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 RF Engineering Quizzes Notable Quotes Calculators Education Engineering magazine articles Engineering software Engineering smorgasbord RF Cafe Archives RF Cascade Workbook 2018 RF Symbols for Visio - Word Advertising RF Cafe Forums Magazine USAF Radr Shop Sponsor RF Cafe RF Electronics Symbols for Visio RF Electronics Symbols for Office Word RF Electronics Stencils for Visio Thank you for visiting RF Cafe!
Amplifier Solutions Corporation (ASC) - RF Cafe
Exodus Advanced Communications Best in Class RF Amplifier SSPAs
 

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

RIGOL Technologies (test equipment) - RF Cafe

Voltage measurement on RF cable - RF Cafe Forums

RF Cafe Forums closed its virtual doors in 2012 mainly due to other social media platforms dominating public commenting venues. RF Cafe Forums began sometime around August of 2003 and was quite well-attended for many years. By 2010, Facebook and Twitter were overwhelmingly dominating online personal interaction, and RF Cafe Forums activity dropped off precipitously. Regardless, there are still lots of great posts in the archive that ware worth looking at. Below are the old forum threads, including responses to the original posts.

-- Amateur Radio

-- Antennas

-- CAE, CAD, & Software

-- Circuits & Components

-- Employment & Interviews

-- Systems

-- Test & Measurement

Ted1234
 Post subject: Voltage measurement on RF cable
Posted: Thu Oct 20, 2005 4:03 pm 
I have a piece of RG58 going into an into an o-scope with a 100 MHz BW. The signal is a sinewave (almost) and I know the power out of my source (10 MHz) is +10 dBm. Problem is the o-scope is reading about exactly twice the voltage I expect to see (which is 2 Vpk-pk). I'm measuring 4 Vpk-pk. Any ideas what might be going on. Thanks.

--- Ted


 
  
 
kanling
 Post subject:
Posted: Thu Oct 20, 2005 4:08 pm 
 
Colonel
User avatar

Joined: Mon Jul 18, 2005 4:31 pm

Posts: 40

Location: Baltimore, MD

I'll bet your scope's input is set to the high impedance mode. Make sure it is set to be a 50 Ohm load. You are exactly right to be expecting about 2 Vpp.

 
   
 
Guest
 Post subject:
Posted: Fri Oct 21, 2005 7:17 am 
Agreed, your scope impedance is not 50 ohms. If you do not have an option for 50 ohms, place a 50 ohm resistor in parallel between clip leads.

 
  
 
Ted1234
 Post subject:
Posted: Fri Oct 21, 2005 10:24 am 
kanling wrote:
I'll bet your scope's input is set to the high impedance mode. Make sure it is set to be a 50 Ohm load. You are exactly right to be expecting about 2 Vpp.

Thanks kanling - you are exactly right :!:

I can't believe I was dumb enough to not think of that. :D

Ted

Posted  11/12/2012

Axiom Test Equipment - RF Cafe

RF Cafe Visitor Comments on News, Articles, System, Design, Components, etc.

Please e-mail your comment to me (Kirt B.), and I will post it here for you - no computers involved!

1 - Your participation will be greatly appreciated. - Kirt B.

Innovative Power Products Passive RF Products - RF Cafe
KR Electronics (RF Filters) - RF Cafe
 

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

These Are Available for Free