On Tuesday, April 20, 2021 at 8:16:13 PM UTC-5, Matt Herron Jr. wrote:
You make a lot of sense Dave. Thanks for the analysis and link. Interference might explain the lopsided reception as well. I have a ferrite sampler kit, but not much experience killing noise in a meaningful systematic way (M.E., not E.E.). I know switching power supplies are a common offender. Any other suggestions from RAS? I have a scope if that helps...
Matt
On Tuesday, April 20, 2021 at 5:41:32 PM UTC-7, Dave Leonard wrote:
You might want to check the ktrax site that does a FLARM transmit range
analysis using OGN receivers, like the one at Williams. The most recent
report for your glider (at least it might be your glider, if not put in
the correct ICAO code) shows better than average transmit range:
https://ktrax.kisstech.ch/plot?device=A7D668
If your transmit range is good but receive range is bad, you might have
an RF noise maker on board jamming your receiver. Or there could be a
lot of interference from ground transmitters causing you range
degradation. Last time I was at Hobbs, 2019, my FLARM receive range
dropped showing mostly less than 1.5 miles. Out at Nephi the next week
it was up to about 6 miles with no changes other than a lot of driving.
I found a bunch of IGC files from other gliders from those two weeks
that had FLARM data in them that showed even worse while at Hobbs ( 1
mile) and a complete recovery to normal later in the season at other
sites. Kind of deceiving when a lot of gliders had ADS-B and very long
range on the display, but the tip off was how many gliders did not show
up at all until entering the same thermal.
-Dave
On 4/20/2021 4:17 PM, Matt Herron Jr. wrote:
Fair enough, but there were 5-6 gliders in the air, including you. I thermaled with many of them in the same thermal.
Matt
On Tuesday, April 20, 2021 at 11:44:15 AM UTC-7, Ramy wrote:
Matt,
I suspect you only had couple of flights at Williams with only couple of gliders., possibly the same gliders. This is not enough variety of data. I suggest to collect more flights with more flarm targets first.
Ramy
On Tuesday, April 20, 2021 at 10:28:54 AM UTC-7, Matt Herron Jr. wrote:
Hi guys,
I just installed a FLARM Fusion and am getting some very poor results. The antennas are installed symmetrically on either side of the canopy rail (see photographs) in an ASW27b. They clip into a plastic adaptor printed from ABS, and each antenna has a clear 180 degree view out the side of the canopy. This seems to me like a pretty ideal setup to avoid the carbon in the cockpit, etc. Can anyone help me understand why the range is not better, and in particular, why the range is better on one antenna vs the other? that makes no sense to me.
Thanks,
Matt Herron
PastedGraphic-4.tiff
PastedGraphic-1.tiff
PastedGraphic-2.tiff
Matt,
A scope is not likely to help unless an exceptionally fast one. These signals are at 1 GHz.
I can't see your photos on Google Groups. Make sure the antennas are clear of any other objects, including the canopy plastic, especially the ends. Make sure there are no nearby metal objects aligned with the antenna as these will reflect the signal and can cause interference. Check the antenna cable for crimps, these can cause reflections that can seriously degrade the reception. Finally, verify that the antennas are tuned to the correct frequency (902 to 928 MHz in North America).
As for in-cockpit interference, that can be quite difficult to track down and cure. Most commercial instruments are probably safe to assume are OK. Additional commercial items like an iPad, Oudie, cell phone, etc. are possible but unlikely and can be more difficult (Oudie interference on COMM frequencies is a known issue, but I haven't heard of FLARM or ADSB interference from these devices). If you have something like a 12v USB port adapter I would be suspicious of that. Try disconnecting it and see if the situation improves. I've had little luck with ferrite beads because at these frequencies the PCBs themselves can radiate very well, bypassing the wires and beads.
Good luck,
Rich L.