16 ms·

43 km line of sight with USB WiFi stick (2005)

341 points by NotAWorkNick 5y ago

mrfusion 5y ago
What about the curvature of the earth?
- ck2 5y ago
  (after posting this I thought of "liquid/atmosphere only" planets and how they are round so obviously my initial thought process on this was wrong, I thought water followed the bottom of its curved-earth container while trying to remain level on top)
  - orangepurple 5y ago
    This is nonsense. Do you believe that water forms a cliff at the edge of the beach so that its curvature tangent to the center of the body of water is zero? Hilarious
    - deleted 5y ago
      [deleted]
  - aeastw 5y ago
    I'm fairly sure water follows the curvature of the earth...
  - smilespray 5y ago
    Teach us more science facts, professor!
  - blueprint 5y ago
    meniscus please
- sushibowl 5y ago
  OP chose a hill 250 meters above sea level, and also has an antenna about 5m high. According to a calculator I found[1] that puts the distance of the horizon at roughly 57km. So plenty of range to still be in LOS of the transmitter. [1] https://www.omnicalculator.com/physics/earth-curvature https://www.omnicalculator.com/physics/earth-curvature
NotAWorkNick 5y ago
An easier to find link that shows how to make the home-brewed antenna for those interested in trying it out for themselves https://flylib.com/books/en/2.434.1/hack_83_make_a_deep_dish_cylindrical_parabolic_reflector.html https://flylib.com/books/en/2.434.1/hack_83_make_a_deep_dish...
- ge96 5y ago
  Those propagation maps are cool, was learning about them 12 years ago for FPV
- genewitch 5y ago
  I seem to have a recollection that a cheap DIY system is to get two RCA 18" dishes (or larger) and remove the LNB from the dish (or whatever the horn part is called) and affix a "cantenna" or other waveguide to the arm, then, using the shortest, largest coax you can manage, connect the two cantenna/waveguides together, and aim them 180 degrees apart. I also seem to remember that putting this "halfway", even if halfway happened to be the highest point, wasn't ideal, it was something like 60/40 or 70/30. Now-a-days, mikrotik or ubnt make doodads you can replace the LNB with that instead provides some wifi band, with PoE, so two of those up on a tower means you have active repeating, and you can probably push that solution out a lot further than 43km. For the record, i put a USB wifi stick inside of a pirouette cookie can and it was a phenomenal "war driving" antenna. I use folded-dipole-fed yagi antennas now for doing wifi surveys, but in a pinch 802.11B 1000mW+ wifi cards are stacked up in a filing cabinet...
  - Breza 5y ago
    War driving back in the 802.11.B days gives me fond memories. Though I never tried anything as cool as your cookie-tenna.
foobarbecue 5y ago
Very impressive! Please correct the error in the title -- it's "line of sight," not "line of site."
- NotAWorkNick 5y ago
  Done, thanks for the heads-up! (Also corrected it to read 'achieved' ;-)
PaulHoule 5y ago
Overall I've had very good luck with the RF performance of external WiFi sticks. All too often the antennas inside laptops and phones are really an afterthought so the WiFi and (particularly) Bluetooth performance is awful.
londons_explore 5y ago
And mine keeps cutting out if someone fat walks between my laptop and the router 6 feet away...
- gunfighthacksaw 5y ago
  Are you sure your friend is fat, and not just wearing a bulky faraday cage?
- Nextgrid 5y ago
  A lot of people don't realize that Wi-Fi pretty much always operates in an extremely degraded mode (on the verge of not working at all - which is why a person walking past can be enough to break it) and it only seems to work for certain applications due to the magic of protocols such as TCP which can recover and essentially conceal packet loss. Jumping onto a call or some other real-time application (where retransmissions don't help and actually make the problem worse) will break the illusion and show you the reality of things. There's also this misconception that speed is the only thing that matters, so "higher speed = better connection" and the vast majority of consumer-grade tools only ever test for this. This is where it will mislead you, as an unstable connection with short bursts of high speed will appear "better" (despite being fragile and completely unusable for anything real-time) than a slower but more reliable connection. In-browser speed tests are extremely bad for this because all the buffering & various layers could even fool the test code itself, making it believe it's getting a steady stream while in reality it's getting merely short bursts of data (in between tons of underlying TCP retransmissions). Iperf & ping are the tools of choice if you actually want to look into it - they are closer to the metal and will give you faster feedback (you will be able to actually see the dropouts due to packet loss).
  - nearlyepic 5y ago
    Is there anything short of "get a better antenna" that helps address these issues? Recently had to switch to Wi-Fi for my desktop and have been frustrated with the inability to stop the connection from constantly being on the edge of not-working.
