On Fri, 9 May 2014 12:31:01 -0400, "Tom Miller"
wrote:


"Jeff Liebermann" wrote in message
.. .
On Fri, 09 May 2014 12:02:50 +0100, Mike Perkins
wrote:

http://802.11junk.com/jeffl/antennas/Monopole/index.html

What is the software model you've used here?

4NEC2:
http://www.qsl.net/4nec2/
4NEC2 does not have an easy way to produce presentable web pages, so I
screen grabbed the JPG's using Irfanview and assembled the web page
with jAlbum.

I also use EZNEC:
http://www.eznec.com

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

Do you believe the numbers it is giving you? 5.19 dB for a 1/4 wave ground
plane antenna? Also, gain is in dB, not dBm. Just a little nit.

It is not that far away, assuming perfect ground, which explains the
lower lobe to reflected upwards, which would explain 3 dB of gain. The
remaining 2.19 dB sounds much like the dipole gain over an isotropic
radiator. So actually, we should talk about 5.19 dBi gain or actually
_directivity_. For electrically small antennas, the efficiency can be
much less than 100 %, thus the _gain_ would be less.