Formulas & Data:
- Electronics
- Mathematics
- Physics
- RF & Microwaves

Parts Vendors:
- all hand-selected

- Amateur Radio
- Vintage Articles:
- Electronics World
- Popular Electronics
- Radio & TV News
- Radio Craft
- Short Wave Craft
- Wireless World

- Events Calendar
RF Cafe Homepage
Copyright 1999-2015   •−•  ••−•    −•−•  •−  ••−•  •   "RF Cafe" in Morse Code  >> Listen to It <<
- EW & Radar Handbook
- Quizzes       - Software
- App Notes
- Calculators
- Advertise on RF Cafe
- About RF Cafe™
- RF Cafe Shirts & Mugs
- RF Cafe Archives
RF Cafe Book Contest
- RF Cafe on Visit RF Cafe on Facebook Visit RF Cafe on Twitter Visit RF Cafe on LinkedIn
- Tech Humor
- Forums Archive
- Job Board
- Donate to RF Cafe
- Kirt's Cogitations
Custom Search
More than 10,000 searchable pages indexed.
Greetings: There is so much good stuff on RF Cafe that there is no way to list or link to all of it here. Please use the Search box or the Site Map to find what you want - there is a good chance I have it here. Thanks!

Antenna placement - RF Cafe Forums

Because of the high maintenance needed to monitor and filter spammers from the RF Cafe Forums, I decided that it would be best to just archive the pages to make all the good information posted in the past available for review. It is unfortunate that the scumbags of the world ruin an otherwise useful venue for people wanting to exchanged useful ideas and views. It seems that the more formal social media like Facebook pretty much dominate this kind of venue anymore anyway, so if you would like to post something on RF Cafe's Facebook page, please do.

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

 Post subject: Antenna placement
Posted: Fri Apr 07, 2006 6:13 pm 
User avatar

Joined: Fri Apr 07, 2006 6:10 pm
Posts: 18

Does antenna placement significantly affect the radiation pattern of an antenna?

For example, I have a dipole connected to a metallic box. Will the dipole pattern change? Or say I have one of those TV antennas, if I place it on a different section of the roof or a different part of the house, will that affect the radiation pattern?


 Post subject: Antenna positioning
Posted: Fri Apr 07, 2006 8:36 pm 
User avatar

Joined: Wed Feb 22, 2006 3:51 pm
Posts: 104
In a word, yes.

Yes, any nearby conductor will affect your radiation pattern. That's why AM broadcasting stations put their antennas over damp ground - it acts like a reflector does for light.

Near enough, and it also affects the impedance the antenna presents to the transmission line and transmitter.

Good Luck!

 Post subject:
Posted: Sat Apr 08, 2006 10:12 am 
User avatar

Joined: Fri Apr 07, 2006 6:10 pm
Posts: 18
Thanks! I got into this discussion because a classmate wanted to have a transmitter installed in his car. He said he was going to get this antenna that showed an omnidirectional pattern at his transmitting frequency. I told him that he should not go with the given pattern because the car's body will change the actual pattern. He said that he does not think that the car frame's frequency response is not the same as his transmitting frequency so he it should not affect the pattern.

 Post subject: Antenna pattern
Posted: Sat Apr 08, 2006 4:29 pm 
User avatar

Joined: Wed Feb 22, 2006 3:51 pm
Posts: 104
Hi again!

The effect of mounting an omnidirectional antenna on a vehicle depends on the type of antenna, and where you mount it. A vertical dipole, in the center of the roof, will be omnidirectional. But most dipoles for lower frequencies are mounted on the fenders or the bumpers, and as a result will have a preferred direction. It's difficult to quantify without a lot of details and an analysis program. Still, bumper mounts are common among the amateur radio HF users.

Good luck,

Posted  11/12/2012

Your RF Cafe
Progenitor & Webmaster

Click here to read about RF CafeKirt Blattenberger… single-handedly redefining what an engineering website should be.

View the YouTube RF Cafe Intro Video Carpe Diem!
(Seize the Day!)

5th MOB: My USAF radar shop

Airplanes and Rockets: My personal hobby website

Equine Kingdom: My daughter Sally's horse riding website