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Viewing 15 posts - 706 through 720 (of 766 total)
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  • in reply to: #12000029 Paisley Scotland #994
    Radu
    Keymaster

    Indeed the crystal needs to be replaced, as a quick fix to get the unit back online.

    in reply to: #12000029 Paisley Scotland #993
    Radu
    Keymaster

    Nice one! 🙂

    in reply to: Filtering options #992
    Radu
    Keymaster

    Thanks, they are in plan, keep the good ideas coming. We’ll also need stats of various types.

    in reply to: New uRad installation 1200002D #988
    Radu
    Keymaster

    Done. COOLVILLE added 🙂

    in reply to: #12000029 Paisley Scotland #978
    Radu
    Keymaster

    The 12000029 is experiencing a ” time dilatation” problem. As weird as it seems, this is what is happening: the quartz crystal responsible for accurate time measurement has failed (acting like a 4MHz instead of 8MHz), and needs to be replaced. Because of this what the unit should see as one minute is actually 2.04minutes. The DS18B20 that requires precise time intervals for initialisation is unable to measure temperature and shows -0.06. The CPM is double, as radiation is measured across a 2.04minutes interval. The duty cycle is half of what it should be.

    Hopefully the unit will be fixed soon and get back online. For the moment I turned it off from the server side.

    This was one of the strangest bugs to track as the quartz crystals only rarely fail like this.

    • This reply was modified 10 years, 4 months ago by Radu.
    • This reply was modified 10 years, 4 months ago by Radu.
    in reply to: New uRad installation 1200002D #977
    Radu
    Keymaster

    Hi Chuck!

    Thanks for providing the coordinates. The location has been updated as per your request.

    I can also override the city if required.

    • This reply was modified 10 years, 4 months ago by Radu.
    in reply to: Marker Colours #970
    Radu
    Keymaster

    Good initiative. Let’s see what can be improved.

    Here’s how they are doing it in Finland: http://www.stuk.fi/sateily-ymparistossa/sateilytilanne/en_GB/sateilytilanne/

    in reply to: What the heck are we counting? #968
    Radu
    Keymaster
    in reply to: Radmonitor in wrong place #967
    Radu
    Keymaster

    Location updated to the coordinates given.

    in reply to: Radmonitor in wrong place #964
    Radu
    Keymaster

    The location is taken automatically, but it is not exact. This automated mechanism is to ensure plug and play to a maximum extent.

    Manually overriding them is possible. The coordinates have been updated to the location indicated.

    in reply to: Client side charts #943
    Radu
    Keymaster

    Superb work, Vinz!

    in reply to: [Solved] Unit won’t connect from 4G network #942
    Radu
    Keymaster

    Hi Lars,

    Glad to see the unit went back online.
    I’ve updated the location as per your request.

    Wish there was a solution for unit 1100009 as well. It shows the same behaviour like your unit when it was on 4G.

    Rick, would you step in to provide more details on the connection used for 11000009? Any additional details might be useful.

    Thanks,
    Radu

    in reply to: [Solved] Unit won’t connect from 4G network #931
    Radu
    Keymaster

    Thanks, let me know if that helps.

    in reply to: cpm -> mSv #928
    Radu
    Keymaster

    Well the dose depends on several factors, that include energy and type of radiation.
    The geiger tubes are unable to provide such information, so calculating the dose using a Geiger tube is only possible for known radiation.
    This is why their datasheets often indicate a CPM to R/h factor, but always for a specific isotope, with a discrete number of emissions (like Ra226, Cs137, Co60, etc).
    For convenience, uRADMonitor webpage shows a value in uSv/h, which is only an approximation, and should be considered so. On the other hand, the exact readings in CPM are provided, and the tube type for all measurements.

    It is know that a geiger tube also expresses a non-linear response to energy, due to the absorption coefficient of any material that increases with decreasing energy. Practically everything below 150keV will trigger a relatively higher response in a Geiger tube.

    The context for what we do here is extremely important: remember that uRADMonitor measures background radiation. This background is composed of cosmic radiation, of very high energy, and three main terrestrial components of background gammas that are K-40 1462 keV, Bi-214 1760 keV from the U decay series, and Tl-206 from the Th decay series. Smaller contributions to total background come from Pb-212 239 keV, Bi-209 609 keV, Tl-208 908 keV and Bi-214 1120 keV. The most serious non-linearity of energy response in uncompensated GM tubes occurs below 150 keV – and most of that below 100 keV – so none of the background emissions listed above will be seriously affected, nor will the majority of cosmic rays.
    The most seriously affected – and, in many ways, the most interesting – part of the background gamma spectrum that will fall within the GM tube’s most non-linear energy response region is skyshine – the radiation scattered by the air above both natural and man-made sources like particle accelerators, reactors, and high-level waste dumps. Most skyshine falls below 500 keV, and most of that below 100 keV.
    So this means that CPM to Gray/hr conversions, using manufacturers data based on either Cs-137 or Co-60 will not be too inaccurate to be of use across the natural background gamma spectrum.

    Regarding the conversion made in uRADMonitor, the following aspects have been used:
    – the uRADMonitor units send radiation measurements as CPM
    – the server calculates the approximation in Sv/h, to serve as a reference, using the CPM value and the specific tube type information.
    – any changes in this calculation will be done on the server, and doesn’t impact in any way the units already deployed

    To derive the best conversion value, the following approach has been performed, separately for all tubes used:
    – measure the background radiation in CPM, over a long time interval (>4h) and scale it against measurements in uSV/h done with calibrated dosimeters (Three have been used: Gamma Scout, Terra-P, Radex 1706)
    – measure the radiation in CPM when exposed to different radioactive samples (Th232, Cs137, Ra226), scale it against measurements done with calibrated dosimeters. Repeat for different geometries (increasing distance).
    – average the results, and compute a linear factor to use with the CPM readings.

    • This reply was modified 10 years, 4 months ago by Radu.
    in reply to: Force accept invalid header HTTP Gets #927
    Radu
    Keymaster

    Hi Ben,

    You are right. I tried mod_headers and it does a good job, but only on valid headers.

    For the 400 ones, the log is the last place where I get to see them, every attempt to handle them fails.

    @Sigitas had the idea of using a proxy between the Apache and the Internet, to filter traffic and intercept the invalid requests in an attempt to fix them.
    I find this very time consuming and I see it as a workaround for the real problem. Yet, I don’t see any other solution.

Viewing 15 posts - 706 through 720 (of 766 total)