8

You can simulate. The idea is to model your RF channel(s) numerically by adding things like AWGN, multipath, clock skew, and so on. And, you want a way to model a lot of these channels, and twiddle the parameters and see how the system responds. There are many software libraries out there that will make this easier. I'd suggest GNU Radio. It has blocks that ...


8

The Hinternet is the "ham internet". In the US, and likely in other countries also, several WiFi channels fall into the 13cm ham band; being in the ham band is advantageous because licensed hams can use higher power than non-licensed ISM (industrial, scientific, medical) band users. So the hinternet generally refers to hams using WiFi gear, often with ...


5

After a long time pondering about this, I realized the trick. The first problem is that I had a version 3v of the router, and I installed the 3g version of the software. That doesn't work at all. I should have used the file bbhn-1.1.2-wrt54g-2.4-squashfs.bin instead of bbhn-1.1.2-wrt54g3g-2.4-squashfs.bin (For the latest, probably something different for the ...


5

5 GHz and 25 km range is hard. Let's do a quick free space loss calculation: $$\begin{align} a &= \left(\frac{4\pi d}{\lambda}\right)^2\\ &= \left(\frac{4\pi dc}{f}\right)^2\\ &= \left(\frac{4\pi \cdot 2.5\cdot 10^4 \text{ m} \cdot 5\cdot 10^9\text{ Hz}}{3\cdot 10^8\frac{\text m}{\text s}}\right)^2\\ &= \left(\frac{5\pi}{3}10^6\right)^2\\ ...


2

One way to estimate line-of-sight before you even step outside is to calculate the radio horizon. For the horizon distance in miles and antenna height in feet, the formula is $$ \text{horizon} = 1.23 \sqrt{\text{height}} $$ For kilometers and meters, it is: $$ \text{horizon} = 3.57 \sqrt{\text{height}} $$ The horizons of each station add. If you need a ...


1

A few comments on amateur LoRa: As others have pointed out, the datarate is measured in tens of bytes per second. Not thousands... Forget about file transfer! LoRa is spread-spectrum and therefore can be used on the 1.25m-band and shorter, with maximum 25W PEP. Enhanced propagation at 1.25m (versus 33cm where LoRa is typically used) opens up exciting ...


1

Ham LoRa does seem to exist, although I haven't seen any mention of it around the Boston MA area. I think to make best use of LoRa on Ham frequencies, one could use the European version that works in the 70cm band. With that, one could higher power level (limited by one's local power limits which vary by physical location) and better antennas -- Yagis for ...


1

25KM is a really long distance. You need to be up fairly high to beat the curve of the earth. If you are at sea level on a beach, and your eyes are 1.7m above the ground, the horizon would be at 4.7km. Source wikipedia:Horizon In actuality both ends would need to be elevated so that the beam path passes high enough over terrain between the 2 points. A ...


1

If you want to calculate the height required for a 25 km radio link. Check out this link. http://www.everythingrf.com/rf-calculators/line-of-sight-calculator This link gives not visual line of sight but also the radio horizon which is slightly longer. At 5 Ghz with sufficient gain antenna to direct the signal as close to the horizon as possible and height ...


1

To add to the already given answer. Most countries have a 100mW / 20dBm ERP maximum for license free usage of those bands. (You will have to check if this is your case, but chances are) As this is usually expressed in "ERP" which is "Effective Radiated Power" it will take antenna gains into account. Example by using an antenna with 3dBi gain, you will have ...


1

Chances are, you have a Picostation 2. AREDN only supports the Picostation M2. I suggest returning it.


1

I'm not sure you can or should log contacts that were not directly between your stations. Contacts through repeaters, packet reflectors, mesh networks, IRLP, echolink etc. don't really count as a measure of your skill and station. Satellites are an exception though. W2RS says here: QSLs are generally not exchanged for contacts made through repeaters (...


1

Ah, the mesh is taking the area by storm. We had a demo at our club last month and folks are working on getting a few of these and starting up some nodes. Flashing the router is probably the trickiest part. Fortunately, the Linksys routers have a long history of being reprogrammed and therefore there is a lot of info on this topic. I would suggest ...


Only top voted, non community-wiki answers of a minimum length are eligible