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RFguy

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Everything posted by RFguy

  1. so be it , prefer none than delayed or rely on a system that may have high latencies. radio should catch others... mobile data is very low reliability over anywhere serviced by multiple base stations and or base stations that are busy. I will see RPT (they have ADSB without ozrunways) , and many GA. if the others dont have at least a SE2, not much I can do except listen in the radio. down the track I might add a interferometer receiver which can determine likely location of transponder only aircraft by trilateration and triangulation.
  2. I'm convinced reliability is straightforward . just keep the oil clean / fresh, temps moderate, fuel line strainers and filters clean, avoid large changes of throttle < 3 seconds, and for continued monitoring watch the oil filter foreign body contamination and do leakdowns.... simple.
  3. I intentionally prevent my Ozrunways from showing any mobile-data derived traffic due to the lag. I just use the SE2 for my traffic reception on the wifi connection.
  4. I had a bit of a chat to them a couple of years ago. Still unsure whether they made it under license or if it was a pure clone without all the know how. I just cannot beleive they would make it to 700 hours (so far back then) (which people I have independently spoken to in EUrope) if it was an 'uninformed clone' .
  5. correction : my 1000m up and down if shielded should read 1000' . feet not meters.
  6. traffic that is 'OLD" or "out of date " (say 3 seconds) needs to be put into a different colour traffic bubble . I dont like anything with a cellular or third party network that does not deliver time definite in the way....
  7. and baro from the SE2 would have a high uncertainty because it's position could be the subject of variations from atmo pressure.
  8. agreed on nice to see say, inbound traffic 8nm the other side of the airport when inbound, gives you some think time to decide your intentions.
  9. good points on delays. lot sof poor / suboptimal implementations out there there isnt complete blocking by wings at least for close proximity - signals conduct and bend around wings , there is re radiation from the airframe etc. At least up to about 1000m above or below it is going to be pretty bulletproof. It does open you up to the ADSB semi-blocked transmission getting stomped on by another in busy airspace , but that's a low likelihood with 120uS bursts and position being transmitted at ~ 2Hz. My production ADSB-TCAS implementation will be real time. and it is predictive. I have ordered 30 sets of raw data capable GPS modules for my project to start with.
  10. yeah. I am was concerned, but I was looking for them late base.... down to my lower left. not out the window to my right. I shoul;d have been able to see them late base since that's a white aircraft over green pastures. Looking to the right is looking into the town and beyond into the hills. I dont understand you mention of trafdfic displays showing the situation in the past- certainly the past but no more than a few seconds Which brings me to a defficiency with looking at traffic in OZRWYS - there isnt a time stamp or time delay shown for that fix.
  11. 240 mag @ 12-14 kts on ground, IE blowing aircraft on downwind and crosswind wide.
  12. All aircraft were using 15 other aircraft is likely to have gone very deep on crosswind leg, or drifted 1nm on downwind. As we had 1.5nm to 2nm separation (or approx 1 minute) when I was in T&G and other aircraft was crosswind leg and then in late downwind we had zero !
  13. Both GNSS altitude and barometric are available and are transmitted. In the RV, your SE2 has an excellent all round view of the sky.
  14. My experiences are in the PA28 with SE2 on the 2nd pax row seats window behind me. (It's currently up on the instrument panel deck until the GPS-35 antenna is fitted for the xponder). OK I think the GPS wont see well through the wet wings, but through the body would be ok otherwise. To recap- we need satellites from around the whole sky to get a good fix. So SE2 position matters if it is blocked in directions. KG : Those experiments were to determine the practical sensitivity to using an 'outside' antenna, a length of cable, and an inside antenna that is close enough to re-radiate the signal to the SE2 on the bench, inside of my shielded box electronics workshop. AND, performance with multiple antennas to a combiner and then to a re-radiating "coupling" antenna near the SE2. The results are good. I think that it might be possible to get good fixes with just a single 2nd antenna on the other window with a coupling antenna near the SE2. and much better with a third antenna on the nose / instrument panel. The receiver is measuring time delay between sats in order to determine position . To get a accurate GPS fix the receiver needs to be able to see SVs (space vehicles ) around the sky so that it gets diversity . IE if all the sats are around the horizon, the vertical accuracy of the fix will be poor without a satellite overhead . In practice we are not after mm of precision, so we dont need much.. Remember the trig tables, and the relationship with small angles .
