VK2RCZ Repeater

	REPEATER TRANSMIT	REPEATER RECEIVE	REPEATER CTCSS
2m	147.075	147.675	123 Hz Required
70cm	439.425	434.425	123 Hz Required

The Chifley Amateur Radio Club 2m Voice repeater was first operational in 1990 at a location in Lalor Park. It was located at the home of Paul VK2YIL, in Sydney's Western Suburbs. The repeater consisted of two hand-held radios connected via line filters. Later, the hand-helds were replaced with Philips FM-814 Base station units, with cavity filters installed to allow a common antenna for both transmit and receive. The antenna itself was a half wave co-linear. The repeater controller was home made, and controlled the repeater identification, time-out and transmitter PTT.

In 1995, the repeater was relocated from Lalor Park to its present location in Mount Druitt. This move was undertaken to make the repeater central to the majority of club members.

The job of relocating the repeater was not as easy as first thought (That's always the case, Murphy strikes again!). Firstly, the cavity filters had to be re-engineered. This involved machining the six 4 inch diameter copper tubing all to the same length, making new pick-up loops (a total of 12 were required), manufacturing the tops and bottoms of the six cavities and drilling the diecast aluminium boxes that were to be installed on top of each of the six cavities.

After the cavities were completed, they required cleaning, which required the use of steel wool and phosphoric acid to remove tarnish and dirt from all parts of the filters. The coupling loops were then installed, and the cavities were aligned. A wooden base plate for the cavities to rest on was also manufactured. This allowed for ease of installation and removal from the repeater cabinet.

An early photograph of the repeater, showing the two Philips FM-828's and the cavity filters. A Later (and better) photo will be here soon.

The 2m (VHF) repeater now consists of two Philips FM-828 mobile radios, one being the receiver, the other the transmitter. These are fed through the cavity filter bank, which consists of the six cavities above, using three for transmit and three for receive. The cavities serve to isolate the transmit signal from the receiver, as there is only 600kHz separation. The output of the cavity filter is fed to a diplexer (which allows both VHF and UHF equipment to share a dual-band antenna) and the diplexer output is fed to the Diamond X-200 dual-band antenna via 25m of LDF5-50 Heliax. The output power of the repeater is 10W measured at the cavity filter output.

The 70cm (UHF) repeater consists of an AWA RT-80 for Transmit, and an FM-828 for receive. A set of 70cm cavity filters serves to isolate the transmitter and receiver, and like the 2m side, the output of the filter is fed to the diplexer. This allows both repeaters to share a single antenna. The 70cm repeater output is 20W measured at the transmitter output.

The 2m repeater controller is a commercial unit. It is an RC-100. This unit controls the repeater identification, time-out and repeater PTT. This particular controller will only control one repeater, however it will also connect to a 'remote base'.

The 70cm repeater is controlled by an XT laptop running BASIC and a program written by Adrian, VK2BFN. The program was the original software used at VK2RBM in the Blue Mountains. Mike VK2EK integrated a voice chip into the system which provides a voice Ident and the time to be transmitted every 15 minutes.

In 2001, the 70cm repeater was coupled with the club's IRLP node, operated by Nigel, VK2KJU.
In June 2004 the IRLP link was moved to Blackett the home of VK2EK. In November 2004 the link radio was repaired. In Feburary 2005 the IRLP computer failed after a number of attempts to repair it a new pc was built up and donated by Michael VK2EK. It was reprogramed by Geoff VK2XJG.

Brett VK2CBH
Mike VK2EK
John VK2JME
Nigel VK2KJU
Vince VK2DVC
Ray VK2FKO
Geoff VK2XJG
Paul VK2YIL

This allows the IRLP node to participate in both the IRLP and the
Echolink networks, however connections are restricted to those Echolink
stations that are RF links (i.e. not someone sitting at a PC with a headset)
Also, the node is not able (or permitted) to connect to both networks at the
same time (the software prevents this from happening...)

In order to connect to an Echolink node, exactly the same process is used as
for an IRLP node, however the node number will begin with a star (*).

Eg - to dial up Echolink node number 12345, you would key in *12345.

To disconnect, you use 73 as normal.