How far is to far

I found myself needing a day off this weekend, so i took time out to construct another little toy. Its a Sat Feed that in theory should illuminate a good portion of the dish and dur to its very small footprint blocks hardly any signal. After a few more tests and some tweaking im sure we will add these to the ever increasing line of Borg Antennas but the reason i designed the device is that i need to strike a 15Km link.

Here are a couple of pictures of the tests, and some netstumbler screen dumps. it was not until i got backl down to the base unit i realised that i had it pointing way to high and i would have been a good few degrees off so once i correct this and go do another test i will update the details.

First up is the test setup. The house with the red ring around it is what im shooting for. You unfortunatley can not see the sat dish on that side as it is behind some trees.

Next was a comparison test.

Now for the results... Fist on the graph was the SatDish, then the 15dBi Grid, then the SatDish again.

Now for those who are interested in the feed. heres a picture. As i said before. It is a very small footprint device

Allmost Forgot. Here is a photo of the base unit. The SatDish is the same as the one above.

Did noone question you wheeling that contraption up the hill there?!

How far was the other end of the link from you there?

What "la fruck" is that contraption you put on the end?

Where can i get one!

Wookie

Hehe, Yea i got a few strange looks while i was wheeling it down the road
BagLady, TrundlerMan, WiFiWheeler...
Had a couple of people turn up to see what i was up to.

Wookie. They are still very much in development. Have a few design things to sort out as they are a little fiddly to make at this stage. But performance certinly looks good so far

And the amount of AP's out this way has atleast trippled!

Andrew

Heh... I wonder how john is going with the patch antenna from wookie as a feed on the 90cm ihug dish....otherwise one of those would probarbly work a treat.

In that orientation, is it horizontal or vertical polarity?

Rich,

Its circular (well should be). will pick up both H and V but you will loose 3dBi over going to one of the same devices. And the trees that i was punching through did not seem to worry the signal much.

Certinly with a few mods this should/would light up his dish a lot better than the pannel antnna. Will have a chat to him about it. erm or you can mention it to him as you will see him before i do

Andrew

Patch antenna hey.... might have to give that a try. If he has a photo of it on the ihug dish an you get him to post it here!!


Cheers

Wookie

We've managed to get about 16 Kilometres out of 2 x huge 24db Parabolics on a couple of Linksys/Cisco 54MB AP's in Closed Bridge Mode. About 2ms ping across it too which is rather exciting I guess.
Its going great, I'll upload some netstumbler and pics soon. And we might do a bandwidth test too.
Boy it gets windy and icy up the pole at Rudd Road and we got submerged in cloud, and the wifi still battled on!
Cheers to Andrew from Borg Ltd for getting the antenna's to us nice and promptly

This gets our network out to Mosgiel (the wop wops)

__________________
Kind Regards

Dan Clark
Network Manager
DunedinWireless
Scarfies.Net Ltd

I have tested 30KM's with 2 x 24dB parabolic dish at each end and 200mW Senao Cards. This was about 1 year ago and one of the antenna was not lined up properly. Have not been back since.

I was running about 10M of RG58 low loss cable. The other end in town was mounted at the antenna.

Only got about 80kbps and a 30% signal level.

More recently tested 20KMs and had 80% signal level and a 1.2MB internet connection tested from Jet Stream's speed test web page.

http://jetstreamgames.co.nz/speed/ADSLdownload500.html

I will have to arange a compitition in Canterbury one day to who can get the longest link for a laugh.

Matt

whoarrr, that's about 50Watts EIRP. New general user license allows for 4Watts with digital devices max. would have been worth the play with though

Gavin.

Im curious as to how you got to that value? 50 Watts? 8O
I used http://www.vwlowen.demon.co.uk/java/eirpie.htm
and unless im putting some value in wrong im not getting the same value as you ops:

No worries:

200mW (0.2W) in to 24dBi (24dB is 251.18864Watts in refernce to
how they work out dB to watts. There for take
the .2W and X it by 251.18864) = 50.237728 Watts.
Maximum legal allowed under the general user radio license
is 1,000mW (1W) 2.4-2.8GHz unless it falls in to a digital
modulation device under note 1 of the license, in which case wi-fi
does as it employ's frequency hopping and/or direct sequence
spread spectrum technology. Note 1 allows a maximum permittable
EIRP or 4,000mW. This means what comes off the antenna after
gain, not before. 50,000mW clearly exceeds this by law. RSM are
also on a crack down this year of fines and equipment seezing,
so be careful.

You can find more conversion information tables and license laws
at www.med.govt.nz/rsm, or www.med.govt.nz/rrf.

To give you a small working formula to figure out dBW (and dBi) conversion in NZ without having a table, is 3dB gain is x2 EIRP. 6dB gain therefore is 2 x another 3dB which is another 2 = 4. 9dB is 6dB which is 4x another 2 (3dBi) = 8 (actually 7.99 something). Keep adding that up to you get close to 24, however the 251 is the exact figure for 24dB. It won't be quite 50W as there's line loss of say 3dB, which will half that for thin coax cable like the small stuff used in wi-fi, so say about 25+W. Still quite high though.

This is a simple printable table for you to follow: http://www.med.govt.nz/rsm/formsfees/dbw-w...atts-table.html it's also how I work my watts out when designing a high-power commercial site by the same principal only with a few calculators I have for the exact purpose.

I tried that link you gave me, I inserted 0.2 in to watts, 2450MHz as the centre frequency, assuming just RG58, 3 meters max, antenna type 'other' as a 24dB antenna is not a half wave, at 2.4GHz it should be a full wave antenna, only 500KHz AM one's require 3-4KM than a few inches for 2.4GHz full wave, gain 24dBi, = 38.908, higher than my 25W guess but depending on the coax length and type, could be as high as 50W, wouldn't put it anywhere less than 15W.

Cheers,
Gavin.