The GB3VM repeater story
This 2 m repeater, on channel RV49, 145.6125 MHz with a -600 kHz shift and a CTCSS tone access of 103.5 Hz, started life at the former BBC HF Transmitter site at Woofferton in Shropshire in April 2004.
In March 1997 the site had been privatised and by 2004 was operated by VT Merlin Communications (VTM) carrying, amongst others, BBC, Radio Free Europe, Radio Liberty, Radio Canada International and Voice of America HF services.
The original concept
An amateur repeater on site was the idea of two Woofferton Senior Transmitter Engineers, R Glyn Jones, G4AIJ and Dave Porter G4OYX. Already mounted at 90 m on the 100 m high “DD” mast near to the transmitter buildings was a 141 MHz Jaybeam collinear antenna fed by 140 m of LDF4/50 Andrew feeder. This had been used in BBC days for voice comms with BBC Sutton Coldfield and Ridge Hill when mobile maintenance was being conducted for the local domestic broadcast services. It was now out-of-service.
The original plan was for a 70 cm 7.6 MHz wide-spaced unit; but with the then, MoD embargo on 70 cm expansion, a 2 m allocation was investigated. RV49 was free in this area so G4AIJ progressed the application to the ETCC and volunteered to be the Repeater Keeper.
In appreciation that of the fact that VTM were offering free mast rental, free insurance and no charge for electricity, the callsign VM, “Vosper-Merlin” was requested. Both it, as GB3VM, and a 25 W output was granted.
A new Procom collinear antenna with 3 dBd gain was bought and installed at the same 90 m point above the ground in place of the old collinear. The site is 76 m asl.
The duplexer came from another former BBC Transmitter Engineer, Ian G8PWE and was a four coupled-cavity device with a circulator made by the Canadian Company, Sinclair, When it arrived it not only had a Tait 370 series repeater installed and ready to go but also a 1U crate containing a logic board from Mike G8CUL.
The entire unit was in a portable pseudo 19” rack on castors and was installed in the corner of an 11 kV AC HV Switchroom that was maintained at a nominal 15°C to 20°C all year round!
There were a few initial concerns that harmonics from the ten 250/300 kW AM senders would cause problems but in the event that was not the case. The only issue was the occasional “rusty-bolt effect” where some stray HF in the antenna field would arc on fences etc. and cause interference on the received input signals. Adoption of the then voluntary (now mandatory) CTCSS helped to keep out any errant HF programme from the senders on site!
Over the years
Over the following 16 years there have been changes, with a 1 kW commercial local radio VHF/FM service, Sunshine Radio 105.9 joining atop DD mast in 2013. In 2014 a Yaesu Fusion DR-1XE unit replaced the Tait 370.
With another regular FM (Tait 800 series) repeater, GB3VN coming on air in 2007 hosted by Chris, M0MTS at Hope Bagot, the Hope Bagot Repeater Group was formed. GB3VN was also converted to Yaesu Fusion in 2014.
In 2015 was added GB7VO; an internet connected 70 cms Icom D Star Unit at Newton, south of Leominster hosted on behalf of the HBRG by Geoff G8BPN.
In 2018 G4AIJ and G4OYX (now both retired) were asked by the MD of Sunshine Radio to consider the installation of a new VHF/FM relay on Clee Hill of Woofferton’s 105.9 MHz.
A brand new site
Mr Muff Murfin, the Sunshine Radio MD, had found a perfect site through a chance conversation at a charity fund-raising event. G4AIJ and G4OYX, now of the HBRG, worked out how to build and the equip such a relay on this new greenfield site. Mains power had to be provided from scratch as well as mast and building provision. Ofcom required us to suggest a frequency for the relay and after checks and consultation of frequency listings 107.8 MHz appeared to be clear. It was subsequently authorised by Ofcom at 250 W with 125 W horizontal and 125 W vertical to a mandatory, specified directional pattern to protect a service to Wolverhampton on 107.7 MHz.
