There is another thread with "Why so many ghosting?", but that author was highlighting two events I'm not really confused about so much as the simple fact that the Varia RCT-715 has been slightly worse from a frequency perspective for not "seeing" cars as they approach from behind. There is no pattern, or manufacturer, or even era of vehicle that seems to explain the fact that I will not be warned of the vehicle.
I have had the Varia RT-535 (or whatever the latest version with the light was) as well as the one with just radar and no light, and those two models had very low occurrence rates for ghost vehicles. I keep my device clean after each ride and well above the rear wheel (high on the seat post) and I use no saddle bag.
I have also had a number of connection issues with the RCT-715 and my recently acquired 1040 Solar. So while the light may be on, I cannot "save clip" or take a photo, nor can I set the light to "Flash mode". This happens 1/10 times, and is remedied by going into connections and manually connecting the radar and then the light.
Apart from these issues, I am quite happy with my new devices. I cannot believe how long it took for me to "give into" the radar devices, but they enhance my sense of safety considerably (which could be erroneous after all).
Cheers
