Ramsey Electronics DA-40 - Manual (Page 15)

RAMSEY DA SERIES DIPOLE ANTENNA Page 15
TUNING YOUR ANTENNA
Hook up your radio to an SWR meter and the antenna. Set it for a portion
of the band that you think you will be using most often. Since all of our
antenna length calculations are for the center of the band, the antenna
should be slightly longer if you wish to work below this frequency, and
slightly shorter if you work above it. Reduce your power down to it’s lowest
setting and transmit on a clear frequency. Your SWR meter should now be
measuring the SWR of your antenna. You will notice that if you tune up or
down, this will change. Try this, and note whether or not the SWR gets
higher or lower as you go up in frequency. If it gets higher as you go up, the
antenna needs to be shortened.
Back outside again (or get a buddy to stand out there), cut about one inch
off of each end of the antenna wire. Rekey your transmitter and repeat the
same test over. If the antenna still needs to be shortened, cut off a bit more.
Over and over, perform this test until the frequency that you wish to tune the
antenna at has a lower SWR than the frequencies above or below it. Now
that your antenna has been successfully tuned, you are ready to try making
a few contacts.