Julian Ilett hey! I love your channel too :)

Let me know when they set up a laser communication link across the Pacific ocean, or Atlantic ocean etc :) www.newscientist.com/article/dn8540-longest-laser-link-bridges-the-gulf-of-space/ But I think they're still trying to figure out where the sun goes at night first - gotta walk before you try to run!

I am sorry, but you are not allowed to ask sensible questions and expect sensible replies from Flatheads. Just try replying to any of their videos. It is fun but can be frustrating. Laser communication across the Pacific is, of course, impossible because of atmospheric conditions. As to where the Sun goes at night, well, it goes out of sight due to perspective, of course. Just don't expect an explanation of what that means or why it disappears from the bottom up. I urge you to join in the sport of Flathead baiting by commenting on Flat Earth videos.

I did that once or twice but I find it far more frustrating than fun. Any point you make that proves them wrong is simply dismissed outright - no logic or sensible reasoning whatsoever.

Haha! :D I wonder how they even get things up in the air, their entire universe upside down

Laser communication across the atlantic is certainly possible. Its an interesting math puzzle. The Earth's radius is 3959 miles and the shortest circumferential jump across the atlantic is from Brazil to Africa at a distance of 1600 miles. The math puzzle is to figure out how tall the radio towers would have to be on each end - assuming a perfect sphere. I suspect that they would have to be pretty tall or use hot air balloons or something similar. A typical TV station around here with a 1500 foot tower only has a range of about 100 miles to a ground based receiver.

I used a beeper in one of my previous tests (~5km) where I was able to drive down a perfectly straight section of road in the beam, I mounted the antenna on the roof of the car and it was pointing the right way the whole time. But this time I needed to carefully point it by hand, I don't think having that same beeper while driving would have helped much, and every time I stopped I would have to dismount and mount it again to aim by hand. I'm not sure what you mean by "maximum point of the lobe tuned to a fixed distance" how is that done? You mean you can make it so that the signal is stronger at say 15km than at 10km? With a yagi?

Sorry I don't talk english but I will try to explain the better I can. At the main lobe you have the maximum energy (emitted [tx] and gained [rx]). In long distances you barely "touch" the tip of both lobes. When you perfectly face two antennas (touching both lobes) you have the maximum possible energy transferred. In free air (with ground under your feet :) you can barely note differences of two slightly misaligned antennas but when you have lake/sea in between there are lots of reflections in the water (in phase and anti-phase) that interfere and attenuates the energy that you have of this two barely touching lobes. For me is not a good idea make this kind of extreme test with water in between. Reflections occurs is normal and is not a good thing, as you noted at the side of that metal structure (gates?) Also you can gain some energy separating the tx antenna from that tree. The dipole of the yagi was so near of that grounded tree :) that was absorbing the radiated energy, and the reflector (the last element) probably wasn't doing his thing. Little details are crucial in this kind of test and every fraction of dB counts because in the analog world (ham radio i.e.) you probably can copy an attenuated message in the middle of the noise but as you are reading digital messages the receiver probably is "seeing" the tx but discarding messages that can't deal with (for that reason some tests are based on the Received Signal Strength Indicator RSSI) Is too long, I know, sorry for that, I like your stuff and I hope this helps.

The requirement for a 100% clear line of sight for a laser makes it not very practical, compared to radio waves that can penetrate objects.

He is not using standard antennas. And the range from these modules with pcb antenna an without power amplifier is almost the same was standard home wifi, so around 20 meters

That would be cool

The program really should use timer 1 to set frequency to 1 hz and do that way. Interrupts for every second.

These modules only go to 100mW as far as I know, all the extra 'work' is done by the antenna.

I was thinking the same propagation issue. Circularly polarized antennas at both ends should help reject reflected signals, cleaning up reception.

Soo true. Hope more people like this existed.

The ones I bought had connectors that just screwed together, nothing special, just regular SMA connectors.

@@iforce2d Ah oh...I was watching some youtube videos on using a VNA to "tune" antennas and compensate for connector impedance etc. etc. I thought you had made those Yagi antennas and I was looking for details. Love watching your content, Thanks much !

Yeah I tried LoRa last year in preparation for the balloon project, for exactly the reasons you mention. I must have had a set of crappy antennas because I was struggling to get much signal past 1500 meters (with transmitter airborne at 100m or so). ukposts.info/have/v-deo/rIWXZ35vfqyCq4k.html

Yeah it seems to have just two of those at the top, and then two dishes lower down the pole as well.

