Originally published at http://www.commondreams.org/views/2020/08/10/tracking-apps-are-unlikely-help-stop-covid-19
A couple of other items, one of which is touched on.
Bluetooth itself is not that reliable. It is, after all, just radio waves we are talking about with all of the problems with absorption, reflection, distance and so forth. One of the principal means of determining distance is unreliable. Here, from the Intercept (May)
Given that Google and Apple’s Bluetooth contact tracing relies on using the strength of a received signal (Received Signal Strength Indication, or RSSI) to determine whether you were within coughing distance of a Covid-19 patient that time you walked to the grocery store, this could be a serious problem. Swarun Kumar, a professor of electrical and computer engineering at Carnegie Mellon University, recently estimated (see video below) that environmental factors could make a Bluetooth device that’s 2 meters away appear to another device as if it’s 20 meters away, or vice versa.ref URL: ~~tps://theintercept.com/2020/05/05/coronavirus-bluetooth-contact-tracing/
Then there is the problem that Bluetooth is basically blind. It has no idea and no data clue as to whether the “near contact” is naked or in full protective gear. Or whether it is inside or outside, windy or not, loud voices or singing voices with a lot of spray or all very still.
Basically this is a very inadequate tool, even if every last person had the same device running the same app.
In the end it is more a shiny distraction than help and needs to be put aside. We just have to do the work, in person.
Adding on (edit): this from the comment section of the Intercept article by “24b4Jeff”
NIce piece, Sam. It is truly amazing that anyone with even a rudimentary knowledge of RF propagation would propose to measure distance based on signal strength. In my career, I've seen literally hundreds of millions of dollars wasted by the military in pursuing various efforts to determine range based on signal strength. None of them worked, even approximately for a great variety of reasons, including but not limited to the ones you listed in the article.
He said something I thought of later but said it better than I might have. Absolutely right. The only ranging devices I’ve ever worked with that used radio (or light) waves used wavelength and frequency against retrodirective reflective targets. This was surveying equipment in the 60’s and 70s. microwaves, and light waves. Trying to use signal strength as a measure is just very crude as well as inconsistent.
Oh, did you cough on me that day when you left your phone at home? How very inconsiderate of you!
We don’t need “no stinking apps”, just require the NSA to give up the data they’ve been collecting on us, problem solved. Make evil do something good.
Tracking is huge part of the solution, it is the lack of will to do it that is the problem. If your phone beeped when you were within 20 feet of + test, it would help, if you were positive and every one close could be notified and tracked and tested…how could that not help? This is a ridiculous argument.
One wek later, August 17
Will County, Illinois south of Chicago with Joliet as largest city.
Public health trackers on phones are met with apathy.
Refusals by the infected to identify their personal contacts.
Lack of leadership if FDR or JFK said track it would be done.
I am trying to understand why so many people are resisting using masks, social distancing, cleanliness.
Maybe arrogance that “I” am singular and nobody is gonna tell me what to do or ask who I have contact with.