[TheList] amplifier

Thu Sep 5 22:20:27 AEST 2013

On 05/09/13 20:21, ron heydon wrote:
> Hi Guys
> I am running a uniden base set scanner of a exterior pole mounted aerial which works fine on one set
> but the second set is on a different level on the house and is down on signal strength and quite noisy
>
> I have aerial to radio 1 via bnc t adapter with the second radio off that
>
> Is this the correct way or do I need a splitter amplifier or bnc splitter
> If so what sort etc
> Also can someone enlighten me on the software to decode pager signals on a pc

A Tee connector won't really do the business: it'll present a huge mismatch to 
the incoming signal setting up huge standing waves on all the lengths of coax.

Results will vary hugely with frequency.

I assume you are using 50 ohm coax. Sadly 50 ohm splitters are rather rare, but 
it'll be worth trying 75 ohm TV splitters.

If you are using 75 ohm coax the results will be good, but they'll be better 
than Tee connectors in a 50 ohm installation.

75 ohm TV and satellite splitters are cheap and widely available. I've seen 
them in the $2 shop.

Using differing coax impedances in your installation will lead to highly uneven 
results too, again especially at different frequencies.

If you are only going to use the system for reception placing a broadband 
preamp at the antenna may help. This reduces the noise figure by the amount of 
attenuation in your coax meaning that you may hear weaker signals. However, 
broadband amplifiers are prone to intermodulation so you may get more spuries 
and interference.

The increased levels at the receivers may also lead to more intermodulation in 
their front ends. Some attenuation at the receiver should help this.