GP100 FM Transmitter 1/4 Wave GP Antenna

This is an honest, non-solicited, non-compensated review of the FMUSER GP100 FM Transmitter Antenna as sold on amazon. Before purchasing this item, I read reviews for this antenna from users on amazon. But first, some brief info about my FM transmitter. It is a NIORFNIO NIODESKTOP –TB SERIES, 6W/15W unit. It came with a telescoping antenna mounted on a heavy metal base, intended to just sit on a flat surface. I modified this arrangement and mounted it on the back side of my house. The top of the antenna was about 2 feet lower than my roofline. I have several FM radios around the house and garage. I got reasonable reception within my home and the signal was just barely receivable in my car to the end of my block. My transmitter was then set to 97.5 MHz, a clear space in the FM band. I was broadcasting Holiday music in my neighborhood during the 2022 winter season. Sometime in early 2023 another strong transmitter was broadcasting on 97.5 MHz, so I abandoned that frequency. I sought out a different clear frequency, which I thought would be 101.1. (explained in next paragraph). I wasn’t getting the clarity or range, so I decided to purchase this new antenna. Upon arriving at my home, I was surprised that the whole system was delivered in a 3-inch x 3-inch, x 17-inch long cardboard box, and placed in a plastic bag mailer. I unpacked all the items as described in the instruction manual. Incidentally, some (early) reviewers complained that instructions were inadequate, or there were no instructions at all. Not the case with my purchase. The manual was fairly well written, with photographs, some even in color. Not explained in the manual was the purpose of the three 24-inch “rods” that extend out from the center, forming a sort of tripod. I’m no broadcast engineer, but I have to assume that they are part of the electro-mechanical characteristic of the antenna. Also not explained was the reason for selecting and installing the correct “frequency bar”. Again, I’d guess these are some sort of band-pass filters to ensure that only the frequency of your transmitter gets through to the antenna, ensuring a clean broadcast. IMPORTANT TIP: Before completely assembling your antenna, make sure you determine a clear frequency in your neighborhood so that you will select the correct “frequency bar”. Initially I set my transmitter to 101.1 MHz, but later found out that there was already a commercial broadcast there. I had a contractor install my antenna on my roof. Once you install the desired frequency bar, you wouldn’t want to have to disassemble the unit and change the bar to your new frequency. To address one reader’s concern about the sharp edge at the bottom of the mast where the coax exits—to extend the mast to mount the antenna to my chimney, I purchased some 1-inch (ID) PVC and placed it at the end of the supplied mast. It helped to get the antenna higher and allowed the three rods to clear the chimney. I also purchased some tubular foam used to insulate copper water pipes. I wrapped the foam insulation around the coax where it exits the 1-inch PVC. OPERATION: I bumped the frequency up to 101.3 and it made a world of difference. Got in my car and had a strong clear signal all the way to my grocery store. According to Google Maps, the Line-Of-Sight distance is about 7,500 feet, or about 1 ½ miles. This through hilly terrain.

I use an FM transmitter to broadcast Halloween sounds and Christmas music during daylight hours and I add video to it that is rear projected onto the bay window of my house when it gets dark enough to see it. I was getting about a 1 block range of static free transmission using the rubber duck antenna that came with my FM transmitter. After that distance the signal faded into a noisy mess. I bought this antenna, assembled it, and stuck it onto a broomstick handle stuck in the ground just to see how it would work. I was able to receive a stable signal for several blocks even with the antenna so low to the ground. I plan to mount the antenna on the roof of my house for the next Halloween and Christmas seasons. I would not be surprised if I get a mile of signal coverage once it is at a decent height. By the way... It doesn't take a rocket scientist to assemble this. The antenna came with limited instructions and a diagram showing what went where. It seems well thought out and fairly solid once you snug everything up.

This antenna works! We tested SWR once assembled for our FM Frequency of 88.7 MHz and it was dead flat 1:1 SWR. Once connected to our ROLLS HR70 FM Transmitter we could drive down the road several businesses down either direction and hear our FM Broadcast signal very well. This test was done only while holding the antenna 6 ft high in our parking lot. If we were to place the FM Antenna higher, say 30 ft I'm am sure the FM Transmitted signal would increase even further away. Good solid construction. Easy to assemble. No brainer! I would highly recommend this FM Antenna to anyone wanting a good FM Broadcast FM Antenna for your Church, Business or School. It works well and SWR is flat on the frequency you assemble the FM Antenna for.

I used this to transmit my Christmas show this year. It worked perfect and was a huge step up from last year.

Antenna has great transmission and easy install. You only need a pipe to mount it to.

Using it as a FM receiver for my favorite station. It picks it up better than any antenna I've used, super clear.

I have a tiny 500 milliwatt FM transmitter (a CZE-05B). It came with a few feet of coax and an external magnet-mount "rubber ducky" antenna. I placed that antenna about 8 feet above ground, and drove around my neighborhood checking the range. It did pretty well and only faded out on the edges of my subdivision. I was able to hear the transmitter about a half mile in every direction. I was pretty pleased with the original range, but I wanted to see if I could squeeze a little more range out of the budget transmitter, so I picked up this antenna. I was STUNNED. I assembled the antenna which was incredibly simple. The antenna came with well written, easy to follow instructions. After assembly, I propped it up on top of a 7-foot latter and secured it in place for testing with some small bricks. Once it was situated on top of the latter, I connected it to the transmitter, put on some music, and got in the car to see if I had wasted my money. I absolutely had NOT. It was amazing. The half-watt transmitter now has a range of 2.5 to 3 miles in every direction! Unbelievable! The antenna is relatively small, and can be broken down easily and quickly for portable use if you have that need. It's well built from high quality aluminum parts, and includes 5 different screw-on antenna extensions to tune the antenna to resonance at a frequency close to the one you broadcast on. Read the instructions once, and you're good to go from then on. This was MASSIVE bang for my buck. I'm still kind of blown away with how far I can now drive and hear that cheap little half-watt FM transmitter!

I got this antenna to replace the little rubber one that came with our transmitter that we use for our Christmas light display. It was easy to assemble and feels robust. I wasn't looking for too much increase in range, just better clarity in the transmission. The signal now broadcasts much further than we need but the improvement in clear sound is amazing! No static or interference now, just nice clean sound.