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  1. rosetta

    blood pressure machines cuff pressure

    Hmmm, wonder how that works? Apply the device to a cylindrical object, a small can, and see if it recognizes the "heart level" by movement. Since the cuff is not pressurized, it must be detecting a heart beat with its audio sensor, but I don't know how that would identify where it is relative...
  2. rosetta

    blood pressure machines cuff pressure

    The Omron A.P.S. (Advanced Positioning System) is an interesting feature. With a wrist monitor, you can move it quite a distance above or below the heart level, whereas the typical upper arm pressure band is always going to be close to the heart level by default. After the Omron starts, can you...
  3. rosetta

    blood pressure machines cuff pressure

    How does your device "know" it is elevated to within a few cm of the heart's elevation? They have an invasive method of measuring blood pressure directly but it is used only in special cases. It would be nice if they could find a method somewhat like they use to measure intraocular pressure...
  4. rosetta

    blood pressure machines cuff pressure

    I purchased a manual sphygmomanometer with an analog aneroid pressure gauge. I found that a good rigid "arm" was an empty 10 Oz (305 gm) soup can. I installed the sphygmomanometer on the can and inflated it to 80 mmHg, fit that into the sleeve of my auto sphygmomanometer and hit the ON button...
  5. rosetta

    blood pressure machines cuff pressure

    Mike Halloran, your comments about "measure the pressure at the skin interface" might just be the solution. Manual sphygmomanometers are pretty cheap, and I don't see any reason why I cannot use a manual sphygmomanometer cuff around a piece of 3" pvc that simulates an arm. I could inflate the...
  6. rosetta

    blood pressure machines cuff pressure

    I would like to clarify what I need. I want to be able to insert "something" into the cuff, cycle the machine, and show the cuff pressure. I will not be able to disconnect the hoses to the actual sphygmomanometer.
  7. rosetta

    blood pressure machines cuff pressure

    I am looking for a portable instrument that can be used to determine the "cuff pressure" of automatic blood pressure sphygmomanometers. I noted a large disparity between the results (systolic/diastolic) of an automatic sphygmomanometer and that of a requested manually operated sphygmomanometer...
  8. rosetta

    recording ultra low frequency ULF

    Ultra low frequency (ULF) signals are being monitored by professionals and "amateurs" already using a variety of devices. The DEMETER (Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions) satellite is monitoring ultra-low frequency electromagnetic signals. This is a...
  9. rosetta

    Very Large Cavity Oscillators

    The article in the following URL states that a student turned MIT's biggest lecture hall, the cavernous Room 26-100, into a low-energy microwave cavity. http://web.mit.edu/giving/spectrum/spring02/hands-on-learning.html The dimensions of the room are not on-line and I wonder if anyone knows...
  10. rosetta

    Sub station earthing

    Found MIL-HDBK-419A on the net, but very big, 9769 KB, and will take awhile for a std modem download. http://www.tscm.com/MIL-HDBK-419A.PDF The conductive quality of the ground in Australia must be quite good in that they run a 12.7 KV 50 HZ power transmission line with just a single-wire...
  11. rosetta

    Sub station earthing

    The aemc.pdf article is more thorough than others I have found, but it presents a slightly different theory on how resistance is calculated. Page 8, Figure 9 in that article states the resistance is based upon concentric shells. On page 2 of the following reference, it states that the theory...
  12. rosetta

    Sub station earthing

    I have searched the electrical power and this forum for information on the methodology of testing an earth ground. My specific question is how the "Fall of Potential" and related processes work when all the resistance is attributed to the "ground under test" and none to the...
  13. rosetta

    Carbon Black EM Enclosure

    The carbon based "paint" seems to be used for a number of applications, one of the biggest being inside and outside coatings on CRTs. That makes them pretty good sized Leyden jars, a convenient filter capacitor and a gatherer of secondary electrons...
  14. rosetta

    Carbon Black EM Enclosure

    Your use of carbon in the form of tissues and mats confirms what I have been reading from a number of sources. Some of the literature I reviewed discussed its use as shielding and this indicated that it would "contain" an EM field, but no one identified it was suitable to use as a...
  15. rosetta

    Carbon Black EM Enclosure

    First, I do not expect to observe the same "energy" efficiencies as with metal structures, just the feasibility at low power levels. Second, many electrically conductive polymers and composites are effective EMI shields, thus demonstrating they have electrical properties that emulate...
  16. rosetta

    Carbon Black EM Enclosure

    Is it possible to use "carbon black" or materials containing it to produce an EM enclosure that will act as a cavity resonator? If so, any info on permissible freq ranges?
  17. rosetta

    heterodyne cavity oscillator

    No mixer, cavity produces two frequencies and internal mixing produces a difference heterodyne. It has been done but I can't find design info.
  18. rosetta

    heterodyne cavity oscillator

    Looking for design info on the structure of a cavity oscillator that will provide a heterodyne difference frequency output.

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