|
Radio
The radio at the heard of GB3IM is a Philips/Simoco PRF1060.
These rugged commercial repeater units have enjoyed immense popularity
with business radio users as well as many emergency services throughout
the world.
The standard configuration of a commercial
repeater does not include the features that have traditionally adorned
amateur repeaters for the last 30 years. In particular, callsigns and
courtesy tones are seldom used. In many cases, the repeater does not
even have a "hang", whereby the transmitter remains on for a few
seconds after the end of the user's transmission.
Many older amateur repeaters are guilty of an
excess of "bleeps and squeaks", where the controller gives forth all
sorts of morse code idents and other tones during the repeater's
operation. Often, these signals do nothing to enhance the user
experience and, in fact, often get in the way.
In its "Stand Alone" mode of operation, GB3IM
will operate as a basic talkthrough repeater with no frills at all and
no "hang time".
CTCSS at 110.9Hz is mandatory and 1750Hz tones will have no effect at
all
upon the repeater.
The Isle of Man's UHF repeater infrastructure is built around the
conept of a group of permanently interconnected repeater sites located
at strategic points on the island.
At the moment, we are unable to directly connect the Snaefell site to
the internet. This, then, requires that the repeater be linked to other
nodes via an RF "Uplink".
In essence, this is a standard radio connected to a PC, located at a
place which does have internet access. When a call comes in from the
network, the radio goes into transmit and the caller is relayed via
Snaefell. When his transmission ends, the PC controlling the link will
transmit a "beep" to indicate the fact and the repeater will then shut
down to await a response. For the internet linking to work correctly,
it is essential that an RF-linked repeater like Snaefell drops its
carrier immediately it is not required.
In reverse, when a caller transmits on the Snaefell frequency, his
transmission will be heard by the link radio and will be passed-on to
the network, allowing him to be heard by any interconnected node.
Node
Structure
We are presently licenced to operate three repeater sites. OfCom has
authorised us to use the same callsign for each site and there are no
stipulations requiring any callsign modifiers to uniquely identify each
site.
The UK Repeaters
website shows each repeater with a suffix letter. This
was done to assist in uniquely identifying the various sites for
administrative purposes and is not an indication of the actual callsign.
|