Van's Air Force
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- Thread starter rwarre
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cfiidon
Well Known Member
More info please
You may need to elaborate a bit.
When you enter a discrete code, ATC tells you they see 1200 VFR (my understanding).
Is ATC reporting 1200 from your transponder or is that an ADSB report?
The Uavionix should not have any effect on your transponder. What I suspect is that the transponder sniffer threshold is set too high. The uavionix defaults to 1200 while your transponder is broadcasting a discrete code. ATC software may report that as two different aircraft co-located.
Perhaps you have already investigated the threshold settings... thus the request for more info.
Don
You may need to elaborate a bit.
When you enter a discrete code, ATC tells you they see 1200 VFR (my understanding).
Is ATC reporting 1200 from your transponder or is that an ADSB report?
The Uavionix should not have any effect on your transponder. What I suspect is that the transponder sniffer threshold is set too high. The uavionix defaults to 1200 while your transponder is broadcasting a discrete code. ATC software may report that as two different aircraft co-located.
Perhaps you have already investigated the threshold settings... thus the request for more info.
Don
moosepileit
Well Known Member
Skybeacon or tailbeacon?
Are you passing PAPRs currently? Check that FIRST before reading the rest of this. IF not, that is the easier fix as your sensitivity is likely too low with too high a number selected. If passing PAPRs, then everything below might help.
https://adsbperformance.faa.gov/PAPRRequest.aspx
IF PAPR is all good, no exceptions, no red boxes...
Current version of the OS is 1.5.1. If you have that and lose a discrete reply for over a minute, your UAT gives "0000" if updated to 1.5.1 which came out 10/2020. If NOT updated, it gives "1200" and needs updating, technically. This alone may not be a full fix to your post. You may simply want to increase sensitivity by lowering your number 1 digit. IF it is dropping to 1200 it is likely throwing some red fails and PAPR exceptions. If your transponder is flashing replies each minute, the UAT shuold sniff and update its 4 number code to match. After a minute of not sniffing, it should drop to where it starts, "0000" with 10/2020 updated or 1200 if out older versions of firmware. I bet you need to increase sensitivity by dropping the # in sensitivity to 1 or 2 less than present for on intermittent issue. If too sensitive with too low a sensitivity # you may get the issue of ATC seeing neither 0000/1200 or your assigned code, but my example of mode 3C replacing mode 3A and really cobfusing ATC.
It should be "0000" NOT "1200" output when NOT in radar and I am not sure how it could replace 1200 over a discrete mode 3A other than being an outdated version, but I will take the time to explain a similar situation I suffered on the beacon current version that did not hapoen previously. Do you need to update your Beacon (via windows computer and wifi)?
Pick your device:
https://uavionix.com/support/
This COULD be another sensitivity issue, similar but different. If you are squawking ATC discrete, non-1200, the beacon should not be able to say 1200, as it does not exist out of your transponder at the time. Mine was to high for any of the documented sensitivities, shifting time slots of Mode 3C in Mode 3A's.
I had a long issue as the default sensitivity is now 35 and I needed the old default of 42, higher number being LESS sensitive.
What the beacon does if TOO sensitive is swap your Mode3C altitude into your Mode3A 4096 settings slot. "1200" becomes "0320" or whatever the decoded altitude translates to and confuses ATC if they read your ADS-B out altitude.
My KT-76A and GRT EFIS as my blind encoder source, antenna, tray connection and RG-400 cable all checked out on the bench, so it had to be the beacon.
The last software update at uAvionix dropped the default sensitivity from 42 to 35 and capped the range at 30 to 40. Turns out you can do a few long touches undocumented in their iOS App store/Google Play app and get the range back up to 45. Only 41 or 42 work for me. 40 and below does not. PAPRS pass at any setting, but less than 41 corrupt what ATC sees when too sensitive/too low a #.
With the current software app locked in a 30-40 range, I can't be the only one with the issue. Maybe yours is similar, if up to date.
My base is towered class D under a Class C, so tower was helpful as they were the ones seeing the 1200 changing to a discrete they didn't assign or otherwise want to see.
Hope this helps, Trevor Mack at uAvionics helped me figure it out after many recorded flights and PAPRs were always passing during this trial.
If NOT sensitive enough, you fail PAPRS. If TOO sensitive, you may run into the issue of Mode3C replacing your Mode3A squawk 1200 or any discrete code.
Send an email on the uAvionics website. Likely Trevor replies, have a PAPR .pdf ready to send him. He will look at the subject flight in more depth than we see unless actively recording our own ADS-B out stream, which I learned to do back in the "What Anonymous is and is not" days when the UATs rolled out.
