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Cendence with patch antenna problems

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I’ve only recently obtained my I2 with Cendence and patch antenna - having had various other DJIs.

My question is how should I be positioning the patch antenna to get the best connection to the I2?

I had a really scary experience today - my I2 was about 100ft up but wouldn’t respond to any input from the right stick meaning I couldn’t get it back to me! I hit RTH and it started to land rather come back to the Home Point. The I2 would have landed on my shed roof if the sensors hadn’t prevented it from doing so - at that point I was able to regain control and everything was fine... all firmware is up to date and the home point was set before I took off. Incidentally as the I2 started to land I ran across my garden to try and rescue it - only to fall head over heels down a bank in my panic - thankfully, no major injury - just to my pride as the whole family was watching 🤣All a bit of a mystery really but with a happy ending.

So, was this down to my patch antenna not being on the ‘best’ position?
 
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I’ve only recently obtained my I2 with Cendence and patch antenna - having had various other DJIs.

My question is how should I be positioning the patch antenna to get the best connection to the I2?

I had a really scary experience today - my I2 was about 100ft up but wouldn’t respond to any input from the right stick meaning I couldn’t get it back to me! I hit RTH and it started to land rather come back to the Home Point. The I2 would have landed on my shed roof if the sensors hadn’t prevented it from doing so - at that point I was able to regain control and everything was fine... all firmware is up to date and the home point was set before I took off. Incidentally as the I2 started to land I ran across my garden to try and rescue it - only to fall head over heels down a bank in my panic - thankfully, no major injury - just to my pride as the whole family was watching 🤣All a bit of a mystery really but with a happy ending.

So, was this down to my patch antenna not being on the ‘best’ position?
Did you updated Cendence FW with Patch Antenna attached? Antenna itself contains some circuitry which must be recognized during FW update. As for positioning ... Patch Antenna is highly directional, therefore maintaining surface perpendicular to VLOS is critical. This is true at short distances in particular. The advantage of PA may be crucial for live video transmission setup (i.e. live feed to a TV truck), or for long distance flights with unobstructed, true BVLOS. In most situations standard omnidirectional sticks are just fine and more suitable.
 
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Did you updated Cendence FW with Patch Antenna attached? Antenna itself contains some circuitry which must be recognized during FW update. As for positioning ... Patch Antenna is highly directional, therefore maintaining surface perpendicular to VLOS is critical. This is true at short distances in particular. The advantage of PA may be crucial for live video transmission setup (i.e. live feed to a TV truck), or for long distance flights with unobstructed, true BVLOS. In most situations standard omnidirectional sticks are just fine and more suitable.
Omni sticks have a week signal dispersion area. It is directly above the tips of the sticks. Therefore they should never be pointed directly at the drone. With the patch antenna, as Dobmatt said, it needs to be perpendicular to the drone. Think of it like it was a mirror, the drone should see itself in it all the time. When the drone is directly above you, this is when the position of the patch antenna becomes increasingly important, its flat surface needs facing the drone, in other words if the drone is directly above you, the patch flat surface must be facing the sky.
 
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The operation of the Cendence and Patch Antenna is as previously described - in theory. With all due respect to the talented engineers of DJI I did some extensive testing of the patch v. standard last summer in preparation for using the Cendence SDI connector to attach to the control booth for live parade broadcasts. I wanted the very best video feed that I could get. After multiple tests at various altitudes and distances, I found that the standard Cendence antenna consistently provided a better and stronger video feed - not to mention that the whole unit was getting heavy with the big Crystalsky screen and patch unit. I have not had any issues with lost connection, but there were times that I noticed a reduction in signal strength. Therefore the patch unit will gather dust on my shelf. Love the Cendence and Crystalsky. Cannot imagine using the old radio and iPad for my commercial work. (also have the Crystalsky adapter on my Mavic, only still use the iPad on my backup I1)
 
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The operation of the Cendence and Patch Antenna is as previously described - in theory. With all due respect to the talented engineers of DJI I did some extensive testing of the patch v. standard last summer in preparation for using the Cendence SDI connector to attach to the control booth for live parade broadcasts. I wanted the very best video feed that I could get. After multiple tests at various altitudes and distances, I found that the standard Cendence antenna consistently provided a better and stronger video feed - not to mention that the whole unit was getting heavy with the big Crystalsky screen and patch unit. I have not had any issues with lost connection, but there were times that I noticed a reduction in signal strength. Therefore the patch unit will gather dust on my shelf. Love the Cendence and Crystalsky. Cannot imagine using the old radio and iPad for my commercial work. (also have the Crystalsky adapter on my Mavic, only still use the iPad on my backup I1)
Thanks for sharing this info. Without trying to be argumentative, may I ask how did you conduct the extensive testing? I did not test anything just took DJI word for it and use patch as standard now. I used to use Omni but experienced one serious issue over time. I lost FPV feed from my drone. I opened up the Cendence as it was just out of warranty. I am a curious person and wanted to see how it is made🤔🙂. Upon close inspection of the RF module I noticed that one wire leading from the PCB to one antenna port was broken off from the antenna port end. The way this has been designed and implemented has a lot to be desired... It seemed to me that the frequent twisting of that wire, as I positioned the Omni sticks from travel position to flying position twisted the wires way too much. It eventually led to material fatigue of the few strands the wires consist of and one of the two wires, the shorter one with less flexibility to cope with the frequent twisting simply broke off. To me this is a serious issue and a design flaw. Since then I decided to use patch as the antenna connectors remain in one position all the time and do not require turning, as is the case with Omni antennas every time they are put in rabit ears position from fully folded one allongside the Cendence body for transport in the case. If I was to use the sticks again I would pull the RF module out and secure the wires in the connectors from inside with a silicone or a hot glue or some other means.
I agree that Cendence with patch and CS becomes just a bit too heavy. With Omni it feels just right. But that is a small price to pay for the comfort of knowing that the antenna wires inside are safe and not stressed from the frequent twisting...
 
