Hi all,

This is my first build thread here and I've already posted tidbits in some other threads, but I figured I might as well start a thread to collect all the notes from my build.
I'll try to share as much detail as I can to help others that may be considering building this.

My intent for this build was to take the awesome original design from Dave_C and modify as needed to be able to fly as far away from the transmitter as possible.
I recently started using the new ImmersionRC Ghost 2.4Ghz radio system and of course I wanted to test it's capabilities, so that was part of my motivation for building a longish range quadcopter.
 
I'll admit this was actually a more challenging build than I expected.
Here's a quick list of some of the challenges I faced along way, with solutions:

Problem: Step-up regulator from Bangood was faulty and outputting almost 9V.  I didn't confirm output before connecting it to my Tramp Nano VTX and I destroyed the VTX.
Solution: Check your voltages before connecting devices.  Also FYI, the IRC Tramp Nano doesn't have overvoltage protection.

Problem: I had ordered two step-up regulators and the 2nd one was working correctly, but during some troubleshooting I accidently caused a short circuit and burned it up.
Solution: Don't be dumb like me

Problem: My video had some pretty significant rolling diagonal lines in it (mostly evident with motor spinning).
Solution: I tried just about everything.  Larger ESR capacitor, coax for video wire, powering camera from VTX.  None of those things seemed to help much.  I believe the change that made the biggest difference was moving the LC filter to the input side of the step-up regulator, instead of the output side as recommended on Dave_C's wiring diagram.  During the time between blowing up my regulator and waiting for the new Pololu one to arrive, I flew without it for a while.  That's when I noticed my video was perfect.  So the addition of the switching regulator was either introducing noise or amplifying existing ESC noise.  My theory is that putting the LC filter ahead of the regulator adds a bit of extra decoupling between the switching reg and the main board.

Problem:  The HGLRC Zeus F411 Nano FC only has 1 UART exposed and I could not get the GPS to work via softserial.
Solution: The Ghost receiver only requires a TX pin, so I used UART 2 TX.  I remapped UART 2 RX to softserial TX for tramp VTX control.  UART 1 is preassigned to the onboard WiFi, so I disabled that and resourced UART1 TX/RX to the LED pin and the S5 pin to connect the GPS.  This is all with Betaflight.  My understanding is that iNAV can't do resource remapping?  Maybe someone can confirm that, because I've never used iNAV.  BTW, yes there are probably other combinations that may work, but this is what I ended up with after many hours of trying to figure this out.

Here's the final parts list:

- Dave_C Nano LR Remixed & Modified Frame (printed in CF PETG) [16.5g]
- RCInpower 1202.5 11500 KV motors [4.3g]
- HGLRC Zeus 411 AIO FC (Betaflight 4.3 and BLHeli_M 48 kHz)
- ImmersionRC Ghost Atto RX and Qtee Antenna (2.4 GHz small antenna, perfect for light builds)
- ImmersionRC Tramp Nano VTX (500mW) [1g]
- Caddx Ant camera
- TrueRC Singularity Lite VTX Antenna
- 220uF Low-ESR Cap (came with FC)
- IFlight LC filter [0.5g]
- Pololu S9V11F5 regulator [0.5g]
- Gemfan 3018 props
- IFlight GPS
- AUW 110g

Rotorbuilds link: #NanoLongRange with Ghost (rotorbuilds.com)

***** Gear *****

Goggles: Skyzone 02C
Goggle Antenna's:
TrueRC OCP 5.8 - 1.6 dBic Omni
TrueRC X²-AIR 5.8 - 13 dBic Patch (long range setup)
TBS 5G8 5 dBi Patch (short range setup)
Radio: Radiomaster TX16S Hall
Transmitter: ImmersionRC Ghost JR Module
Transmitter Antennas: TrueRC True-MoX 2.4

More posts to come with build photos and videos...

Version 1:
This was before I received the battery holder (actually I still haven't received it).
Also didn't have a working GPS at this point.
   