This is how I matched my proper 3C out to see it misplaced by the over sensitive beacon setting- GRT has a set menu discrete output page if you happen to use one.
Example, ATC or your recoder sees "0320" in your squawk instead of your "1200" or assigned at an encoder height of 1000 feet. Wiki Gillham grey codes to see the binary tables.
000 000 110 010 binary is 0320 grey code at 304.8 Meters or 1000 foot height.
But GRT shows it as the below in discrete outputs: "on" for B1, B2 and C2. See that is 1000' by checking those on:
http://www.avionictools.com/graycalc.php
Are you passing PAPRs currently? Check that FIRST before reading the rest of this. IF not, that is the easier fix as your sensitivity is likely too low with too high a number selected. If passing PAPRs, then everything below might help.
https://adsbperformance.faa.gov/PAPRRequest.aspx
IF PAPR is all good, no exceptions, no red boxes...
Current version of the OS is 1.5.1. If you have that and lose a discrete reply for over a minute, your UAT gives "0000" if updated to 1.5.1 which came out 10/2020. If NOT updated, it gives "1200" and needs updating, technically. This alone may not be a full fix to your post. You may simply want to increase sensitivity by lowering your number 1 digit. IF it is dropping to 1200 it is likely throwing some red fails and PAPR exceptions. If your transponder is flashing replies each minute, the UAT shuold sniff and update its 4 number code to match. After a minute of not sniffing, it should drop to where it starts, "0000" with 10/2020 updated or 1200 if out older versions of firmware. I bet you need to increase sensitivity by dropping the # in sensitivity to 1 or 2 less than present for on intermittent issue. If too sensitive with too low a sensitivity # you may get the issue of ATC seeing neither 0000/1200 or your assigned code, but my example of mode 3C replacing mode 3A and really cobfusing ATC.
It should be "0000" NOT "1200" output when NOT in radar and I am not sure how it could replace 1200 over a discrete mode 3A other than being an outdated version, but I will take the time to explain a similar situation I suffered on the beacon current version that did not hapoen previously. Do you need to update your Beacon (via windows computer and wifi)?
Pick your device:
https://uavionix.com/support/
This COULD be another sensitivity issue, similar but different. If you are squawking ATC discrete, non-1200, the beacon should not be able to say 1200, as it does not exist out of your transponder at the time. Mine was to high for any of the documented sensitivities, shifting time slots of Mode 3C in Mode 3A's.
I had a long issue as the default sensitivity is now 35 and I needed the old default of 42, higher number being LESS sensitive.
What the beacon does if TOO sensitive is swap your Mode3C altitude into your Mode3A 4096 settings slot. "1200" becomes "0320" or whatever the decoded altitude translates to and confuses ATC if they read your ADS-B out altitude.
My KT-76A and GRT EFIS as my blind encoder source, antenna, tray connection and RG-400 cable all checked out on the bench, so it had to be the beacon.
The last software update at uAvionix dropped the default sensitivity from 42 to 35 and capped the range at 30 to 40. Turns out you can do a few long touches undocumented in their iOS App store/Google Play app and get the range back up to 45. Only 41 or 42 work for me. 40 and below does not. PAPRS pass at any setting, but less than 41 corrupt what ATC sees when too sensitive/too low a #.
With the current software app locked in a 30-40 range, I can't be the only one with the issue. Maybe yours is similar, if up to date.
My base is towered class D under a Class C, so tower was helpful as they were the ones seeing the 1200 changing to a discrete they didn't assign or otherwise want to see.
Hope this helps, Trevor Mack at uAvionics helped me figure it out after many recorded flights and PAPRs were always passing during this trial.
If NOT sensitive enough, you fail PAPRS. If TOO sensitive, you may run into the issue of Mode3C replacing your Mode3A squawk 1200 or any discrete code.
Send an email on the uAvionics website. Likely Trevor replies, have a PAPR .pdf ready to send him. He will look at the subject flight in more depth than we see unless actively recording our own ADS-B out stream, which I learned to do back in the "What Anonymous is and is not" days when the UATs rolled out.
This is how I matched my proper 3C out to see it misplaced by the over sensitive beacon setting- GRT has a set menu discrete output page if you happen to use one.
Example, ATC or your recoder sees "0320" in your squawk instead of your "1200" or assigned at an encoder height of 1000 feet. Wiki Gillham grey codes to see the binary tables.
000 000 110 010 binary is 0320 grey code at 304.8 Meters or 1000 foot height.
But GRT shows it as the below in discrete outputs: "on" for B1, B2 and C2. See that is 1000' by checking those on:
http://www.avionictools.com/graycalc.php
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