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 RF Cafe Archives RF Cascade Workbook 2018 RF Symbols for Visio - Word Advertising RF Cafe Forums Magazine Sponsor RF Cafe RF Electronics Symbols for Visio RF Electronics Symbols for Office Word RF Electronics Stencils for Visio Sponsor Links Saturday Evening Post NEETS EW Radar Handbook Microwave Museum About RF Cafe Aegis Power Systems Anritsu Alliance Test Equipment Amplifier Solutions Anatech Electronics Axiom Test Equipment Berkeley Nucleonics Bittele Centric RF Conduct RF Copper Mountain Technologies Empower RF everything RF Exodus Advanced Communications Innovative Power Products ISOTEC KR Filters Lotus Systems PCB Directory Rigol RF Superstore San Francisco Circuits Reactel RFCT TotalTemp Technologies Triad RF Systems Windfreak Technologies Withwave LadyBug Technologies Wireless Telecom Group Sponsorship Rates RF Cafe Software Resources Vintage Magazines Thank you for visiting RF Cafe!
Copper Mountain Technologies (VNA) - RF Cafe

noob coax question - RF Cafe Forums

RF Cafe Forums closed its virtual doors in 2010 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.

NOTICE: The original RF Cafe Forum is available again for reading, and the new RF Cafe Blog is an active board.

-- Amateur Radio

-- Anecdotes, Gripes, & Humor

-- Antennas

-- CAE, CAD, & Software

-- Circuits & Components

-- Employment & Interviews

-- Miscellany

-- Swap Shop

-- Systems

-- Test & Measurement

-- Webmaster

crossection
 Post subject: noob coax question
Posted: Sun Oct 05, 2008 2:14 pm 
 
Lieutenant

Joined: Sun Oct 05, 2008 12:44 pm

Posts: 1

Location: CA

Apologies if this isn't the right forum for this question...

I need to build a coaxial line that will have perforations in the outer conductor to allow me to see the interior. The visual access section will be about an inch in length, and the coax is built from 1.5" i.d. copper tube (outer conductor) and 0.375" copper rod (inner conductor).

Perforations will be small - about 1mm diameter on 4mm pitch arrayed around and along the 1" sight section. Frequency is 2.45 GHz, so the perforations are small compared to the wavelength (dielectric is air).

My question is whether I'll have significant radiation from the perf'ed section - significant would be ~1% or more of the incident power. I have successfully used perforations to give nonradiating visual access in rectangular waveguide (symmetric hole patterns centered on the short wall).

My math says that a coax wall won't radiate under these conditions, but since I've never worked with coax before, I don't have full confidence in my math model. I'd like to get another opinion before I cut metal and maybe warm up the room in an unanticipated way!

Thanks for your help.


 
   
 
WA9WVX
 Post subject: Radiating Coaxial Feedline
Posted: Wed Dec 24, 2008 12:13 am 
 
Captain

Joined: Mon Jul 07, 2008 9:42 pm

Posts: 7

Location: Northern, IL

Sounds like you want to re-invent Andrew's Radiax Coaxial RF Cable. This has also been known as Leaky Line. This 50-Ohm RF cable has been available for 40 or 50 years and is heavily used in large multi-level buildings such as: hospitals, hotels, downtown offices, football, Basketball, baseball, horse racing stadiums, museums and tunnels. The RF cable allows signals to penetrate areas where outside antennas are unable to reach marginal or dead spots within the buildings and it allows the signals to work both ways in a two-way radio communications system.


Andrew is now a division of Commscope and here's their website:

http://www.commscope.com/andrew/eng/product/trans_line_sys/coaxial/radiating/1206639_13611.html


73,

Dan

WA9WVX

Posted  11/12/2012

RIGOL Technologies (test equipment) - RF Cafe
Innovative Power Products Passive RF Products - RF Cafe
TotalTemp Technologies (Thermal Platforms) - RF Cafe
Innovative Power Products Passive RF Products - RF Cafe
Windfreak Technologies Frequency Synthesizers - RF Cafe

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

These Are Available for Free

 

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 tying 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