bjt2n3904 5y ago
But did they establish a link and transfer data? Broadcast packets with the SSID aren't too difficult to get. You only need to get one. Fun regardless, but I'm curious for more info.
- jandrese 5y ago
  I doubt it. The remote side was a generic AP with an omni antenna I think. The return traffic is going to be way down in the noise floor.
mcgeez 5y ago
This is an old article, dating back to at least 2005 as per Web Archive[0] please edit the title to reflect that. [0]https://web.archive.org/web/20050201000000*/https://www.qsl.net/9a4qv/WiFi_Ri.htm https://web.archive.org/web/20050201000000*/https://www.qsl....
- ajross 5y ago
  And the ideas are older still. The days of the Pringles Can Antenna were pretty wild. I'm not aware of any similar hacks at 5 GHz though.
  - rolph 5y ago
    a 5GHz waveguide AKA "cantenna" is between beer can and bean/soup can https://en.wikipedia.org/wiki/Cantenna https://en.wikipedia.org/wiki/Cantenna width or diameter is a criticalproperty: https://www.everythingrf.com/tech-resources/waveguides-sizes https://www.everythingrf.com/tech-resources/waveguides-sizes https://web.archive.org/web/20161029045619/http://www.pwmn.net/wiki/index.php?title=How_to_make_5ghz_cantenna_-_feeder_for_sat-dish https://web.archive.org/web/20161029045619/http://www.pwmn.n... have fun, and dont cut yourself, they do work well when used at both ends of the line. https://web.archive.org/web/20071012133113/http://www.saunalahti.fi/elepal/antenna2.html https://web.archive.org/web/20071012133113/http://www.saunal...
- dang 5y ago
  Year added above. Thanks!
jll29 5y ago
I wonder how modern (2022) equipment might fare? Certainly the author picked a beautiful region to do that kind of outdoor experiment in.
- OJFord 5y ago
  > Certainly the author picked a beautiful region to do that kind of outdoor experiment in. I don't mean to be argumentative, but I wonder what the ugliest 43.33km line of sight environment one could find would be? I imagine it's quite a good proxy for beauty, the maximum distance you can see.
  - bombcar 5y ago
    Ugliest would be point-to-point in a some run-down city.
    - drewzero1 5y ago
      There's an old dish antenna on the roof of my office that's pointed at a building we used to have in the 90s. I've wondered if I could get it to do anything cool, since my house is near the other building, but I don't think I could get an antenna high enough to get line of sight.
      - bombcar 5y ago
        I would not be surprised at all if half or more of the dishes you see on commercial buildings are just vestigial, waiting for a signal that will never come again.
        drewzero1 5y ago
        I have seen so much obsolete equipment that was left in place after replacement, some of it even still plugged in and running but not connected to anything. My favorite was an SCO box that beeped every day when it attempted to dial out to another server, long since decommissioned, over a phone line that was disconnected years ago.
ng55QPSK 5y ago
actually, LoS over open water, is following physical laws. GSM (with a range limitation of 35km by timing) was very well recievable from ships.
bombcar 5y ago
He got the Wifi network to show up, but did he get a connection? A bit higher quality point-to-point can be obtained with a bit of specialized equipment, Mikrotik has a bunch: https://mikrotik.com/product/MTAD-5G-30D3-PA https://mikrotik.com/product/MTAD-5G-30D3-PA for example, can go 40+ km.
- deleted 5y ago
  [deleted]
chrissnell 5y ago
And why not? When I lived in Utah, I could easily hit a mountain-top ham radio repeater 20+ miles away with my little 5W handheld radio. A small weather balloon with a sub-1W transmitter can easily be heard at 100K feet altitude by people hundreds of miles away. So long as you have LoS, it's not problem.
- dragontamer 5y ago
  Water molecules block 2.4Ghz spectrum that WiFi uses. This is on purpose: the idea is to make the common WiFi (and Bluetooth) bands short range on purpose, so that many people within a city block can have local WiFi or local Bluetooth without interfering with each other. So 2.4GHz over a long distance kinda goes against the design of WiFi / Bluetooth.
  - bonzini 5y ago
    The idea really was that 2.4GHz spectrum was already polluted by microwave ovens (because microwave ovens operate at the resonance frequency of water molecules), so it was left for public use.
    - jwilk 5y ago
      That's a common misconception: https://www.wtamu.edu/~cbaird/sq/2014/10/15/why-are-the-microwaves-in-a-microwave-oven-tuned-to-water/ https://www.wtamu.edu/~cbaird/sq/2014/10/15/why-are-the-micr... > The microwaves in a microwave oven are not tuned to a resonant frequency of water. […] > They heat the food through simple dielectric heating. […] Many types of molecules in the food absorb energy from the microwaves in this way, and not just water molecules.
    - sandworm101 5y ago
