We actually did seriously consider this as a solution to a a very
difficult problem in an industrial situation some years ago when we were
colleagues and dealing with a situation that involved both electrical
noise and hazardous materials. The problem we ran into at that time was
an economic one viz. horrendously expensive and a client who took the
attitude that "it hasn't been done that way before"! Of course, these
days the basic technology is well established and the costs are so much
lower that you wouldn't not do it that way! It is now commonplace for RF
feeds to be distributed this way.
For many of us amateurs, the relatively short distances are going to
cause few problems - most will be the mechanics of protecting the fibres
against damage.
Alan also had the idea, at the time, of doing the interstage coupling of
MF transmitters by fibre links - which if you think about it - gets rid
of a lot of problem areas.
With the falling costs of devices and the availability of equipment on
the surplus market this sort of technology is worth looking at in more
depth. Could be (as they used to say about the microprocessor) "a
solution going round looking for problems"!
Anyway, it is Friday night and I am going to put the "hobbyhorse" back
in his stable!
Good Weekend All
73
On Fri, 2011-01-14 at 17:36 +0100, Roelof Bakker wrote:
> > Hi Roelof,
> >
> > Some interesting comments there.
> >
> > On the topic of feeder pick up Alan G3NYK and myself have had many
> > conversations over the years about ways to deal with the problem and a
> > method we've never got around to trying but I now have some components
> > to try (when I get a "roundtooit") is to convert (E/O) electrical to
> > optical at the feedpoint and then conduct by fibre through the noise
> > field converting back to demodulated baseband in the shack. The problem
> > of powering the feedpoint equipment may be overcome by using batteries
> > (possibly solar-charged) thus avoiding further noise pick up and
> > re-radiation from power source cabling.
> >
> > 73
>
> Yes, this is an excellent idea and to be honest I have already acquired
> the necessary parts for some time, but have not come round yet to use
> them. An other idea that I have tested and can give excellent results in
> difficult cases is to use CAT5 network cable.
> I used rf-isolating transformers at both ends for the signal pair and
> common mode chokes at both ends for the pair carrying power to the antenna.
>
> 73,
> Roelof, pa0rdt
>
--
73 es gd dx de pat g4gvw
qth nr felixstowe uk
(east coast, county of suffolk)
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