Gray-Hoverman, the wideband TV antenna

 Author:   Posted on:   Updated on:  -
Air TV channels transmit on frequencies ranging from 170 MHz to 860 MHz. The VHF-Hi band covers 175 to 230 MHz, while UHF covers 470 to 860 MHz. The gap between is used for cable TV. Receiving all these frequencies is difficult when using a single antenna.

The Gray-Hoverman antenna has been designed by Doyt R. Hoverman and it was patented in the sixties. His design only covered a part of UHF band. However, with some improvements, the antenna can receive well both the UHF as well as VHF-Hi. This post will show two variants of this antenna that can be used to receive 170 to 230 MHz channels (5 - 12) and a part of UHF between 470 - 720 MHz (21 - 52 channels) with a minimum gain of 5 - 6 dBi. These are the simplest to build. There are however designs that offer a minimum gain of 8 dBi on VHF and 10 dBi on UHF (check the Links section). These antennas can be used for any kind of signal that can be received on the mentioned frequencies: analog TV, DVB-T, DVB-T2, ISDB-T, ATSC. The design is distributed according to the GNU GPL version 3 license.

Gray-Hoverman with NAROD antennas

GPL v3

Gray-Hoverman with NAROD antenna (VHF/UHF)
Variant 1 (links 2 and 4)
Gray-Hoverman with NAROD antenna (VHF/UHF)
Variant 2 (link 3)
All dimensions are in milimeters. The antenna can be built with aluminium or copper of 3 to 8 mm diameter.

The gain of these antennas is shown below (4nec2 simulation).

Gray-Hoverman with NAROD antenna gain plot (4nec2)
Gain (dBi) of variant 1.
Gray-Hoverman with NAROD antenna gain plot (4nec2)
Gain (dBi) of variant 2.
The antenna impedance is 300 ohms balanced. A balun should be used. You can buy one or you can build one similar to those in commercially available antenna amplifiers. If you don't have the parts for it, you can ommit it and connect the cable directly, although it is highly recommended.

Wideband VHF/UHF impedance adapter (balun)
The balun
Detailed instruction about how to build this matching transformer can be found at: Make a wideband antenna matching transformer.

The performance of these antennas can be improved by adding some reflectors. See the designs here. No reflector variant is easier to build and receives two sides. See its radiation pattern below.

Radiation pattern of no reflector Gray-Hoverman
Radiation pattern of no reflector antenna
A construction variant is shown below. The antenna sits vertically, as shown.

Gray-Hoverman antenna with NARODs for VHF/UHF
Construction detail. 1. Duct tape 2. Pass through hole to prevent a cable position that would allow water to enter and oxidize the cable wires.
For an easy way to build those NARODs (the horizontal "hat"-like elements) see unclesam's bending jig on Instructables [5].

Have you built this antenna? How does it perform for its simplicity?


  1. Wikipedia. Television channel frequencies.
  2. The Gray-Hoverman Antenna for UHF Television Reception - Digital Home Canada
  3. Nikolai Mladenov. nikiml's Antenna pages.
  4. SBGH-6 Tophat NARODs for VHF-Hi.
  5. unclesam. NAROD Bending Jig for Gray Hoverman TV Antenna (CC-BY-SA). Available on Instructables.
  6. Новые антенные усилители.

No comments :

Post a Comment

Please read the comments policy before posting.