Electronics World articles Popular Electronics articles QST articles Radio & TV News articles Radio-Craft articles Radio-Electronics articles Short Wave Craft articles Wireless World articles Google Search of RF Cafe website Sitemap Electronics Equations Mathematics Equations Equations physics Manufacturers & distributors Engineer Jobs LinkedIn Crosswords Engineering Humor Kirt's Cogitations Engineering Event Calendar RF Engineering Quizzes USAF radar shop Notable Quotes App Notes Calculators Education Engineering Magazines Engineering magazine articles Engineering software Engineering smorgasbord RF Cafe Archives RF Cascade Workbook 2018 RF Stencils for Visio RF & EE Shapes for Word Advertising RF Cafe Homepage Sudoku puzzles Thank you for visiting RF Cafe!
Exodus Advanced Communications

Electric Field strength to power conversion.. - RF Cafe Forums

The original RF Cafe Forums were shut down in late 2012 due to maintenance issues - primarily having to spend time purging garbage posts from the board. At some point I might start the RF Cafe Forums again if the phpBB software gets better at filtering spam.

Below are the old forum threads, including responses to the original posts.

-- Amateur Radio
-- Anecdotes, Gripes & Humor
-- Antennas
-- CAE, CAD, & Software
-- Circuits & Components
-- Employment & Interviews
-- Miscellany
-- Swap Shop
-- Systems
-- Test & Measurement
-- Webmaster

bparker
 Post subject: Electric Field strength to power conversion..
Posted: Tue Apr 12, 2005 8:01 am 
 
Lieutenant

Joined: Fri Aug 27, 2004 11:25 am
Posts: 4
Location: Cape Town, R.S.A.
Hi All,

I was hoping someone could help me with a fundamental issue.

I have had some EMC problems (radiated) and am trying to analyse the results.
The test is done by monitoring the radiated signal with an antenna placed 1m from the DUT. The levels are then given in dBuV/m.
I understand that this is a measure of the Electric field strength, but my question is how to relate this to an absolute power measurement.
Is it a straight conversion from dBuV to dBm, assuming a 50 ohm system, and can the /m part of the unit be dropped because of the distance between DUT and antenna being 1m?
If this reasoning was followed, a +30dBuV/m translates to -77dBm/m, or -7dBm power level at source if a cable with 70dB isolation was used. (cable connected to known source of offending signal and terminated into 50 ohm)

Am I way off the mark, and if so can someone please shed some light?

_________________
B.K.P.


 
   
 
RMYREHN
 Post subject: Electric Field strength to power conversion..
Posted: Tue May 10, 2005 10:13 am 
To convert from dBuV to dBm in a 50 ohm system, just subtract 107 from the value in dBuV. As far as dropping the /m (per meter), you will need to obtain the antenna correction factor (which should have been supplied with the antenna) and subtract it from the value. Once you have this answer, it is no longer a field strength though. This is useful if you want to determine what level to inject (bypassing the antenna) when checking out your measurement system




Posted  11/12/2012
Qorvo / Custom MMIC (RF amplifiers, mixers, attenuators) - RF Cafe MPDevice microwave devices - RF Cafe
NorthEast RF Antenna Testing Services Res-Net Microwave - RF Cafe
About RF Cafe
Kirt Blattenberger - RF Cafe Webmaster
Copyright: 1996 - 2024
Webmaster:
    Kirt Blattenberger,
    BSEE - KB3UON

RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The World Wide Web (Internet) was largely an unknown entity at the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps while typing up your telephone line, and a nice lady's voice announced "You've Got Mail" when a new message arrived...

All trademarks, copyrights, patents, and other rights of ownership to images and text used on the RF Cafe website are hereby acknowledged.

My Hobby Website:  AirplanesAndRockets.com

spacer

Please Support RF Cafe by purchasing my  ridiculously low−priced products, all of which I created.

These Are Available for Free