GP100 FM Transmitter Antenna Outdoor, 1/4 Wave Professional GP Antenna for 87-108mhz 0.5w-100w FM Broadcast Transmitter, Waterproof FM Antenna with 26FT TNC/BNC Cable

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 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.

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.

Good: SWR 1:1 at the marked frequency. Wider frequency range once the frequency was set, than expected. We love how our LPFM station audio sounds using this dipole. Assembly without really using the owners manual was straight forward.Poor: Shipping box came with two bracket screws punching holes through the box. Because of this, one of those required screws was lost during shipping. Fortunately I had extra screws leftover from a previous FMUser junk antenna. The reported antenna gain on the sticker (pictured) is typical for a simple dipole when compared to isotropic (all directions at the same time).

Work well for FM band. The slide enclosure over the elbow joint is nice for keeping the antenna straight for vertical use. Elbow joint has a noticeable click and seems to hold in position strongly.

I've been using this antenna for several months now with no problems. The cable length was perfect for my installation and setup was super easy using the simple to understand instructions. I've checked the SWR several times at my frequency and it's almost non-existent. The system operates about 12 hours a day running at about 50mw (at the moment) using a 20 watt MaxPro 3+ Transmitter Board and SE3+ Stereo Encoder both from PCS Electronics. I keep the modulation in check with a BEHRINGER DSP1424P and CRATE Constant Q Graphic Equalizer. This antenna matches up perfectly with this setup. The only improvement I made was to add self sealing shrink tubing over the ground plane joints hopefully insuring a long trouble free life. Since going on-air in 2008 this seems to be the best bang for the buck so far.