Antenna/Frequency Calculation
- Thread starter WA9JGB
- Start date
- Status
doctordialtone
Member
Formula
1 over 2 pi FC
https://www.easycalculation.com/physics/electromagnetism/antenna-wavelength.php
1 over 2 pi FC
n5ims
Member
- Joined
- Jul 25, 2004
- Messages
- 3,949
West Mountain Radio - Antenna Calculator
For the typical vertical antenna used on VHF/UHF bands, use the "E" length, that's a quarter wave. For a full dipole, use the "L" length, cut in half with the coax attached there (shield to one side, center conductor to the other side).
Note that although the calculated lengths will be accurately calculated and use the correct formulas, they won't necessarily be the exact length you'll need in YOUR situation. They are based on the antenna being a sufficient distance away from anything that could alter the values. It's generally best to cut your antenna a bit long and shorten it until it's actually resonant as installed in the area it will be used in. Also note that for a vertical antenna (that "E" length measurement) it assumes that a proper counterpoise (sometimes called a ground plane) is there acting as the "other half" of the antenna. That counterpoise generally "is what it is" and the tuning of the antenna for lowest SWR or closest resonance is how you can compensate for what you have available.
For the typical vertical antenna used on VHF/UHF bands, use the "E" length, that's a quarter wave. For a full dipole, use the "L" length, cut in half with the coax attached there (shield to one side, center conductor to the other side).
Note that although the calculated lengths will be accurately calculated and use the correct formulas, they won't necessarily be the exact length you'll need in YOUR situation. They are based on the antenna being a sufficient distance away from anything that could alter the values. It's generally best to cut your antenna a bit long and shorten it until it's actually resonant as installed in the area it will be used in. Also note that for a vertical antenna (that "E" length measurement) it assumes that a proper counterpoise (sometimes called a ground plane) is there acting as the "other half" of the antenna. That counterpoise generally "is what it is" and the tuning of the antenna for lowest SWR or closest resonance is how you can compensate for what you have available.
Last edited:
N0IU
Member
You already have several answers that will (should?) answer your question, but I just wanted to say howdy to another "traveling man".
- Joined
- Jan 2, 2005
- Messages
- 422
- Status