  15. Ublox receiver sitting on log. There is a PATCH antenna on the bottom of that receiver , so it is just sitting on it, SE2 with log periodic this is good and about the best reliable distance . works up to about 65mm my GPS antenna power injector (since the roof top antennas need power on the cable) checking polarization dependence this iis cross pol (poor)
  16. Today I was messing around with multiple GPS antennas on active repeaters. they're really all active because most GPS antennas have amplifiers in them to cope with the lossy long thin cable. had couple of antennas on the roof, fed with a power injector, and a few different rerad antennas. I also updated the SW in my SE2 to 2.41 Started working with some ublox receivers I have with the very fancy U-center program that tells you all the backroom GPS data. then I moved to using the SE2. It's clear why the SE2 will report some very poor position fixes. It's bar is very low. With NIC (Navigation integrity category) =0 and NACp (Navigation uncertainty category) = 6 (on the wifi GUI) the box shows GPS green. If we ignore NIC of 0 means containment radius integrity is unknown. IE NFI ! The NACp of six means better than 566 m in horizontal and worse than 45m in vertical. (95% confidence) So what I see (transmission of poor fixes) makes sense. WHen life is good, I see up to NIC=6 and NACp = 8. Now, this is much better - NACp of 8 implies better than 93m in H, but STILL > 45m in V . (95% confidence) and containment radius better than 926m. The SIL for a SE2 is 1, which means likeihood of being beyond the containment radius is < 1 in 1000. I've seen a NACp of 9, which implies better than 30m H and better then 45m in V Now, what is accepted by receivers and processors and displayed online like flight aware and flight radar might be very different to what is displayed by ATC IE ATC are unlikely to display poor NIC and NACp numbers (or shouldnt) . I wonder what SE2 pass to the EFB. NACp is transmitted in ADSB message type 31 in V2. so the nav performance is transmitted. So, of all this I think it is very practical to be able to provide a supplemental GPS antenna to a skyecho, so that the SE2 can be on some inside back window, and also have an aux GPS antenna on the window on the other wise of the aircraft. I started with a log periodic wideband antenna and then made a little dipole antenna to gauge polarization matching sensitivity, and there is that to it. The antenna in the GPS receiver should be a circularly polarized type, but its a very very simple little thing and seems to be rather random but with a preference of paralell to the board axis. Pictures to come
  17. well, today or tomorrow was going to fly to Port Macquarie for a get together. However, the GAF is more than just a couple of sentences, its a couple of pages of hazards.. Instructor was right. If the GAF is more than a couple of lines stay on the ground. MOD MTW, SEV TURB and low cloud.
  18. yes, true. Best to lead by good example instead of spite.
  19. No excuse now not to have ADSB TCAS. I'm muttering about doing somethhing, have been experimenting with my zero spare time on using multiple basic GPS receivers to get a good position fix with distributed antennas, since the SkyEcho GPS position fixes can be terribly poor if they dont have a good view of the sky, SKyecho can be improved- Certainly worthwhile also doing an active dual antenna >> skyecho adaptor- needs two patch antennas on each side of the aircraft that can see out the window, and uses a basic RF combiner (a $5 tv-sat one works) , and a 3d printed cosy sits over the top of the skyecho GPS antenna and couples the combined signals into the skyecho GPS antenna. That works OK. Needed to remember how to use my 3d printer... needs to be a metalized plastic because needs to shield the re-radiating antenna so the aux antennas dont feedback. but standalone ADSB-TCAS wuld be triple GPS , triple antenna , to use multiple low cost cheap looks at different areas of the sky. avoids RAaus aircraft havign to put GPS-35 antenna in the top of their aircraft skin. just take average of the fix works OK by various literature (been done many times) . Step up from that is use a couple of high performance GPS receivers and use raw data from each combined in a central CPU to produce a high performance fix from the raw data from each antenna (IE you get distance and direction for each satellite from the Nth receiver, and use the combined set to produce the fix externally. There's a few ways to generate sanity checks which is well covered in literature. Target is 10m accuracy in XY and Z. Good Z axis requires some sats overhead. X and Y need low angle sats distributed around the azimuth. anyone not having ADSB in their aircraft , which includes the flying school aircraft I will treat as persona non gratia . IE. "XYZ do you mind if we backtrack with you down to the end of 33 ?" " NO , I do mind." . what happened at YCWR the other day is BS and it's not been taken seriously.
  20. agreed if its in a fuel tank and you do NOT want blobs coming adrift and blocking inlet. good reason to have finger strainers.
  21. Skip, maybe for your experimental application, just some decent automotive fuel tank/ fuel pump gasket silicone etc Repco Australia | Auto Parts Store - Aftermarket Car Parts WWW.REPCO.COM.AU Repco Australia | Auto Parts Store - Aftermarket Car Parts WWW.REPCO.COM.AU
  22. although your 1 hour flight will chew up $50 of fuel and $17 of engine time ? maybe you can get a bit from the locals.
  23. any any idiot can get an airplane airborne IF they manage to keep it straight on the TO roll. landing though is a different story.
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