Doki wrote:
"Serge Auckland" wrote in message
...
Doki wrote:
"Serge Auckland" wrote in message
...
Laurence Payne wrote:
On Wed, 9 May 2007 15:16:42 +0100, "Doki" wrote:
I've got an old Aiwa Reciever, probably dates back to the 70s or
early 80s - massive heavy aluminium front, needle tuner etc.
Anyway, it's got a rather strange connector on the back for the
antenna - 3 holes in a row marked "FM Aerial". Any ideas on what I
should be hooking up to it?
A FM aerial? :-)
I suppose it might be a combined 75 ohm/300 ohm connector. Try your
FM downlead into any pair of holes, see which work best! I suppose
it might be worth looking for a voltage on any of the holes first,
just in case it's some special arrangement for e.g. powering a
mast-head amplifier.
My guess is that the outer two are for a 300 ohm balanced downlead
with the centre pin being ground. If so, then either connect a
balanced lead to the outer two pins, or a coaxial cable to either
one (not both) and the centre pin. It would be as well to check for
volts as Lawrence has suggested.
What's one of them then?
What's one of what?
A 300 ohm balanced downlead.
This is a cable which has two parallel conductors spaced about 2 cm
apart. Unlike Coax, it doesn't have a screen. It is used mostly in
continental Europe. It has a characteristic impedance of 300ohms, and
having two identical connectors, is balanced, hence 300 ohm balanced
downlead.
It's not something you can buy easily in the UK, and indeed, coax is
preferable, as 300ohm cable is susceptible to interference.
I would use coax, and connect it to one outer terminal and a ground
point, typically the chassis of the receiver, or the centre pin of your
socket if that is ground connected.
Hope this helps
S.
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