GB7NS (Digital) Motorola DR 3000
Normal operating Frequencies
TX freq 439.1625MHz RX freq 430.1625MHz
DMR is a digital mode which uses TDMA technology. This allows for either two voice channels at the same time or one voice and one data channel. Slot 1 and Slot 2 are the respective audio channels available within a 12.5 KHz channel spacing.
It now requires a Colour Code set as 3, not 1 as previous, it is also now connected onto the DMARC network via the Internet.
Talk groups (TG) should be set as 9, for local repeater communications using
Also on slot 2, with a TG of 235 will communicate with all UK repeaters set up to allow this.
TG 8 will be used later as a London Roam Function.
Slot 1 is used for international
TG1 being World Wide and brings up all DMARC connected repeaters around the world, this being over 300 units, active in 18 countries and expanding at a very fast rate.
TG 2 is used for European base stations being accessed.
TG 3 brings up North American units.
TG All call should no longer be used.
You will also need to leave a two second pause before PTT back on a active channel to allow the network to keep up with the connections of multiple repeaters around the world.
The coupling of the two units onto the same antenna, has reduced the power output to just under half the power that was available on the duel mode unit, but now there can be two digital and a analogue conversation, all going on at the same time.
History of GB3NS
Due to loss of original site the repeater was moved to a local commercial site on 15th December 2011, after some initial aerial changes the repeater provided good coverage to it’s original service area. MB7NS was co-sited and provided better service than previously probably due to increased aerial height. because of a change in the site owners building requirement the repeater was turned off on 4th June 2012.
The repeater was then sited at a temporary location in IO91vh providing some coverage of the London and North Surrey Areas.
Operating Frequency – 70.3875 MHz
MB7NS continues to operate form the temporary site.
Unfortunately it will not be possible to move MB7NS to the same site because of other commercial units operating on adjacent frequencies. There is a possibility to relocate MB7NS to an alternative North Downs site, in the meantime it continues to operate from an emergency site. There is still the possibility of developing MB7NS into a full repeater, however this will not happen until Ofcom have finished new band allocations, where additional frequencies in low band may become available to allow this to happen.
MB7NS uses a Motorola GM900 mobile using ADS-SR1 Simplex Repeater module. Carrier squelch operation, which will record signal for up to 120 seconds, or carrier drop if before, and then replays recorded message after 2 seconds drop of input signal.
Callsign / beacon, voice every 5 minutes, Morse Ident every 5 minutes.
Power output 10 Watts ERP
The group also provide and maintain GB3SEE microwave propagation beacons located at Reigate Hill IO91vg, radiating 1W ERP on 10,368.850 MHz & 1W on 24048.960MHz.
These are now Frequency locked and operating reliably.
10 GHz beacon has been heard by OZ1FF at 733 Km JO45bo
Best DX on 24 GHz Beacon is 123 Km to G4BEL JO02bi