randallpittman
New member
I'm part of a research team that uses an onshore tower-mounted FAR2127BB (25 kW X-band) radar to image ocean waves. We record the data with an external (Cambridge Pixel) data acquisition card connected to one of the sub-display ports on the RPU.
In the last year or so we've been seeing a sort of "image doubling" in the radar video. It appears to be along the radial dimension. This appears both on the Furuno display output as well as in the digitized video signal captured with with the Cambridge Pixel card. See the below image for the Furuno display with red lines highlighting some of the "doubled" wave crests
The following images are generated from the data we recorded with our DAQ card. The first shows the incoherence while the latter is improved. Note in particular the buoy between the jetties that is doubled in the first image and not in the second.
After fiddling with the tuning and running the tune initialization I was able to achieve the second image. Unfortunately, I think this messed up the auto gain (?) such that I had to revert to manual tuning or else the video on the Furuno display became almost completely washed out (dim). Even while leaving the radar set to manual tuning, after a few hours the incoherency/doubling returned.
I'd really appreciate some insight into all this. As an aside, is there any way to adjust the auto gain that got reset by the tune initialization without taking the radar out to sea or a big field? The transceiver/antenna unit is on top of a tower and not easy to move.
In the last year or so we've been seeing a sort of "image doubling" in the radar video. It appears to be along the radial dimension. This appears both on the Furuno display output as well as in the digitized video signal captured with with the Cambridge Pixel card. See the below image for the Furuno display with red lines highlighting some of the "doubled" wave crests
The following images are generated from the data we recorded with our DAQ card. The first shows the incoherence while the latter is improved. Note in particular the buoy between the jetties that is doubled in the first image and not in the second.
After fiddling with the tuning and running the tune initialization I was able to achieve the second image. Unfortunately, I think this messed up the auto gain (?) such that I had to revert to manual tuning or else the video on the Furuno display became almost completely washed out (dim). Even while leaving the radar set to manual tuning, after a few hours the incoherency/doubling returned.
I'd really appreciate some insight into all this. As an aside, is there any way to adjust the auto gain that got reset by the tune initialization without taking the radar out to sea or a big field? The transceiver/antenna unit is on top of a tower and not easy to move.
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