I do realise that this is of course dependant on the aircraft FL).

Thanks for any responses.
Cheers.


#2

Looks like you have a good antenna setup already.

When it comes to antennas, it’s usually ‘the higher, the better’. That said, you may soon be covered by the “Law of Diminishing Returns”.

If it’s not too much work and complication, go ahead, otherwise enjoy what you have.


#3

With Dxista here, it might be of benefit, but if all it takes is a bit of work and not a wad of cash, then try it. If you really do have an unobstructed horizon in all directions, then it probably won’t help greatly, but it might just fill in a gap or two. It most definitely won’t reduce your range.

Currently I have a 14 metre mast, but in one direction I have a close to 17 metre tree.Three metres would make a huge difference.


#4

@VivPike
Fully agree with @Dxista and @belzybob.

  1. If antenna cannot “see” horizon in most or some directions, every ft. of height increase improves range.

  2. To know if your antenna REALLY “sees” the horizon in all (or most) directions, first use following link to create a reference to judge if you have already achieved maximum possible range with your antenna location and current height. If your actual range is equal or somewhat more than the one predicted by this method, than your antenna “sees” the horizon in those directions.

    You can also create another one using current height + 6 ft.

    What is the Maximum Range I can Get?

  3. If you come to conclusion that your antenna REALLY “sees” the horizon in all directions, increasing height will give negligible benefit, while the effort and cost may be substantial. However, there is no harm in increasing height if too much complications, cost, and effort are not involved.

    Below is an example table showing this phenomenon on a level terrain (i.e. no surrounding hills or steeply rising terrain) and provided antenna can see horizon on ALL these heights.


#5

Short answer is: “maybe.”

I just built a new antenna and mounted it 2~3m higher than the old one. Positions Reported is up 30%, but I’m in the shortest house in the street. A small difference at my end, makes a big difference to my view of the horizon.