View Single Post
  #41   Report Post  
Old February 5th 05, 01:29 PM
CWB
 
Posts: n/a
Default

The formula for a DIPOLE is 468/freq in Mhz = length in ft.....the formula
234/freq is for one leg OR usually quoted for a 1/4wave vertical but the
standard dipole formula is 1/2 wave (just to clarify that).

As for a good FM omni antenna, he should build a simple 1/4 ground plane or
coaxial sleeve antenna.....OR a turnstile (cross dipoles)..

FM stations USUALLY use Circular Polarization.....(similar to horiz and
vertical at the same time...)
so an antenna set for horiz or vertical will work (but lose 3db of signal
compared to a CP antenna!)

Chris
WB5ITT

"Buck" wrote in message
...
On 30 Jan 2005 17:14:42 -0800, wrote:


I don't know why you want FAT. It will give you lower gain. However,
you might consider building a dipole out of 1/2 copper tubing. A
piece of PVC T connector and two elements about 2.4 feet long each can
be connected to the coax, painted (if desired) and mounted inside the
attic or outside if desired.

The formula for a dipole is 234/frequency in Mhz = 1 leg of a dipole
or 1/4 wave length approximately. (Each dipole needs two legs.)

the copper pipe will give plenty of band width and do as well or
better than three inches.

You don't have to be worried about perfect dimensions as you aren't
worried about SWR so the elements I showed you will work very well.

Someone correct me, but don't FM stations transmit both vertical and
horizontal?

I hope this helps.


--
73 for now
Buck
N4PGW