I’ve learned more in 6 minutes watching your video than I’ve learned in the last 6 months. Thank you for explaining it in a way a knucklehead like myself can understand!
Excellent job explaining a complex subject, I was looking at that screen earlier and didn't have a clue what it was about. At least now I know what it is so I won't be afraid that I'm doing or not doing something critical. Thanks
thanks I was just taking real estate shots today and my signal was terrible.... I couldn't depend on my screen at all. I felt like I'm back to my first drone with the gopro mounted to the drone... I've also had similar problems 2days ago while I flew in downtown Chicago thats why I'm asking if I can change safely during the flight because I'm going to downtown now to test it... I've also relinked RC since I found out that may resolve my problem... Any advices? Is that true that DJIGo4 app requires 2ram memory on phone?? If so My iPhone6 has only 1gb.... I can upgrade my phone if that will solve the problem... Thanks for quick reply... I need to retake those Real Estate shots tomorrow or on Sat at the latest Cheers
thanks for the post. you mention the 5.8 has 'distance' limitations compared to the 2.4. Have you tested this and noted and compared the distance results?
Excellent Billy, but how do you make the signal to reach the central control in a live concert in order they can send your shooting to big LED screens? That is Lightbridge 2? Thanks a lot.
Great videos, Billy. One question. Why is there a lag between where your drone is, and what you see on screen? Is there a way to reduce the delay? I crashed my old Phantom 2 Vision Plus as I watched the screen, and looked up and it was in the trees, while the screen showed it still flying. I have a Mavic Pro now. There seems to be a slight lag.
+patmartel100 It's not going to be instant as the data needs to transmit from the drone back to the controller. With the being said, the lag is (at most times) not noticeable.
Very Informative. However, "range" is still a question regarding frequency choice. How much safe range should I expect in a clear environment at 5.6 GZ? If the picture breaks up a lot, what are other possible reasons such as loose/damaged cables, cell tower and other types of interference? Describing potential interference sources would assist in troubleshooting. Thanks again.
coll billy - thanks a lot - i am having some issues and was advised to try 5.8. was very confusing when i first looked but your video explains very well -
You also said it allows better communication between the phone or tablet and the Drone correct? I was under the impression again that when you connect the cable you can even shut the Wi-Fi off in your phone so how does the Wi-Fi have anything to do with connecting your phone to the mavic Pro Controller unless you're just flying with your phone? The cable is basically just an image signal transmission that's it. Am I missing something? A lot of times I'm out to lunch sorry LOL
Hey Billy really enjoy your explanations...clear. How can I capture the video information on controller when recording to my SD card.Would like to play back my video with all the flight data on the SD card.
Thank you Mr. Bill I think you helped me fix my jidder stop & go problem. PS my initials are the same as yours I used to use the same "Brand" BK in a circle. Thanks again, Bob
Billy I have a question! I just got my dji fpv and it’s telling me image transmission stopped. I did switch to digital mode could that be the problem my app won’t find my fpv
great video . I Have a problem with my Phantom 4 rthe screen is green can see shadows also when i put in a Sd Card it still says no Sd card is in the qoudcopter also cant move the camera up or down and no crash has been involed. Thanks a Thousand keep up the great work
Does the quality of your phone/tablet have any effect on the transmission of the video? My cheap 120 dollar tablet doesn't display the video when I fly, like if the signal was very weak. I was flying in an open area without any buildings around.
Hoping Billy or others can help clear something up for me. What, if anything, does the image transmission settings have to do with distance that the RC can control a Spark? Is it possible that a RC could still control the craft even if it is out of range to stream video? My theory was that there were two wifi connections to the Spark over both frequencies and that the RC would use whichever was not being used for the video stream to control the Spark. Does same apply if using the phone to control the Spark? Why would OTG allow folks to fly further as that only controls the connection between remote and app. Is that because if using local wifi to communicate between RC and device the other freq is used to control RC to Spark? Bottom line, how do OTG, and freq contribute to longer flight distance, if at all?
Billy, could this issue relate to my problem? Out of the blue, my phones and two tablets developed an 8 second delay between my control input to the mavic (instant) and the screen showing the movement. Mechanically everything seems fine. But I'm not seeing any inputs (gimbal or flight controls) for 8 seconds on any screen. All flights have been in my backyard. I had no problems flying in Europe most of the summer. Nor any problems before I left for vacation. But, first flights after coming home... and here I am asking for help! Any thoughts???