      Almost. 2.4GHz had been set aside for consumer devices long before wifi. Microwaves are essentially very powerful unlicensed transmitters. Wifi devices are also all unlicensed transmitters. So 2.4GHz devices don't use the same space despite microwaves, they use it because that space had already been given over to unlicensed devices. If not for microwave ovens we might not have wifi as it is today. Back when people were gobbling up the spectrum, the military didn't care about 2.4GHz because of the water absorption issues. It wasn't good for communication at long distances and so it was allowed for consumer devices.
RF_Savage 5y ago
Huh, did not know that Adam 9A4QV had also that site in addition to the Microwave Croatia blog and the LNA4ALL product blog. Dude has done all kinds of cool stuff.
meatsauce 5y ago
My guess is that they had an inversion layer, tropospheric duct, or other enhancement condition. 43km is a long way on 0.02 watts.
- bprater 5y ago
  As a reference, folks that fly quadcopters, drones and flying wings often will transmit at 1 to 2 watts of power using line of sight. (Yes, at the edge of legal.) .02 watts is an insignificant amount of power for radio transmission.
  - spookthesunset 5y ago
    It’s not edge if legal if you are a licensed ham operator. Then could fly with more than a thousand watts! Of course you’d have a little problem with the battery :-)
  - bananasbandanas 5y ago
    Given a good control link such as ExpressLRS [0], people can also fly quadcopters 10+ kilometers on as little as 10 mW. See for example the range competition at [1]. Of course, the VTX is usually a different matter.. [0]https://www.expresslrs.org https://www.expresslrs.org [1]https://www.expresslrs.org/2.0/info/long-range/ https://www.expresslrs.org/2.0/info/long-range/
  - bri3d 5y ago
    I think it's much more fair to compare EIRP to EIRP, I don't know the gain of this crazy foil dish but it's probably pretty high. FPV is way harder since you can't use a highly directional transmit antenna and you're weight and size constrained, so you usually have dinky <3dB transmit gain and have to make up for it with big radio amplifiers.
- ryanmarsh 5y ago
  From the diagram in the article the entire fresnel zone was unoccluded.
alasr 5y ago
Approximate locations of the setup & measurement on the OpenStreetMap: https://www.openstreetmap.org/directions?engine=fossgis_osrm_car&route=44.983%2C14.145%3B45.327%2C14.441#map=11/45.1731/14.1930&layers=Y https://www.openstreetmap.org/directions?engine=fossgis_osrm...
aledalgrande 5y ago
To someone that understands this, I'm curious: is line of sight, especially this far, impacted by something like a bird flying in the middle?
- marcodiego 5y ago
  By line of sight, I think it means that it must be held in a tall enough mast not to be impacted by curvature of the earth. IIRC curvature of the earth limits line of sight to around 35km at 1.7m of height.
- Reventlov 5y ago
  This might interest you: https://en.wikipedia.org/wiki/Fresnel_zone https://en.wikipedia.org/wiki/Fresnel_zone
- topspin 5y ago
  Not unless the bird is very close to the antennas at either end. This is a neat exercise in antenna design. They've built high gain directional antennas and minimized transmission line losses. The 15 dBi antennas aren't even that remarkable; you can buy 30+ dBi wifi antennas. My first 'better than dial-up' internet connection was a 2.4 GHz wifi service across 7 miles. On my end was a roof mounted aluminum parabolic grid antenna. It worked rather well and sometimes I wish I still had it.
  - creeble 5y ago
    Mine too! Though mine was the other way ‘round: I had a frac T1 line (256kbps iirc) and shared it with two other locations via a central omni antenna. Breezecom radios that I think were frequency-hopping (pre-spread-spectrum).
- ajsnigrutin 5y ago
  Nope, not really. Very simplified, the signal is carried within a "fresnell zone", which s basically a 3d ellipse, that is relatively wide in the middle, and you'd have to cover a lot of that area, to block the signal... definitely more than a bird can do. https://en.wikipedia.org/wiki/Fresnel_zone#Clearance_calculation https://en.wikipedia.org/wiki/Fresnel_zone#Clearance_calcula... ...unless the bird is standing infront of the transmitter/receiver.. then yes.
0000011111 5y ago
You can hit the space stations repeater with a $40 boafeng radio. Line of site baby!
- beeskneecaps 5y ago
  Love my UV5R! I put a telescopic, 1 meter antenna on mine and was able to hit a repeater on Mount Diablo from the Twin Peaks in SF ~42 miles away! PSA: we need more HAMs out there! Check out https://hamstudy.org https://hamstudy.org and get your license https://hamstudy.org/sessions/remote https://hamstudy.org/sessions/remote
  - creeble 5y ago
    Let me add my favorite, https://hamexam.org https://hamexam.org
  - throwaway48375 5y ago
    What antenna?
    - genewitch 5y ago
      just get a legitimate nagoya and call it good, if you want 100% portable and "not likely to break if you sneeze while using it".
      - int_19h 5y ago
        And if you want something that's often just as good, but you don't have to worry about breaking it, get a Signal Stick: https://www.eham.net/reviews/view-product?id=13357 https://www.eham.net/reviews/view-product?id=13357
