For your radio communications needs. Prepare yourself!
Published in QST February 2003
Ed first introduced the concept of this antenna in the February 2003 Issue of QST Magazine. It is the same antenna that appears on the front cover of the ARRL VHF/UHF Antenna Classics Handbook. It also won the best paper of the month award. It offers true ½ wavelength performance at both VHF and UHF with no ground radials. The antenna design has been so successful that it has been adopted by the Red Cross, ARES and numerous municipalities for emergency deployment. Copies of these agencies evaluation reports are available by emailing Ed. A good benchmark is that if an antenna configuration does not appear in a ARRL publication, it likely does not perform as claimed.
The antenna is available in Ham Band (144-148 MHz VHF and 440-450 MHz UHF) or Commercial Band (152-157 MHz MURS and 460-470 MHz GMRS) versions. Either version handles up to 75W input power. When deployed, it will offer about +6dB of gain over a rubber duck antenna. It comes complete fully assembled with end caps and an SO-239 connector. Just insert it into the PVC pipe and you are ready to go. N-connector version available as an option. Also available via special order is a 250W input power version, please inquire for details.
This antenna is complete with exception of 5 feet (153cm) of ¾ inch (20mm) Class 200 PVC pipe needed for the antenna. Cost of ordering and shipping of the 5' PVC tube is $15 so we rather you go to Lowe’s (stock # 23990) or Home Depot (SKU #282-477) or Menard (SKU #6899684) and buy the PVC pipe for about $3. If you are unable to find the PVC pipe, it can be ordered separately on this page. DO NOT USE SCHEDULE 40 OR OTHER PIPE TYPE/MATERIAL, WARRANTY WILL BE VOID FOR NON-APPROVED USES.
Overall Length: 5 feet, 50 ohm feed impedance, no ground radials. Antenna feed point is 10 inches above the connector. U clamps, hose clamps, etc. can be used for mounting up to the first 10 inches of the antenna without affecting performance. Antenna offers “true” ½ wavelength radiator at both VHF and UHF.
VHF (144-148 MHz) ham modelConfiguration: 1/2 wave radiating elementMaximum power: 75 wattsSWR: less than 1.5 to 1 over a 3 MHz bandwidth and less than 1.7 :1 over 4 MHz bandwidth.Gain: 2.1 dBiImpedance: 50 ohms
UHF (440-450 MHz) Ham modelConfiguration: 1/2 wave radiating elementMaximum power: 75 wattsSWR: less than 1.3 to 1 over a 6 MHz bandwidth and less than 1.5 :1 over 10 MHz bandwidth.Gain: 2.1 dBi (6db gain over a 2 meter J pole used at 450 MHz)Impedance: 50 ohms
The published papers on these antennas are available upon request. Building these antennas are difficult because of the limited availability of materials. Twin-lead has long been out of production. All of our twin-leads are custom ordered from our manufacturer. It is 300 ohm open air ladder line designed for transmitting. Also the ability to measure velocity factor is difficult and is absolutely necessary for this antenna to operate effectively. One can attempt using 450 ohm open ladder line but it will not fit into a 3/4 inch Class 200 PVC pipe and spacing is also too wide for UHF. Thus Ed and his students produce this antenna to the general public at reasonable cost.
NOTE: Don’t be fooled by claims of dual band performance from the competition: Although traditional VHF J-pole antennas will resonate at UHF, they suffer a –6dB loss at UHF over a ¼ wavelength ground plane. Although we see many claims of dual band performance antennas sold on the internet; however, when purchased samples are placed on test equipment, they reveal themselves to be just VHF antennas that also resonate at UHF. At UHF most of these imitations have horizontal loss of -6dB. Examples include: "Copper J-poles"; "Slim Jim"; "Arrow".
You guys are very thoughtful.
Thanks for taking the time to go over setup details with me. I really appreciate it!