Hi Biily, do I understand correctly that we can use 2.4g or 5.8g to control the quad. (Mavic)? I use 5.8g for FPV video and was wondering what is used to transmit the video signal for the Mavic. (Will my 5.8g goggles receive the signal from the Mavic. I know just try it. lol) Thanks!
Thanks for the help, I'm a new spark owner and I have only seen my footage recorded on my phone. And I don't think it's as good as it should be. And I'm trying to figure out how to make it look like every other spark footage I've seen. Mine is a little grainy and I see a lot of the digital squares when light changes. Any help would be appreciated. Also I'm your newest sub!
I'm confused I was under the impression and you can see it on a DJI Pro Controller at the top right-hand corner it automatically switches back and forth between 2.4 G and 5.8 G to give you the best signal when you're flying so I don't know why you would switch this.. unless dji's technology is not good at switching back and forth?
Hey Billy, I have a Mavic 2 Zoom with the Crystalsky monitor, I fly about 3000 feet away and I loose my HD signal what should I look for as far as problems, if i bring the drone up to 350 feet it is a little better. The area I fly is well wooded. I never have had this issue before, I have flew up to two miles away last summer. Screen says i have lost signal. Any help would be great
perfect explain. I loved room explain. thank you for make me see why I can't fly my drone behind the buildings at 5.8 Ghz. it should be 2.4 ghz, as I get. right ?
Hello mate please reply I’m not seeing the 5.8 or 2.4 Goapp for phantom 4 I’m in the uk all I see is in HD IS AUTO CUSTOM WONT WORK if I change Region win the device and the customer that works there is no box for 2.4 or 5.8
Hi Billy!! Im new with this Phantom 4 pro...my problem is I dont have image coming out in my screen...I only used it one time...then I notice that no image coming out on my ipad..
+Kabal LV I've gotten to a distance of about 2000 feet before the image transmission got really choppy on 5.8 ghz. The only time that I switch to 2.4 ghz is if I'm in a remote location that isn't very busy, thus less interruption.
I've read recommendations of when to switch that match the detailed explanation that you provided. Essentially 5.8 is best for short range flights and urban environment. 2.4 is better for longer range flights and wilderness areas. I had forgotten this until you posted this video. Thank you! This is perhaps the one settings screen that receives the least bit of attention.
Hey Billy, nice video, can you cover in more depth about the bitrate (image quality)? I read in a forum that decreasing the bitrate will give you a longer range, is this true? Looking forward to seeing a video on that, thanks and subbed :)
Thanks, I have the problem that I'm not sure if it is related to frequency. I have a DJI Mavic Pro and when flying it the image in my phone look full of pixels and it is very slow... I've changed the cable but still I get the same problem, however the video in the sd card it looks fine.
Hi sir i have a dji spark drone, i have fly my drone with 2,3 different companies andriod mobile phones, when i select 5.8 channel, then show there your mobile has not 5.8 wifi band. Pls tell me which mobile has both wifi bands 2.4ghz and 5.8ghz. thx
Hi, my custom settings are greyed out in the image transmission settings. I can only select Auto 2.4 or 5.8 but not the channels... I have IOS Phantom 4 Pro. Do you know why?
Hello friend I want your help. On my DJ I Phantom 4 advanced there is a big problem . Video disturbance is my big problem. Whenever I fly my drone I can't see anything that what I am shooting there is lot of disturbance in my screen. Please help me. What should I do.
Just received my phantom 4 pro V2- all sorts of learning curves going on but mainly I am having trouble get compass calibration and outbofv10 goes I get it once but then I have lost my right joystick control for forwards backwards left and right ..I think I might have disabled it but I can’t get it working. Left joy stick works fine...help please
Any idea on how to fix the black screen problem ppl are getting on their phones with mine I can still take pic and videos with the mavic pro but my phone screen is black no pic of what the cam on the mavic is showing.
I get strong interference and I do not have any signal on 5.8 gh This is happening for 7 days without reason, it worked perfectly so far Please help ... I read that you can install a cfg file but i do not know which .. thank you My drona is phantom 4 pro
I second this request on discussing exposure lock. It's a camera feature that receives much less attention than resolution, white balance, fps, iso, and shutter speed. Also, perhaps a video on color options that are updated to the current DJI GO 4 app.
