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Oz Jon

Paul,

I just had a quick look at the path from your apartment to the farm on Google Earth (copy attached).

I can't see any big hill blocking the path with a quick look at heights reported by Google!

What am I (or you) doing wrong?

 

?Paul5GHz.thumb.JPG.1849ef3d53a25665928969a0b3906c64.JPG

 

Ah! - now I see it! - you are just grazing the side of a hill 2/3 along towards the farm.  You may just get away with a 5GHz link!  Depends on how accurate these locations are plotted on Google..... Maybe, even use the side of that hill as a reflector! .... a very tricky path!

Edited by Oz Jon
ps
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Parrothead

A guy has a used 1.8 Ghz parabolic antenna, for sale on eBay. Trouble is, it's in the US.

 

PWPF-18S_DataSheet.pdf

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Oz Jon
Just now, Parrothead said:

A guy has a used 1.8 Ghz parabolic antenna, for sale on eBay. Trouble is, it's in the US.

 

PWPF-18S_DataSheet.pdf

That URL is for a 1.8GHz grid antenna! - I understood that you planned to use a 5GhZ link?

If so, then you will need a solid reflector antenna - eg a good quality 6ft dia parabolic antenna will give you about 35 to 37dB gain.

 

If you are actually going to work at 2GHz, that may (or may not) work OK, even with a bit of an obstruction.  A very difficult path to design though.

At least a 2 beer design fee!

 

 

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Parrothead
46 minutes ago, Oz Jon said:

Ah! - now I see it! - you are just grazing the side of a hill 2/3 along towards the farm.  You may just get away with a 5GHz link!  Depends on how accurate these locations are plotted on Google..... Maybe, even use the side of that hill as a reflector! .... a very tricky path!

 

Chan just noticed I was viewing them. She said she learned in school that one of the hills on the right of the following image is 70 meters in height. So, I am pretty certain the larger of the two on the left, is nowhere near 70. Hopefully so, anyway.

hills2.jpg

 

I need to go have a look at both of these hills:

hills.jpg

 

 

12 minutes ago, Oz Jon said:

I understood that you planned to use a 5GhZ link?

 

Yes. That is what I said. I just happened to see that antenna while looking at directional / beam / yagi antennae. It would work for my backup internet access. Sorry. I was thinking more out loud, than anything.

 

My apologies for the confusion. 

 

 

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Parrothead
10 minutes ago, Oz Jon said:

At least a 2 beer design fee!

 

I already owe you a case.

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Parrothead
6 minutes ago, Parrothead said:

I need to go have a look at both of these hills:

 

If can go to the top of the larger one, I can use my altimeter app on my cell phone to determine the height. Of course, Google Earth may give me a similar result. But, less exercise with Google Earth. :D

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Oz Jon

Well, the path line you drew and the (quick and dirty) one I drew differ by only a small amount in plan, but the effect is enormous!

Your line picks-up a 2nd obstruction which my line didn't! And your line has a much higher main obstruction than mine showed.

 

So, accurate path plotting is a critical first step.... That's your department!

 

Also, we need to resolve just what frequency band you plan to use.

 

Whatever, this is not an easy path to design - design impossibility cannot be ruled out!

I don't give up easily, but sometimes reality must be faced.

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Oz Jon
17 minutes ago, Parrothead said:

 

If can go to the top of the larger one, I can use my altimeter app on my cell phone to determine the height. Of course, Google Earth may give me a similar result. But, less exercise with Google Earth. :D

Well, the path line is the critical first thing to determine - does it cross 1 hill or 2 or neither/  And if it does cross a hill, at what obstruction height?

 

Not easy to do! .... even for a man with your capability! - Lol!

 

ps. I noticed that the big hill has a heavy tree growth on it - that's not helpful for RF reflection and it will make surveying the path line difficult too - You probably cannot see the farm or your apartment easily through the trees if you climb that hill to try to determine the path line.... [note my avatar!]

Edited by Oz Jon

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Parrothead
1 minute ago, Oz Jon said:

Also, we need to resolve just what frequency band you plan to use.

 

I can use any frequency for broadcasting to the farm. Just a matter of using what I have here, or buying others antennae to broadcast / receive.

2 minutes ago, Oz Jon said:

Well, the path line is the critical first thing to determine - does it cross 1 hill or 2 or neither/  And if it does cross a hill, at what obstruction height?

 

I will just see if I can sort the highest point on each hill, and go from there. 

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