@@iforce2d the cellphone tower looking antenna up there are each 60 degree antenna and the dish ones are directional antenna to point at another dish antenna on a property that subscribes to the internet service, one of the main ones using this setup nowadays is StrataNet internet provider

Regulations? 2.4GHz is only freedom we have left. This should be your last concern. We are allowed to comunicate at 2.4-2.5GHz at 100mW, just tiny part out of all GHz of band used by tv, gsm, and military, governments so on.. they use hundreds of watts.. And GSM, 3G, LTE node is 30-60W and your most concern is "Did you meet regulations dude". Yes he meet.

You mean the little OLED screen? goo.gl/N7bZdP

See the description for the caps I'm using.

It's actually the default setting, bit I recommend writing that for nice clear code

I think so too...

In a quiet rural area you might get that range with the normal antennas, but if not then you could try a yagi like the ones I used in this video.

Sounds like a bad connection somewhere in the antenna.

@@iforce2d thank you.. you are right..the antenna have problem..

I would say almost impossible unless you have some extremely good antennas and a very high location at both ends. At 100m above sea level the horizon is only 36km away. en.wikipedia.org/wiki/Horizon#Distance_to_the_horizon

@@iforce2d I have Yagi antenas and I want to attach one of the my nrf24l01+pa+la module to the high altitude balloon. Is 100 km possible in this case?

That sounds more possible, but still difficult. On my balloon I had some signal at 35km using a yagi on the ground and a normal dipole on the balloon. Of course you would not put a yagi on the balloon though. Still I think 100km might be expecting a bit much. For the kind of range you are talking about, some other (lower) frequency would be more suitable.

@@iforce2d like Lora modules? Or CC12x modules by the Texas Instruments?

@@emmetray9703 something in the 433mhz range (license free) or less (lower ISM bands)

no, why would I do that.... ukposts.info/slow/PLzidsatoEzeieT03YQ6-LpO0bR1yfEZpx The yagi is for shaping the radio signal into a narrow beam - you sacrifice omni-directional capability for long range. So as such you can use them for whatever you use radio waves for, so yes both flight control and fpv

That playlist is the cheap ass build, not the larger Quadcopter that you wrote code for using an Arduino sketch, 'follow', rth, orbit etc. I want to go long range with powered gliders etc. Would a yagi give me increased distance say, even just using a stock 5.8Gh module? Flight control alone?

search for "iforce2d follow me" in either google or youtube, I'm sure you can find it. Yes, a yagi will help with range either on the receiver or transmitter. Just remember that it narrows the beam a lot so you can't just fly wherever you like.

is a patch antennae wider? In beam.

Yes, in general a patch will be wider. Depends on how many elements the yagi has though. Watch these: ukposts.info/have/v-deo/pZRoe6CIiGiKomQ.html ukposts.info/have/v-deo/eqhom4OMrmd-qKs.html

If we assume the 100% value is 545 packets per second, an estimate of packets lost would be 545 minus the PPS reading.

It depends what's in the way

Link to sketches is in the description. I got all my info from here: arduino-info.wikispaces.com/Nrf24L01-2.4GHz-HowTo Check my other videos for dozens more about these transceivers.

not sure what you mean by a scientific article.... how about if I made a video and uploaded to UKposts ? :)

The back of a turtle is round

I got 35km with a yagi on just one end: ukposts.info/have/v-deo/p2F7amqlmHt2qY0.html

Not with the current gas prices, nope :)

@@iforce2d if they petrol prices come down would you make an atempt again, I'm trying to find a spot to try it myself but time is not on my side with work

tbh it's pretty unlikely. I mean if you really want to communicate long distance there are plenty of better options than this. fwiw on my high-altitude balloon I got some signal at 35km with a yagi on the ground and a normal dipole on the balloon, that's the actual furthest I've used these.

@@iforce2d fair enough and 35kms is nothing to sneeze at

Ping typically refers to the time taken for a message to be received and returned, over a network with many hops through different servers. This is a one-way connection so there is no reply, and with nothing in between the time is essentially instantaneous. There is still a little time taken for the microcontroller to fetch the data from the radio module though, so I would estimate maybe 1ms if that part was programmed well. These radios are not suited to internet style connections if that's what you're thinking, but the response time is certainly fast enough to control something like a fast racing drone in real time.