On my app there is no "frequency" option or "channel mode" option at the "HD" page, cant do nothing to get more range? (weak signal at 800m on open area) Edit: Using Phantom 4 pro and sony xz1
Hi I've got a dji phantom 3 4k and I have weak video signal on mine I can't change the to custom on mine it keeps going back to auto how do you stop it going back to auto by it self?
This is a good vid but I can't find that option on my dji mavic pro with a iPhone 6s?? My problem is if I go further thn 300-400 m the camera signal starts to weaken with jutters and then can goes black but I can still see the map and use that to control it back into signal, why is this happening?🤔
Hello am using inspire 1 with two remotes for live production for tv broadcasting, master remote I use to fly the aircraft and everything, the slave remote I connect the hdmi out put to the video mixer (tricaster) and everything goes well. today I faced one problem, hdmi couldn't give the signal output. I tried to connect with master controller also it didn't give me the output signal, I changed the cables and recheck them to other devices cables are OK am stuck how can you help me
and I have a really big question that no one can seem to answer for some reason when I put my SD card in my Phantom it's still recordes only to my phone and doesn't record it on the SD card is there a problem with my Phantom should I take it back and get a new one I don't know if anyone else has had this problem thanks in advance for any help
I have a P4P and I cannot change my frequency. why ? it's locked in on 2.4 and not clickable even if I switch it to manual/custom channels. any ideas why ???
![Gunna - HIM ALL ALONG [Official Visualizer]](http://i.ytimg.com/vi/HiCxoDeo0hc/mqdefault.jpg)
Great stuff. Really enjoying your content.
+snlexa Thank you!
I’ve learned more in 6 minutes watching your video than I’ve learned in the last 6 months. Thank you for explaining it in a way a knucklehead like myself can understand!
Thank You For Explaining This In Plain English! Very Helpful!
Best explanation for 2.4 and 5.8 ghz I've ever heard or read in a few words. Congrats!
Gday Billy. Always struggled with this feature but you have done a good job of enlightening this old brain. Thanks Billy. Cheers. 🇦🇺
As usual you deliver the message clear and and well understood. I am a dedicated follower
Thanks for the informative video!! I like how you get straight to the point and don't blab on about unnecessary dribble!!
Great Info as always Billy, after watching this I've just downloaded a spectrum analyser app
+jedburgh01 Thanks, glad to help!
Excellent job explaining a complex subject, I was looking at that screen earlier and didn't have a clue what it was about. At least now I know what it is so I won't be afraid that I'm doing or not doing something critical. Thanks
Can you change frequency during the flight or that will cost loosing signal with the drone?
Yeah you can change
thanks I was just taking real estate shots today and my signal was terrible.... I couldn't depend on my screen at all. I felt like I'm back to my first drone with the gopro mounted to the drone... I've also had similar problems 2days ago while I flew in downtown Chicago thats why I'm asking if I can change safely during the flight because I'm going to downtown now to test it... I've also relinked RC since I found out that may resolve my problem... Any advices? Is that true that DJIGo4 app requires 2ram memory on phone?? If so My iPhone6 has only 1gb.... I can upgrade my phone if that will solve the problem... Thanks for quick reply... I need to retake those Real Estate shots tomorrow or on Sat at the latest
Cheers
That explains it perfectly, I incorrectly assumed 5.8 would get me more distance. Keep up the great work.
+David Boorman Will do, thanks David!
Billy, one of your best videos. Very informative, explained perfectly and very easy to follow.
👍🏽✌🏻
thanks for the post. you mention the 5.8 has 'distance' limitations compared to the 2.4. Have you tested this and noted and compared the distance results?
Excellent Billy, but how do you make the signal to reach the central control in a live concert in order they can send your shooting to big LED screens? That is Lightbridge 2? Thanks a lot.
Great videos, Billy. One question. Why is there a lag between where your drone is, and what you see on screen? Is there a way to reduce the delay? I crashed my old Phantom 2 Vision Plus as I watched the screen, and looked up and it was in the trees, while the screen showed it still flying. I have a Mavic Pro now. There seems to be a slight lag.
+patmartel100 It's not going to be instant as the data needs to transmit from the drone back to the controller. With the being said, the lag is (at most times) not noticeable.
