There are now a number of repeaters in our area which offer Internet Connection to other nodes using voice over IP technology.
There are two man types used one is the Internet Radio Linking Project and the other is the other is Echolink.
The repeater GB3PZP in Stalybridge radiates a good signal into the Warrington area and we will take this one as an example.
The repeater GB3ZP:
transmits on 430.900MHz (your receive frequency)
receives on 438.500MHz (your transmit frequency)
NB most repeaters have an input 1.6 MHz above the output GB3PZP is different in this respect
access with CTCSS 82.5Hz or 1750Hz tone (CTCSS is usually rquired to link to other nodes)
This is using a 7.6MHz split (you may need to set this manually). Do not despair about this frequency split most radios are already programmed to allow 7.6mhz split. Some Kenwood radios for example provide double negative and reverse options selected together provide a +7.6MHz split. ( --r ). eg. Kenwood radios: Select 438.500 then using shift select until two negative signs appear then select the reverse key. Other manufacturers radios either default to 7.6MHz split or can be redefined to 7.6MHz split. Your radio should be showing the receive frequency of 430.900MHz and when in transmit 438.500MHz.
Satellite Link
HT Internet Repeater Link UK Internet Repeater Link USA HT
A radio transmission is received by the repeater station. This audio is then
fed into the sound card of the stations computer. The transmitted audio is processed
by a dedicated piece of computer software and transferred in to the Internet
link.
This software may be Linux and Speak Freely for IRLP nodes
Echolink is an alternative software which runs on the Windows operating system as well as Unix and McIntosh. and offers similar connectivity.
For more information about these and other software.
The signal is directed by the software to a predetermined station by the repeater operator using the up to date world directory of current radio amateurs logged in to the system. The receiving stations computer software then processes the incoming audio. The signal is transmitted via a vox unit (voice activated switch) and the receiving stations transmitter. This signal is received by a radio amateur on another radio so completing the final radio link. The dedicated software will only allow transfer of audio in one direction at a time. This is generally known as a simplex operation.
Most repeaters offer now connection to an Echolink or IRLP simplex node and these are ususaly well sited stations which allow mobile or pedestrian portable operation.
An alternative connection may be made by a simplex node, here there is no repeater involved and you need to transmit and receive on the same frequency if you are using this node.
Another term which you may come across is the reflector. Reflectors are devices which connect together a number of nodes and allow a net to include many operators in different areas or countries. A reflector has been described as a digital repeater. It takes a digital bit stream in, and repeats it to all other connected sites making a digital "partyline"
There are two types of signals which are used to control the nodes, these can be generated by your rig.
One of these is DTMF tones, these are the same as telephones use to dial numbers and are required to connect to a numbered node.
CTSS are sub audible tones which are continuously transmitted and open the signal path through the node, basically used to limit interference from other signal sources which are not intended to be part of the QSO.
When setting up a rig to connect to a node or repeater you need to set the shift on a repeater and the CTSS tone.
More Information
For a list of repeaters and simplex nodes available in this area click here.
For comprehnsive information about repeaters:
The UK FM Group (Western) membership £4 - donations voluntary
Comprehensive IRLP Node Lists for DX connections are availble from http://status.irlp.net/
List an activity status of Echolink Nodes
page updated by M0BXR Aug 2006
• Home
• St George's Island
• Programme
• News DX and Radio
• Favourites
• Membership
•
• Chairman's Message
• Projects
• Digital Power Meter
• CDG2000 Rig
• Forum •