Airborne testing - mixed results

[captchaos]

On Sunday a friend and I tried some ground and airborne tests with mixed results. The recent State of the Nation post makes this less relevant but may be useful and some may have useful observations to make.

The units were in use but only normally two at a time.

Unit A my first effort which is soldered and has no baro
Unit B with Jeremy's ARF shield with baro
Unit C with Jeremy's ARF shield with baro running on Pi B model (A & B on Pi B+)

All three units currently get GPS fix from tablets whilst that slow boar makes its way from China.

Unit A has two GSM style aerials as some have recommended on here. They are close together on one end of the case.

Unit B has the standard aerials the components come with as does unit C.

Experiences
After a quick verification of P3i signals being seen on units A and C we go airborn. Unit C generally saw the P3i traffic info 3-5 miles away and Skydemon gave good interpretation of collision risk when appropriate. i.e. red aircraft graphic and heading line and warning message with range. As you will hear I haven't seen this! but Paul unfortunately couldn't take a screen shot.

Disappointingly, unit A only showed the P3i when flying in very loose formation! something like 100 feet.  I then swapped over to unit B and we achieved pretty much the same results. Paul commented that unit C gave him good warning about a collision and was looking for some time before becoming visual in slightly hazy conditions (we were flying at approx 100 kts with me orbiting). There was some impact on range depending on direction with better range if I was flying toward unit C. Both units were on the coaming with a possibility of blanking by the compass. Unit A & B were in an RV8 and unit C in a  Bulldog.

We went back to using units A and C and repeated the exercises with similar results. After landing we placed unti B and C in the Bulldog and walked away with unit A. Unit A lost unit C again at 100 ft but we got more like 700 ft on unit B. it also seemed that the two GSM like aerials were interacting with one blanking the other if it was in line.

One suspicion was power in the Bulldog but checking the voltage on the GPIO pins it was 4.90 and 3.3 respectively. However this was through a cigarette style adapter running a tablet and the PAW although it says it can provide 2.1A to both sockets. I would like to try a power pack like is used on units A & B in the future.

We then set up the final test with unit B in the Bulldog and unit A using the taller standard aerial on the P3i part.  We got similar result again.

We got excellent range on ADSB traffic but mixed results on P3i, one aircraft getting a useful warning range but not the other.

For the future we will be adding the onboard GPS and trying a battery pack (we I know works) to eliminate that as a factor. Any other thoughts appreciated.

[ianfallon]

Great to see some more air-air testing. My first reaction is "metal aircraft"

Also, running two units in v close proximity could saturate the ARF frequency and cause more problems (?)

Keep up the testing - v interesting.

[captchaos]

Ian, yes metal aircraft but units on top of the coaming so mainly perspex surrounding them, especially in the RV. Also the fact I could be picked up on P3i at 4-5 miles was encouraging. Just wish it also worked the other way too.

Re proximity comment, there was only one unit active in each aircraft during airborne testing. When I swapped units I powered one down before powering the other up, it was only on the ground we had two in close proximity.

I must admit I hadn't flown the RV so slow, for so long, to match the Bulldog,  for a while!

[ianfallon]

There are reports of some good range as well as not so good so far. I have heard one report of 8+ miles and if I am correct we had one unit picking up mine air-air at about 25km / 14nm.
A bit hesitant to claim that yet but it looks that way.

I know what you mean about formation with slower a/c - had a great flight with a friend in formation in his Taylorcraft recently. Felt very strange flying the RV at 90-100 mph!

[Paul_Sengupta]

We got excellent range on ADSB traffic

Indeed. Driving from Popham to Bourne Park I was picking up airliners from north of Birmingham down to France, from Wales to Kent, with the filter set to +/- 40000ft. When I set it more selectively, I was still watching Heathrow and Gatwick traffic descending to land from our air test near Andover.

Ian, yes metal aircraft but units on top of the coaming so mainly perspex surrounding them, especially in the RV. Also the fact I could be picked up on P3i at 4-5 miles was encouraging. Just wish it also worked the other way too.

How far are the markers on Sky Demon? I first picked CC up when just under the two markers. Is each one 5 miles? If that's so, then that's maybe 9 miles. He could only pick me up from being in formation! As mentioned in the other thread, similar results on the ground or in the air.

I must admit I hadn't flown the RV so slow, for so long, to match the Bulldog,  for a while!

More so as I was flying at "loiter" power, down around 80 knots!

[captchaos]

It is much more fun testing these devices with a friend in the air, thank you Paul. However, we were thorough in our preparation and had one of Popham's full English Breakfast whilst briefing!

[ianfallon]

It is much more fun testing these devices with a friend in the air, thank you Paul. However, we were thorough in our preparation and had one of Popham's full English Breakfast whilst briefing!

I like that approach a lot 

[Alan Walker]

In which case all 'Centres of Test' should have a reputable 'Greasy Spoon'!

[Paul_Sengupta]

Yes, it should be made law.

CC, what battery packs are you using?

[captchaos]

Paul, the black one is an Aukey 20000mah USB battery pack.