Thanks !
Very Informative. However, "range" is still a question regarding frequency choice. How much safe range should I expect in a clear environment at 5.6 GZ? If the picture breaks up a lot, what are other possible reasons such as loose/damaged cables, cell tower and other types of interference? Describing potential interference sources would assist in troubleshooting. Thanks again.
Hi Billy so, which is better 2.4ghz or 5.8ghz for DJI phantom 4?
This is an informative and a must video for every dji flyer, its year 2020 and still Phantoms are still flying out there 😊👍👍👍🚀🚀🚀
Thank you!!!
@@billykyle you're welcome 😊
coll billy - thanks a lot - i am having some issues and was advised to try 5.8. was very confusing when i first looked but your video explains very well -
You also said it allows better communication between the phone or tablet and the Drone correct?
I was under the impression again that when you connect the cable you can even shut the Wi-Fi off in your phone so how does the Wi-Fi have anything to do with connecting your phone to the mavic Pro Controller unless you're just flying with your phone?
The cable is basically just an image signal transmission that's it.
Am I missing something?
A lot of times I'm out to lunch sorry LOL
Hey Billy really enjoy your explanations...clear. How can I capture the video information on controller when recording to my SD card.Would like to play back my video with all the flight data on the SD card.
Thank you Mr. Bill I think you helped me fix my jidder stop & go problem. PS my initials are the same as yours I used to use the same "Brand" BK in a circle. Thanks again, Bob
Nice investigation job!
thanks for your time
+Jose A. Rubio No problem Jose!
Aloha Billy, so which do you use normally? 2.4 or 5.8? Or do you switch them depending on if in an urban environment or open area?
Billy I have a question! I just got my dji fpv and it’s telling me image transmission stopped. I did switch to digital mode could that be the problem my app won’t find my fpv
great video . I Have a problem with my Phantom 4 rthe screen is green can see shadows also when i put in a Sd Card it still says no Sd card is in the qoudcopter also cant move the camera up or down and no crash has been involed. Thanks a Thousand keep up the great work
Does the quality of your phone/tablet have any effect on the transmission of the video? My cheap 120 dollar tablet doesn't display the video when I fly, like if the signal was very weak. I was flying in an open area without any buildings around.
Hoping Billy or others can help clear something up for me. What, if anything, does the image transmission settings have to do with distance that the RC can control a Spark? Is it possible that a RC could still control the craft even if it is out of range to stream video? My theory was that there were two wifi connections to the Spark over both frequencies and that the RC would use whichever was not being used for the video stream to control the Spark. Does same apply if using the phone to control the Spark? Why would OTG allow folks to fly further as that only controls the connection between remote and app. Is that because if using local wifi to communicate between RC and device the other freq is used to control RC to Spark? Bottom line, how do OTG, and freq contribute to longer flight distance, if at all?
Billy, could this issue relate to my problem?
Out of the blue, my phones and two tablets developed an 8 second delay between my control input to the mavic (instant) and the screen showing the movement. Mechanically everything seems fine. But I'm not seeing any inputs (gimbal or flight controls) for 8 seconds on any screen. All flights have been in my backyard. I had no problems flying in Europe most of the summer. Nor any problems before I left for vacation. But, first flights after coming home... and here I am asking for help!
Any thoughts???
does the Mavic Pro and Phantom 3 Professional have these transmission options you are talking about?
Hi Biily, do I understand correctly that we can use 2.4g or 5.8g to control the quad. (Mavic)? I use 5.8g for FPV video and was wondering what is used to transmit the video signal for the Mavic. (Will my 5.8g goggles receive the signal from the Mavic. I know just try it. lol) Thanks!
Excellent video. Thanks for sharing all the knowledge you learned! I don't remember seeing an auto option on the Spark. Great job.
Could you preface by indicating App version and OS? My menus are different. Thanks, cool info.
+Steve McGavren Will do Steve. Sorry about that.
Billy, are there also image transmission quality setting for the P4P? As in HD, Regular, etc? ...or is that only on the Mavic?
Thanks for the help, I'm a new spark owner and I have only seen my footage recorded on my phone. And I don't think it's as good as it should be. And I'm trying to figure out how to make it look like every other spark footage I've seen. Mine is a little grainy and I see a lot of the digital squares when light changes. Any help would be appreciated. Also I'm your newest sub!
