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FLARM Fusion Range



 
 
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  #21  
Old April 22nd 21, 05:27 PM posted to rec.aviation.soaring
Dan Daly[_2_]
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Posts: 718
Default FLARM Fusion Range

Have you tried swapping the two antennas? If the bad performance moves, you have a bad antenna or a bad mount. I have seen two antenna failures in my club; one a club glider, one a privately-owned glider. If you have an OGN receiver nearby, you can use "Glidertracker" to see your received power at the antennna (this is how I diagnose bad FLARMs, and also use a known good antenna to test the antennas); (click on your glider icon, a window pops up showing info including received signal strength at the receiver. In each failure, the power at our OGN station was 20 db lower on the bad antennas (OEM), about 50m away). I have saved shipping two FLARMs for unnecessary diagnosis by discovering bad antennas. Antennas are cheap, and they sometimes arrive dead, or break, particularly if they are often touched/handled/'twanged'. Link for Glidertracker is https://glidertracker.org/#lat=1105585&lon=6428048&z=5 . You can zoom it to your area. OGN stations are inexpensive and very useful for crew wondering how their pilot is doing.
  #22  
Old April 22nd 21, 05:42 PM posted to rec.aviation.soaring
George Haeh
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Posts: 257
Default FLARM Fusion Range

I use long antennas ($20 each) on foam blocks:

https://photos.app.goo.gl/tg8GHbnkDu3Lj7t78

Range:

https://drive.google.com/file/d/12rM...w?usp=drivesdk

Installing a short antenna next to a conductive item about the size of the antenna can interfere with the antenna performance. I attached a short antenna diagonally on a steel tube in a towplane and got abysmal performance.
  #23  
Old April 22nd 21, 05:52 PM posted to rec.aviation.soaring
George Haeh
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Posts: 257
Default FLARM Fusion Range

Oh yes,

Looking at your antenna in the bracket, the lead runs parallel to the antenna when it should run at a 90° angle directly away from the dipole.

You really need to carefully read: FTD-041Â*Application Note FLARM Antenna Installation

https://flarm.com/wp-content/uploads...stallation.pdf
  #24  
Old April 22nd 21, 06:48 PM posted to rec.aviation.soaring
Darryl Ramm
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Posts: 2,403
Default FLARM Fusion Range


Matt

Well since there is a PAPR report sitting there I'll bite.

Not that this will cause any FLARM antenna performance issues, but you need to get that ADS-B Out system performing correctly. Seems to be set up for 2020 (aka 14 CFR §91.227) compliance. Is this a TN72 GPS and a Trig TT22? It is not reporting altitudes correctly. It is totally useless as is, the FAA system is ignoring you, not making the glider a TIS-B client for example. And this system would not give you any ADS-B Out airspace privileges.. You are a candidate for a friendly FAA "she not be working, please explain" letter.

Start with what is the firmware version of this transponder and control head. Shown briefly on the LCD screen as the TT22 powers on... take a photo.

The minimal firmware version to support 14 CFR §91.227 compliance is transponder version 2.12 and TC20 Control Head version 1.14. The system must be at least at these levels. Older versions absolutely will not work. There is no advantage at being on transponder software version 2.13, ugt it's fine if you are. Oh and these are simple counting numbers after the decimal point, so say 2.4 is not 2.40 and is not later than 2.12 (this has confused at least two folks recently).

Is the ships static correctly connected to the TC20 control head? Had the transponder passed its biannual tests, including static/alt encoder checks? (and sure as heck, don't normally mess with the alt calibrations in the TT22 ADS-B setup menus). You can email me offline if stuck, there may be another local glider showing similar issues I am helping look at.

---

As for the FLARM antennas, touching the canopy/static concerns are extremely unlikely to be relevant. regardless of what the manual says. As folks have pointed out... get that coax away from the dipole arms, that is a bad setup. If plastic is RF opaque aslo as pointed out that will not be good. I would try just tapping the antennas (and coax lead) on the inside of the canopy and testing.

This may not be a very good location, You are close to metal components, rods, handles in the canopy mechanisms, wishing the RF near field which can significantly affect RF patterns. May be close to carbon in the fuselage canopy edge, even if the canopy frame has itself is RF opaque etc. There are likely no great choices for location, up on the instrument cover area is a conflict between ADS-B GPS antenna sky view, FLARM A and 1090ES so may not be much better. But you are really messing this up now with the coax running close parallel to the antenna. Lets see what the pattern looks like when you undo that.

On Wednesday, April 21, 2021 at 10:25:49 PM UTC-7, 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?

