FLARM Fusion Range

Thanks for the suggestions Rich.

The tops of the dipoles are very close to the canopy plex (by design) and I think one is even touching. How would the non conducting canopy hurt the signal? I think the frame of the canopy is Kevlar/Carbon (anyone know?) Could that cause reflection/interference? Wouldn't it also hurt transmission as well? (which seems to be fine).

On Wednesday, April 21, 2021 at 7:49:56 AM UTC-7, Matt Herron Jr. wrote:
Thanks for the suggestions Rich.

The tops of the dipoles are very close to the canopy plex (by design) and I think one is even touching. How would the non conducting canopy hurt the signal? I think the frame of the canopy is Kevlar/Carbon (anyone know?) Could that cause reflection/interference? Wouldn't it also hurt transmission as well? (which seems to be fine).

Matt,

Some antenna comments from the Fusion Installation Manual
Ensure that the antennas are not in contact with or close to any other object through which there might be an electrostatic discharge, e.g. the canopy.. When two FLARM antennas are installed, ensure that they are at least 30 cm apart.

The antennas must be mounted vertically since the radio waves are vertically polarized (this is unrelated to the radiation pattern). Up to 15° tilt is normally acceptable.
The antennas must be insulated to protect against electrostatic discharges, e.g. from the human body. Otherwise, the device may be damaged.
When utilizing antenna diversity, ensure that the antennas complement each other in terms of the radiation pattern (fuselage shielding).
Connecting more than one antenna to one RF Port (e.g. via a passive splitter) is not permitted. This will most likely result in signals cancelling themselves out and/or severely degraded range.

Richard
www.craggyaero.com

"The tops of the dipoles are very close to the canopy plex (by design) and I think one is even touching"

Matt, that's a big NO-NO.

I mount my antennas with a (little) finger thickness between the tips and the canopy, which requires a ½" thick block or support between the middle of the antenna and the canopy.

Contact between the antenna tip and canopy tip can damage your unit.

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

You can't past images to Google groups, or USENET like this. Can you share the image somewhere, like Google Drive and provide a link to them (and in jpg not TIFF?).

And to be clear you are talking FLARM A and FLARM B antennas? Where is your 1090 MHz antenna?

Hi Darryl,

Here is a link to the pix. Sadly they are TIFFs: https://www.dropbox.com/sh/dhe9415hd...5VFoQ9eMa?dl=0
Yes, I am talking FLARM A, and B. ADS-B is dead center up high under the glare shield and seems to be working fine. you can find a recent FAA report there as well.

Matt



On Wednesday, April 21, 2021 at 3:20:17 PM UTC-7, Darryl Ramm wrote:
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
You can't past images to Google groups, or USENET like this. Can you share the image somewhere, like Google Drive and provide a link to them (and in jpg not TIFF?).

And to be clear you are talking FLARM A and FLARM B antennas? Where is your 1090 MHz antenna?

On Thursday, April 22, 2021 at 12:25:49 AM UTC-5, Matt Herron Jr. wrote:
Hi Darryl,

Here is a link to the pix. Sadly they are TIFFs: https://www.dropbox.com/sh/dhe9415hd...5VFoQ9eMa?dl=0
Yes, I am talking FLARM A, and B. ADS-B is dead center up high under the glare shield and seems to be working fine. you can find a recent FAA report there as well.

Matt
On Wednesday, April 21, 2021 at 3:20:17 PM UTC-7, Darryl Ramm wrote:
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
You can't past images to Google groups, or USENET like this. Can you share the image somewhere, like Google Drive and provide a link to them (and in jpg not TIFF?).

And to be clear you are talking FLARM A and FLARM B antennas? Where is your 1090 MHz antenna?
Matt,

I'm looking at picture 2 and have a couple of concerns:
-The antenna is not shown in the mounting bracket, but from picture 3 it seems certain that the lower arm would be very close and probably touching the fiberglass frame of the canopy. The upper arm is very likely close or touching the canopy itself.
-If the canopy frame is carbon, mounting so close would definitely affect performance, probably severely.

Even though the plexiglass or polycarbonate canopy is not conducting, they both have a higher dielectric constant than air and will definitely affect the tuning of the antenna. Most likely tuning it to a lower frequency than intended. The suggestion to use a wood mounting block to space the antenna away from the mounting surface is a good idea. I'd suggest trying to move it somewhere where there is at least an inch or two air around the antenna (especially the ends of the arms, the mounting bracket is OK as long as it is only near the middle).

I can't say for sure this will fix your problem. The RF design of these systems assume a considerable amount of attenuation from things like this, but if there is too much attenuation you will definitely see unacceptable range. I would also check the cable for crimps and loose SMA connectors.

Rich L.

Hi Rich,

You are correct in that the lower portion of the antenna gets very close to the canopy frame. The upper portion does as well. This was done to get as much forward and rearward view for the antenna as possible. I believe moving the antennas inboard 1-2 inches would really hurt my front range, which is important of course. The fact that one antenna is performing much better in range than the other can't be ignored, and leads me to suspect some other root cause than placement. BTW, the system performs better than average in transmission (according to OGN). Is there a way to measure attenuation?

Cable crimps are good, and SMA connections are tight.

Matt,

I'm looking at picture 2 and have a couple of concerns:
-The antenna is not shown in the mounting bracket, but from picture 3 it seems certain that the lower arm would be very close and probably touching the fiberglass frame of the canopy. The upper arm is very likely close or touching the canopy itself.
-If the canopy frame is carbon, mounting so close would definitely affect performance, probably severely.

Even though the plexiglass or polycarbonate canopy is not conducting, they both have a higher dielectric constant than air and will definitely affect the tuning of the antenna. Most likely tuning it to a lower frequency than intended. The suggestion to use a wood mounting block to space the antenna away from the mounting surface is a good idea. I'd suggest trying to move it somewhere where there is at least an inch or two air around the antenna (especially the ends of the arms, the mounting bracket is OK as long as it is only near the middle).

I can't say for sure this will fix your problem. The RF design of these systems assume a considerable amount of attenuation from things like this, but if there is too much attenuation you will definitely see unacceptable range. I would also check the cable for crimps and loose SMA connectors.

Rich L.

Matt,

Are you sure the that the Black Mount ABS does not have carbon for a colorant?

Richard
www.craggyaero.com

On Thursday, April 22, 2021 at 8:29:43 AM UTC-7, Richard Pfiffner wrote:
Matt,

Are you sure the that the Black Mount ABS does not have carbon for a colorant?

Richard
www.craggyaero.com

Matt,

I suspect that the colorant in ABS is carbon black.
Make sure there is little to no carbon content, which would seriously alter antenna and system performance. BLACK anything -- including plastics -- is usually the worst, as they often have high carbon content. Think of applying black paint with carbon in it as applying very thin, black tin foil. Would you do that? Of course not. It would be both a shield and reflector, both of which are bad for the antenna (shield), the system connected to it (reflected power, VSWR, etc.), not to mention system performance.

Matt

I suspect that the colorant in ABS is carbon black.

Make sure there is little to no carbon content, which would seriously alter antenna and system performance. BLACK anything -- including plastics -- is usually the worst, as they often have high carbon content. Think of applying black paint with carbon in it as applying very thin, black tin foil. Would you do that? Of course not. It would be both a shield and reflector, both of which are bad for the antenna (shield), the system connected to it (reflected power, VSWR, etc.), not to mention system performance.

Richard
www.craggyaero.com