What frequency should I use to fly over my city? I am currently using 2.4 and I lose signal at 2000 feet out and 300 feet high . Any suggestions?
I'm confused I was under the impression and you can see it on a DJI Pro Controller at the top right-hand corner it automatically switches back and forth between 2.4 G and 5.8 G to give you the best signal when you're flying so I don't know why you would switch this.. unless dji's technology is not good at switching back and forth?
This vid is still and will continue to help noobs like me! Mahalo from Hawai’i
Hey Billy, I have a Mavic 2 Zoom with the Crystalsky monitor, I fly about 3000 feet away and I loose my HD signal what should I look for as far as problems, if i bring the drone up to 350 feet it is a little better. The area I fly is well wooded. I never have had this issue before, I have flew up to two miles away last summer. Screen says i have lost signal. Any help would be great
Great explanation Billy. Even a dummy like me now understands the differences.
This is what I was looking for. Thanks!
thanks for the video. does this work on P3P?
perfect explain. I loved room explain. thank you for make me see why I can't fly my drone behind the buildings at 5.8 Ghz. it should be 2.4 ghz, as I get. right ?
Billy, you are a great teacher!
great video! really help a lot. i hope maybe you can made a video on how to fly in nite time and some tips
+sicong liu Good idea! Thanks!
As always very informative information, Billy. Thank you for that in-depth transmission settings good to know!
No problem!
Very useful and appreciated information. Thank you Billy.
No problem John
do you recommend doing the extra channel hack??
Hello mate please reply I’m not seeing the 5.8 or 2.4 Goapp for phantom 4 I’m in the uk all I see is in HD IS AUTO CUSTOM WONT WORK if I change Region win the device and the customer that works there is no box for 2.4 or 5.8
What version of DJI GO 4 was this video done on? On Ver 4.1.5 there does not seem to be an option to pick 5.8G.
Hi Billy!! Im new with this Phantom 4 pro...my problem is I dont have image coming out in my screen...I only used it one time...then I notice that no image coming out on my ipad..
Very useful information, thanks!
So, do you ever switch between 5.8 or 2.4 Ghz ? And how far can you fly outside with 5.8 without losing feed ?
+Kabal LV I've gotten to a distance of about 2000 feet before the image transmission got really choppy on 5.8 ghz. The only time that I switch to 2.4 ghz is if I'm in a remote location that isn't very busy, thus less interruption.
I've read recommendations of when to switch that match the detailed explanation that you provided. Essentially 5.8 is best for short range flights and urban environment. 2.4 is better for longer range flights and wilderness areas. I had forgotten this until you posted this video. Thank you! This is perhaps the one settings screen that receives the least bit of attention.
+Brady Schickinger Thanks Brady! Glad to help
The transmission quality option what should it be set on is 10 better than 4 for quality?
Hey Billy, nice video, can you cover in more depth about the bitrate (image quality)? I read in a forum that decreasing the bitrate will give you a longer range, is this true? Looking forward to seeing a video on that, thanks and subbed :)
Thanks for that vid ...so clear and easy to comprehend ....DJI should employ you and pay you lots of money 🙂
Thanks, I have the problem that I'm not sure if it is related to frequency. I have a DJI Mavic Pro and when flying it the image in my phone look full of pixels and it is very slow... I've changed the cable but still I get the same problem, however the video in the sd card it looks fine.
Excellent explanation my brother
Great video ty, but l do not get the transmission quality option you show in your video
me 2
Good evening, I have a phantom 4 pro, when I turn it off after 10 meters it lags and loses the image while I have a full signal
thanks bro ! short and sweet !
dude, I don`t have HD option om my DJI app! I have phantom 3 standard - aren`t that included?
This helped me no end ,thank you. Liked and subscribed.
Hi sir i have a dji spark drone, i have fly my drone with 2,3 different companies andriod mobile phones, when i select 5.8 channel, then show there your mobile has not 5.8 wifi band. Pls tell me which mobile has both wifi bands 2.4ghz and 5.8ghz. thx
Hi, my custom settings are greyed out in the image transmission settings. I can only select Auto 2.4 or 5.8 but not the channels... I have IOS Phantom 4 Pro. Do you know why?