Version 2:
This was with new frame remix found on Thingiverse that included a battery holder.
I ordered the Keystone battery contacts from Amazon.  I also designed a small battery clip to hold the GPS.
This is the version I was able to fly out 4.5km and back.
   


Version 3:
I used Tinkercad to lighten the frame further and increase cooling in the underbelly.  
Also, changed the Ghost antenna mounting.  I expected this antenna mounted to be better in terms of shadowing from the battery, but I was surprised that the ziptie actually seems to block some signal  . I didn't do a ton of testing, but my LQ was always slightly lower when flying towards the transmitter.
   

Version 4:
Custom redesigned frame to fit a 21700... it was a disappointing fail.
Based on eCalc results, I should've gotten improved range and flight time, but this was just too heavy.
I was using a Molicel 4000mAh 21700 and I just couldn't squeeze more that 3000 mAh out of the battery.  I think because of the weight on 1S the voltage sag was just too much.  I tried 24 kHz, 48 kHz, but nothing worked.  The best flight time I could get was 15min.  Interesting experiment, but that design went in the bin!
   

Version 5:
This is my current version.
I lightened the frame a bit further and moved the RX antenna to the front bottom in horizontal orientation, so we'll see how that does.
I'm just waiting for the right weather to try one more time to get this to go out 5 km and back.
I don't think I can get much lighter than this, so we'll send how far we can send it!
   

Here are the weights of my current frame for anyone interested:
       

I've printed with 2 perimeters and 2 top/bottom layers.
20% cubic infill.
Those settings are about as "lean" as I'd want to go.  It's already a little "flexy".

Here's some quick milestones that I've reached so far with this build:

• >9.5km total flight distance (4 degC almost windless)
  
• 20.5 minutes of hover time (at 24 kHz PWM in 20km/h gusty winds)
  
• 5km away from transmitter, but then crashed 4km from home (and amazingly I found it)
  

Goals:

• 10km total flight distance
  
• 5 km from transmitter with successful return
  
• Test again for maximum hover time in calmer weather
  
• Still testing to see what PWM frequency is the most efficient
  

More numbers....

• I found without the step-up regulator video is lost around 2.9V
  
• With the Pololu step-up I used, it works down to 2V, but in practice I can hover down to 2.2V before it falls out of sky (yes I'm sacrificing my batteries)
  
• If camera is not powered by VTX (which is powered by step-up), you'll lose video at 2.5V (I originally wired this way, but now camera and VTX are power by step-up)
  
  

That's really cool I've been waiting to see one of these crack 5km. Yours is getting really close.

Here is my 5km out flight video:


Take a look at my comments in the Youtube description about my theory as to why it crashed.
Would love to hear your theories!

Altitude was my though watching it. The way video and rc simultaneously dropped the signal, almost looks like you might have dipped too low and put an obstacle in your path. Looked like you where riding on the edge of loosing video the whole way back too. But the first failsafe was at a higher altitude and wouldn't account for that.
Scrolling back to the beginning there's nothing really in front of you close enough to be that worrisome either.
Background rf is very possible and the polulu, the only other common link between video and rc link.

(17-Apr-2021, 12:03 AM)EVILsteve Wrote: Altitude was my though watching it. The way video and rc simultaneously dropped the signal, almost looks like you might have dipped too low and put an obstacle in your path. Looked like you where riding on the edge of loosing video the whole way back too. But the first failsafe was at a higher altitude and wouldn't account for that.  
Scrolling back to the beginning there's nothing really in front of you close enough to be that worrisome either.
Background rf is very possible and the polulu, the only other common link between video and rc link.

Appreciate the feedback.  You might be right about the altitude.
I went back and re-watched the DVR and on the way out I was at about 110m altitude and had no issues through those bad spots.
When I turned around at the 5km mark, I was at about 75m and then continued to drop until the area where I had the first failsafe at which point the lowest altitude I could read was around 61m.  Then I went back up briefly and dropped again into the 60's before I crashed.
Still not sure why Rescue Mode didn't work.  Assuming one of the sanity checks didn't pass.