  #25  
Old April 24th 21, 12:36 AM posted to rec.aviation.soaring
Matt Herron Jr.
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Posts: 548
Default FLARM Fusion Range

Hi Darryl

Thanks for the ADS-B heads up. I checked the software, and it is at V2.12, FPGA v1.2 The controller is V1.14 so there must be some other problem. You helped me configure the system in the past, to the point where I got a passing grade from the FAA. So something else must have changed. Thoughts? Bad GPS antenna? (seems unlikely) Interference from other equipment? The only change to the panel has been replacing the PFlarm with a Fusion (including GPS antenna).

Matt

On Thursday, April 22, 2021 at 10:48:30 AM UTC-7, Darryl Ramm wrote:
Matt

Well since there is a PAPR report sitting there I'll bite.

Not that this will cause any FLARM antenna performance issues, but you need to get that ADS-B Out system performing correctly. Seems to be set up for 2020 (aka 14 CFR §91.227) compliance. Is this a TN72 GPS and a Trig TT22? It is not reporting altitudes correctly. It is totally useless as is, the FAA system is ignoring you, not making the glider a TIS-B client for example. And this system would not give you any ADS-B Out airspace privileges. You are a candidate for a friendly FAA "she not be working, please explain" letter.

Start with what is the firmware version of this transponder and control head. Shown briefly on the LCD screen as the TT22 powers on... take a photo.

The minimal firmware version to support 14 CFR §91.227 compliance is transponder version 2.12 and TC20 Control Head version 1.14. The system must be at least at these levels. Older versions absolutely will not work. There is no advantage at being on transponder software version 2.13, ugt it's fine if you are. Oh and these are simple counting numbers after the decimal point, so say 2.4 is not 2.40 and is not later than 2.12 (this has confused at least two folks recently).

Is the ships static correctly connected to the TC20 control head? Had the transponder passed its biannual tests, including static/alt encoder checks? (and sure as heck, don't normally mess with the alt calibrations in the TT22 ADS-B setup menus). You can email me offline if stuck, there may be another local glider showing similar issues I am helping look at.

---

As for the FLARM antennas, touching the canopy/static concerns are extremely unlikely to be relevant. regardless of what the manual says. As folks have pointed out... get that coax away from the dipole arms, that is a bad setup. If plastic is RF opaque aslo as pointed out that will not be good. I would try just tapping the antennas (and coax lead) on the inside of the canopy and testing.

This may not be a very good location, You are close to metal components, rods, handles in the canopy mechanisms, wishing the RF near field which can significantly affect RF patterns. May be close to carbon in the fuselage canopy edge, even if the canopy frame has itself is RF opaque etc. There are likely no great choices for location, up on the instrument cover area is a conflict between ADS-B GPS antenna sky view, FLARM A and 1090ES so may not be much better. But you are really messing this up now with the coax running close parallel to the antenna. Lets see what the pattern looks like when you undo that.
On Wednesday, April 21, 2021 at 10:25:49 PM UTC-7, 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?

  #26  
Old April 24th 21, 12:41 AM posted to rec.aviation.soaring
Matt Herron Jr.
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Posts: 548
Default FLARM Fusion Range

Another thought on ADS-B. I did an annual a month ago, and the seat pan had to come out. The antenna lead runs under it. Crushed coax? Also, to replace the Fusion, I had to unplug the Trig box. I will check for good connection, bent pins etc.

Matt
  #27  
Old April 24th 21, 01:56 AM posted to rec.aviation.soaring
Matt Herron Jr.
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Posts: 548
Default FLARM Fusion Range

All connections and pins look good on the trig setup...

On Friday, April 23, 2021 at 4:41:44 PM UTC-7, Matt Herron Jr. wrote:
Another thought on ADS-B. I did an annual a month ago, and the seat pan had to come out. The antenna lead runs under it. Crushed coax? Also, to replace the Fusion, I had to unplug the Trig box. I will check for good connection, bent pins etc.

Matt

  #28  
Old April 24th 21, 02:21 AM posted to rec.aviation.soaring
Matt Herron Jr.
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Posts: 548
Default FLARM Fusion Range

Interestingly, Andy B (9B) had the same altitude errors on the same day I did. See the report he https://www.dropbox.com/s/yzst4lmpri...48690.pdf?dl=0

Possible GPS TESTING/JAMMNG?

