I purchased a home and an antenna came with it. I don't know what the
original owner used it for and I'd like to find out what kind it is. It's a
verticle antenna mounted on a pole, the mast extends about 18 ft. up. At
the base it has three rods about 9 ft. long stretched horizontaly and at the
very top it has three 12" rods horizontal. The coax attaches to the bottom
and runs into the house, Is this Ham, CB or something for a scanner? Is
there any way of finding out?

Thanks

It is probably a CB antenna. Have someone with something like an MFJ
ANTENNA ANALIZER check the antenna and find resonant frequency.
If you can find a make or model number on the antenna you may find it on
the internet!

Les, AA4F

PC wrote:
I purchased a home and an antenna came with it. I don't know what the
original owner used it for and I'd like to find out what kind it is. It's a
verticle antenna mounted on a pole, the mast extends about 18 ft. up. At
the base it has three rods about 9 ft. long stretched horizontaly and at the
very top it has three 12" rods horizontal. The coax attaches to the bottom
and runs into the house, Is this Ham, CB or something for a scanner? Is
there any way of finding out?

Thanks

The 18 feet indicates it could be a half wave CB Antenna, but to be su

Borrow an Antenna Analyzer such as MFJ-269 and find the resonant frequency
of the antenna.
Most Hams will be happy to help and make the measurements for you.
An Antenna Analyzer is a better way of testing as you don't have to
transmit.

Once you know the resonant frequency of the antenna.

See Ham Band plans at URL:
http://www.icomamerica.com/downloads/bandchar.pdf

See CB Frequencies at URL:
http://listen.to/welfarewally

For any others, see FCC Spectrum Chart - URL:
http://www.ntia.doc.gov/osmhome/chp04chart.pdf

--
73 From The Signal In The Noise
Caveat Lector Ya All
----------------------------------------------------------------------------
"PC" wrote in message
news:hL79b.449290$uu5.79598@sccrnsc04...
I purchased a home and an antenna came with it. I don't know what the
original owner used it for and I'd like to find out what kind it is. It's
a
verticle antenna mounted on a pole, the mast extends about 18 ft. up. At
the base it has three rods about 9 ft. long stretched horizontaly and at
the
very top it has three 12" rods horizontal. The coax attaches to the
bottom
and runs into the house, Is this Ham, CB or something for a scanner? Is
there any way of finding out?

Thanks

(Richard Harrison) wrote in message

The 12-inch rods are capacitance loading used to improve current
distribution in the vertical radiator and to reduce its required length
at resonance.

They do operate that way I suppose, but the makers always used to
advertise them as "static hats". Supposably reduces static buildup and
noise. About the same principal as a round ball. Dunno how well they
actually work, but I think they are a little quieter than one with a
sharp tip. Being the antenna is an appx 5/8 wave in total length, the
difference in current distribution should be pretty small. Max current
is already higher than the halfway point even with a straight
radiator. Seems that max current point would still be the same appx
height from the base, hat or not.
Does make the antenna a foot shorter, probably with very little
reduction in performance. But, I don't think the original designers
had capacitive loading in mind when they stuck those on there. :/ A
full size "all vertical" 5/8 should be better than any loaded one.
Most CB 5/8's are on the shorter end of being a 5/8. This actually
makes sense for an antenna used for mainly ground/space wave. You
usually get a cleaner pattern with less high angle radiation with a
shorter 5/8 rather than a longer one. IE: .60-.62 wave vs .64 wave or
longer. .64 wave is the maximum gain point in theory, but not always
the best length for the real world. Most AM-BC's also prefer a shorter
5/8 for the same reasons, as I'm sure you know . I modeled this once.
I forgot the length for best pattern, but it was .62 wave or slightly
less I think. MK