RadioBanter - View Single Post

January 31st 05, 07:35 AM

On 30 Jan 2005 17:14:42 -0800, wrote:

I want to build a fat dipole antenna for FM listening for my
brother-in-law, who refuses to get an antenna rotator.

He is located with antenna's all around him but not on top of him.

I would of course orient it vertically and use 75 ohm coax from where
it is mounted to his tuner.

Does the ARRL Antenna Handbook have directions on building one of
these?

I would be using 8 inches as the diameter. Is the math to figure out
the length gonna get me - I've been out of college for 30 years and
have only done business math since....

Thanks,

Brad

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