Repeater Linking-Hub System.

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This is one of the most versatile systems and has been called by other names eg. Satellite system, etc.

Briefly it consist of a Hub which radiates out via the spokes of the wheel to stations on the outer of the wheel.

Now let's put some figures in to make it a little more illustrative.

1. Each of Stn.A , Stn.B ,.......Stn.F is a Repeater with an UHF link attached back to back.

Stn.A  is a Rpt on 146.625 with a link on Tx 440, Rx 420.
Stn.B  is a Rpt on 146.650 with a link on Tx 440, Rx 420.
Stn.C  is a Rpt on 146.675 with a link on Tx 440, Rx 420.
Stn.D  is a Rpt on 146.700 with a link on Tx 440, Rx 420.
Stn.E  is a Rpt on 146.725 with a link on Tx 440, Rx 420.
Stn.F  is a Rpt on 146.750 with a link on Tx 440, Rx 420.
(& there could be more)

Note that the UHF Link gear is transceivers -Not repeaters.

2. The Hub is a Repeater on TX 420 Rx 440 (or freqs could be vice-versa for Hub & satellites). The bandplan provides for link freqs in the 420 & 440 MHz segments , thus keeping them away from the normal repeater systems.

3. Now if Stn.A receives a mobile on it's 2 Mx input then it

   will (a.) radiate a signal on it's 2 Mx output. &
        (b.) because it is back to back with the UHF Link transceiver
            then the signal will also go out on 440.

4. The Hub will pick up the 440 and because it is a repeater, it
   will output the signal on 420.

5. Then Stns. B to F will receive the 420
AND, as they are back to back with their 2Mx machine,
will thus fire it up and thus achieve output on all the 2Mx rpts.

BENEFITS of the System.

a. The Outer Stations ie A to F , only need to have a Transceiver
(ie 420 rx,440 tx), not a Repeater, on the Link frequencies, thus no requirement for dozens of cavities.

b. The Hub Repeater has a freq separation of 20 MHz and thus minimum filtering is required. (when the ACMA remove us from the 420-430 segment, then the lower freq will move to 430 ie. 10 MHz separation)

c. The Outer Stations may have high gain beams pointing at the hub, thus enabling them to use low power. A must if using solar power.

d. Other linked stations may be added without re-engineering the whole system.

e. All links 'must' have CTCSS or DCS, thus minimising interference on the link and preventing unauthorised transmissions on the links.

f. The Hub 'could' contain other gear with the appropriate control codes for control of the system (eg.link on/off) or to link to other systems.(eg postcode numbers dialup).

g. Each Repeater 'could' contain other gear with the appropriate control codes for control of that repeater (eg.repeater link on/off)

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Vk4xz 24/8/04