LinkBack Thread Tools Search this Thread Display Modes
Prev Previous Post   Next Post Next
  #6   Report Post  
Old February 14th 10, 07:14 PM posted to rec.radio.amateur.antenna
external usenet poster
 
First recorded activity by RadioBanter: Jun 2007
Posts: 1,336
Default Why 50 ohms?

On Sun, 14 Feb 2010 01:33:58 -0800 (PST), phaedrus
wrote:

why are transmitters normalised to 50 ohms
when clearly 450 ohms would enable us to enjoy cheaper, do-it-
yourself, lower loss feeders?


A 450 ohm coaxial cable would be rather large.
Zo = 450 = 138 log(b/a) (where b=OD and a=ID)
For an inner conductor diameter of 1 mm, the outer shield diameter
would need to be 1800 mm or about 71 inches.


--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
75 Ohms - It's Not Just For TV Anymore RHF Shortwave 10 August 15th 08 01:09 AM
antenna impedance - calculated 10 - 20 Ohms - measured 36 Ohms?? dansawyeror Antenna 31 March 4th 06 05:54 PM
73 Ohms, How do you get it? Harry Antenna 97 October 3rd 05 04:57 PM
DDS 50 ohms buffer ? Gillis Homebrew 2 February 23rd 04 11:43 PM
DDS 50 ohms buffer ? Gillis Homebrew 0 February 23rd 04 11:07 PM


All times are GMT +1. The time now is 09:14 AM.

Powered by vBulletin® Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
Copyright ©2004-2025 RadioBanter.
The comments are property of their posters.
 

About Us

"It's about Radio"

 

Copyright © 2017