User's Instructions

77Hz CTCSS tone

You need a 77Hz CTCSS tone encoded on your transmission to access the repeater. Always. Continuously.

Audio Delay

There is a delay of a few  milliseconds applied to the through audio of the repeater but the squelch control is done in real time. The effect of this is to remove any squelch tails as the receiver mute closes at the end of the mobile's transmission. The delay also allows the controller to fully mute the DTMF tones through the repeater.

 

2.5KHz peak deviation

If your peak deviation is more than 2.5KHz then not only will you be interfering with users on the adjacent channels ( OK so 6m aint that busy ) but more importantly you will be exceeding the bandwidth of the IF filter in the repeater's receiver and this makes you sound very distorted through the repeater. In extreme cases the repeater will be unable to decode your CTCSS tone and will mute the through audio. Result - broken up audio and people asking you to repeat what you are saying.

It's not really any good just talking further from the mic either! Get inside your radio, find the deviation pot and adjust it down - its not a critical adjustment!

Update March 2005 - since no-one paid any attention to the above I have replaced the IF filter in the repeater with a 7.5KHz bandwidth filter!

Signal Report Function

There is a function on the repeater which will allow you to obtain a signal strength report back from the repeater. DTMF 09 (zero nine) will activate this function and will give you a reading in percent when you drop carrier. This reading is purely a relative signal strength report, it is NOT percentage quieting or anything else! It is just an indication of your signal strength into the repeater's receiver. For the technical among you, the receiver IF signal is amplified, rectified and the DC level is fed into an OPAMP. This level is then fed into two more OPAMPs, one is a comparator which is used to drive the ( nasty carrier ) squelch circuitry and the other is a buffer amp, providing a voltage between zero and 5v. This is connected to one of the analogue inputs on the RC210 repeater controller ( see the TECHNICAL page for more on this ). The DTMF zero nine kicks off a macro which plays a message ( "Receive Meter is at ...) then  reads out the analogue input port value. Cool!

DTMF Commands

The repeater has some useful ( and some useless ) facilities on it if you can generate DTMF tones.

25/12/04