That's all GPS altitude too, so not sure how much I trust it.
I guess lesson learned is when I'm that far out I need to watch my throttle more closely and make sure I keep my altitude.
I'm still pretty amazed that the video made it that far, considering I'm using the built-in receiver on the Skyzone's and the VTX is only 500mW.
I think my next investment might be a Fusion or Rapidfire receiver though for the sensitivity bump.

Also, this was the first and only time I ever witnessed those rolling horizontal lines of static.
It's also the first (and last time) I used F1, so I'm chalking it up to that being a bad frequency for that area.  Every other time I've been on R1.

It's pretty crazy how much altitude can affect these long range flights. At 5km with 60m altitude the angle from horizontal to aim your receiver at the quad is 0.688 degrees. A tree line across a field can start being an issue at those distances.

(17-Apr-2021, 01:59 AM)EVILsteve Wrote: It's pretty crazy how much altitude can affect these long range flights. At 5km with 60m altitude the angle from horizontal to aim your receiver at the quad is 0.688 degrees. A tree line across a field can start being an issue at those distances.

Ya, good point.
There's probably some buildings and trees a few hundred meters out the transmitter that could've been in the LOS path or at least most of the fresnel zone, so very possible that altitude change made all the difference.  I just don't have the guts to try it again on that same path!

BTW, I recently found this cool little trick in Google Earth for visualizing line of sight between different elevations.
Guide to Google Earth - Start Your Own ISP
Go to the section "Lines with Different Heights" and follow the instructions.  It actually works really well.
If you then right click your line and select "show elevation profile" it gives you a profile view and a pointer that slides along your LOS line showing the elevation along the line.

I was having some brief video black out, always at the same point on a different flight path that I take often and using this tool I figured out it was because I was directly in the shadow of a wind turbine.  Pretty cool.

(17-Apr-2021, 02:32 AM)amped_fpv Wrote: Ya, good point.
There's probably some buildings and trees a few hundred meters out the transmitter that could've been in the LOS path or at least most of the fresnel zone, so very possible that altitude change made all the difference.  I just don't have the guts to try it again on that same path!

BTW, I recently found this cool little trick in Google Earth for visualizing line of sight between different elevations.
Guide to Google Earth - Start Your Own ISP
Go to the section "Lines with Different Heights" and follow the instructions.  It actually works really well.
If you then right click your line and select "show elevation profile" it gives you a profile view and a pointer that slides along your LOS line showing the elevation along the line.

I was having some brief video black out, always at the same point on a different flight path that I take often and using this tool I figured out it was because I was directly in the shadow of a wind turbine.  Pretty cool.

First of all, congratulations on hitting the 5km mark on a 1S quad. And also sad you didn’t make it on the return and I assume you did not recover the quad. But hey you win some and you lose some, that’s the fun in doing it.

I feel GPS rescue saved your craft but also used up some of the valuable battery power being a self leveling mode till you gained back signal.

Yes, Google Earth has a useful elevation profile feature which I often use for various things apart from FPV and gives us a good ballpark set of numbers to understand the elevation change along a path.

One thing to note is that your altitude may not be accurate at all since the your FC does not have an onboard barometer and is providing the altitude based on GPS info. Depending on where you live this could vary considerably.

With regards to maintaining the best height for a given distance, there is a useful calculator posted at this website that can help and his method is based on trigonometry:

https://www.mrd-rc.com/tutorials-tools-a...OSAResults

I also did a post a few months ago trying to understand the above calculations and stumbled upon a more scientific method give us the best estimates for optimal altitude posted here: https://intofpv.com/t-simple-fpv-antenna...calculator

It was evident everyone is flying based on rules of thumb for optimal altitude based on range and do not want to be scientific about it but in case of a nano LR quad this might make all the difference.

