Thank you for visiting RF Cafe! Electronics World Cover,TOC,and list of posted Popular Electronics articles QST Radio & TV News Radio-Craft Radio-Electronics Short Wave Craft Wireless World About RF Cafe RF Cafe Homepage RF Cafe in Morse Code Google Search of RF Cafe website Sitemap Electronics Equations Mathematics Equations Equations physics Manufacturers & distributors Engineer Jobs Twitter LinkedIn Crosswords Engineering Humor Kirt's Cogitations Engineering Event Calendar RF Engineering Quizzes AN/MPN-14 Radar 5CCG Notable Quotes App Notes Calculators Education Magazines Software,T-Shirts,Coffee Mugs Articles - submitted by RF Cafe visitors Simulators Technical Writings RF Cafe Archives Test Notes Wireless System Designer RF Stencils for Visio Shapes for Word Search RF Cafe Sitemap Advertising Facebook RF Cafe Forums RF Cafe Homepage Thank you for visiting RF Cafe!

Electric Field Strength to Power Conversion.. - RF Cafe Forums

The original RF Cafe Forums were shut down in late 2012 due to maintenance issues. Original posts:

Amateur Radio | Antennas | Circuits & Components | Systems | Test & Measurement

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

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?


 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

RF Cafe Software

   Wireless System Designer - RF Cafe
Wireless System Designer

RF & EE Symbols Word
RF Stencils for Visio
Calculator Workbook
RF Workbench
Smith Chartâ„¢ for Visio
Smith Chartâ„¢ for Excel

About RF Cafe

Kirt Blattenberger - RF Cafe WebmasterCopyright
1996 - 2022
Kirt Blattenberger,

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 Internet was still largely an unknown entity at the time and not much was available in the form of WYSIWYG ...

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:

Try Using SEARCH
to Find What You Need. 
There are 1,000s of Pages Indexed on RF Cafe !