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Continuing problems seeing ATCRBS transponders with Mode Sinterrogators
Continuing problems seeing ATCRBS transponders with Mode S
interrogators Hey all, I work in, lets call it 'an associated industry' and we are still seeing ATCRBS transponders that reply to some interrogators, and not to others. At one time this was known as the 'P4 problem', sometimes as the 'Terra problem', just want to ask if anyone out there flying with an ATCRBS xpdr is still having trouble being 'seen' by some interrogators, but no problem with others. Thx- Dave |
#2
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Continuing problems seeing ATCRBS transponders with Mode S interrogators
wrote in message
... Continuing problems seeing ATCRBS transponders with Mode S interrogators Hey all, I work in, lets call it 'an associated industry' and we are still seeing ATCRBS transponders that reply to some interrogators, and not to others. At one time this was known as the 'P4 problem', sometimes as the 'Terra problem', just want to ask if anyone out there flying with an ATCRBS xpdr is still having trouble being 'seen' by some interrogators, but no problem with others. You need to provide more symptoms, locations, interrogator identifiers, etc. Some types of interrogators have the ability to selectively interrogate ModeS transponders (although I'm not sure if any of them do in actuality). Early on in the ModeS program there were sensor problems with side lobe suppression and reflection rejection, although those problems may have been addressed with later modifications. This is my best guess as far as to what you're referring to, although it would actually be more correctly referred to as a "P2 problem" although I've never heard it called that. |
#3
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Continuing problems seeing ATCRBS transponders with Mode Sinterrogators
On Sep 24, 12:21 am, "Mike" nospam@ microsoft.com wrote:
wrote in message ... Continuing problems seeing ATCRBS transponders with Mode S interrogators Hey all, I work in, lets call it 'an associated industry' and we are still seeing ATCRBS transponders that reply to some interrogators, and not to others. At one time this was known as the 'P4 problem', sometimes as the 'Terra problem', just want to ask if anyone out there flying with an ATCRBS xpdr is still having trouble being 'seen' by some interrogators, but no problem with others. You need to provide more symptoms, locations, interrogator identifiers, etc. Some types of interrogators have the ability to selectively interrogate ModeS transponders (although I'm not sure if any of them do in actuality). Early on in the ModeS program there were sensor problems with side lobe suppression and reflection rejection, although those problems may have been addressed with later modifications. This is my best guess as far as to what you're referring to, although it would actually be more correctly referred to as a "P2 problem" although I've never heard it called that. This is a Mode S/ATCRBS interrogator, short P4 pulse on the ATCRBS interrogations, certain percentage of the ATCRBS transponders are visible to a nearby ATCRBS-only interrogator but do not reply to the MODE S interrogators ATCRBS-ONLY ATCRBS interrogations. The P4 problem was where an ATCRBS transponder would suppress on the P3-P4 pair, mistaking it for a P1-P2 pair. Dave |
#4
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Continuing problems seeing ATCRBS transponders with Mode S interrogators
wrote in message
... On Sep 24, 12:21 am, "Mike" nospam@ microsoft.com wrote: wrote in message ... Continuing problems seeing ATCRBS transponders with Mode S interrogators Hey all, I work in, lets call it 'an associated industry' and we are still seeing ATCRBS transponders that reply to some interrogators, and not to others. At one time this was known as the 'P4 problem', sometimes as the 'Terra problem', just want to ask if anyone out there flying with an ATCRBS xpdr is still having trouble being 'seen' by some interrogators, but no problem with others. You need to provide more symptoms, locations, interrogator identifiers, etc. Some types of interrogators have the ability to selectively interrogate ModeS transponders (although I'm not sure if any of them do in actuality). Early on in the ModeS program there were sensor problems with side lobe suppression and reflection rejection, although those problems may have been addressed with later modifications. This is my best guess as far as to what you're referring to, although it would actually be more correctly referred to as a "P2 problem" although I've never heard it called that. This is a Mode S/ATCRBS interrogator, short P4 pulse on the ATCRBS interrogations, certain percentage of the ATCRBS transponders are visible to a nearby ATCRBS-only interrogator but do not reply to the MODE S interrogators ATCRBS-ONLY ATCRBS interrogations. The P4 problem was where an ATCRBS transponder would suppress on the P3-P4 pair, mistaking it for a P1-P2 pair. Before ModeS systems were commissioned this was a known problem and a ATCRBS all-call interrogation was added to the ModeS systems (No P4 pulse). That's why I'm asking you which sensor you are referring to because none of them should have the problem you are describing, although some transponders may still not reply to some ModeS all-call interrogations, they should still be displayed due to the ATCRBS all-call interrogation from the ModeS sensor. My understanding was the problematic transponders would be subject to an AD and fixed, but I don't know if this ever happened. |
#5
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Continuing problems seeing ATCRBS transponders with Mode Sinterrogators
On Sep 24, 11:05 am, "Mike" nospam@ microsoft.com wrote:
wrote in message ... On Sep 24, 12:21 am, "Mike" nospam@ microsoft.com wrote: wrote in message ... Continuing problems seeing ATCRBS transponders with Mode S interrogators Hey all, I work in, lets call it 'an associated industry' and we are still seeing ATCRBS transponders that reply to some interrogators, and not to others. At one time this was known as the 'P4 problem', sometimes as the 'Terra problem', just want to ask if anyone out there flying with an ATCRBS xpdr is still having trouble being 'seen' by some interrogators, but no problem with others. You need to provide more symptoms, locations, interrogator identifiers, etc. Some types of interrogators have the ability to selectively interrogate ModeS transponders (although I'm not sure if any of them do in actuality). Early on in the ModeS program there were sensor problems with side lobe suppression and reflection rejection, although those problems may have been addressed with later modifications. This is my best guess as far as to what you're referring to, although it would actually be more correctly referred to as a "P2 problem" although I've never heard it called that. This is a Mode S/ATCRBS interrogator, short P4 pulse on the ATCRBS interrogations, certain percentage of the ATCRBS transponders are visible to a nearby ATCRBS-only interrogator but do not reply to the MODE S interrogators ATCRBS-ONLY ATCRBS interrogations. The P4 problem was where an ATCRBS transponder would suppress on the P3-P4 pair, mistaking it for a P1-P2 pair. Before ModeS systems were commissioned this was a known problem and a ATCRBS all-call interrogation was added to the ModeS systems (No P4 pulse). That's why I'm asking you which sensor you are referring to because none of them should have the problem you are describing, although some transponders may still not reply to some ModeS all-call interrogations, they should still be displayed due to the ATCRBS all-call interrogation from the ModeS sensor. My understanding was the problematic transponders would be subject to an AD and fixed, but I don't know if this ever happened. Yes, my understanding also was that any transponders with this behavior had been purged or fixed. We are still trying to find the common thread on this one, could be something completely different, even an excessively low MTL on the transponder that is picking up the leading S1 pulse (TCAS ATCRBS Whisper-Shout interrogations). Thanks- Dave |
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