LowPowerLab Forum

Hardware support => Moteino => Topic started by: Tasm-Devil on October 14, 2014, 05:48:33 PM

Title: Range-Test with two biquad antennas - 2.5km range
Post by: Tasm-Devil on October 14, 2014, 05:48:33 PM

I'm Pascal from Germany and today a tried to figure out the maximum distance, I can get with biquad antennas connected to two moteinos.
The basestation mote is mounted on the back of a 35 mm x 35 mm Perspex pane. Aluminium foil is glued on the front side as a reflector.
The second node has a omnidirectional biquad antenna. I use SMA connectors and an SMA to U.FL pigtail to connect the antenna to the moteino.
The 2 mm copper wire was 8 x 83,7 mm (868 MHz) long so its total length is two wavelength. Here is the formula including the velocity factor:
http://www.wolframalpha.com/input/?i=2997924*0.97%2F%28+4+*+868+%29%29%2F10 (http://www.wolframalpha.com/input/?i=2997924*0.97%2F%28+4+*+868+%29%29%2F10)

In my experiment today I established a 2,5 km line of sight connection! This was the maximum distance I could test. I used an LED-array to display if the last 8 acknowledges are received.
Here are some pictures:
http://deneaux.de/store/Forums/lowpowerlab/biquad1.jpg (http://deneaux.de/store/Forums/lowpowerlab/biquad1.jpg)
http://deneaux.de/store/Forums/lowpowerlab/biquad2.jpg (http://deneaux.de/store/Forums/lowpowerlab/biquad2.jpg)
http://deneaux.de/store/Forums/lowpowerlab/biquad3.jpg (http://deneaux.de/store/Forums/lowpowerlab/biquad3.jpg)
http://deneaux.de/store/Forums/lowpowerlab/biquad4.jpg (http://deneaux.de/store/Forums/lowpowerlab/biquad4.jpg)
http://deneaux.de/store/Forums/lowpowerlab/biquad5.jpg (http://deneaux.de/store/Forums/lowpowerlab/biquad5.jpg)

I am interested in your estimation.

Edit by Felix - added photos from Flickr:
(https://farm4.staticflickr.com/3932/15545445032_a0d7f49027.jpg) (https://flic.kr/p/pFGtdm)
(https://farm4.staticflickr.com/3946/15545445052_004560dda0.jpg) (https://flic.kr/p/pFGtdG)
(https://farm6.staticflickr.com/5605/15358462968_f4cb5ecaeb.jpg) (https://flic.kr/p/ppb8XE)
(https://farm4.staticflickr.com/3937/15545444882_1ba9e9b87c.jpg) (https://flic.kr/p/pFGtaL)
(https://farm6.staticflickr.com/5607/15520900026_4e5f2320d7.jpg) (https://flic.kr/p/pDwEQA)
Title: Re: Range-Test with two biquad antennas.
Post by: Felix on October 14, 2014, 10:47:15 PM
Very nice work!
Others have gotten similar range results with improved antennas.
I am wondering about a few things:
- Did you do any temperature compensation?
- What were your bitrate/BW settings? Any possibility to share your register configuration/code?

With your permission I would like to include your pictures in my Moteino-projects Flickr pool and include them in this post.