Thread: Antennae
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  #15  
Old July 20th 19, 02:59 PM posted to rec.aviation.soaring
Dan Daly[_2_]
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Default Antennae

On Saturday, July 20, 2019 at 9:07:24 AM UTC-4, wrote:
On Saturday, July 20, 2019 at 6:44:25 AM UTC-4, Dan Daly wrote:
On Friday, July 19, 2019 at 10:30:50 PM UTC-4, George Haeh wrote:
Hi Dan,

I do get different range patterns for the Flarm A&B antennae, which I have mounted on both sides of my canopy.

What I don't know is whether my Flarm is seeing a glider that's not seeing me.

But at least one of us knows about the other.


Interesting! I will have to install a second antenna (I'm grandfathered) and have a go...


It's worth having the two antennas even if the "B" antenna only receives. That fills in gaps in your reception pattern. And as far as the FLARM range report, that is ONLY using reception data - it has no way to know who can receive your transmissions, since the protocol is a blind broadcast with no acknowledgment.


You can see some of that with the Open Glider Network (OGN). The KTrax range analysis shows receipt by OGN stations (if you have any nearby). Here is an example (ASW24): https://ktrax.kisstech.ch/cgi-bin/fl...flarmid=C05FDB from last week. You can see the glider got about 15 km from one station, and another 33 km distant picked up the glider from 33-38 km.

Here's another glider (PIK20) which flew from one OGN station to the other. At 40 km, still 5 dB.

The OGN network is also handy for troubleshooting cabling, antennae, etc since you can get a signal strength reading directly (swap a cable or antenna to see if they're bad - might save a trip for $$ troubleshooting). It also has SAR features.