Possibly five per floor - one in the middle and one at each corner.
At extreme, one for each room.
Taking your own TTIG and doing a mini-survey by moving it & your device around to measure signal strength is the only sure fire way and is in fact exactly what weād do in the first instance. If you put the TTIG on the middle floor and then go to the top & then the bottom of the building, youād get an answer in minutes. Almost everything else is just advanced guess work.
Ok, so which LoRa Gateway would you suggest?
It should be cheap cheap as possible and run out of the box. If I can get no connection would be good with external antenna port.
Just try with your TTIG - youāve got it plugged in - itās as simple as you going downstairs and trying it out.
And as @LoRaTracker says, no one here can make a suggestion based on the information you have given and even then, probably not at all because, as I said, weād do a site survey.
Any which make use of the core Semtech GW chipsets! (SX1301+2xSX125x, Sx1308+2xSX125x, SX1302+ā¦, SX1303+ā¦) ie they are all much of a muchness with only minor variances based on build standard, components, temp range and environmental targets! and how well they follow or increment from the original Semtech reference designs and layoutsā¦I repeat
Main issue is if relative position (GW directly above door sensor) is correct then the polar plot of the ant (any ant - even external ones) will show relative nulls directly above or below, reducing sensitivity - hence suggestion to offset relative position if possible. Given your new/added info above showing another building in close proximity as Stuart suggests reflections may be your freind! The only way to be sure is JFDI! ('scuse the French) - deploy and test, anything else per Nick is speculation and educated guessingā¦I had 1 UK client years ago who deployed to an office block in Florida US - GW and main sensors were in basement (Plant room!), with last minute need to add another spare sensor to plant room attop the escalator shaft at top of buildingā¦some 20-25 stories above! They got signal through - but suspicion was it wasnt by direct through floor connection or even signal propogation down stairwells or elevator shaft but rather by reflection from other tall office blocks a couple of kilometers away! Such conditions difficult to predict on a forum postingā¦
Now, as it happens, I was testing this just yesterday.
With a LoRa device in a small sweet tin and transmitting at SF12, BW 125Khz, 14dBm, LoRa reception in my Shed was marginal when the transmitter was in the tin on a table in the house about 10M away.
Its not something I have measured as such, but I recall I was doing (receiving signals from a LoRa device in my fridge\freezer) to measure the frequency drift of the SX126X devices that can operate at bandwidths down to the 7800hz minimum as they use TCXOs.
But I guess it would be useful to know how many dBm a fridge will absorb, watch this space.
SF7 - typically -72ā78dbm aro SNR8.5-11, with GWs 2 rooms away - 7-12m with 2 walls/internal windows/doors
All three fridges are monitored here. See similar values across them all (BTW all are ābuiltā in types so behind cupboard doors alsoā¦) Worst gives typically -82 to -88dbm - they are in different rooms/locations.
It was partly a joke back to Nick after his question, however, since you ask - A couple of data points below out of the fridge (and in open room) similar distance from closest GW (a TTIG) - tends to be the main receiver reporting relevant RSSI, one floor below a Mikrotik (approx 45deg up angle from node similar horizontal distance to the TTIG, 2 floors below test LPS8, iMST Lite & TTN KSGWs! The others capture/report RSSI if TTIG busy or misses and RSSI range is typicall -73 to -91 across the test GW suite
ā2nd floorā contradicts the ā3rd floorā in the title.
Mailbox on the second floor (instead of basement or first floor). Does that mean the mailbox is located more deeper inside the building and not on the outside?
Below the buildings is a shopping mall which has ~2 floors. So donāt care about it, cause both buildings have same ground level. Mailbox is not deeper inside the building.
@mensa I did not see your response to this but the sensorās antenna and its placement are (at minimum) of equal importance as gateway antenna and placement.
Yes, the mailbox is metal. Itās the Dragino LDS02 sensor. I think itās antenna is not the best. Do you have any experience?
Tried what exactly?
I am still waiting for suggestions for a cheap and simple gateway which could do this. I currently only have the TTIG.
I know one posted the chipsets here, but isnāt there any out-of-the-box running gateway for beginners with much better coverage than the TTIG?
(SX1301+2xSX125x, Sx1308+2xSX125x, SX1302+ā¦, SX1303+ā¦) ie they are all much of a muchness with only minor variances based on build standard, components, temp range and environmental targets! and how well they follow or increment from the original Semtech reference designs and layoutsā¦I repeat
