What are the noise floor readings in your area .... ?
More than likely your power supply is suffecient enough for the 112 and sr9 ... what most fail to realize is that the 900mhz band is completely differet from other UNI/ISM bands in that there is usually a ton of noise at any given time. Most of this noise is found in the vertical polirization. Remember, you have cell carriers that use 900mhz in their technology.. (ever wonder how that signal seems to get everywhere
) but my suggestion is to change the polarity of both your transmitting and receiving antennae and you will be much happier, a channel filter to would be nice.