Re: Longer legal links?

From: "Josh Howlett" <[email protected]>
> >> Unfortunately, I think the major problems of range (within cities) are
> >> due to obstacles blocking LOS, and not lack of power.
> >
> > Without a doubt.  This is more of a breakthrough for long-haul backbone
> > links, such as connecting a cluster of nodes in Kingswood with a cluster
> > in Clifton/Bishopston.
>
> For the benefit of radio illiterates such as myself, could someone explain
> the break-through in english, please :-) ?

OK, the problem we have in this country is that we are restricted on
transmit power.  The more power we use to transmit, the better distance we
can achieve.  We can also get better listening power using higher gain
antennas.  The problem we've had is that most cards use the antennas for
transmit *and* receive.  This means that upgrading the receiving antenna
does the same for the transmit antenna (they are one and the same), hence
making the setup illegal.

The way round this is to use seperate antennas for transmit and receive.
This allows us to have a high performance receive antenna, and a low
performance transmit antenna to remain legal.  The normal way to do this is
with a circulator, which is expensive.  Now, we have some cards that are
programmable to do this, and even a hardware hack for some cards to gain
this feature.  This means that our previous best distance of just under a
mile can now be 9 miles, whilst remaining legal.

Andy (hoping he's making this easy enough)