Thanks

Hey @@iforce2d perhaps nerfnet can change your mind about internet connections, please have a look at it

I checked my devices with a regular compass before leaving home, they work well enough. At 30km the beam would be wide enough that it's easy to be inside it. I don't see how a tripod would be much better than a tree really? What's to say it doesn't move, because it's stuck on there really well, that's what :)

Ok, but as you can admit from the experience when using the devices. If you look it up you will find that these mobile devices compass have a 0.5 degrees. So calibrating them would likely include a level of discrepancy. Would still be a good idea to get a good resolution map of the terrain and plot accurately on a map where you plant the antenna. It is an interesting project, such a compact device and the range possible would be a good development for people with huge farms and need a form of data line for internet link to home, as long as theirs line of site, theres scope to possibly develop a multi channel type of link with relay capability. The idea of that could give an opening to a way of controlling a drone over a big area and relaying images. Theres plenty of scope to develop the application. Out of interest what is the power output of the transmission and is the frequency fixed I have seen the video of the drone controlled by an arduino which I thought was pretty damned cool trick. Have you tried different antenna types with this transmitter? say a pole type transmit and directional as pickup and directional transmit. Quality of the signal may be an issue and how does that affect the transmit receive range. Is there any way of developing the transmitter to also have a receive cycle like send out x bits then listen for a return signal and then dump what it received and the transmit end sends the data and also records what it received and sent then compare the records. Have you thought of adding an audio signal to indicate a signal pulse, sort of a metal detector for radio signals. As this is the first video that youtube has offered up as something I might like, its a nice video and I can appreciate why my dad spent 5 years out there working and I wish I'd come over.

Whats to say that it didn't, wind, duct tape... may stick well but theres going to be flexing in both the tree and the tape where as a tripod can be anchored to the ground, set level and steady like an antenna should be to minimise movement. Also, signals can be blown off course, a moderately strong wind can affect any type of broadcast, it is especially noticeable (well here it is) when theirs a lot of wind and the picture shows some signal drift because the image quality falls off. Then you have that curvature of the earth, so a tripod with a level to set the beam angle much more accurately is going to improve the reception on the other end. Its late, I'm tired and my math may be wrong but I think that you are talking about a margin of error in the order of 130 meters over 30km with a 0.25 degree margin of error which could account for why you got a signal where you didn't expect and where you expected one you got nothing. All you have to do is calculate the length of the arc of a 30km circle at 0.5 degrees to give you a ball park figure of how far off your line of sight could be which is why to be accurate at the sending end is important and it wouldn't hurt to carry your compass to verify you are on the right path ;)

... and then you have a narrow beam you transmit and also collect with a narrow beam. Have you considered making a dual antenna that is of a pole type and the other a directional type and have the unit switch between the two antenna output so you can test two (or more) types of antenna.

yeah, for a yagi you dont have to be this precise (the yagi typically have a 30deg wide beam) only if you are using a dish and with higher frequencies in the X, K and Ku bands some yagi antennas have reflectors on the back or/and 2 other anetenna pointing skyward and ground-ward to nullify the waves sent useless above and below the horizon, to have higher gain on the horizontal, but their beam width is still around 20-30deg

thats the gnome calculator, also commonly used with XFCE...

Is that an order?

Polarization isn't needed for digital signals, only for analog ones.

Several real life tests I've done confirms the exact opposite what you state :)

hm, maybe you are right. But the benefits are not always that great. It depends on to much different variables (like he experience in the Video). RF is a science for it self. I can understand why CP antennas are used for Satellite communication (different air layers and therefore extreme multipathing which interrupts high bandwith applications). But for simple longrange things like this to send some simple packages, a linear one should be good enough

I can only state what i have measured in my backyard with all the apple and other fruit trees around there, wanted to use ground-to-ground radios. On all 433,868mhz and 2.4ghz CP gave extremely good results compared to mono,dipole and other NP antennas. Especially on 433, the range in that environment was a few 10meters, using a CP 3 cloverleaf was over 800meters without packetloss using 1/10 power (10mW) compared to simple monopole (where i used 100mW). Incredibly good, downside at 433 is the huge pizza box sized antenna...

Careful, there maybe flatties watching this cuz it was rather nicely flat land with only a few hills, wasn't it? LOL

Also 24 meters for standard modules with pcb antennas