P25 UHF Pre-Amp

[cpetraglia]

I have a simple question. When using a pre-amp for 800MHZ P25 Phase I digital system, should it be a 'Narrow Band' or a 'Wide Band'? ARR sells Freq. specific pre-amps (somewhat pricey) in both types.
In my case, my P25 system is in the 854 to 860 range. They make an 806 to 896 preamp. I am thinking the band pass rejection has to help, I just want to make sure I get the right model.

Thanks, Chuck

[jackj]

It shouldn't make much difference, Chuck.

[kb2vxa]

It only makes a difference if you have a cell tower nearby in which case you need to reject cell phone frequencies. That's what re-banding was all about, PS being interleaved with cell caused major problems but they're still close enough to upset scanners which have wide band front ends, that's just the nature of the beast.

[rbm]

The spec. will indicate what an amplifier does within a particular frequency range.
It doesn't normally tell you what it will do outside of that range.

Here's an example of one of my Mini-Circuits ZQL-1900MLN amplifiers. http://www.minicircuits.com/pdfs/ZQL-1900MLN.pdf
The specifications are for the range of 1850-1910 MHz.
But you can see the amplifier performs quite well from below 440 MHz to well above 1900 MHz.

Rich

Edit: I should have mentioned that if you watch ebay, you can get some great deals on Mini-Circuits or other brands of pre-amps. ($49-$99 or so)
You may have to buy some adapters to go from SMA to the type of coax connectors you're using, and you can power the pre-amp with a 'wall-wart' power supply. (5.5 x 2.1 mm connections)
Using connectors like these: 5 5mm x 2 1mm 2 1 DC Female CCTV LED DC Power Jack Adapter Connector Camera | eBay

[rbm]

Originally Posted by cpetraglia

I have a simple question. When using a pre-amp for 800MHZ P25 Phase I digital system, should it be a 'Narrow Band' or a 'Wide Band'? ARR sells Freq. specific pre-amps (somewhat pricey) in both types.
In my case, my P25 system is in the 854 to 860 range. They make an 806 to 896 preamp. I am thinking the band pass rejection has to help, I just want to make sure I get the right model.

Thanks, Chuck

Without knowing how much is too much......................

There are two 'Mini-Circuits ZQL-900MLNW 800-900 MHz RF Amplifiers'
available on ebay now for $89.99 each with free shipping.
They sell new for $249. http://www.minicircuits.com/pdfs/ZQL-900MLNW+.pdf

I've found them to be better than 'hobby' type amps.

Rich

Model: ZQL-900MLNW
RF amplifier rated for use 800-900MHz (datasheet shows performance 750MHz-1GHz)
Gain: 22dB min.
Very low noise figure, 1.7dB max.
High IP3, +41dBm typ.
Rugged, shielded case
RF connectors: SMA (female)
VSWR: 1.3:1 input, 1.4:1 output, typ.
Power: 15VDC 200mA (max)