UPDATE
whole new antenna + holder solution.
Soldered on uFL connectors and designed a new card + antenna holder.
Antennas are the microVeeHD from ProDrone.
2 Likes
Hi, love the build and appreciate your time keeping us up to date with progress. I am going to attempt to emulate your build as best I can for my 1st attempt on openHD.
When you purchased the pi3 mini it appears to force you to go for some accessories which is ok, looks to cost around $9 which seems very cheap, is this correct?
Any advice welcome.
Hi
I think you must choose option „B“ for around 17$ for the actual module. The other things are an optional power module (not used in my build) and various wifi cards.
The buyer agent‘s livechat I used was very helpful translating, even calling the seller and answering some questions I had.
After experimenting today with some more gps mount‘s I have to say that the gps issues I have (7-8 satellites after 5-10 minutes), are not significantly better with my new antennas. So I ordered the more expensive Matek M8Q-5883 GPS + compass Module. Hope this helps.
Hi CopterGUI,
Now I have finally got the system working on the bench I am going to try and emulate your build with similar components, possibly integrate eventually with a fully 3d printed frame.
I am going to use the Asus AC-56 to start with and I was wondering if you had the .step file for the T4U? I don’t think it needs much modification for the AC-56.
Hi Dickiebird,
unfortunately my 3D software of choice, only spits out STL and similar. But as this is a pretty easy part, I’m sure you can replicate something similar for ac56 in no time 
Got my Matek GPS today, now it’s much better !!
I get a valid fix in around 1 minute with the new one. Integrated magnetometer is also happy down there.
This is how it looks now:
Yesterday I was informed that I mixed up the main and secondary antenna port on the T4U V1 WiFi card In use.
(Thank you Sergey !)
So if anybody wants to use this card with just one antenna, use Conn1 !!!
That’s the original massage:
„I have measured the output power on the T4U connectors and got 45 mW at conn0 and 316 mW at conn1 with STBC and the others set to N. So if someone is going to use a single antenna, solder it to conn1. Or it maybe just my conn0 amplifier chip is fried 
I’ve also seen on the other wifi cards conn1 labelled as Main and conn0 labelled Aux.“
1 Like
Look above 
Thanks for pointing this out! But then PCB antenna must be really good. I was able to get almost 2km with 5dbi dipole on conn0 and PCB antenna on conn1.
Also, I actually did thermal imaging on amps. And if I remember correctly, results were consistent with primary idea that conn0 is main port. But then again, it might be because of different antennas. So I would say that it has to be investigated further:)
Finally, I am also planning to put two antennas and use STBC.
hi I’m from China.，this T4U V1 wificard radio frequency is 5022T，The output power is 64mw。
Would you mind sending out the power test results?
I’m sorry my English is not very good…
I’ve tested the output power of different ports,In different settings, both antennas have outputs
Hi, have you checked the other frequencies, for example, 5745 MHz?
yes… My usual frequency is 5180 5200 5220 5240 5022T output power is 64mw。
The USB wifi card we often use now is Samsung w01、also 5022T+SKY85601 about 64mw
Try high frequencies, closer to 5.8.
Would an rpi compute module 3 and a micro I/O expansion like this one Page Not Found - Aliexpress.com work as a replacement for TPCAST board?
Hi,
I think it will not fit (physically) in this quadcopter frame. From a hardware/software perspective it should work, but I have never tested on a CM3. Maybe the CM4 or any other Pi is a better option.
My suggestion is a Pi0 and one of those wide angle m12 lens pi camera V1 clones for ~10-20$
Isn’t pi0 performance limited? I’ll try with an Orange Pi Zero Plus2 with H3/H5. It has a CSI camera header and should perform somewhere around a rpi2/rpi3, it can be found for around 40 euro.
Yes it is but OHD can only run on Pi‘s currently. This TPCast board is an exception because it is the same hardware as Pi3B on an other pcb.