RadioBanter - View Single Post

January 3rd 06, 10:31 PM posted to rec.radio.amateur.antenna

wrote:
Hi de KJ4UO,

I have a MFJ-269 and I measured a value of 65 and j16 for my 6-meter
dipole, the dipole is a little long so I assume that the j16 is
inductive and I need to add a cap of equal reactive value.
Also, The measurement was taken directly at the antenna feedpoint
without any coax.

Once I back calculate the cap value ,should I place this cap across the
antenna input at the feed point or in series with the signal line of
the feed point to cancel out the j16 and leave me with 65 ohm
resistive?

tnx de KJ4UO

Adding a cap with 16 ohms reactance in series will bring your impedance
to 65 ohms resistive. Adding a 280 ohm reactance cap in parallel will
cancel the inductance but the resistive component will now be about 69 ohms.

Why not just trim the dipole a bit?

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com