[TowerTalk] Antenna Directivity

[Jim Brown]

On Fri, 30 Jul 2004 09:29:06 -0400, RICHARD BOYD wrote:

>Resulting in the conclusion we often hear, "You can't have too many 
>antennas," meaning it's nice to be able to switch to different antennas to 
>find the best one in the circumstance.

Yes.

A week or so ago, someone posted a wonderful treatise on something as 
simple, yet complex, as how to drive a vertical stack of antennas on some 
band. The issues were as varied as the distance to the other station, the 
conditions of the ionosphere, the tropospheric conditions, surrounding noise, 
etc. There was no single answer. Rather there were multiple VERY GOOD 
answers, each of which was better for a given set of conditions. And, as I 
recall, the author noted that he was set up to switch between them to take 
advantage of conditions. 

Some other examples. I live in RF noisy flatland -- a Chicago neighborhood 
that is a mix between business and residential. A commuter train line is across 
the street. My antennas are simple, have only modest directivity, and I don't 
hear very well, but being able to switch between them in the middle of a QSO 
or contest is a HUGE help.  

My only 6m antenna is a horizontally polarized PAR loop that is advertised as 
being pretty omni. I haven't measured it, but I suspect that it is. In about 8 
months, I have worked 44 states and 192 grids on 6m with that antenna and 
100 watts. A fair number of those grids have come from some direction other 
than that of the major opening. That is, everyone is working into FL and AL, 
and I'm working a guy in UT.  And by the way -- this simple rig has given me a 
fair number of Aurora contacts. 

Without question, the additional directivity of a beam on any of these bands 
could help my receiving a lot. But simply switching between antennas with 
modest directivity can help a lot. 

Jim Brown  K9YC