<div dir="ltr"><div>A distance of 1km is not that far and can be easily achieved with off the shelf WiFi systems. I am currently working on a project that has an Ubiquiti M2HP radio attached as the base system mounted at the top of a building with an omnidirectional antenna, and the same radio with a smaller omnidirectional antenna mounted on the mobile unit and we can easily get that distance.</div><div><br></div><div>The previous solutions are good, but to me, WiFi that just works out of the box is a simple solution.</div><div><br></div><div>As for my balloon communications, I had a 2-meter radio in the ham band, broadcasting at about 2W and was able to get 100+ miles, but that small antenna was up in the air over 15-20 miles high. I also tried using WiFi with a parabolic dish on the ground and I was able to test that out to over 2 miles on the ground, but that is a directional antenna - not very good for your setup.</div><div><br></div></div><br><div class="gmail_quote"><div dir="ltr">On Thu, Oct 25, 2018 at 3:23 PM Charles West via TriEmbed <<a href="mailto:triembed@triembed.org">triembed@triembed.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div>Hello!</div><div><br></div><div>I'm in Lansdale, PA now but I was hoping I might be able to pick you guy's brains. My current big project is trying to build one or more robots to deliver food/drinks on golf courses. I'm currently trying to figure out the best way to maintain continuous(ish) contact between a access point/basestation at it's base of operations and 1 or more robots operating on the course.</div><div><br></div><div>At a minimum, I would like to have the robot report its basic status (battery percent, GPS position) but it would also be great if it could stream video when required to allow teleprescence steering or determination of what is going on. The robot would probably be about 1 km from the base station at max. <br></div><div><br></div><div>I'm currently considering 3 possible solutions but I'm pretty open to ideas:</div><div><br></div><div>1. Use a mobile hotspot/cell modem:<br></div><div> For fixed $130 and monthly $20, I can get a mobile hotspot which provides one gig of data per month and more data for $5/gig. If I keep the reporting really light, this could work but the communication would have to be kept pretty limited.</div><div><br></div><div>2. XBee:</div><div> These modules seem to float somewhere between $25 and $60 in prices, so a pair would be somewhere in the $50 to $120 range. Sparkfun had a good guide to XBee (<a href="https://www.sparkfun.com/pages/xbee_guide" target="_blank">https://www.sparkfun.com/pages/xbee_guide</a>) but they are listing almost all of their products as retired (besides old series 1) and most of the stuff I read about XBee is from 2015-2016 so I am not sure what the best options are anymore. In any case, it looks like it would provide a low baud rate connection over the desired range. The main problem is that it requires working through XBee and making my basestation have to have special software to forward information. I'm also not sure about security and it is certainly not going to be streaming video.</div><div><br></div><div>3. Long range Wifi:</div><div> Rodney's done some work in this area before with his weather balloon projects. I don't recall off the top of my head how far he managed to get but I do remember he had to use higher power than allowed without a higher grade amateur radio license. That power level would not work for a commercial operation. There are some companies that are selling solutions aimed at farms (<a href="http://ayrstone.com/www/?v=7516fd43adaa" target="_blank">http://ayrstone.com/www/?v=7516fd43adaa</a>) and there seem to be off the shelf solutions that can get 500 ft (mostly aimed at hotels). The hotel systems seem to be in the $350 range and the farm systems in the $500 or so. The robot could use a high gain antenna, but it is not clear how much it helps. These systems have security built in and potentially can stream video if the range is long enough. Like hotspots, writing software for them would also be easy. <br></div><div><br></div><div>What do you guys think?</div><div><br></div><div>Thanks,</div><div>Charlie<br></div></div></div></div></div>
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