That front strut is too close to the PAW antenna. I suspect it may be acting as a reflector and improving the signal to the left at the expense of the right.
Many microloghts and Gyros have the coms antenna on the top of the nose, as far forward as possible. Is that an option?
Hi Geoffrey / Ian,
Sorry, I’m playing catch-up on the Forum.
I agree, the PAW polar diagram appears to show significant obscuration to the front right, but with the antenna in its 'new' position as shown in the most recent photo, I would be surprised if the front strut alone would cause such a significant area of shadow to the right side of the plane - as the greater part the antenna is now
above / in front of the strut. I must admit, however, that I'm at a loss to think what else in the plane would be obstructing your PAW signal to the front right to such a broad extent, so maybe there
is more to this (as Ian suggests) than at first appears likely. The 'gap' might of course just have been poor line-of-sight to the Ground Station antenna(s) at whatever range and heading you were when being received by them. Blocking of your PAW signal to the right rear, however, will almost certainly have been due to a combination of the front strut, plus (to a varying degree, particularly bearing in mind that the receiving stations are predominantly below), the front fork and wheel assembly, battery, instruments in the panel, plus (presumably) your phone or tablet - as well as Pilot / Passenger / engine and rear suspension as you alluded to earlier (as well as potential line-of-sight issues to the Ground Station antenna(s)).
I was about to suggest moving your existing antenna to just inside the outer edge of the
upper windscreen - as high up as you can manage, which would clear the immediate (close) obstructions, and help to reduce obstruction to the right rear due to Pilot, Passenger, Pylon and Engine, etc., but have just seen your recent post about dropping the wing for storage, which would make this awkward (though not impossible - it would just involve disconnecting the cable from the antenna before removing the upper screen).
And Yes Ian, it would be 'possible' to fit a PAW antenna externally on the upper front of the pod, but very difficult to align it vertically (if using a standard Rohan 'external antenna') and, as the front strut goes on down through to a bracket at the front of the base tube, it would still be right behind the antenna, so could actually make coverage to the rear worse. As you say, Geoffrey - worth checking results with Brian M first.
WRT fitting an external antenna further back
below the pod, that's the option I have settled on after considerable trials. Mine is fitted just in front of the fuel tank with a flexible ground-plane on the inside (my Txpdr antenna is mounted through the rear skirt on a separate aluminium sheet ground plane, earthed to the base tube). I have now been using this setup for over a year, with excellent results, though from the attached diagram I still seem to be seeing
some obscuration from the rear undercarriage and to the front by the front wheel and suspension, though I currently only have the one polar diagram from one single (approx 1hr 30) flight past 3 ATOM Ground Stations on Christmas Eve, two of which were at fairly long range (my most recent previous flight was well in excess of 30 days prior to the introduction of the Vector Tool due to the Scottish travel restrictions).
I did, however carry out a fairly short local flight immediately prior to the test flight shown, involving a 'circuit' of the area around my local airfield at up to about 5 miles range from the ground station, with several fairly tight 'orbits' at various points in the flight while still well away from the station (to ensure 360 degree visibility to the station antennas). I then checked the Vector track immediately after landing and prior to the main test flight. The initial report showed pretty effective 360 degree coverage, though of course with a maximum range of 5 miles, but unfortunately I omitted to take screenshots as I was pushed for time to get the main flight in before dark, so this is incorporated in the main report. In view of the relatively short flight and relatively long range from two of the 3 Ground stations reported during my main test flight, and my previous ‘good results’ from other evaluation tools, I suspect the 'gaps' in the Polar Diagram may be due to ground obscuration at or near the Ground Stations or simply my heading in relation to them during this single test flight rather than simply obscuration at the plane. I need to do some further testing once the travel restrictions are relaxed to confirm this.
If you do decide on the option to add a PAW antenna below the pod, I wouldn't worry about 'missing' aircraft above you. We did lots of testing for this in early PilotAware trials and found that it was almost impossible for a plane to approach from above (or vice versa with a top mounted antenna) without it being seen well before it got above us (or below as appropriate). IMO below is a much better option for external antennas, especially if you want to receive Ground Station uplinks reliably.
In closing, I’m not sure why your Vector search is bringing up your PAW results from your flight from 9th August - Vector is only 'supposed' to report on flights from the past 30 days (though I
have seen a few flights listed on other ICAOs from ‘30 + a few’ days)..
WRT your ADSB issues, it definitely looks like a fault to me. Loss of GPS to the Txpdr -
would prevent Mode-S/ES transmission, but would also affect PAW transmissions and would be reported as gaps on your Nav System and PilotAware Tracks, so relatively easy to check. Please let us know how you get on.
Best Regards
Peter
