Homepage - RF Cafe
Webmaster: Kirt Blattenberger | KB3UON | Sitemap | ©1996-2014
Menu below is just a small sample of what is here!
Custom Search
More than 10,000 searchable pages indexed.
•−•  ••−•    −•−•  •−  ••−•  •
RF Cafe Morse Code >Hear It<

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
A Disruptive Web Presence

Custom Search
Over 10,000 pages indexed! (none duped or pirated)

Read About RF Cafe
Webmaster: Kirt Blattenberger

RF Cafe Software

RF Cascade Workbook
RF Cascade Workbook is a very extensive system cascaded component Excel workbook that includes the standard Gain, NF, IP2, IP3, Psat calculations, input & output VSWR, noise BW, min/max tolerance, DC power cauculations, graphing of all RF parameters, and has a graphical block diagram tool. An extensive User's Guide is also included. - Only $35.
RF system analysis including
frequency conversion & filters

RF & EE Symbols Word
RF Stencils for Visio

Product & Service Directory
Personally Selected Manufacturers
RF Cafe T-Shirts & Mugs

RF Cafe Software

Calculator Workbook
RF Workbench
Smith Chart™ for Visio
Smith Chart™ for Excel
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!)

5CCG (5th MOB): My USAF radar shop

Airplanes and Rockets: My personal hobby website

Equine Kingdom: My daughter Sally's horse riding website