Location

The Somerset and Dorset Railway Heritage Trust are based at the former Midsomer Norton South Railway Station. The postal address is Midsomer Norton Station, Silver Street, Midsomer Norton, BA3 2EY. However, there are some specific details that will be of interest to radio hams:

  1. Lat/Long: 51.281077°,-2.482759°
  2. IARU: IO81sg
  3. IOTA: EU005 (UK Mainland)
  4. WAB: ST65 – England

Google Map of Midsomer Norton Railway Station

Introduction

The weekend of 26/27 September, aside from being the weekend of the National Hamfest, is the weekend set aside for Railways on the Air. This is our fifth year of operation from the Somerset and Dorset Railway Heritage Trust at Midsomer Norton and to coincide with the planned re-introduction of train operations we are hoping to be able to put on a larger display of Amateur Radio activities.

So, at precisely a little after 09:00 on Saturday 26 September 2015 we began to assemble at the restored Midsomer Norton South Station and began to set up the HF SSB station. The aim was to be on air sometime around 10:00 and we believed that with our experience from previous years and sufficient hands this would be straightforward.

Whilst the setting up of the equipment in the railway carriage that was to be our home for the next couple of days went reasonably smoothly antenna erection was a little more complicated than originally envisaged.

Before we go into the antenna there was one amusing little incident inside the railway carriage. Andy G7KNA was connecting the rig, power supply, ATU, laptop etc. He switched on the laptop which hadn't been used since the Lighthouses weekend in August and prepared to load the logging program. The laptop dutifully started up and whilst waiting for Windows 98 (yes really our laptop is that old!) he switched on the PSU. Or rather he didn't, because no amount of switch clicking would bring a spark of life from the trusty Manson 925 unit. Everyone automatically went into diagnostic mode: must have power because the laptop is working, check cables, is plug fully inserted in extension lead, check fuses etc. Before too much was dismantled David G7BYN pointed out that the socket where the extension lead was plugged in wasn't turned on and the laptop despite being in store for 5 weeks or so was actually booting off its internal battery!

And so to our antenna. This part of the tale is probably cautionary, in that by deviating from our usual proven arrangements we accidentally introduced a raft of new problems.

In previous years we have operated from the same railway carriage with a half size G5RV antenna erected more or less horizontal or with a very slight inverted vee arrangement. This has been a successful and practical arrangement partly due to the physical size of a half size G5RV and a standard railway carriage.

Time to be an anorak, but bear with us, not only is this interesting it's also informative!

Carriage Undeframe Length Bogie Centres Body Length
British Rail Mark 1 Short
Built 1951 – 1963
17.3m (56ft 11in) 12.2m (40ft) 17.7m (58ft) Gangwayed
17.4m (57ft 1.75in) Non Gangwayed
British Rail Mark 1
Built 1951 – 1963
19.33m (63ft 5in) 14.17m (46ft 6in) 19.7m (64ft 6in) Gangwayed
19.35m (63ft 5.75in) Non Gangwayed
British Rail Mark 2
Built 1963 – 1975
    19.66m (64ft 6in)
British Rail Mark 3
Built 1975 – 1988
    23m (75ft)
British Rail Mark 4
Built 1989 – 1992
    23m (75ft 6in) over buffers
23.4m (76ft 9in) over couplings

The key point, in case you hadn't realised, is that a half size G5RV at 15.63m (51.3ft) long is just 4m (13.2ft) shorter than a Mark 2 carriage which makes it very easy to suspend from a couple of roach poles temporarily fixed to the ends of the operating carriage and a freestanding 20ft flagpole to support the centre section held in place by some suitable scrap track lengths.

The situation described above had been successfully used for the past 2 years. But we failed to heed the adage "if it ain't broke don't fix it" and decided that what we needed this year was a full size G5RV 31.26m (102.6ft) long erected over two carriages.

The theory was fine, the centre feed point was hoisted using a 6.1m (20ft) flag pole, but as railway carriages are around 3.79m (12ft 5in) rail to roof the feedpoint was only around 2.3m (7.5ft) above the roof of the carriage. The ends of the antenna were tied off to convenient fixing points comprising a container at one end and the coupling of a goods waggon at the other end. The ends were, however, considerably closer to the roof of the carriages than the feedpoint and it is considered that this was the root cause of the problems we subsequently faced.

We believe that the carriages were in some way coupling with the antenna as it proved next to impossible to match the antenna on 40m using either a manual or automatic tuner. The auto tuner would find some sort of match it wasn't stable, often retuning on each over.

Full size G5RV feedpoint in its original trackside positionLeg of the replacement 40m dipole

The full size G5RV was abandoned in favour of a simple half wave dipole on 40m. This was better but the antenna had been hastily erected and was low to the ground and shielded by the carriages and buildings and was fed with coax without the benefit of a balun. The result was an antenna that did get a signal out but the noise floor made anything but the strongest of stations inaudible.

