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Handy little antenna mod using IPEX 8dBi Antennas

ph2t

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Hey there crazy modders. I have found these antennas a cool and easy mod that improves reception and video.

They are antennas mounted on a pcb and they come with double sided tape to make mounting easy.

I’ve used these on my carbon fiber mod with a fair amount of success. I’m not sure on the radiating pattern of these antennas but more tests will occur soon.

I came across these antennas when Raul was talking about the ESP wifi chips in another thread.

7B789523-0F2B-4B4F-B3F4-4D60A3EBA36C.jpeg
3717AC6D-BE2A-42F0-B8F4-CE62B60858B2.jpeg

You can use my pcb and antenna reference thread to see where to solder them to the pcb.

Here is a pic of them mounted on my cf frame.

1012891F-6F80-45BD-B240-861D5ADDCBB2.jpeg

I think given that they are built for 2.4ghz and come with backing stickers and fit along the legs of the tello they make an easy to do mod.

Cheers,

Ph2t.
 

Flydrone

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Really very interesting this your "New" Tello!(y)
 

Guorium

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Wow sick mod. I hope you found a way to fix the front camera? Also, the new air frame looks neat, how much is the weight now?
 
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Stele

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I´m not sure if they will perform good. Usually high gain comes at the cost of coverage. As you can see in this picture omnidirectional high gain antennas produce a "donut" around them
wifi-antenna-2-4-G-16-dbi-omnidirectional-high-gain-antenna-WIFI-router-network-AP-antennas.jpg

that would mean your tello won´t recieve or transmit anything in front or behind it.

for more details on antennas watch this video (good and simple explanation):
 
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ph2t

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@Stele, that's right mate. I believe range will be something I need to test thoroughly. It's hard to get some park time at the moment. :(

I must say though I have been really impressed with the change of video quality.
Below is a RAW video from the tello, set to 4mbps with auto EV.
I have noticed I don't get the frame drops anymore. Even with being very close to the tello, in FAST mode there would always be frame drops, especially whilst turning.


Please have a look to see what I'm talking about. unless I'm the unlucky one and everyone else gets good video in fast mode! haha.

Cheers,

ph2t.

PS. a sidebar to the discussion. in FAST mode the camera's FOV is increased by the tello software. See the first few seconds of the video above - I change from NORMAL to FAST mode and the camera FOV changes too. :)
 
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bmelody

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I´m not sure if they will perform good. Usually high gain comes at the cost of coverage. As you can see in this picture omnidirectional high gain antennas produce a "donut" around them
View attachment 3104

that would mean your tello won´t recieve or transmit anything in front or behind it.

for more details on antennas watch this video (good and simple explanation):

Stele, Excellent video! But ph21 has an additional problem that was not explained in the video. That is horizontal and vertical polarization. Two antennas horizontal to horizontal will work well. Two antennas vertical to vertical will also work well. But horizontal to vertical is not good. There is a 30 dB drop in power when you cross poll antennas. You will actually decrease the distance even if the the 2 antennas have gain. Lets say each antenna has 6 dB of gain. So in theory you have a total of 12 dB of gain over 2 dipole antennas. Now if one of the antennas was horizontal and the other vertical instead of 12 dB of gain you would actually have a net system gain of -18 dB. Unfortunately the quad antennas are a compromised designed because of available space, vertically polarized and not very efficient, at best 0dBi. So the net gain when crossed pole would be approximately -24 dB. Not good at all. Now add to that another compromised antenna in the phone and the range is very short. This is why a WiFi range extenders works so well. Since the WiFi extender is close to the phone (near field) the weak signal from the phone is easily picked up by the WiFi extender. The signal is then amplified and repeated using a high gain (higher than the phone anyway) vertically polarized antennas.

My main concern with hp21 antenna installation would be if the drone is far away (out of near field) and the drone rotates 90 degrees (off the ends of the antennas) he will lose connection and control of the drone. In close up (near field) it may work well.
 
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ph2t

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@bmelody - Thankyou for that information mate, very helpful! Unfortunately I’ve modded this poor tello to hell and back and currently I’m experiencing the dreaded -13 motor error so I’m not getting anywhere fast at the moment.

I think I’m going to mod the next tello I get with some ipex antenna connectors and mount them on the pcb so I can change out antennas. For the sake of testing with accurate results I won’t mod anything else on the replacement tello.

Hopefully I’ll have a range test done in the next couple of weeks.

Cheers,
ph2t.
 
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LELET81

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Raul, you're the record man, let's go buy another extender wifi+... One onboard and one on the floor :ROFLMAO:
 

Customerx

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It's still working a treat, does reduce flight time a little. To around 8 mins. Haven't done any more distance tests since started getting trolls on YouTube about LOS rules. Will do the bitrate one probably next week when kids are back at school 🙏 lol
 
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ph2t

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@ph2t,

I am surprised IPEX 8db antenna you are using looks like the one into WIFI+S Extender, WIFI+S Range Extender vs Xiami WIFI Repeater It seems a well know high performance design.

WIFI+S Extender internal antenna:
View attachment 3281
Your IPEX 8db antenna:
View attachment 3282

Isn't it ?

Raul.
Yes mate, very similar. I think the pattern is because they are trying to fit a length of antenna that conforms to the correct wavelength at 2.4ghz but the pcb is shorter.
 

volate!lo

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actually most PCB antennas look like this, nothing special. Just crack open your notebook and phone
 

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