> "Mike Dietrich" <m.dietr...@...> wrote:
> The main way of thinking is that you want to put the
> pre-amp after the band pass filter.
> The reason for this is that if it is before the b/p
> filter, it amps anything it sees, noise and unwanted
> stuff alike. If its behind the b/p filter, it only
> amps the signals that are left and need it.
It's a good way of thinking... but many of us in the
commercial radio world are thinking more along the lines
of what happens to the preamplifier and the receiver
during large input signal events. How does the preamp
and the receiver perform during signal over-loads and
how to best prevent those over-loads from causing
grief.
The best placement of the added RX Preamp is not always
the convention thinking best/first choice.
> You might need to add a several DB attenuator between
> the pre amp and the receiver to keep from over driving
> the front end.
In some cases, one might need an attenuator... which sort
of highlights why I had previously mentioned the receiver
front-end performance.
More time to freak everyone out... we have more than a
few applications with two series Rx Pre-amplifiers. There's
a lot more hardware going on (in place) than just parking
two Pre-amplifiers in series so please don't be mislead by
my initial description. But yes, we do often use two
Rx Pre-amplifiers and when properly done they work killer
(very, very well).
> Advanced Receiver Research makes very good low noise
> preamps as so do several other companies.
> Hope this helps,
> Mike
I like ARR and Angle RX Preamplifiers... ARR makes a T/R
Relay switched version, which for a number of reasons is
really neat to be able to remotely control.
cheers.
s.