    - beeskneecaps 5y ago
      RH 660s. I was skeptical at first, but it has really held up. I get really good signal reports and people always say they're surprised when I'm using a UV5R. I did drill the microphone port open a little wider by the way and I think that helped get some more gain/clarity as well. Note that the RH 660s is 27 centimeters collapsed (11 inches), and 1 meter fully extended. It is rigid so not one of the floppy antennas. Collapsed it can take abuse, but when extended, bending is a risk.
jollybean 5y ago
Ukranians interested in this now.
stagger87 5y ago
The WIFI beacon he received is likely using the 1Mbps DSSS 802.11b PHY, which has 11dB of processing gain which also helps quite a bit here.
NovemberWhiskey 5y ago
As always with radio, it's mostly about unobstructed line of sight and the gain in your antenna system. We're still in communication with Voyager 1, which is operating on a grand total of about 20W of RF power; and is currently about 14.5 billion miles away.
- Sporktacular 5y ago
  It's also handy when you only need a low data rate and can make your channel bandwidth was wide as you like without worrying about licensing restrictions.
  - KennyBlanken 5y ago
    That's...not how that works. The FCC requires power be dropped to compensate for antenna gain. https://afar.net/tutorials/fcc-rules/ https://afar.net/tutorials/fcc-rules/
    - Sporktacular 5y ago
      For a space probe? I'm saying to get that performance NASA has some operating freedoms the rest of us don't.
    - Sporktacular 5y ago
      Besides, I didn't mention power level. Yes, effective radiated power is regulated.
- dr_orpheus 5y ago
  And gets up to a whopping 1.4 kbps downlink and 16 bps uplink! https://voyager.jpl.nasa.gov/mission/spacecraft/ https://voyager.jpl.nasa.gov/mission/spacecraft/
  - mshockwave 5y ago
    that is amazing for something 14.5 billion miles away
giantg2 5y ago
I wonder if you could boost output even farther using a colinear antenna in the reflector dish.
digitallyfree 5y ago
I wonder if optical communications (with lasers or similar technology) would be a better choice in this situation, given that there is line of sight. With WiFi you are mostly limited by the legal requirements regarding transmit power. See https://en.wikipedia.org/wiki/Free-space_optical_communication https://en.wikipedia.org/wiki/Free-space_optical_communicati....
- wmf 5y ago
  With eye-safe optical power, FSO is limited to very short range under 5 km.
- Sporktacular 5y ago
  Nope, they suck. Rain, pollution, low clouds, fog, thermals etc and it drops to nothing.
ape4 5y ago
Now LoRa seems like a better choice
subinsebastien 5y ago
I want this to be part of a Hollywood movie. The protagonist is using his makeshift wifi setup to hack into a bank computer systems 43Km away from his location, and the bank people has no idea what is going on.
- anaganisk 5y ago
  Why? Im not interested to answer why our router is not capable of that, and there is no such router in the market. But on a serious note, some enterprise networks are unsecured enough, that you could probably login to root of their server from anywhere in the world.
  - kayodelycaon 5y ago
    CW: TV Tropes... https://tvtropes.org/pmwiki/pmwiki.php/Main/RuleOfCool https://tvtropes.org/pmwiki/pmwiki.php/Main/RuleOfCool
- sgt 5y ago
  Unless the bank has a 43km perimeter with trenches and guard dogs, why doesn't he just move closer?
  - contingencies 5y ago
    Uhh, maybe a believable plotline like "Because the protagonist lives on a crumbling bridge with a military-trained dolphin encircled by cyborg psychopaths and Japanese megacorp military types while a highly infectious disease ravages remnant humanity and it's the end of the world?" https://www.imdb.com/title/tt0113481/ https://www.imdb.com/title/tt0113481/
    - ant6n 5y ago
      Well, obviously.
    - BLKNSLVR 5y ago
      Hah! I only just watched that again a couple of weeks ago. With every re-watch I'm reminded of how terrible that movie is, and with all the passing of time between re-watches my memory of it continues to improve it until it seems worthy of another re-watch, and then I'm disappointed again.
1970-01-01 5y ago
This reminds me of another old story I have bookmarked, but it's for a wireless keyboard: https://web.archive.org/web/20061205205844/http://www.aftenposten.no/english/local/article427668.ece https://web.archive.org/web/20061205205844/http://www.aftenp...
wanderer_ 5y ago
I loved looking at that laptop - a translucent chassis, crazy!
Sporktacular 5y ago
Without the bit rate there's not enough information to know if it's impressive or not. Define a low enough bit rate as a usable radio link and it can be 10 times that length with a 10th of the power level (Shannon-Hartley). Perhaps given the limitations of 802.11 it means something but in theory it's meh.
simonjgreen 5y ago
The software in use for LOS test looks like Radio Mobile which is a great piece of free software for radio work
deleted 5y ago
[deleted]
ppeetteerr 5y ago
Fun game: using only the map, try to guess the country

