Hi Joost,
How would you keep the power “shit” outside?
In most cases it will enter the building somewhere?
(unless using some energy harvesting and accumulation option outside like solar, wind or watermill)
Same for network connection in most “typical cases”
Although fiber might help indeed.
I’m using Wifi in one of my gateways which seems to be quite OK (but this is in a rural area: not much going on on the Wifi bands there 
)
Hi .
In my line of work we always use shielded cables. and the number of cables are running in the 3 digits 
the grounding is always an issue … i see it to often that is is not done …
the number of lightning hits over the last 10 years are <5 with over 300 transmitter sites…
this are big FM and DAB transmitter sites…
/Joost .
The solution I proposed in another thread was using an isolated power supply (industry standard) and grounding your antenna. This offers near to perfect protection at marginal extra cost. When lightning strikes, the antenna grounding will provide the low impedance path to ground and it will clamp the voltage so that it never surpasses the isolation barrier of the PSU (industry standard is 6kV). Add an ethernet isolator and the electrical and IT equipment behind it will stay safe, even on a direct hit.
Aren’t we trying to apply industrial grade protection to household equipment here?
exactly my tought to … a bit ‘over the top’ , this type of protection cost probably more then a new gateway
I’m now spending my evening watching TV shows about lightning… thank guys
Depends on how much you value your home. An industrial grade isolated power supply and an ethernet isolator will indeed set you back around €80 combined, but how much does your fire insurance cost . I for one would gladly pay a few bucks extra just to be sure.
Also, we need to keep in mind people who place gateways on buildings that aren’t theirs, e.g. I’m working on placing gateways on public buildings in the city I work in. Best to point them to the best possible solutions to minimise liabilities.
First of all, I think we should split the scenarios where someone puts an antenna on his own house and placing a gateway on a high building.
For the own house-scenario I think this might be a false dilemma. Even with these isolated power supplies I myself wouldn’t feel comfortable without grounding, provided that I would think there was a significant risk. Adding external grounding adds a few hundred euros to the bill. But given lighting rods protection shape (the ‘pyramid’) and the remark about that even those commercial high cell phone sites were hardly hit the chances that something will happen to a normal house seem acceptably low. Still, you can convince me with data proving these isolated power supplies will really protect you from such a huge load of a lighting strike. Reason is that I find it very hard to believe that lighting will stop when it hits something like a fuse because it even traveled a long way through the air.
For the external site it’s different. I would say that you would simply have to comply with whatever regulation exists for those sites. It also makes me wonder if this is attractive for privately owned TTN gateways; For the price tag of a kerlink including professional installation and protection you could get 5 or so kickstarter gateways which may cover the same area when placed in less optimal positions. But they take a lot less talking and persuading efforts. High placed gateways may be more interesting if the company using the building provides them as sponsoring. Including the full installation, maintenance and responsibility.
agree … @TijnOnlijn …
I know that the cost of such a professional installation cost more than the gateway it self …
one way you mentioned to reduce cost is to let the cost of the grounding and electrical work be sponsored …
Another way to finance this is to setup a “stichting” foundation at which people can donate money to setup a local ttn network.
all equipment is than owned by the foundation and provides a more stable and permanent coverage.
This has also a advantage towards big companies that you are not just a hobbyist but a more processional minded group.
by experience i know this works …
you can get companies to be your sponsor,etc people can donate via eg a paypall account.
/joost .
I specifically said ‘isolated power supply AND grounding’ 
. An isolated PSU on its own won’t do a thing; Grounding is most important, and adding an isolated PSU makes it intrinsic safe.
[QUOTE]For the external site it’s different. I would say that you would simply have to comply with whatever regulation exists for those sites. It also makes me wonder if this is attractive for privately owned TTN gateways; For the price tag of a kerlink including professional installation and protection you could get 5 or so kickstarter gateways which may cover the same area when placed in less optimal positions. But they take a lot less talking and persuading efforts. High placed gateways may be more interesting if the company using the building provides them as sponsoring. Including the full installation, maintenance and responsibility.
[/quote]
I think that building a city or even a region spanning network based on private gateways tucked away in peoples living rooms or attics is a pipe dream, and that we need the involvement of companies and the exploitation of high value sites like tall buildings to make TTN a success. As community leader of TTN Ghent, I sent a questionnaire on our mailing list. Turns out that 80% of the people interested in placing gateways are companies! If they place a gateway on the roof of their customers, they will have to comply to safety regulations as you say. But even expensive hardware like the Kerlink is not intrinsically safe, in fact it offers just the same kind of safety towards lightning strikes as a IMST+RasPi gateway. So I think these kind of discussions are very useful for everyone.
Well I do think you have a valid point. But not for household type gateways. Wouldn’t it be an idea to make a labs entry for ‘how to place a gateway on a commercial building?’ That’s an entirely different situation about which currently only limited information is available on TTN.
btw, same goes for node antennas. Everyone’s focusing on the gateways but some smart ideas about node antenna’s wouldn’t hurt either. I recently tested a semtech loramote and it performed far better than our normal piece-of-wire nodes.
To summarize the antenna part. I think there are of the shelf categories plus the DIY option.
And then the DIY option. I think it’s great, but it’s a different league. But that also depends on how well one could expect to get it trimmed by just building it and measure the physical dimensions. Given the 3 types above, would the DIY antenna built someone not familiar with radio at least give reasonable results?
Yeah, I was thinking about writing a summary about lightning protection in a lab post. I’m gonna ask some input from some colleagues who teach antenna theory at our department.
For a personal gateway you are right, especially because it is almost impossible for most people to run a solid 10mm² copper wire to their roofs (the only adequate way to protect against lightning strikes). However if lightning rods are already in place (e.g. commercial buildings) than it’s just a small extra to also protect your gateway.
A company next door sells Procom equipment, I’m gonna ask for some quotes there.
Hi,
Thank you for this Labs story
I am currently considering doing my own gateway with an outdoor antenna and this is very intersting pieces of information.
Now, as I am new to this, I have just 1 small (stupid) question: you mentionned the issue with the gain and that it would be solved by configuring the sending power. My question is, how (and where) do we configure the gateway? What would be the parameter? Would it be “–mix SX1257 Tx mixer gain trim, [0:15]”?
Thank you
I can get the Procom CXL 900-3LW-NB/868MHz for €225 incl. VAT excl. shipping. Delivery time 3 to 5 weeks. Price could go lower if we order ten or more. Sounds like a reasonable price for a professional piece of hardware.
What do you mean?
@Epyon, you mentioned using an isolated power supply to complement a grounded antenna cable. Do you have any pointers on where to get those isolated power supplies? I’m having a bit of trouble finding them, at least in versions that are properly sealed off, with a standard 230V connector (as opposed to screw terminals for the 230V connection).
would an old pc power supply do?
