Adding and tuning a dipole (to your boat/house)

Feb 17, 2006
5,102
Lancer 27PS MCB Camp Pendleton KF6BL
While searching the internet about shipboard antennas, I chanced across these instructions on how to tune a new dipole without too much hassle. Haven't done it yet but makes perfect logic.

1. First write down the total length of your new antenna after using the old formula. (468/freqMhz = total length in feet) Hoist the antenna to its operating position.

2. With an analyzer or low level RF, find the frequency (F) of the lowest swr of your dipole. Note: Check several frequency points between top and bottom end of the band.

2a. Record the lowest swr frequency!

3. Multiply the original length from step 1, (L) by the frequency (F) in step 2 of lowest swr to get new constant.

3a. Example - Original cut (468/14.3 = 32.73 ft)
3b. Example - New SWR found at 14.235. New constant (32.73 * 14.235 = 466)

4. Now use the new "constant" obtained from step 3b above in the formula rather than the 468 to get new length in total feet. Adjust to that length and put the antenna back in the air. Should now be at the lowest SWR for that frequency.

4a. Example - 466 / 14.3 = 32.6 ft. Lower your antenna, adjust your antenna to this new length, hoist the antenna and your SWR should be where you want it.
 
Oct 6, 2009
97
Custom Bluehull Kennesaw, Ga.
Sounds like a good way to go. You are now the Wireman. :dance:

Keep us posted.