GB3EY

From BATC Wiki
Jump to: navigation, search

A new NoV was issued for GB3EY in August 2018 allowing the move to the East Yorkshire Repeater Group's site at Cave Wold Radio Station near South Cave in East Yorkshire. The QTH locator is IO93RS37ME. The new site is 155m ASL with a good take off in most directions. The predicted coverage was created using Radiomobile and assumes 10m mast with a 15dBi antenna at the receiving end. This will be a substantial improvement over the old site on the North Sea coast at Aldbrough.

GB3EY Coverage



The repeater is returning using digital ATV to reduce the bandwidth occupied. The parameters have not been finalised but are currently 2MS/s, FEC 3/4, with MPEG-2 encoding on 1308MHz. Test transmissions were run from a temporary mast from August to October 2019 until the main tower was renovated and a single Alford Slot antenna was installed at 25m AGL fed with 30m of Andrews LDF5-50A. The Alford was made by G3GJA and uses a coaxial 4:1 balun formed from RG141 semi-rigid. This was found to be much easier to construct and test than the usual slotted sides coax approach.
Tower.jpg
A work party at the EYRG site checking the P80 tower with 5m extension. A further 3m extension has been added for the Alford Slot

A temporary breadboard (actually plywood!) transmitter comprising of a BATC DTX1, a G4DDK PGA103+ pre-drive, a G4BAO driver and a G8EQZ built M57762 Mitsubishi bipolar brick PA producing 4.8w RMS has been running test transmissions since then. So far it has been received at 79km from the repeater which is very good for 11w ERP. A video source derived from a first generation Raspberry Pi provides a slideshow of testcards and photos of East Yorkshire. No inputs are available at this time.

Progress to date is good; the logic from the analogue repeater has been renovated and updated by Bill G3RMX, a Comag receiver has been found and the transmitter, comprising of two modules funded by G4YTV and made by Bert PE1RKI have been tested and mounted on the RF deck along with two SMPS for 12v and 28v rails . The original G3JVL filter has been retuned and a new duplex filter has been tested but it flashed over at the 20w power level. A solution using Teflon tubing will be tried to correct the problem. Isolation between the TX and Rx ports of the duplexer at 1308MHz is 75dB which might just be enough without further filtering from the JVL filter for single antenna working.

In the longer term, a dual band beam for 2m and 70cm will be installed with a Minitioune for inputs on those bands in the future with 333kS/s or similar RBDATV signals. G4YTV has funded a HamKits video switcher that will be used to build a new logic around a Raspberry Pi. We hope to resurrect GB3XY the 10GHz ATV repeater, that was operational from the same site, as a DATV repeater linked to GB3EY. However, designs for upconverters for 3cm are not readily available.

The site is exclusively used by the East Yorkshire Repeater Group and is a former Pye Telecoms location. It also hosts GB3HS a 2m triple mode repeater, GB7HU a 70cm D-Star repeater and a Raynet repeater that can be configured for cross-band 2m / 70cm or in-band 70cm operation.

Please send reports of reception to clive AT hesh.co.uk; if you do receive it there's a number visible that you can send an SMS to with your report.