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  1. lighterup

    Patent No. 6,901,353

    Has anyone here tried the Normalized Hilbert Transform method described in the subject patent for instantaneous frequency measurement? We are thinking about trying it on some radar signal processing applications and possibly licensing it. I would appreciate any feedback you may have on it...
  2. lighterup

    Flex circuit molded into plastic cavity?

    I have used polyamid boards downhole at 200 degrees C for many hours without any problems. The thing that was the problem there was the solder, if we happened to go through a zone which exceeded 200 C for very long. I have also done an embedded cell phone antenna on a polyamid flex circuit...
  3. lighterup

    array antennas in HFSS

    You're in luck! I just happen to be working a six element collinear array right now. The procedure is to draw two rectangles from the ends of your feed microstrips perpendicular to said microstrips through the dielectric to the groundplane of your board. Do not assign any material to these...
  4. lighterup

    Absorber Question

    All suggestions so far have been valid, and I am grateful for your input. However, my original query was about a simple absorber inverted umbrella which could be fitted inside the rigid radome of the system. Has anyone had any experience with this stuff as a sidelobe suppression mechanism...
  5. lighterup

    Absorber Question

    Visualize this, ve1bll: There is an large warehouse within 3 km of the site with about an acre of tin roof with a slight pitch which has a pretty good cross section as the height increases and the surface begins to become more normal to any lobes which may be incident on it.
  6. lighterup

    Absorber Question

    Hmm...I think I can do the ground plane extension without too much form factor upset. Good idea. Thanks lighterup
  7. lighterup

    Absorber Question

    The scan is azimuthal. The elevation receive beamformer is a Blass coupler structure, and there is a known lobe in the receive pattern about -15 degrees elevation. My hope is, if we can eliminate some of the transmitted energy at negative look angles with absorber, that energy will not be...
  8. lighterup

    Absorber Question

    Here is a link to a photo of a similar system. http://www.defenselink.mil/transformation/factsheets/LCMR.pdf I do not believe the feedlines are radiating significantly, as the input is only about 10dBm. The coax lines to the element columns terminate into microstrip, and the onboard PAs see...
  9. lighterup

    Absorber Question

    A more appropriate description would have been a 360 degree cylindrical array of collinear arrays. You are correct, in that the collinears do not show much energy at a negative look angle when measured in the chamber, but when integrated with the entire mechanical structure, there seems to be...
  10. lighterup

    Absorber Question

    Thanks, VE1. My transmit antennas consist of a collinear vertical array of six dipoles. The elevation pattern looks good when the array is measured without the support structure, but evidently it develops some lower lobes when placed on the support structure, as we are seeing severe clutter...
  11. lighterup

    Absorber Question

    I am having trouble with what I believe to be parasitic scatterers in the support structure of a circular antenna array. My proposed solution is to install a layer of tuned elastomeric absorber, such as Cuming C-RAM FLX inside the radome below the array to keep the transmitter from lighting up...
  12. lighterup

    Fuel Consumption Sensing

    Thanks for all the input. My vehicle is a 2000 Mazda B3000 truck, and it has an injector system, but the speedometer is an old fashioned mechanical cable. I looked at the Flo Scan site, and they calculate gallons per hour for marine applications. I suppose if I were really ambitious I could...
  13. lighterup

    Solenoid coil drop out speed

    Keith has the most cost-effective solution to the problem, a surge eliminator. I have seen this implemented by installing a parallel vertical closed-end pipe stub filled with air, which unlike water is compressible. The air acts as a shock absorber, and dampens the pressure wave created by the...
  14. lighterup

    Fuel Consumption Sensing

    I rented a luxury Buick on a business trip the other day, and in addition to XM radio and lots of other goodies, I noticed it had a real time readout of fuel consumption in MPG. Does anyone here know what sensor is used to calculate this? ie fuel flow, fuel weight, etc etc. Also, are there any...
  15. lighterup

    Material question

    Does anyone read this forum? I have done some further study on the triboelectric process and have actually found a standard, ASTM F23.20.05 which covers this phenomenon for hazardous vapor duty materials. Are there any textile jocks on this site who could help me with this?
  16. lighterup

    Radome Material Question

    Thanks to everyone who has contributed to this thread. I think Brian has come upon the answer, although it is not within the specific microwave materials that Saint-Gobain markets. They also make a Kevlar composite material used for chem-bio and vapor protection gear which is rated very good...
  17. lighterup

    Radome Material Question

    Thanks Brian. I have contacted them to see if they know where their fabric is in the triboelectric series, shown in this URL: http://www.school-for-champions.com/science/static_materials.htm We are also looking for a combination polyester-nylon fabric, which should have pretty good anti-static...
  18. lighterup

    Radome Material Question

    Thanks Hig. That material is a machineable stock similar to delrin, except it is semi conductive. I think I may try it in an ESD sensitive gluing process for one of the press fixtures used there where we currently use a delrin platten.
  19. lighterup

    Radiated emissions testing

    I am looking into retrofitting one of our Agilent 4407 spectrum analyzers as an emi receiver for doing in-house precompliance testing for the MIL-469E RExxx tests. Does anyone know of a good, reasonably priced alternative receiver with all the specs needed to do measurements prior to shipping...
  20. lighterup

    Full Duplex on a single wire

    There is a FO device called a wave division multiplexer (WDM) which accomplishes the color (wavelength) discrimination for you. These work well, and are used widely in the industry. The only drawback, at least from the days when I used to do a little FO work, is that they are difficult to...

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