This page contains information about GB7KH. Some useful, some not so much!
The table below has some of the key specifications for GB7KH repeater. Please note, that the frequencies listed are the frequencies for the repeater. Your transceiver will need to swap the TX and RX frequencies, in order to transmit on the repeater’s receive frequency, and visa-versa.
|Latitude / Longitude||51.671592N / 0.256369E (map)|
|Repeater Frequencies||DVU49 (TX 439.6125 MHz / RX 430.6125 MHz)|
|DMR (Colour Code)||3|
||Motorola GM340 UHF|
|Transmit Power||12dBW (~16W) ERP|
|Antenna||Skymasts 414.04-405-T5 (5° down-tilt)|
|Antenna Height AGL||42 metres to base of antenna|
|Site Height ASL||130 metres|
|Repeater Controller||MMDVM Multimode DV Modem|
|Gateway PC||MicroServer 1U Low Power with SSD|
|Internet Access||24 GHz wireless link|
|Port Tunnelling||OpenVPN to remote datacentre|
|UPS||APC UPS BK500EI (~30m uptime)|
|Remote Control||Remote login via SSH. Emergency shutdown via GSM.|
Configuring your Radio
Digital voice modes aren’t like traditional repeaters that just require a tone-burst or CTCSS tones. With DV modes, the repeater needs to have been properly addressed with its callsign, ID or colour code before it will answer. You therefore need to enter some parameters into your radio to use the repeater. The information depends on what what mode you are planning to use, and is different for each mode.
You may have a “DR” (digital repeater or directory of repeaters) option on your radio to store these settings for you in an easily navigable way. You may have to enter them yourself and save them.
|Your (UR)||CQCQCQ / <remote station callsign>|
|Repeater 1 (RPT1)||GB7KH^^B|
|Repeater 2 (RPT2)||GB7KH^^G|
|MyCall (MY)||<your callsign>|
With the RPT1 and RPT2 parameters, the carat (^) represents a space. The B and G must be in the 8th (end) position. The callsign you use in the MY field must be registered with the D-STAR network in order to use repeater linking and reflectors. You may register here. To use some of the community developed features with D-STAR, you may need a CCS7-ID (DMR ID). It is probably worth applying for a CCS7-ID at the same time as you register with D-STAR. GB7KH will connect to all types of reflector (REF, DCS, XRF, etc.) and supports DTMF commands.
DMR Radios use a codeplug to hold repeater information. GB7KH is on the BrandMeister Network, which operates slightly differently to some of the other DMR networks. BrandMeister uses reflectors in a similar way to D-STAR reflectors, as opposed to the more traditional TalkGroup design. You will need a CCS7-ID (DMR ID) to access any DMR network, and the same ID is universal across networks. You may register here.
||TalkGroup 9, Slot 1|
|Reflector||TalkGroup 9, Slot 2|
GB7KH reflector defaults to Reflector 4400 (UK Wide), where it is acceptable (at the time of writing) to hold short QSOs. Long ongoing discussions are asked to QSY to Reflectors 4401-4405, as free. You can see a complete list of reflector numbers here. Reflector 9990 will provide Echo functionality.
Yaesu System Fusion
The Yaesu Fusion/WiresX system will inquire services the repeater offers, along with available reflectors, from the repeater, assuming the frequencies and duplex offset is correctly set up.
Please note: Since YSF is the newest amateur digital mode, the code is still under development. YSF doesn’t function as well as the other modes. The DN mode is known to work correctly. This is because of differences in specifications. It is also noticed that the RSSI value reported by the repeater is usually incorrect for YSF. These issues are known bugs.
This section is still to be written. P25 is supported by the repeater, but is untested. Contact the Keeper for details. You will need a CCS7-ID (DMR ID) to access P25 services.
The internet link at GB7KH is via 24 GHz (12mm) microwave link. The internet is occasionally temperamental – there is, realistically, nothing that can be done about this. The connection suffers from variable packet loss and jitter, which are not ideal for real-time streaming applications such as DV.
The mains power on site is also somewhat temperamental. There is a small UPS to keep the repeater running until two Rolls Royce diesel generators kick in – if mains fails, the internet connection will be lost. The repeater will continue to function until the UPS shuts it down when the battery is near depletion.
The following map was provided by UK Repeaters. You can click on the map for a more detailed image
The map below was produced by RadioMobile by VE2DBE software to compare with the RSGB ETCC provided map above.