341 points by NotAWorkNick 5y ago

mrfusion 5y ago

What about the curvature of the earth?

ck2 5y ago
(after posting this I thought of "liquid/atmosphere only" planets and how they are round so obviously my initial thought process on this was wrong, I thought water followed the bottom of its curved-earth container while trying to remain level on top)
- orangepurple 5y ago
  This is nonsense. Do you believe that water forms a cliff at the edge of the beach so that its curvature tangent to the center of the body of water is zero? Hilarious
  - deleted 5y ago
    [deleted]
- aeastw 5y ago
  I'm fairly sure water follows the curvature of the earth...
- smilespray 5y ago
  Teach us more science facts, professor!
- blueprint 5y ago
  meniscus please
sushibowl 5y ago
OP chose a hill 250 meters above sea level, and also has an antenna about 5m high. According to a calculator I found[1] that puts the distance of the horizon at roughly 57km. So plenty of range to still be in LOS of the transmitter. [1] https://www.omnicalculator.com/physics/earth-curvature https://www.omnicalculator.com/physics/earth-curvature

NotAWorkNick 5y ago

An easier to find link that shows how to make the home-brewed antenna for those interested in trying it out for themselves https://flylib.com/books/en/2.434.1/hack_83_make_a_deep_dish_cylindrical_parabolic_reflector.html https://flylib.com/books/en/2.434.1/hack_83_make_a_deep_dish...

ge96 5y ago
Those propagation maps are cool, was learning about them 12 years ago for FPV
genewitch 5y ago
I seem to have a recollection that a cheap DIY system is to get two RCA 18" dishes (or larger) and remove the LNB from the dish (or whatever the horn part is called) and affix a "cantenna" or other waveguide to the arm, then, using the shortest, largest coax you can manage, connect the two cantenna/waveguides together, and aim them 180 degrees apart. I also seem to remember that putting this "halfway", even if halfway happened to be the highest point, wasn't ideal, it was something like 60/40 or 70/30. Now-a-days, mikrotik or ubnt make doodads you can replace the LNB with that instead provides some wifi band, with PoE, so two of those up on a tower means you have active repeating, and you can probably push that solution out a lot further than 43km. For the record, i put a USB wifi stick inside of a pirouette cookie can and it was a phenomenal "war driving" antenna. I use folded-dipole-fed yagi antennas now for doing wifi surveys, but in a pinch 802.11B 1000mW+ wifi cards are stacked up in a filing cabinet...
- Breza 5y ago
  War driving back in the 802.11.B days gives me fond memories. Though I never tried anything as cool as your cookie-tenna.

foobarbecue 5y ago

Very impressive! Please correct the error in the title -- it's "line of sight," not "line of site."

NotAWorkNick 5y ago
Done, thanks for the heads-up! (Also corrected it to read 'achieved' ;-)

PaulHoule 5y ago

Overall I've had very good luck with the RF performance of external WiFi sticks. All too often the antennas inside laptops and phones are really an afterthought so the WiFi and (particularly) Bluetooth performance is awful.

londons_explore 5y ago

And mine keeps cutting out if someone fat walks between my laptop and the router 6 feet away...

gunfighthacksaw 5y ago
Are you sure your friend is fat, and not just wearing a bulky faraday cage?
Nextgrid 5y ago
A lot of people don't realize that Wi-Fi pretty much always operates in an extremely degraded mode (on the verge of not working at all - which is why a person walking past can be enough to break it) and it only seems to work for certain applications due to the magic of protocols such as TCP which can recover and essentially conceal packet loss. Jumping onto a call or some other real-time application (where retransmissions don't help and actually make the problem worse) will break the illusion and show you the reality of things. There's also this misconception that speed is the only thing that matters, so "higher speed = better connection" and the vast majority of consumer-grade tools only ever test for this. This is where it will mislead you, as an unstable connection with short bursts of high speed will appear "better" (despite being fragile and completely unusable for anything real-time) than a slower but more reliable connection. In-browser speed tests are extremely bad for this because all the buffering & various layers could even fool the test code itself, making it believe it's getting a steady stream while in reality it's getting merely short bursts of data (in between tons of underlying TCP retransmissions). Iperf & ping are the tools of choice if you actually want to look into it - they are closer to the metal and will give you faster feedback (you will be able to actually see the dropouts due to packet loss).
- nearlyepic 5y ago
  Is there anything short of "get a better antenna" that helps address these issues? Recently had to switch to Wi-Fi for my desktop and have been frustrated with the inability to stop the connection from constantly being on the edge of not-working.

bjt2n3904 5y ago

But did they establish a link and transfer data? Broadcast packets with the SSID aren't too difficult to get. You only need to get one. Fun regardless, but I'm curious for more info.