G4AIJ and G4OYX suggested to Sunshine Radio that all the engineering, many component parts and commissioning of the broadcast relay could be provided by HBRG members free-of-charge in return for continued free mast/site rental and electricity for the repeater after the move of GB3VM. This was agreed.
It was most fortunate that this site change was on the cards as by then the new repeater at Stafford, GB3SV had been allocated RV49 and was a such co-channel. With GB3VM being now on the southern flanks of Clee Hill, there would be much more protection to the NNE and any interference would be much reduced.
The new site is 434 m asl and on a 15 m steel lattice mast is mounted the Italian “Label AKG-7R” directional antenna for Sunshine Radio. For GB3VM, on a 6 m scaffold pole mounted on the side of the building is a new Procom lightweight collinear. A type 7528 Jaybeam folded dipole is also present as a reserve on the same pole.
A sad loss
Regrettably, very near to the commissioning of the FM relay, G4AIJ went SK on February 1, 2021 so was not able to see the fruits of his labours. However, with the help of fellow HBRG member Phil, G4HQB and the metal-working skills of Richard 2E0FDA; G4OYX was able to complete the build and the FM came on air late February 2021.
With the loss of G4AIJ a new Repeater Keeper for GB3VM was required, HBRG member Matt G8XYJ volunteered. He was able to complete the site request change and remit the application. The official administration change took just four days with the ETCC and Ofcom so now the pressure was on to make the move.
The move itself
Over the weekend of 20th/21st March 21, 2021 the Yaesu DR1-XE Repeater, the Mascot 20 A power supply and duplexer crate was transferred from Woofferton to the new site. The tune of the duplexer was checked by G8PWE and it had survived the trip well with no retuning being needed. Through losses of 2.2 dB on TX and 3.1 dB on RX were achieved. Notches of -116 dB and -114 dB were recorded for TX and RX respectively and no RX de-sense was able to be measured.
Final results – a win/win!
Initial indications show the coverage to be much improved to the east, south and west with a considerable degree of shielding to the co-channel repeater, GB3SV at Stafford.
G4AIJ would no doubt have been pleased with the final successful result and it was such a shame he was not able to QSO through the new GB3VM.
The Hope Bagot Repeater Group look forward to reports.
Mr Murfin is delighted with the coverage of his relay station so a win/win!
Future plans for the old VM 2 m antenna at the Woofferton Transmitter site
The antenna that is located at Woofferton for 2m, will be used by the five radio amateurs that work on site, they are all part of the Woofferton Club and have the Club call of M0WOF.
The HBRG have plans to utilise the mast for an APRS iGate (MB7RLE – licenced in 2021), which we hope will eventually become an APRS Digipeater.
More update news
On Monday April 26th 2021 a move was made of the GB7VO repeater from Hill House, Newton, Leominster to the new site on Clee Hill. The antenna was de-rigged and transferred along with the VO crate. Matt G8XYJ and Dave G4OYX did most of the decommissioning and transport. They were joined by Mike Stanford G4IIA who de-rigged the antenna and coaxial cable. Later in the day the 4 m long mast pole was re-rigged to take the Procom 3 dBd CXL70-3 70 cms collinear antenna The feeder run had already been installed so all that was required was the connecting up of the GB7VO crate which was now alongside GB3VM in the cabin. Permission had already been obtained, taking only a few days, from the ETCC and Ofcom so it was legal to power up the D Star repeater. Coverage was excellent as expected.
Regrettably, there was in October 2021, a failure of the Icom D Star repeater with a loss of the receive sensitivity. That, coupled with the fact there were few users anyway of the D Star unit it was decided to swap it out for a Yaesu DR-1E repeater. According to the Ofcom licence conditions this is a digital-only channel so the DR-1E is set to permanent C4FM/Fusion.
The APRS Digipeter is now in service at Woofferton Transmitter and has been accessed from as far north as Merseyside!
Written by HBRG Secretary Dave G4OYX and Matt G8XYJ