17
Operation of the Antenna
The ups and downs of the antenna
The following assumes that there is a three foot whip attached to the top of
the antenna:
Adjust the control switch so that about 1.5 inch of the coil winding is above the collar. Set the
transceiver to a mode that produces a steady-state carrier (AM, RTTY, CW or FM). Generally
speaking, you cannot tune the antenna for minimum SWR while in the SSB mode. Set the
transceiver to 7200 KHz and reduce power to 10 to 20 watts. Watch the SWR meter and continue
to increase the inductance by moving the coil up until a sharp dip in the SWR occurs. Adjust for
lowest reading by moving the control switch back and forth. You are now tuned to 7200 KHz.
Increase the power to approximately 100 watts and recheck for resonance. Due to the design of the
SWR meter, a minor adjustment to the antenna will likely be needed when the power is increased.
SWR meters do change readings when the power level is changed.
If your transceiver does not have an SWR meter, you can use the power output meter. Just tune for
maximum output which will occur at minimum SWR. It does not matter whether or not you use
maximum out watts or minimum SWR. Either reading will result in a properly tuned antenna at a
frequency.
The highest frequency occurs at the minimum inductance position. Tuning will be sharp. So watch
carefully for the dip in the SWR or the increase in output power. On some installations, the lowest
frequency may occur above 3.5 MHz. On some installations, the highest frequency may occur
below 6 meters. It is also possible for the spring contact to run off the bottom end of the coil.
Chapter
4