Hi,
I will soon go on vacation to a mountain cabin in the alps, and I need internet there.
Reception is very bad however, with a normal phone no connection is possible at all.
Last time I was at the cabin I managed to get a tiny bit of reception by putting my phone in a big stainless steel cooking pot with some cardboard spacers to roughly center it.
It was enough to receive some emails, but even that took ages.
Searching the internet for capable modems with good antennas, I came across the Mikrotik LHG LTE series and the ATL LTE18, but not being an RF expert, I don’t know if these are a good solution for my situation, and if so, which one to choose.
The problem is that I have no line of sight to any cell tower.
Actually, if you would “draw” a straight line from the cabin to any cell tower, it would go through kilometers of rock.
And these are no small mountains, they extend hundreds of meters above said “line”.
The map I attached shows the situation:
https://imgur.com/a/ez4UA1S.png
The red dot is the cabin where a modem is to be installed, the blue dots are cell towers.
And this is a photo from what the antenna would be pointed at:
https://imgur.com/a/Kw0XL5h.png
For orientation, the mountain right in the middle of the picture is the “Schwanspitz”, which is at the top of the map right under the lake.
Without line of sight to any tower it seems that the signal I was able to pick up with the cooking pot has to have been a reflection of some sort, which makes me wonder:
Is a high-gain antenna like on the LHG series or the ATL LTE18 even the right choice here, given that I wouldn’t even know where exactly to point it at?
Will those modems work there, or do I need something less directional like the SXT LTE6?
Or do I need something with bigger external antennas, especially since I suspect I will be using the lower frequency bands given the lack of line of sight?
Since you don’t have line of sight, whatever signal you will get will be reflections, most probably off the mountains on the opposite side of the valley. In those conditions usually lowest frequencies give the service. Which are the frequencies depends on particular network operator and particular cell tower. Either ask network operator about cell tower specifics or look for a site where crowd posts observed cell tower characteristics. In Europe, most often it’s 800MHz band (part ob B20) or more recently 700MHz band (B28).
As @chechito already noted, most MT products are really bad at lower frequencies, making them often even worse than smart phones. Unfortunately, with antennae size does matter and to make decent antenna for low frequencies, the antenna has to be rather large … a decent log-periodic antenna is slightly more than 1m long and one has to use a pair of antennae to make use of 2x2MIMO.
Wavelength of the 700/800 MHz bands is aprox 40 cm. And as Mkx pointed out, check with your Mobile Network Operator (MNO) about the location of the nearest tower and see if it is possible to set up your own mast to achieve Line-of-Sight. Then you might even use the higher bands as well, which are normally less crowded in rural areas.
Starlink is probably a better option from a pure throughput perspective as many base stations in the Alps are still connected using radio links when located far from any major resort.
Thank you all for your answers so far.
After reading what @mkx wrote and researching a bit more, I think a modem with big external directional antennas is the way to go. @Larsa the horizon is very high in all but one directions, so Starlink would likely have problems, and also it’s much more expensive.
According to cellmapper.net, both of the two closest towers exclusively use band 20 at 800MHz, though I don’t know how up to date and correct that information is.
Would it be better to get a broadband Log-periodic antenna like the Iskra P-58 L700 UNI with 10 dBi in the 800MHz band but wich is also good at higher frequencies (datasheet: https://www.iskra.eu/f/docs/75808/Antenna_Systems_catalogue_web_2017_5.pdf , page 38 (36))
Or a narrow-band antenna like the Iskra P-22 LTE with 11dBi in the 800MHz band but probably really bad gain at higher frequencies (datasheet: same link as above, page 37 (35)) ?
The narrow band one is smaller (78cm vs 107cm) and has higher gain at 800MHz so that’s some clear advantages, but is there something I might need the higher frequencies for, like 3G fallback maybe?
How much difference does 1 dBi gain make?
Both Iskra antennae are excellent. Using narrow-band one is fine if higher frequencies are out of question. In medium turn, all network operators will switch off 3G (and probably keep 2G for backwards compatibility and emergency services over SMS or voice), so this consideration might not be relevant. And given that you are trying to get service “in the middle of nowhere” it not likely for network operators to introduce high frequency services on those cell towers. More likely they will introduce B28 for 5G and Iskra P-58 covers that part of spectrum as well.
As to 1 or 2 dB of difference in antenna gain: usually it’s not a life saver (if lower gain doesn’t give the signal offer service, then having a dB or two higher gain might give service but it certainly won’t be stellar). However, good antennae help also in other aspects (directionality in case of side interference, well defined polarization planes for better 2x2 MIMO, etc.), which in your case probably won’t change much either. Another nice property of Iskra antennae is a decent antenna cable (it’s fairly thick, but when it comes to antenna cables, thicker is better), some other solutions come with short thin antenna cables which makes optimal positioning of antennae very hard.
If signal strength is poor to mediocre, those one or two dBi of gain can mean significantly better service (e.g. 10Mbps instead of 5Mbps or something like that). So to me it seems a dilemma: slightly better service on B20 versus potentially better performance on B28 (if it materializes).
In any case, you’ll need a pair of antennae and mount them appropriately (mounting hints (including orientation at 90° between them) are on the P-58 product page I linked above, they are applicable to all log-periodic / yagi antennae when used for 2x2 MIMO).
Of course you need to know that antenna manufacturers will always cheat on you w.r.t. the published “gain”.
The gain of a logperiodic antenna is about 6dBi and any higher figure in the datasheet is pure fantasy.
In this case it appears that for their combo of 2 antennas to be used in MIMO, they have specified the gain as if they were “stacked”, i.e. connected to the same source via a power splitter, and mounted in the same polarization.
Then it is achievable to have about 9dBi gain. Add some wishful thinking and you have “9-11 dB”.
But in MIMO setup it will just be 2 antennas of 6dBi gain each.
Logperiodic antennas are used because they are wide-band. Buying a larger one results in a larger bandwidth (ratio of lowest to highest usable frequency), but on a single frequency within the antenna bandwidth the gain will always remain the same.
When you want more gain, you could mount a logperiodic as feed of a large dish, or you could use a yagi design optimized for your operating frequency. That will have much more gain for the same physical dimensions.
Then, considering everything so far, I will go with a pair of Iskra P-58, just ordered them.
Also I took the version with a shorter cable (5m instead of 10m), because it is long enough for me and I will have less attenuation on the cable.
The t-mobile coverage map says that LTE advanced is available down in the valley, so there has to be at least one other Frequency band in use, and the 1 dBi i lose over the other antenna, i get back with the shorter cable (narrow band antenna is available only with 10m cable).
Chateau LTE6 seems like a good deal for a cat 6 router, it should work fine here right?
I was just about to say that before you order anything, check which channels and signal levels are available with your smartphone in field test mode. Then you will know what to expect in terms of throughput and what equipment is needed accordingly. If the signal levels are low, skip the antenna cable and place an outdoor device directly connected (ie as close as possible) to the antenna.
And before completely dismissing StartLink as an option, check with their customer support using your exact location. There are also online tools available for this purpose.
