Antennae

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.

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...

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.

At 13:07 20 July 2019, 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,
=20
I do get different range patterns for the Flarm A&B antennae, which I
h=
ave mounted on both sides of my canopy.=20
=20
What I don't know is whether my Flarm is seeing a glider that's not
see=
ing me.=20
=20
But at least one of us knows about the other.
=20
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
rang=
e 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
n=
o acknowledgment.

Not quite true. If you are in an area where the OGN network is active and
has tracked you, you can see how others see you.

URL is https://ktrax.kisstech.ch/flarm-liverange/

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.

That's very interesting!

Having both A and B antennae on top of the glare shield in my Stemme, I
get poor results with gliders directly below me (carbon fuselage).Â* I'll
try this again afterI move the antennae to the canopy rail and see what
improvement I get.

On 7/20/2019 7:59 AM, Dan Daly wrote:
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.

--
Dan, 5J

On Saturday, July 20, 2019 at 10:00:07 AM UTC-4, Tim Newport-Peace wrote:

Not quite true. If you are in an area where the OGN network is active and
has tracked you, you can see how others see you.

URL is https://ktrax.kisstech.ch/flarm-liverange/

I meant the range report the FLARM website offers, via analyzing your flight logs. Those capabilities of OGN are cool, but I didn't think about OGN since I am in the USA, where OGN is very sparse.

On Saturday, July 20, 2019 at 10:36:32 AM UTC-4, Dan Marotta wrote:
That's very interesting!

Having both A and B antennae on top of the glare shield in my Stemme, I
get poor results with gliders directly below me (carbon fuselage).Â* I'll
try this again afterI move the antennae to the canopy rail and see what
improvement I get.


Dan, the benefit of using two antennas is maximized if you separate them as much as possible. That's why I'd like to install the "B" antenna behind the pilot seat, to help reception from the rear. Of course in a carbon fuselage that may not be a viable option. Unless you have a glass-fiber turtledeck, which I gather some gliders do, although the top part of the tailcone would still be in the way.

The turtle deck on the Stemme is fiberglass but I already have two
antennae on top of the glare shield.Â* I'd like to put one on the bottom
of the aircraft.Â* An ideal location would be on the propeller dome, but
the transponder antenna is mounted on the bottom of that in the middle
fore and aft.Â* What's the minimum spacing required between a transponder
antenna and a flarm antenna?

Another possibility would be to install an antenna in the engine bay
right at the bottom.Â* I think the lower cowl is fiberglass, but I'd have
to check.

Since I trimmed the antenna cables to length when I installed them on
top of the glare shield, I'll have problems that may require buying new
antennae.Â* Bummer...

On 7/20/2019 9:25 AM, wrote:
On Saturday, July 20, 2019 at 10:36:32 AM UTC-4, Dan Marotta wrote:
That's very interesting!

Having both A and B antennae on top of the glare shield in my Stemme, I
get poor results with gliders directly below me (carbon fuselage).Â* I'll
try this again afterI move the antennae to the canopy rail and see what
improvement I get.

Dan, the benefit of using two antennas is maximized if you separate them as much as possible. That's why I'd like to install the "B" antenna behind the pilot seat, to help reception from the rear. Of course in a carbon fuselage that may not be a viable option. Unless you have a glass-fiber turtledeck, which I gather some gliders do, although the top part of the tailcone would still be in the way.

--
Dan, 5J

On Saturday, July 20, 2019 at 9:37:25 PM UTC-4, Dan Marotta wrote:
The turtle deck on the Stemme is fiberglass but I already have two
antennae on top of the glare shield.Â* I'd like to put one on the bottom
of the aircraft.Â* An ideal location would be on the propeller dome, but
the transponder antenna is mounted on the bottom of that in the middle
fore and aft.Â* What's the minimum spacing required between a transponder
antenna and a flarm antenna?

Another possibility would be to install an antenna in the engine bay
right at the bottom.Â* I think the lower cowl is fiberglass, but I'd have
to check.

Since I trimmed the antenna cables to length when I installed them on
top of the glare shield, I'll have problems that may require buying new
antennae.Â* Bummer...

I'd keep all other antennas as far as possible from the transponder antenna, since it transmits (in short bursts) at about 200 watts.

Extra FLARM antennas are cheap he
https://www.mouser.com/Passive-Compo...16+MHW&FS=True