RioRand (TM) Upgraded RRT251 0-25W adjustable FM stereo transmitter broadcast radio station

I have bought a few FM transmitters in the past and this one has the best sound quality out of all of them. Many other ones in the $100 range would have a slight hum but this one is very quiet and sounded a lot like the professional radio stations in the area. I don't need anything over 1 Watt but I went with this one because it allows very fine control over the transmitter power.I hooked up the included antenna and put it about 30' in the air. I tried it at 1 watt and was able to get a clean signal over 3 miles away. It was way to powerful. I then tried turning it down to .5 watts but it seems that if change the power to 0.6 watts or lower the SWR jumps up to 9.9 and the transmitter does not work very well at all. If I change it to 0.7 watts the SWR will go to 1 which is perfect but I can still hear it about 3 miles away which is way to powerful. I was hoping to tune the power to so it only picks up a mile at the most.I ordered a 3 db and 6 db attenuator that gets installed between the transmitter and the antenna to cut out some of the power so hopefully I can leave the transmitter at 0.7 watts and cut it down to around 0.3 watts. I will update my review when I test it out and let you know how it works.

The good things about this transmitter are that the sound quality is very good, it does put out 25 watts. The case is nice and it has RCA inputs. The antenna I'm sure works good, it's just a 1/4 wave ground plane and will work as good as any other 1/4 wave vertical. The bad things about this transmitter are the noise the fan puts out is very load and will be picked up by any open mic in the same room. The fan puts out a whine around 2KHz. I own two other transmitters, one 7 watt and a 15 watt unit, the noise is not near as bad on the lower powered units. This noise problem needs to be fixed by the manufacture. The unit has about 9 menus, one is input audio level and once adjusted you can exit this menu but once your on the main page of the transmitter and you turn the nob, the audio input level will change also. This makings locking that setting impossible. As someone also said, running this unit under about 700 mW will fault out the SWR protection shutting the transmitter's power off. The power supply was not used, I have a Astron supply running at 12.70 VDC to a 12ahr battery and then to the transmitter, very clean. The fan whine noise is by far the worst part of this unit, if anything changes I will edit this review. (edit) The unit was run at full power for 4 hours on a dummy load and the 2khz whine seems to be fading and just getting the noise from the air movement now. still loud but much better. The temps with a SWR of 1.13:1 stays in the 37C area after 4hours.

Sound quality is 100. This thing would do the job for a drive in movie theater VERY well. Amazing sound quality. Signal, and high SWR/Antenna drop it down a star, the antenna is crap, this thing won't go ANY 5 miles be warned, but it will go a mile or two. I have the antenna on our chimney and tested this setup with a 2000 general motors Delphi stock Chevrolet stereo (very sensitive, good radio)

I still can’t use the transmitterI try to use last year when I bought and when I plugged it say high temperature warning and beeping all the time. They call me and saying could be the antenna in a bad spot so I try again and never work so I packed and stored it. I just unopened again and try to use and still doing the same thing so I lost my money.

Works great and is turn-key ready to use. Sound quality is good using a good power supply. The included 12 volt power supply is noisy. The only complaint I have is the small fan is very noisy when the unit heats up.

The review on chzfm transmitter and RioRand T251

I still do not know how far of signal of this thing

great product