UHF Antenna Calculator

Results

Wavelength: —

Element Length: —

Enter a frequency between 300-3000 MHz to calculate.

A UHF Antenna Calculator is an online or software tool used to determine the dimensions and parameters needed to design an antenna for the Ultra High Frequency (UHF) range, which spans from 300 MHz to 3,000 MHz (3 GHz). These calculators help radio enthusiasts, engineers, and hobbyists build antennas tailored to specific frequencies within the UHF band, commonly used for television broadcasting, cell phones, Wi-Fi, Bluetooth, two-way radios, and other wireless communications.

How It Works

UHF antenna calculators typically calculate key antenna dimensions, such as the length of the antenna elements, based on the desired operating frequency or wavelength. The most common types of antennas designed using these calculators include:

  1. Dipole Antennas: A half-wave dipole antenna consists of two quarter-wavelength conductors placed end-to-end. The calculator computes the total length using the formula: L=468fL = \frac{468}{f}L=f468​ where L L L is the total length in feet, and f f f is the frequency in MHz. For example, at 1000 MHz, the dipole length is approximately 5.62 inches or 0.14 meters.
  2. Quarter-Wave Ground Plane Antennas: These consist of a quarter-wave radiating element and radials (usually 12% longer than the radiator). The calculator provides the length of the radiator and radials, factoring in a velocity factor (typically 95%) to account for the speed of radio waves in the antenna material.
  3. Yagi-Uda Antennas: These directional antennas have multiple elements (driven element, reflector, and directors). Calculators determine element lengths and spacing based on frequency and design parameters.changpuak.chk7mem.com
  4. Other Antennas: Calculators may also support designs like loop, slot, or BiQuad antennas, providing dimensions for specific UHF applications.

Inputs Required

To use a UHF antenna calculator, you typically need to provide:

  • Desired Frequency: The specific frequency (in MHz) within the UHF range (e.g., 470 MHz for TV or 915 MHz for RFID).
  • Antenna Type: Dipole, ground plane, Yagi, etc.
  • Material Details: Wire or tubing diameter, as thicker conductors may require length adjustments (using an adjustment factor, k k k).omnicalculator.comk7mem.com
  • Environmental Factors: Some calculators account for nearby objects (buildings, trees) that affect resonance and impedance.

Outputs Provided

The calculator outputs:

  • Element Lengths: Total length and individual leg lengths (e.g., for each arm of a dipole).
  • Wavelength: The corresponding wavelength for the input frequency, often expressed as half-wave or quarter-wave.
  • Adjusted Lengths: Adjustments for conductor diameter or environmental effects.
  • Other Parameters: For advanced designs (e.g., Yagi), it may provide spacing between elements, feed-point impedance, or radiation resistance.omnicalculator.

Practical Considerations

  • Trimming: Calculated lengths are approximate, so antennas often need slight trimming to achieve the lowest Standing Wave Ratio (SWR) for optimal performance.hamradiosecrets.com
  • Environmental Effects: Nearby objects like trees or metal structures can affect resonance, requiring adjustments.hamradiosecrets.
  • Feedline and Balun: For dipole antennas, a 1:1 balun is recommended to match the balanced antenna to an unbalanced coaxial cable (50 or 75 ohms).westmountainradio.com
  • Construction: For UHF, antennas are smaller due to shorter wavelengths, making them easier to build with materials like copper wire or chassis-mount connectors (e.g., N-Type or SO-239).

Example Calculators

  • West Mountain Radio Antenna Calculator: Provides dipole dimensions and recommends a balun.westmountainradio.com
  • Ham Radio Secrets: Calculates dipole and inverted V lengths, with explanations of environmental impacts.hamradiosecrets.com
  • M0UKD Quarter-Wave Ground Plane Calculator: Computes radiator and radial lengths for UHF ground plane antennas.m0ukd.com
  • 3Roam UHF Antenna Calculator: Focuses on dipole lengths for UHF frequencies.3roam.com
  • Everything RF Dipole Calculator: Computes dipole lengths based on frequency and wire diameter.

Why Use a UHF Antenna Calculator?

These tools simplify antenna design by providing precise measurements, saving time, and ensuring the antenna resonates at the desired frequency. They are especially useful for amateur radio operators, RF engineers, and hobbyists building antennas for UHF applications like TV, ham radio, or wireless networks. However, calculated dimensions should be considered starting points, as real-world conditions often require fine-tuning.

Scroll to Top