TWAYRDIO UHF/VHF Mobile Ground Plane Antenna Enhance Signal UHF Female to PL 259 Male Connector for Car Radio Mobile Transceiver

This thing awesome it really improved my reception by a lot I’m about 40 miles from my nearest international airport and with this ground plane my reception has been amazing and the quality of the audio has improved greatly. Definitely recommend. It’s a little smaller then I thought and I do wish they make it a 6 antenna instead of a 3 but over all I highly recommend especially for a tripod setup like I have here

Screw this onto a SO259 antenna base, then screw the PL259 antenna onto this adapter. Select either VHF or UHF operation by attaching the longer or shorter counterpoise whips (respectively) into the threaded holes in the adapter. As the instructions mention, be gentle - the threads are small and soft. Make certain the whips are inserted straight and not cross-threaded, then carefully screw them in with fingertip pressure only. DO NOT FORCE and use no tools. Given that these are for stationary base use, they don't need to be very tight, simply secure enough to make reasonable electrical contact. For mobile use, for example on a motorcycle or plastic top with insufficient metal to provide a suitable ground plane, I would recommend using adhesive or cement after attaching the counterpoise whips to ensure they don't back out with vibration. It should be something removable, however - changing between VHF and UHF frequency ranges requires removing one set of whips and installing the other. Once installed, this does a good job of improving the ground plane of an antenna that does not include one as part of the basic design. That is typical of mobile antennas designed to be installed on a metal vehicle which use the metal surfaces at the ground plane. It's also easy to set up and take down for portable operation, setting up a temporary base operation in support of community service or an emergency. Disassemble, put the parts in a zipper bag, and keep it with the stand used to hold the antenna. You will be ready to support a temporary base operation at a moment's notice.

Not terribly effective, but well made

A good desktop antenna as well

Excellent solution for a mo ile mount antenna to be converted to a pole mount

If you need a ground plane for a portable radio situation, I love this product

I dont think anyone would notice a difference on VHF/UHF, maybe 900mhz +

I purchased this kit to use on a service vehicle that has a fiberglass topper. The original antenna I was replacing performed well, but was only a 1/4 wave stubby that utilized a corroded 6" diameter aluminum disk as its ground plane. I upgraded to a 5/8 wave vertical and wanted to replace the corroded aluminum ground plane with something wouldn't require much time to do so. Unfortunately, this unit wasn't a good solution. After installing this ground plane kit and checking the antenna system with an analyzer, I realized that something was definitely wrong. High SWR readings were all I could see on my test equipment. After tinkering with the installation and having no luck lowering the SWR's, I removed the ground plane kit and replaced it with a stainless steel disk. The SWR reading dropped to 1:1. Out of curiosity, I tried the ground plane kit on another UHF system that has no issues, and the same high SWR problem had shown up once again. I'm a professional Electronics Technician that performs RF installations on a regular basis. I've tuned thousands of transmitter antennas throughout my 30 years in the field. I have a service van full of RF testing equipment and multiple antenna analyzers at my disposal. I wouldn't recommend using one of these on a high power UHF transmitter. If you plan on doing so, make sure you use an antenna analyzer or even a cheap SWR meter to verify your installation doesn't damage your equipment.