M-100 Professional (24-2300 MHz) Pre-Amplifier

Works like it should very happy

If you install this at the receiver it won't impress, that's because it will be amplifying the noise floor AFTER losses in the cable. It is best installed right under the antenna to compensate for losses in the downlead. I have mine set to +20dB, wideband, mounted under a discone in the loft, a power cable runs up with the antenna down lead allowing me to switch it on and off. The gain is significant and notable bringing previously unintelligible signals into intelligibility and revealing signals not previously received. Spatter from powerful signals like FM broadcast and pagers is minimal, this might vary by location. My spectrum analyser (noise floor -95dBm) reveals no generation of harmonics, when tuned to twice the frequency of local powerful signals my main receiver isn't picking up harmonics.

At first was disappointed! I realised dirty electric was my issue causing high threshold of static rendering RF gain useless! Put ferrite chokes on all electrical items; with static reduced it works well!

Works well but is let down by poor design. Replacing the battery is a pain as 4 screws have to be removed and there isn't an actual battery compartment, the battery just hangs loose in the box. The preamp has a female BNC connector at both ends so you can't mount it directly on a hand held scanner without an adapter.

Basically this device weakens the signal and totally kills it when turned off. The only thing you need between a radio and antenna is a good quality coax, not something that splits it and then attempts to boost it again. The dc power source also adds noise. Total waste of money for a useless device.

A expensive noise blanket Update after returning the first one with a intermittent fault I now eat my words found to be very good

this pre-amp does just what it claims,it amplifies weak signals so you can hear them better than you did before.with selectable frequency band switch and adjustable gain you cant go wrong.if you have a scanner you have to get one of these, i'm glad i did.the description of the pre-amp does not say that its powered by 12v DC or a 9v PP3 battery, the PP3 fits inside the case.i use this pre-amp with my  Bearcat UBC3500XLT 2500 Channel Wideband Handheld Scanning Receiver

Pre Amp works in respect of amplifying wanted signals and by nullling out unwanted signals. The amplification seems to be not quite as good as a similar more expensive Pre Amp but it does its job well enough.