Full size G5RV feedpoint in final position also showing trackside 40m dipole feedpointFull size G5RV in final position

We persevered with this arrangement for a short while whilst trying to come up with an alternative or indeed a reason why the original arrangement hadn't worked. Cyril G3XED and Eddie M0LJT decided to re-erect the full size G5RV away from the carriages some 3m (10ft) or so at the other side of the outdoor seating area. This proved to be a good choice. Once put up and connected the noise floor dropped to a manageable level and our signal improved.

Mark M6FKV operating GB0SDR with Peter G0DRX loggingMark M6FKV operating GB0SDR with Peter G0DRX logging

On Sunday, having resolved the antenna issues for the main SSB station on Saturday it was possible to:

  • Operate the main SSB station using the original manual ATU
  • Return to auto ATU to the Data Station

The data station being set upCyril G3XED, Club President, and Eddie M0LJT admire their handiwork from Saturday

One of the downsides of the final position of the full size G5RV is that it precluded the use of the Delta Loop antenna for the data station as in last years experiments this had been set up more or less where the G5RV was now sited.

The data station antenna in 2014G5RV feedpoint in 2015 showing proximity to proposed data station antenna location

The planned Delta Loop antenna was replaced with a 20m whip affixed by mag mount to Dave G7BYNs van in the upper car park. This was a compromise and exhibited a higher than desirable SWR but at least allowed the data station to get on air and make some contacts. After the event it was decided that if we have to follow this layout next year it will be more efficient to situate the data station in the lower car park and operate out of the boot of an estate car or van allowing a better antenna to be erected even if it is a little lower since it is felt that a better antenna will more than offset the loss in elevation.

