NOTICE: Due to a lapse in annual appropriations, most of this website is not being updated. Learn more.
Form submissions will still be accepted but will not receive responses at this time. Sections of this site for programs using non-appropriated funds (such as NVLAP) or those that are excepted from the shutdown (such as CHIPS and NVD) will continue to be updated.
An official website of the United States government
Here’s how you know
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
Uncertainties in NIST Noise-Temperature Measurements
Published
Author(s)
James P. Randa
Abstract
Uncertainty analyses are presented for NIST measurements of noise temperature. All systems currently used in NIST calibrations of thermal-noise sources are treated. These include tuned systems for 30 and 60 MHz, coaxial total-power radiometers for 1 to 12 GHz, a switching radiometer for the WR-90 (8.2 to 12.4 GHz) waveguide band, and total power waveguide radiometers for the WR-62 (12.4 to 18 GHz), WR-42 (18 to 26.5 GHz), WR-28 (26.5 to 40 GHz), and WR-15 (50 to 75 GHz) bands. Measurements through adapters are also analyzed. Typical expanded (k = 2) uncertainties for the measurements are in the range 0.7 percent to 1.4 percent, depending on the particular system and the frequency.
Randa, J.
(1998),
Uncertainties in NIST Noise-Temperature Measurements, Technical Note (NIST TN), National Institute of Standards and Technology, Gaithersburg, MD, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=11498
(Accessed October 17, 2025)