rfi management for single dish radio astronomy at nrao green bank n.
Download
Skip this Video
Download Presentation
RFI Management for Single Dish Radio Astronomy at NRAO Green Bank

Loading in 2 Seconds...

play fullscreen
1 / 23

RFI Management for Single Dish Radio Astronomy at NRAO Green Bank - PowerPoint PPT Presentation


  • 111 Views
  • Uploaded on

RFI Management for Single Dish Radio Astronomy at NRAO Green Bank. Some Considerations. Single dish RA is more vulnerable to RFI than array configurations. Protection and source-mitigation are the preferred options but not always possible.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'RFI Management for Single Dish Radio Astronomy at NRAO Green Bank' - naoko


Download Now An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
some considerations
Some Considerations
  • Single dish RA is more vulnerable to RFI than array configurations.
  • Protection and source-mitigation are the preferred options but not always possible.
  • Weak, narrowband, or intermittent RFI lends itself to excision; strong, constant, or wideband noise-like RFI does not.
protection and mitigation
Protection and Mitigation
  • National/International (Protected Bands)
  • Regional (NRQZ)
  • State (WVRAZ)
  • Site (Site Policy)
the national radio quiet zone
The National Radio Quiet Zone
  • Established by an act of congress in 1958
  • Approx. 13,000 sq. mile area
  • Requires coordination for all permanent, fixed, licensed transmitters
  • Administered through NRAO Green Bank for the mutual benefit of NRAO and the Sugar Grove Facility
wv radio astronomy zone
WV Radio Astronomy Zone
  • Established through §37A-1-2 of the West Virginia Code “The Radio Astronomy Zoning Act”
  • Applies to any electrical equipment that causes harmful interference to Radio Astronomical Observations
  • Increasingly difficult and complex problem due to the proliferation of wireless technologies
  • Our Strategy:
    • Problem-driven component: we will seek enforcement only as a last resort, if friendly requests repeatedly fail.
    • Proactive component: We solicit voluntary cooperation: PR campaign is in progress to raise awareness
zones 1 2 on site rfi policy
Zones 1 & 2: On-Site RFI Policy
  • IPG Develops Policy; Site Director has final authority
  • ITU-R RA.769 Limit applies
assessing equipment for rfi compliance anechoic chamber testing

Amplifier

Assessing Equipment For RFI ComplianceAnechoic Chamber Testing

Receive (Rx) Antenna

Equipment Under Test (EUT)

Cable #1

Cable #2

Distance (Dtest)

Spectrum Analyzer

Cable #3

PowerTx(dBm) = Pmeasured(dBm) + Lspace(dB) – Gantenna(dB) – Gamplifier(dB) + Lcables(dB)

the show me project1
The “Show Me” Project

~3:1 or 5dB SNRatio

…but anechoic chamber prediction said worst-case emissions exceed ITU-R line limit by 22dB....17dB discrepancy????

60s integration time of test vs. ITU-R line limitassumed 2000s integration:

10Log(60/2000) = -15dB (close enough)