Hi Kafie1980,

Thanks for the reply and the useful info.  I'll definitely check out those links.
Regarding the GPS altitude accuracy, I agree with you and my next LR build I will definitely find a way to incorporate a barometer (if the FC doesn't have one).

And believe it or not, I actually found the quad 4km from where I took off.  
Here's an excerpt from a posted I made earlier in another thread:

"After making it out to the 5km mark.... on the return home everything was going great and I actually have no idea what brought it down.
Seemed like some incredibly strong radio interference, because I lost video and control link.  I had BF rescue mode setup, so I wasn't sure if it kept flying or went down.  I waited at home for a while looking at the sky with my fingers crossed. LOL.  No luck.

I wasn't even going to look for it, but my wife convinced me to try, so going by the last GPS coordinates in the DVR we drove out and hiked an old rail trail to the last known location.  On either side of the trail was either forest or farmers fields and I figured the battery must've ejected during the crash, so there's no way I'm going to be able to pick up a signal. Again, I wasn't even sure if it went down there or it kept flying.

I literally said out loud, "well we might as well head back now, there's no way we're going to find it"... and a second later my radio blurts out "Telemetry Recovered"!!  There's a longer story, but the short one is I walked around looking at the RSSI dbm value on the radio and finally found it sitting in the grass about 6 ft off the trail.  Only damage was a broken arm and ripped motor leads."

I replaced the motor and frame and it's made quite a few flight since then 

(17-Apr-2021, 04:09 AM)amped_fpv Wrote: Hi Kafie1980,

Thanks for the reply and the useful info.  I'll definitely check out those links.
Regarding the GPS altitude accuracy, I agree with you and my next LR build I will definitely find a way to incorporate a barometer (if the FC doesn't have one).

And believe it or not, I actually found the quad 4km from where I took off.  
Here's an excerpt from a posted I made earlier in another thread:

"After making it out to the 5km mark.... on the return home everything was going great and I actually have no idea what brought it down.
Seemed like some incredibly strong radio interference, because I lost video and control link.  I had BF rescue mode setup, so I wasn't sure if it kept flying or went down.  I waited at home for a while looking at the sky with my fingers crossed. LOL.  No luck.

I wasn't even going to look for it, but my wife convinced me to try, so going by the last GPS coordinates in the DVR we drove out and hiked an old rail trail to the last known location.  On either side of the trail was either forest or farmers fields and I figured the battery must've ejected during the crash, so there's no way I'm going to be able to pick up a signal. Again, I wasn't even sure if it went down there or it kept flying.

I literally said out loud, "well we might as well head back now, there's no way we're going to find it"... and a second later my radio blurts out "Telemetry Recovered"!!  There's a longer story, but the short one is I walked around looking at the RSSI dbm value on the radio and finally found it sitting in the grass about 6 ft off the trail.  Only damage was a broken arm and ripped motor leads."

I replaced the motor and frame and it's made quite a few flight since then 

Wow, thats a story with a happy ending.

Hi amped_fpv,

So, this little guy is obviously sub 250 gram. Now, what about Fly Time and Total Distance Flown?  Can you get 30 minutes out of it...and... you got out to 5k, so if you make it back that would be 10K...you can do it, right? Now, do you want to put this one in the Challenge ??

(18-Apr-2021, 03:49 AM)iFly4rotors Wrote: Hi amped_fpv,

So, this little guy is obviously sub 250 gram. Now, what about Fly Time and Total Distance Flown?  Can you get 30 minutes out of it...and... you got out to 5k, so if you make it back that would be 10K...you can do it, right? Now, do you want to put this one in the Challenge ??

Its going to be tough, but if it wasn't I guess it wouldn't be a challenge!
yes, please enter it in the challenge and I'll give it my best shot!...
I think 10km is possible, but the real challenge is going to be 30min in the air.
I'll give it a shot though. Just have to wait for the right conditions.
Thx

Even the Mavic's 30 mins is based on very specific wind conditions and extremely low speed flying.

Yes, wait for the right conditions.