jandrese 5y ago
I doubt it. The remote side was a generic AP with an omni antenna I think. The return traffic is going to be way down in the noise floor.

mcgeez 5y ago

This is an old article, dating back to at least 2005 as per Web Archive[0] please edit the title to reflect that. [0]https://web.archive.org/web/20050201000000*/https://www.qsl.net/9a4qv/WiFi_Ri.htm https://web.archive.org/web/20050201000000*/https://www.qsl....

ajross 5y ago
And the ideas are older still. The days of the Pringles Can Antenna were pretty wild. I'm not aware of any similar hacks at 5 GHz though.
- rolph 5y ago
  a 5GHz waveguide AKA "cantenna" is between beer can and bean/soup can https://en.wikipedia.org/wiki/Cantenna https://en.wikipedia.org/wiki/Cantenna width or diameter is a criticalproperty: https://www.everythingrf.com/tech-resources/waveguides-sizes https://www.everythingrf.com/tech-resources/waveguides-sizes https://web.archive.org/web/20161029045619/http://www.pwmn.net/wiki/index.php?title=How_to_make_5ghz_cantenna_-_feeder_for_sat-dish https://web.archive.org/web/20161029045619/http://www.pwmn.n... have fun, and dont cut yourself, they do work well when used at both ends of the line. https://web.archive.org/web/20071012133113/http://www.saunalahti.fi/elepal/antenna2.html https://web.archive.org/web/20071012133113/http://www.saunal...
dang 5y ago
Year added above. Thanks!

jll29 5y ago

I wonder how modern (2022) equipment might fare? Certainly the author picked a beautiful region to do that kind of outdoor experiment in.

OJFord 5y ago
> Certainly the author picked a beautiful region to do that kind of outdoor experiment in. I don't mean to be argumentative, but I wonder what the ugliest 43.33km line of sight environment one could find would be? I imagine it's quite a good proxy for beauty, the maximum distance you can see.
- bombcar 5y ago
  Ugliest would be point-to-point in a some run-down city.
  - drewzero1 5y ago
    There's an old dish antenna on the roof of my office that's pointed at a building we used to have in the 90s. I've wondered if I could get it to do anything cool, since my house is near the other building, but I don't think I could get an antenna high enough to get line of sight.
    - bombcar 5y ago
      I would not be surprised at all if half or more of the dishes you see on commercial buildings are just vestigial, waiting for a signal that will never come again.
      - drewzero1 5y ago
        I have seen so much obsolete equipment that was left in place after replacement, some of it even still plugged in and running but not connected to anything. My favorite was an SCO box that beeped every day when it attempted to dial out to another server, long since decommissioned, over a phone line that was disconnected years ago.

ng55QPSK 5y ago

actually, LoS over open water, is following physical laws. GSM (with a range limitation of 35km by timing) was very well recievable from ships.

bombcar 5y ago

He got the Wifi network to show up, but did he get a connection? A bit higher quality point-to-point can be obtained with a bit of specialized equipment, Mikrotik has a bunch: https://mikrotik.com/product/MTAD-5G-30D3-PA https://mikrotik.com/product/MTAD-5G-30D3-PA for example, can go 40+ km.

deleted 5y ago
[deleted]

chrissnell 5y ago

And why not? When I lived in Utah, I could easily hit a mountain-top ham radio repeater 20+ miles away with my little 5W handheld radio. A small weather balloon with a sub-1W transmitter can easily be heard at 100K feet altitude by people hundreds of miles away. So long as you have LoS, it's not problem.

dragontamer 5y ago
Water molecules block 2.4Ghz spectrum that WiFi uses. This is on purpose: the idea is to make the common WiFi (and Bluetooth) bands short range on purpose, so that many people within a city block can have local WiFi or local Bluetooth without interfering with each other. So 2.4GHz over a long distance kinda goes against the design of WiFi / Bluetooth.
- bonzini 5y ago
  The idea really was that 2.4GHz spectrum was already polluted by microwave ovens (because microwave ovens operate at the resonance frequency of water molecules), so it was left for public use.
  - jwilk 5y ago
    That's a common misconception: https://www.wtamu.edu/~cbaird/sq/2014/10/15/why-are-the-microwaves-in-a-microwave-oven-tuned-to-water/ https://www.wtamu.edu/~cbaird/sq/2014/10/15/why-are-the-micr... > The microwaves in a microwave oven are not tuned to a resonant frequency of water. […] > They heat the food through simple dielectric heating. […] Many types of molecules in the food absorb energy from the microwaves in this way, and not just water molecules.
  - sandworm101 5y ago
    Almost. 2.4GHz had been set aside for consumer devices long before wifi. Microwaves are essentially very powerful unlicensed transmitters. Wifi devices are also all unlicensed transmitters. So 2.4GHz devices don't use the same space despite microwaves, they use it because that space had already been given over to unlicensed devices. If not for microwave ovens we might not have wifi as it is today. Back when people were gobbling up the spectrum, the military didn't care about 2.4GHz because of the water absorption issues. It wasn't good for communication at long distances and so it was allowed for consumer devices.