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Good info. My testing was pretty basic. I simply set a predefined flight path with variable altitude and distance (including flying directly above). Altitude was <100' and distance <750'. I would modify the patch and the omni antennas for the location of the I2. I recorded video (1080 / 29 - broadcast standard) while flying. I also had the strength bars on the display and kept my eyes on them. I did the same flight with both antennas. I did not have my iphone running at the time and the area was pretty free of electrical interference (rural area - big field to fly in). I made my decision from those tests AND the resultant video. I concur with your issues with the standard omni antennas. I never transport my Cendence with the antennas folded together. It was obvious that the radio was a bit resistant to moving them that way. When I need to put the radio in a case, I have a bigger separate case where the antennas can simply be straightened out instead. When I need to put everything in a case, I always try to avoid boxing the radio. Just as soon carry it carefully. I rarely have work where I need to fly and check anything in. I totally concur with possible issues with the Cendence antennas. They appeared fragile to me and thus I do not mess with them. I was bummed that the patch did not work better. But still the non-directional omni gives me less to deal with.
 
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Good info. My testing was pretty basic. I simply set a predefined flight path with variable altitude and distance (including flying directly above). Altitude was <100' and distance <750'. I would modify the patch and the omni antennas for the location of the I2. I recorded video (1080 / 29 - broadcast standard) while flying. I also had the strength bars on the display and kept my eyes on them. I did the same flight with both antennas. I did not have my iphone running at the time and the area was pretty free of electrical interference (rural area - big field to fly in). I made my decision from those tests AND the resultant video. I concur with your issues with the standard omni antennas. I never transport my Cendence with the antennas folded together. It was obvious that the radio was a bit resistant to moving them that way. When I need to put the radio in a case, I have a bigger separate case where the antennas can simply be straightened out instead. When I need to put everything in a case, I always try to avoid boxing the radio. Just as soon carry it carefully. I rarely have work where I need to fly and check anything in. I totally concur with possible issues with the Cendence antennas. They appeared fragile to me and thus I do not mess with them. I was bummed that the patch did not work better. But still the non-directional omni gives me less to deal with.
I guess the 100' altitude and 750' distance were not really "testing" the signal strength. Both of these are relatively modest in terms of reach and I am sure Omni would perform flawlesly as they should.. The benefit and perhaps "strength" of the patch might proof itself over longer distances. Your routine of not folding the Omni to transport position and leave them in one position might have saved your Cendence from malfunctioning. I place my Cendence in the case every time and transport and store everything in it, so I was "abusing" the internal antenna wires not being aware of the design flaw and how flimsy the wire connection inside of the antenna port was..
 
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Concur. I was really looking to see how good and reliable the HD signal was. It was critical that it was the best for live TV coverage. It was no time to fiddle around with marginal signals. I did experience a few issues with the signal and I was able to also test both antennas when plugged into the master control in a transmission test a week before. The omni worked the best. The reason I decided earlier not to fold the antennas was simply because it seemed the Cendence was fighting the relocation of them. And then they also squeaked during the rotation. All not good, and I had a feeling the radio was not designed for that type of use. So I completely avoided messing with that part of the radio. The result, I have had zero issues with the Cendence. Totally great radio with the Crystalsky with very low latency.
 
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Concur. I was really looking to see how good and reliable the HD signal was. It was critical that it was the best for live TV coverage. It was no time to fiddle around with marginal signals. I did experience a few issues with the signal and I was able to also test both antennas when plugged into the master control in a transmission test a week before. The omni worked the best. The reason I decided earlier not to fold the antennas was simply because it seemed the Cendence was fighting the relocation of them. And then they also squeaked during the rotation. All not good, and I had a feeling the radio was not designed for that type of use. So I completely avoided messing with that part of the radio. The result, I have had zero issues with the Cendence. Totally great radio with the Crystalsky with very low latency.
My Cendence suffered from the same squeaky antenna issue. After the FPV loss and the broken wire DJI replaced the Cendence for a brand new one even though my old one was a couple of months out of warranty. On the new radio the antennas turn smoothly and without the squeaky sound and no excessive force is required to turn them. So they must have addressed that part with later radios..
 

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