RadioBanter - View Single Post - Ideas for Simple Homemade 17 Metre Antenna

Tam/WB2TT · September 5th 07, 01:50 AM posted to rec.radio.amateur.antenna

"Highland Ham" wrote in message
...
wrote:
On Sep 3, 3:56 am, Andiroo wrote:
All

Can anyone point me to some simple designs for a home made 17 metre
antenna. I am looking for some simple half wave dipole type designs.

468/18.1mhz=25.85 total feet for a half wave dipole. Divide by two for
each leg.
Feed with 50 ohm coax. Can't get much simpler than that. Can't get
much more
efficient either unless maybe you have to run 500 ft of coax. .
MK
===================================
A current balun near dipole in the shape of ferrite cylinders or ,when
using RG58 type of coax, 7 - 9 windings of the coax on a larger toroid ,
will ensure no RF interference in the shack /house (eg no RF current
flowing along coax braid)
It is even better to use a balanced feeder instead of coax.
You then either need a matching unit for a balance feeder or use a balun
as described above near the transmitter ,connecting coax to feeder
through a dual plastic connecting block .

Personally I would always use a balanced feeder for any wire antenna.

Frank

Use 50 Ohm coax (RG8X, or better) unless you are in love with your antenna
tuner. I have tried it with and without a balun, and can't really tell any
difference. However, right now there is a 1:1 current balun at the feed
point. Trim the length for best SWR, 25.85 might be a bit long. I am using
#14 stranded/insulated wire.

Tam/WB2TT