RF_Savage 5y ago

Huh, did not know that Adam 9A4QV had also that site in addition to the Microwave Croatia blog and the LNA4ALL product blog. Dude has done all kinds of cool stuff.

meatsauce 5y ago

My guess is that they had an inversion layer, tropospheric duct, or other enhancement condition. 43km is a long way on 0.02 watts.

bprater 5y ago
As a reference, folks that fly quadcopters, drones and flying wings often will transmit at 1 to 2 watts of power using line of sight. (Yes, at the edge of legal.) .02 watts is an insignificant amount of power for radio transmission.
- spookthesunset 5y ago
  It’s not edge if legal if you are a licensed ham operator. Then could fly with more than a thousand watts! Of course you’d have a little problem with the battery :-)
- bananasbandanas 5y ago
  Given a good control link such as ExpressLRS [0], people can also fly quadcopters 10+ kilometers on as little as 10 mW. See for example the range competition at [1]. Of course, the VTX is usually a different matter.. [0]https://www.expresslrs.org https://www.expresslrs.org [1]https://www.expresslrs.org/2.0/info/long-range/ https://www.expresslrs.org/2.0/info/long-range/
- bri3d 5y ago
  I think it's much more fair to compare EIRP to EIRP, I don't know the gain of this crazy foil dish but it's probably pretty high. FPV is way harder since you can't use a highly directional transmit antenna and you're weight and size constrained, so you usually have dinky <3dB transmit gain and have to make up for it with big radio amplifiers.
ryanmarsh 5y ago
From the diagram in the article the entire fresnel zone was unoccluded.

alasr 5y ago

Approximate locations of the setup & measurement on the OpenStreetMap: https://www.openstreetmap.org/directions?engine=fossgis_osrm_car&route=44.983%2C14.145%3B45.327%2C14.441#map=11/45.1731/14.1930&layers=Y https://www.openstreetmap.org/directions?engine=fossgis_osrm...

aledalgrande 5y ago

To someone that understands this, I'm curious: is line of sight, especially this far, impacted by something like a bird flying in the middle?

marcodiego 5y ago
By line of sight, I think it means that it must be held in a tall enough mast not to be impacted by curvature of the earth. IIRC curvature of the earth limits line of sight to around 35km at 1.7m of height.
Reventlov 5y ago
This might interest you: https://en.wikipedia.org/wiki/Fresnel_zone https://en.wikipedia.org/wiki/Fresnel_zone
topspin 5y ago
Not unless the bird is very close to the antennas at either end. This is a neat exercise in antenna design. They've built high gain directional antennas and minimized transmission line losses. The 15 dBi antennas aren't even that remarkable; you can buy 30+ dBi wifi antennas. My first 'better than dial-up' internet connection was a 2.4 GHz wifi service across 7 miles. On my end was a roof mounted aluminum parabolic grid antenna. It worked rather well and sometimes I wish I still had it.
- creeble 5y ago
  Mine too! Though mine was the other way ‘round: I had a frac T1 line (256kbps iirc) and shared it with two other locations via a central omni antenna. Breezecom radios that I think were frequency-hopping (pre-spread-spectrum).
ajsnigrutin 5y ago
Nope, not really. Very simplified, the signal is carried within a "fresnell zone", which s basically a 3d ellipse, that is relatively wide in the middle, and you'd have to cover a lot of that area, to block the signal... definitely more than a bird can do. https://en.wikipedia.org/wiki/Fresnel_zone#Clearance_calculation https://en.wikipedia.org/wiki/Fresnel_zone#Clearance_calcula... ...unless the bird is standing infront of the transmitter/receiver.. then yes.

0000011111 5y ago

You can hit the space stations repeater with a $40 boafeng radio. Line of site baby!

beeskneecaps 5y ago
Love my UV5R! I put a telescopic, 1 meter antenna on mine and was able to hit a repeater on Mount Diablo from the Twin Peaks in SF ~42 miles away! PSA: we need more HAMs out there! Check out https://hamstudy.org https://hamstudy.org and get your license https://hamstudy.org/sessions/remote https://hamstudy.org/sessions/remote
- creeble 5y ago
  Let me add my favorite, https://hamexam.org https://hamexam.org
- throwaway48375 5y ago
  What antenna?
  - genewitch 5y ago
    just get a legitimate nagoya and call it good, if you want 100% portable and "not likely to break if you sneeze while using it".
    - int_19h 5y ago
      And if you want something that's often just as good, but you don't have to worry about breaking it, get a Signal Stick: https://www.eham.net/reviews/view-product?id=13357 https://www.eham.net/reviews/view-product?id=13357
  - beeskneecaps 5y ago
    RH 660s. I was skeptical at first, but it has really held up. I get really good signal reports and people always say they're surprised when I'm using a UV5R. I did drill the microphone port open a little wider by the way and I think that helped get some more gain/clarity as well. Note that the RH 660s is 27 centimeters collapsed (11 inches), and 1 meter fully extended. It is rigid so not one of the floppy antennas. Collapsed it can take abuse, but when extended, bending is a risk.

jollybean 5y ago

Ukranians interested in this now.

stagger87 5y ago

The WIFI beacon he received is likely using the 1Mbps DSSS 802.11b PHY, which has 11dB of processing gain which also helps quite a bit here.