Matt
  #29  
Old April 24th 21, 03:50 AM posted to rec.aviation.soaring
Darryl Ramm
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Posts: 2,403
Default FLARM Fusion Range

On Friday, April 23, 2021 at 4:41:44 PM UTC-7, Matt Herron Jr. wrote:
Another thought on ADS-B. I did an annual a month ago, and the seat pan had to come out. The antenna lead runs under it. Crushed coax? Also, to replace the Fusion, I had to unplug the Trig box. I will check for good connection, bent pins etc.

Matt


OK great it's not a firmware version. It's unlikely to be any thing to to with the antenna or transponder/ADS-B Output RF side of things if it was you'd see other failures. And your report is very clean except for 100% failure on the GPS and pressure altitude data.

I forgot I'd helped on your setup before. It's hard to see what will cause GPS Altitude and Pressure Altitude to fail, esp. if nothing has changed. BTW the ADS-B settings are actually stored in the TC20 control head, so if that's ever replaced the settings are lost and need to be redone--but I'm at a loss because there is no config setting that I can think of that could cause both these altitudes to not report. Failing pressure altitude alone might be caused by things like having the pitot connected to the TC20 head static line. And other unrelated problems might explain a GPS Altitude problem.. But regardless of what that does and what the system might interpret is bad with pressure altitude it should still separately transmit the GPS Altitude, they are sent across different position reports, some with pressure alt, some with GPS alt. And it's hard to see how a data wiring problem could cause this but not other issues.

Maybe the easiest thing to is pull an PAPR report for a different recent flight and see if that is also failing. And when the FAA email that to you (or for this one here) just reply to the email and ask for a detailed kmz (Google Earth) and spreadsheet data reports. Eyeballing the data may give clues... although you don't actually see the real raw data, it's all unfortunately processed a bit).

Another simple thing to check is what FL is being shown in the transponder display during flight (or pull a slight vacuum on the static and see the FL climb to just confirm that the transponder encoder in the TC20 head is working at all.

Failing that I'm already looking with Andy at his JS3 which as you noted has some ADS-B Out weirdness also showing GPS Alt and Pressure Alt fails, but also has other issues, and if that turns up anything I'll be in touch.

No, GPS Jamming or anything else related to RF signal will not explain the lack of pressure altitude data. (And GPS jamming would need to be very sophisticated to just trash GPS Altitude, the average idiot with a cheap jammer purchased off EBay can't do anything like this even if hacked with high output power). I'd suspect a fault with say the FAA ground system or PAPR report if multiple aircraft experienced this at the same time... were other gliders with ADS-B Out or TABS flying at the same time... we can pull PAPR reports for them as well. If you reply to the FAA PAPR email and ask for those detailed reports you might mention the altitude failures and how that's difficult to explain and ask if other flights in the area were experiencing GPS Alt and Pressure Alt data problems... those emails seem to be read by humans.

---

Oh the frustrations with ADS-B, nothing today really uses GPS altitude AFAIK -- and this came up recently in the NTSB report on the Ketchikan Alaska fatal mid air collision where pilots did not receive ADS-B traffic collision warning because the ADS-B Out in one aircraft was not getting pressure altitude data, but *was* getting and transmitting GPS altitude data... but the other ADS-B-In completely ignored the GPS Altitude and did not issue a traffic warning. A failure of design, and more a failure of maintenance and company processes, including the basic failure to obtain a PAPR report to validate ADS-B Out is working after maintenance... may not necessarily be required but damn common sense to do so. NTSB info he https://www.ntsb.gov/news/events/Pag...141AB-BMG.aspx. And to show the value of periodically checking with a PAPR report, in this case of Matt's glider if the altitude reporting problems are real we know that no other aircraft are getting ADS-B based traffic alerts from this glider, and ATC is not going to be seeing the glider via ADS-B (and maybe not transponder either) traffic (If this has happened for a while the glider will have been black-listed by the FAA as non-compliant and will be totally ignored).

  #30  
Old April 24th 21, 08:51 PM posted to rec.aviation.soaring
Matt Herron Jr.
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Posts: 548
Default FLARM Fusion Range

ads-b update

I looked at the FAA report for two other pilots that flew out of the Williams area on Friday 4/16, Ramy ( https://www.dropbox.com/s/f7wgkinoru...55266.pdf?dl=0 ) and Peter Deane ( https://www.dropbox.com/s/8vkprmv4gu...57927.pdf?dl=0 ). They both had pretty identical long flights all the way around the top of the valley to Trinity Center and back down the Eastern edge of the valley, then back to Williams. Ramy showed a normal report, while Peter showed 48.01% fail on Baro., and 48.01% on GPS. alt. Why are these two 48.01% numbers identical? Bad ground station for part of the flight? If so why did Ramy have no issues with Baro. or GPS Alt.?

Matt
 




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