Take it off the Auto setting I would guess
Deezu
Hello friend I want your help. On my DJ I Phantom 4 advanced there is a big problem . Video disturbance is my big problem. Whenever I fly my drone I can't see anything that what I am shooting there is lot of disturbance in my screen. Please help me. What should I do.
Thanks Billy! Nice breakdown of info.
In Finland it doesn't give the image transmission settings because of the European CE version and limited legal frequencies
Just received my phantom 4 pro V2- all sorts of learning curves going on but mainly I am having trouble get compass calibration and outbofv10 goes I get it once but then I have lost my right joystick control for forwards backwards left and right ..I think I might have disabled it but I can’t get it working. Left joy stick works fine...help please
Any idea on how to fix the black screen problem ppl are getting on their phones with mine I can still take pic and videos with the mavic pro but my phone screen is black no pic of what the cam on the mavic is showing.
so if I set the 2.4 that I should be able to get out farther with my drone?
Thank you for a very insightful video!
How did you record the app screen?
I get strong
interference and I do not have any signal on 5.8 gh This is happening
for 7 days without reason, it worked perfectly so far
Please help ... I read that you can install a cfg file but i do not know which ..
thank you
My drona is phantom 4 pro
great vid! would dig to see one on exposure locks and modes & diferences in android vs iphone settings
+Luke Roman Good ideas, thanks!
I second this request on discussing exposure lock. It's a camera feature that receives much less attention than resolution, white balance, fps, iso, and shutter speed. Also, perhaps a video on color options that are updated to the current DJI GO 4 app.
On my app there is no "frequency" option or "channel mode" option at the "HD" page, cant do nothing to get more range? (weak signal at 800m on open area)
Edit: Using Phantom 4 pro and sony xz1
Vilkka same with mines, there no option for that
Hi I've got a dji phantom 3 4k and I have weak video signal on mine I can't change the to custom on mine it keeps going back to auto how do you stop it going back to auto by it self?
Great job discussing this !
Excellent tips and explanations. Tks.
+Doug Kinney Thanks Doug
how i stop the glitches in my video my spark recording good but when I play back the video it's choppy and glitched up
Video lag in display in my drone but recording is good and no work frequency option how to solve my problem please tell
Nicely done. That was very informative.
+bakhteria Thanks! Glad to help out
This is a good vid but I can't find that option on my dji mavic pro with a iPhone 6s?? My problem is if I go further thn 300-400 m the camera signal starts to weaken with jutters and then can goes black but I can still see the map and use that to control it back into signal, why is this happening?🤔
thank you for your clear, accessable information.
+Andrew kift No problem Andrew!
Thank you for nice explaine.
Very usefull for me.
I had problem to image transmisson.
Hi why has dji taken the 5.8 ghz off the phantom 4pro plus it's just a black icon now
Hello am using inspire 1 with two remotes for live production for tv broadcasting, master remote I use to fly the aircraft and everything, the slave remote I connect the hdmi out put to the video mixer (tricaster) and everything goes well. today I faced one problem, hdmi couldn't give the signal output. I tried to connect with master controller also it didn't give me the output signal, I changed the cables and recheck them to other devices cables are OK am stuck how can you help me
thank you for the informative video
Fantastic is the norm comment from me Billy, and it once again stinks, thank you!
As always great job
+Wes case Thank you Wes
Thanks for the video 🙂
how are you showing the on screen images in your video?
Nice explanation,thanks 👍👍
Brilliant video thank you
+Cider Talbot Too You're welcome!
I am enlightened. Thank you!
great video again man!!
+Speedy2246 Thanks!
and I have a really big question that no one can seem to answer for some reason when I put my SD card in my Phantom it's still recordes only to my phone and doesn't record it on the SD card is there a problem with my Phantom should I take it back and get a new one I don't know if anyone else has had this problem thanks in advance for any help
I have a P4P and I cannot change my frequency. why ? it's locked in on 2.4 and not clickable even if I switch it to manual/custom channels. any ideas why ???
very well explained thanks
Billy I don't get the same screen as you do I'm running iOS what are you running? Why is my choices different?
+Andrew Karahalios Are you using the DJI Go 4 app?
Billy Kyle yes
+Andrew Karahalios Are you on the most recent version?
Billy Kyle yes 4.0
same running latest app version but mavic pro and android. gives a wierd graph and freq range but no channel selection