NovemberWhiskey 5y ago

As always with radio, it's mostly about unobstructed line of sight and the gain in your antenna system. We're still in communication with Voyager 1, which is operating on a grand total of about 20W of RF power; and is currently about 14.5 billion miles away.

Sporktacular 5y ago
It's also handy when you only need a low data rate and can make your channel bandwidth was wide as you like without worrying about licensing restrictions.
- KennyBlanken 5y ago
  That's...not how that works. The FCC requires power be dropped to compensate for antenna gain. https://afar.net/tutorials/fcc-rules/ https://afar.net/tutorials/fcc-rules/
  - Sporktacular 5y ago
    For a space probe? I'm saying to get that performance NASA has some operating freedoms the rest of us don't.
  - Sporktacular 5y ago
    Besides, I didn't mention power level. Yes, effective radiated power is regulated.
dr_orpheus 5y ago
And gets up to a whopping 1.4 kbps downlink and 16 bps uplink! https://voyager.jpl.nasa.gov/mission/spacecraft/ https://voyager.jpl.nasa.gov/mission/spacecraft/
- mshockwave 5y ago
  that is amazing for something 14.5 billion miles away

giantg2 5y ago

I wonder if you could boost output even farther using a colinear antenna in the reflector dish.

digitallyfree 5y ago

I wonder if optical communications (with lasers or similar technology) would be a better choice in this situation, given that there is line of sight. With WiFi you are mostly limited by the legal requirements regarding transmit power. See https://en.wikipedia.org/wiki/Free-space_optical_communication https://en.wikipedia.org/wiki/Free-space_optical_communicati....

wmf 5y ago
With eye-safe optical power, FSO is limited to very short range under 5 km.
Sporktacular 5y ago
Nope, they suck. Rain, pollution, low clouds, fog, thermals etc and it drops to nothing.

ape4 5y ago

Now LoRa seems like a better choice

subinsebastien 5y ago

I want this to be part of a Hollywood movie. The protagonist is using his makeshift wifi setup to hack into a bank computer systems 43Km away from his location, and the bank people has no idea what is going on.

anaganisk 5y ago
Why? Im not interested to answer why our router is not capable of that, and there is no such router in the market. But on a serious note, some enterprise networks are unsecured enough, that you could probably login to root of their server from anywhere in the world.
- kayodelycaon 5y ago
  CW: TV Tropes... https://tvtropes.org/pmwiki/pmwiki.php/Main/RuleOfCool https://tvtropes.org/pmwiki/pmwiki.php/Main/RuleOfCool
sgt 5y ago
Unless the bank has a 43km perimeter with trenches and guard dogs, why doesn't he just move closer?
- contingencies 5y ago
  Uhh, maybe a believable plotline like "Because the protagonist lives on a crumbling bridge with a military-trained dolphin encircled by cyborg psychopaths and Japanese megacorp military types while a highly infectious disease ravages remnant humanity and it's the end of the world?" https://www.imdb.com/title/tt0113481/ https://www.imdb.com/title/tt0113481/
  - ant6n 5y ago
    Well, obviously.
  - BLKNSLVR 5y ago
    Hah! I only just watched that again a couple of weeks ago. With every re-watch I'm reminded of how terrible that movie is, and with all the passing of time between re-watches my memory of it continues to improve it until it seems worthy of another re-watch, and then I'm disappointed again.

1970-01-01 5y ago

This reminds me of another old story I have bookmarked, but it's for a wireless keyboard: https://web.archive.org/web/20061205205844/http://www.aftenposten.no/english/local/article427668.ece https://web.archive.org/web/20061205205844/http://www.aftenp...

wanderer_ 5y ago

I loved looking at that laptop - a translucent chassis, crazy!

Sporktacular 5y ago

Without the bit rate there's not enough information to know if it's impressive or not. Define a low enough bit rate as a usable radio link and it can be 10 times that length with a 10th of the power level (Shannon-Hartley). Perhaps given the limitations of 802.11 it means something but in theory it's meh.

simonjgreen 5y ago

The software in use for LOS test looks like Radio Mobile which is a great piece of free software for radio work

deleted 5y ago

[deleted]

ppeetteerr 5y ago

Fun game: using only the map, try to guess the country