Software Radio / Data Tunneling - Sending a network over radio - Page 1
Forum section: electronics / general

author: Unknown
author_rank: Unknown
timestamp: January 25, 2012, 02:05:46 pm
content: The latest video from one of the guys I am subscribed to.It does what is says on the tin.There are many other interesting videos about SDR on his channel and also quite curiously videos about the history of my city Istanbul of all things. The history videos have a few errors and misconceptions but are good enough for a non historian westerner. The software defined radio videos are very nice. So, recommended.

author: sonicj
author_rank: Frequent Contributor
timestamp: January 25, 2012, 04:02:42 pm
content: interesting. not much throughput though... wonder what advantage that setup has over just a pair of WRTs in a bridge configuration? im sure he can get a lot more distance at 900MHz over 2.4Ghz, but 100K is pretty slooow for modern internet stuff. i guess data logging some sensors from a few miles away or something....ok, i just looked that thing up and its $1,300 usd! you can do exactly what he just did with 2 of those $20 routers and smoke that 100K link...i don't follow.wish i was that proficient from the command line!-sj

author: ndictu
author_rank: Regular Contributor
timestamp: January 25, 2012, 05:59:30 pm
content: Quote from: sonicj on January 25, 2012, 04:02:42 pmYeah, exactly what I was thinking. It's low BW and also from the ping it seems there is a lot of latency, so you may use that for something that doesn't transmit that much stuff. But then again, it's expensive, pretty big and I'm sure also power hungry, so I wouldn't use it in some remote battery/solar powered sensor thingy. Not sure what the intended audience and usage of that thing is.

author: Unknown
author_rank: Unknown
timestamp: January 25, 2012, 06:09:35 pm
content: Guys its a demonstration of a concept. Blinking a led with arduino is not efficient use of resources either but that is not the point.

author: ndictu
author_rank: Regular Contributor
timestamp: January 25, 2012, 08:47:37 pm
content: Quote from: HAL-42b on January 25, 2012, 06:09:35 pmOf course, I'm just wondering what that device actually is for? Too expensive in general; too slow (both bandwidth and lag) for net, video streaming etc; too bulky and power hungry (I assume) to be used in some remote weather station or something like that. I just can't think of a usage scenario where this hits the sweet spot. (The product website wasn't helpful either)

author: Unknown
author_rank: Unknown
timestamp: January 25, 2012, 08:58:27 pm
content: Quote from: ndictu on January 25, 2012, 08:47:37 pmIts a software defined radio. one of the better ones AFAIK.

author: NiHaoMike
author_rank: Super Contributor
timestamp: January 26, 2012, 03:29:05 am
content: Quote from: ndictu on January 25, 2012, 08:47:37 pmWith proper tuning, it can perform very well. The 900MHz band would actually be a good choice for long range wireless. High power amplifiers for that frequency are relatively cheap and lower frequencies propagate better, while still having enough bandwidth for practical use. (Tiffany Yep and I should get together and create a standard and reference hardware for long range wireless mesh networking at 900MHz, but I'm not sure if there's much demand for now...)

author: Unknown
author_rank: Unknown
timestamp: January 26, 2012, 09:40:19 am
content: Quote from: NiHaoMike on January 26, 2012, 03:29:05 amIndependent mesh networking is vital and interest should be growing after SOPA - PIPA mockery. Also think of the people whose government closes their internet just so that can oppress them better, Egypt Libya Syria all did and maybe are still doing it.

author: Unknown
author_rank: Unknown
timestamp: January 26, 2012, 11:58:35 pm
content: 900 MHz is used for GSM in many parts of the world. Using high power amplifiers at that frequency might get some other government agency knocking on your door, even before SOPA/PIPA/OPEN/... get signed into law. In other countries you'd need an amateur radio license to be allowed to use enough power to use it for long(ish) distance communication, ISM is usually limited to a fairly low power level.Even for independent mesh networking, I'd look into WiFi equipment that's cheap and plentiful, not some niche device owned by a small number of people and requiring specialized knowledge and licenses.

author: NiHaoMike
author_rank: Super Contributor
timestamp: January 27, 2012, 02:50:17 am
content: In the US, 900MHz is an ISM band. In some other countries, it's 850MHz instead. And the idea is to layer the networking technologies to optimize performance. Wired (copper or fiber) is the fastest and most reliable, but can only rarely be deployed between buildings. Free air laser (or focused light) can do almost as good, but requires direct line of sight. Within RF wireless bands, lower frequencies propagate further for a given power but carry less bandwidth. High power amplifiers above 1GHz or so start getting really expensive. PLC is a really promising technology, but uncertain for linking buildings as it is unpredictable if two neighboring buildings share the same transformer and phase. For the purpose of file sharing, even physically transporting devices that carry data counts as a transmission medium.

author: Unknown
author_rank: Unknown
timestamp: January 27, 2012, 07:27:44 am
content: What's the max. power for the 900 MHz ISM band in the US?

author: sonicj
author_rank: Frequent Contributor
timestamp: January 27, 2012, 09:00:11 am
content: ithinkits around 80mw unlicensed. not sure...-sj