hello all!

i am considering two frame mounting options of my HGLRC M100 MINI gnss module. please see pics below:





my initial experience with the M100 mini has been excellent so far! it came as you see in the pics with the 200cm cable soldered in place. i just repositioned the 4-pin wire to match the FC, a totally solderless affair. BF4.3.1 set up was also a breeze. i did it indoors beside a window where it easily locked on to 5 satellites within the first minute after powering up. then i proceeded outdoors (minus laptop) to check goggle OSD and it very quickly locked onto 8 satellites within 30secs. it locked on to 17 satellites within +1min. i must admit the M10 must really be a world of improvement at a very tiny form factor.

short Q&A below:

1. rear top frame option affords the best and highest location on the quad. however this puts it in close proximity to the shortish vtx antenna. would there be any issues?

2. motor arm installation affords the best location away from the vtx if this were the major source of noise which may impede the module’s performance. but this puts it between the motor and caddx vista AU. any issues with this as well?

3. i plan to wrap the gnss module and the entire cable length with rubber shrink wrap tubing to protect from exposure and isolation from the carbon frame. is it acceptable to wrap the antenna with opaque rubber material? or should i use the included clear shrink wrap instead?

4. for added security, i also plan to strap the module with ziptie for good measure. from an OC perspective will this bit of nylon straddling across the antenna top affect its performance?

5. for the purist OC option i may still consider having a custom rear mounted TPU which will house the vtx antenna, gnss module and ELRS T-antenna in one install. should i just take this route? my main reservation with this is a rear impact crash puts the tpu assembly directly in harm’s way. not to mention the added weight.


looking forward to user feedback, wisdom and experience from the intofpv.com folks!

I have an AOS 3.5 and a Walksnail Avatar VTX v.1, to avoid interference from the VTX, I placed the GPS receiver farther in the tail.



Update1: I assembled the quadcopter and tested it in flight, I get enough signals from the satellites. But if you turn off Walksnail, you get even more satellites.

how would gps interference manifest itself during flight? is it like losing all locked satellites after arming the quad then taking off to fly? for starters i am going to perform a test flight with the module strapped to the arm and rear top frame for comparison. still hoping others who did the same chime in. cheers!

Momobrut posted a lot of details on his findings of GPS placement interference in his Scythe HD thread, you can check that out.
And yes even with lock, you can easily lose satellites once you start flying.

If you are using WS VTX, Madstech did an analysis and seems the V1 VTX puts out RF interference exactly on the GPS band so that would make it even more challenging to keep good lock.

(04-May-2023, 01:44 PM)mstc Wrote: Momobrut posted a lot of details on his findings of GPS placement interference in his Scythe HD thread, you can check that out.
And yes even with lock, you can easily lose satellites once you start flying.

If you are using WS VTX, Madstech did an analysis and seems the V1 VTX puts out RF interference exactly on the GPS band so that would make it even more challenging to keep good lock.

points well taken! i am using the caddx vista which i typically run at 700mW only which hopefully does not swamp the gps lock. after some reading from pavel’s YT channel its still the rear tpu mount that should provide the best position despite being directly underneath the vtx antenna. hopefully if the proverbial recommended 5cm distance from any RF noise source actually works then i would have the vtx base extended to exceed this length.

I think arm is a good spot to start with if you don't mind it sticking out there. Then after you test it, you can decide if you need to relocate it or not. On an analog 3" pick I had to move it around and got good results between the arms, but I can hear it blocking the airflow.

https://intofpv.com/t-which-nano-gps-is-...hlight=gps