"The Old KØRWU AMARC 146.925 Repeater System Technical Information"
This was the KØRWU AMARC 146.925 repeater system from 2ØØØ to 2ØØ6. At that time it was replaced with newer equipment.
It was owned, built, and maintained by the station trustee, KØRWU, Paul Schlipp.
This repeater was interfaced with a separate, 1Ø and 6 meter, FM base stations. The repeater was also interfaced with the internet. This repeater system was located at the Club's High Ridge, MO radio tower.
This repeater system worked just fine, and gave very little trouble. It was all replaced for newer equipment, and newer type systems.
Since this repeater was sold in 2ØØ6, none of the following statements about use of this equipment is valid, the information is simply in remembrance of this old repeater.
Note: These pictures were taken with a cheap digital camera, before the repeater was placed in service, Also, they were taken in my basement, under poor lighting conditions.
The Yaesu FTR-241ØA Repeater Top Side
The repeater receiver and transmitter are self contained, shielded units. Easy to maintain and align.
The Yaesu FTR-241ØA Repeater Bottom Side
All control functions, CTCSS tone and switching relays are contained inside the repeater.
The MCC RC-1ØØ Repeater Controller
All control functions, CW ID, and audio switching, are performed with the Micro Computer Concepts model RC-1ØØ Controller.
The Repeater Audio Coupler
The brown perf board is the Audio Coupler circuit board. Left of the audio circuit board, the Communications Specialists TS-32 CTCSS tone decoder for the repeater receiver. To the right, a separate SS-32 CTCSS tone encoder for the transmitter. Below, the Yaesu repeater controller interface.
The RC-1ØØ controller has replaced the factory Yaesu repeater controller, although some of the receiver audio, squelch, and transmitter audio circuits are on the board, and are still in use. All audio controls (Repeater, 6 Meter RB, 1Ø Meter RB) are leveled on the Audio Coupler circuit board. Also, since this picture was taken, 2 PL filter amps. were added to separate and add additional PL filtering to the remote base transmitters. Some time was spent adjusting the audio components to match the input audio quality for all 3 radio systems.
A 6ØØ ohm to 3K ohm audio transformer was needed to isolate and match audio from the RC-1ØØ to the Yaesu transmitter.
The KØAMC 146.925 Mhz Repeater Back Side
The lower half and back of the repeater cabinet. The Yaesu repeater cable connections are all on the back side, separate din connectors are used for the 6 and 1Ø meter remote bases. Making service of any component a snap. Cross bars were installed for the repeater and power supply units rear support.
The 6 & 1Ø Meter GE Remote Bases Back Side
The equipment mounting rails had to be cut and moved back to allow clearance for the GE radios, while the bottom rail sections are mounted forward to allow clearance of the larger repeater and power supply. All three radios are self contained and can be disabled or removed for maintenance.
Remote Base Channel Relay
A closer view of the 1Ø meter RB shows an additional relay mounted on the far top left below the large barrier strip. Both remote bases have had this modification. This relay switches the channel frequencies. Set up for 2 channels each, the RB's can be made to switch 4 channels each with additional relays. I feel 2 frequencies are sufficient for FM use. The default frequency is the National Calling and the second is a chat frequency.
The 6 Meter GE Remote Base
A close up of the 6 meter RB shows the monitor speaker and transmit disable switches. All tuning and maintenance is performed from the front.
Both the 1Ø meter and 6 meter RB's are identical, except for the operating band. The transmitters have had a modification to the mic amplifier. A 1 mfd capacitor was added to the first speech amp. emitter to the ground bus. Due to their age, the receivers have had extensive modifications. The first RF amplifier stage was completely removed and a Hamtronics model LNY pre-amp was installed in it's place. The newer BF-998 dual gate mos-fet gives the receiver much better sensitivity and signal to noise ratio. A noticeable improvement performed in the early days of the system. The pre-amp mounted nicely in the bottom of the receiver strip. The original front end pre-selector is between the antenna and the pre-amp.
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