GB0SDR Log

Date Time (UTC) Station Worked Band or Freq'cy Mode RST Name QTH Notes
Sent Rec'd
26/09/15 11:22 GB0SCR 40m LSB 59 59 Colin   RotA: Swindon and Cricklade Railway
26/09/15 11:32 PA3EMN 40m LSB 59 59 Roel Amsterdam  
26/09/15 11:34 GB6AR 40m LSB 59 59 Neville   RotA: Amerton Railway Allerton Staffordshire
26/09/15 11:36 G8LJY 40m LSB 59 59 Alan Bath  
26/09/15 11:40 PE2JB 40m LSB 46 44 Jace Netherlands  
26/09/15 11:41 2E0IMI 40m LSB 59 59 Clive Windermere  
26/09/15 12:02 GB0FLR 40m LSB 59 59 Ian   RotA: Foxfield Light Railway
26/09/15 12:05 MM6RLL 40m LSB 59 59      
26/09/15 12:07 G6FCH 40m LSB 59 59      
26/09/15 12:11 G3XIV 40m LSB 59 59 Geoff    
26/09/15 12:15 MI1AIB 40m LSB 59 59 Paul    
26/09/15 12:22 2E0DAO 40m LSB 59 59 David    
26/09/15 12:23 G1IZQ 40m LSB 59 59 Tom Northampton  
26/09/15 12:25 EI5HIB 40m LSB 59 59 Noel Central Ireland  
26/09/15 12:28 M6FPW 40m LSB 59 59 Steve Northamptonshire  
26/09/15 12:29 G4STP 40m LSB 59 59 Tony County Durham  
26/09/15 12:35 GB2WS 40m LSB 59 59 David   RotA: Princess Royal Class Locomotive Trust
26/09/15 12:36 M0DFW 40m LSB 59 59 Dave Cambridge  
26/09/15 12:47 M0ZAE/P 40m LSB 59 59 Henry Ranworth Norfolk Broads  
26/09/15 12:50 G0STK 40m LSB 59 59 Allan York  
26/09/15 12:53 G0KAF 40m LSB 59 59 Bryan Ellesmere Port  
26/09/15 12:54 G3KKJ 40m LSB 59+20 59+ Alex Dorset Operating for 60 years
26/09/15 12:56 GI6FHD 40m LSB 59 59 Alfred    
26/09/15 12:59 G6GXE 40m LSB 47 58 Lance Folkstone 5W
26/09/15 13:00 M3OZP 40m LSB 57 57 Chris Folkstone  
26/09/15 13:04 MI6GGF 40m LSB 59 59 Andy Lisburn Northern Ireland  
26/09/15 13:10 MX0PHX 40m LSB 59 59 Alan   RotA: Nottingham Transport Heritage Centre – Phoenix Radio Group
26/09/15 13:13 G8RZ 40m LSB 59 59 Peter Workington TS590D
26/09/15 13:15 GI4SZW/M 40m LSB 59 58 Jim Newry  
26/09/15 13:19 GB0ESR 40m LSB 47 59 Jeffry   RotA: East Somerset Railway
26/09/15 13:23 G3RXA 40m LSB 59+10 59+ John Norwich 13 miles South West of Norwich. TS830 Carolina Windom
26/09/15 13:25 M3GJA 40m LSB 59+20 59+20 Trevor Kings Lynn TF61
26/09/15 13:28 M0PDG 40m LSB 59+20 59 John Arnold Nottingham  
26/09/15 13:30 EI5DD 40m LSB 59 59 Steve Gallway FTDX5000MP
26/09/15 13:33 M0KRR 40m LSB 59+20 59 Alistair South East Cornwall  
26/09/15 13:35 G4DUL 40m LSB 59 59 Martin Toddington South Bedfordshire  
26/09/15 13:37 G0TRB 40m LSB 59 59 Roger Tamworth Staffordshire  
26/09/15 13:39 G0JKY 40m LSB 59+ 59+ Brian Dudley  
26/09/15 13:42 DL1YAR 40m LSB 59 57 Willi    
26/09/15 13:47 G3TGB 40m LSB 59 59 Brian Braintree  
26/09/15 13:52 G8WPL 40m LSB 59+ 59 Don Manchester  
26/09/15 13:54 GB2OCG 40m LSB 48 59 Tony   RotA: Eastbourne Miniature Steam Railway
26/09/15 13:57 GB2RER 40m LSB 57 57     Special Event Station
26/09/15 13:59 M0DMA 40m LSB 59 59 Derek    
26/09/15 14:02 2M0JVR 40m LSB 59 59 Victor    
26/09/15 14:06 G4GQL 40m LSB 59 59 Alan    
26/09/15 14:08 G3OKA 40m LSB 59 59 John Wirral Liverpool  
26/09/15 14:10 G0JNT 40m LSB 59 59 Les Grimsby  
26/09/15 14:12 G4GTX 40m LSB 59 59 Stewart Sunderland  
26/09/15 14:19 G4KEE 40m LSB 59 59 Victor Exeter  
26/09/15 14:21 2E0TGL 40m LSB 59 58 Andy Liskard  
26/09/15 14:23 GM4JPI 40m LSB 59 57 Pete Shetland Isles  
26/09/15 14:27 G4BHD 40m LSB 59 59 Trevor Camborne Cornwall  
26/09/15 14:29 G4AWJ 40m LSB 59 59 Gordon Heathfield East Sussex  
26/09/15 14:31 G1PIR 40m LSB 59 59 Dave Cheadle  
26/09/15 14:33 2E0MDM 40m LSB 59 59 Steve Windsor  
26/09/15 14:35 GW6TYJ 40m LSB 59 59 Jeff Swansea  
26/09/15 14:40 G3KAG 40m LSB 59 59 Tony Royston Derbyshire  
26/09/15 14:45 G0WFH/P 40m LSB 59 59 Chris Bletchley Park 10w
26/09/15 14:48 G0OLZ 40m LSB 59 59+20 Roy March Cambridgeshire  
26/09/15 14:51 M0WID 40m LSB 59+10 59+ David Redhill Surrey  
26/09/15 14:56 G3SCZ 40m LSB 59 59+10 Ray    
26/09/15 14:59 G0CTR 40m LSB 59+ 59+ Peter Ellesmere Port  
26/09/15 15:01 G0SYF 40m LSB 59+10 59 Bob Wotton Under Edge No QSL cards
26/09/15 15:05 GB0DR 40m LSB 59 57/59 John   RotA: Dartmoor Railway Okehampton Station
26/09/15 15:10 2W0MCB 40m LSB 59 59 Mike Brecon Beacons  
26/09/15 15:13 M3DMV 40m LSB 59 59 John Grantham  
26/09/15 15:16 MWVJN 40m LSB 59 59 Tristan    
27/09/15 09:34 GB0HBL 40m LSB 59 59     RotA: Helston Railway
27/09/15 09:38 GB0BR 40m LSB 59 59 Gavin   RotA: Bluebell Railway
27/09/15 10:11 GB0DRC 40m LSB 59 59 Dave   RotA: Didcot Railway Centre
27/09/15 10:123 GB4GNW 40m LSB 59 59 Ian   Special Event Station
27/09/15 10:22 SQ6PLE 14.068419 PSK31 599 599 Irek Grzybowo  
27/09/15 10:29 GB2LHR 40m LSB 59 59 Bill   RotA: Lakeside and Haverthwaite Railway
27/09/15 10:38 GB2MGN 40m LSB 59 59 Linda   RotA: Whitewell and Reepham Railway
27/09/15 10:57 GB0EOR 40m LSB 59 59 Sid   RotA: Epping and Ongar Railway
27/09/15 11:07 GB0SCR 40m LSB 59 59 Collin   RotA: Swindon Cricklade Railway (Second Contact)
27/09/15 11:08 SA4AZC 14.068507 PSK31 599 599 Christer Norsbron  
27/09/15 11:16 EA7HGX 14.068508 PSK31 599 599 Salvador La Cañada – Almería  
27/09/15 11:17 GB0HBL 40m LSB 59 59 Cliff   RotA: Helston Railway (Second Contact)
27/09/15 11:20 EA7GTJ 14.068512 PSK31 599 599 Jose Bentarique (Almería) – Spain  
27/09/15 11:31 DL2UWL 14.068506 PSK31 599 599 Manfred Munich  
27/09/15 11:40 GB2RER 40m LSB 59+20 59+10 Peter Cumbria Special Event Station
27/09/15 11:45 DL4LTM 14.068445 PSK31 599 599 Gerd Leipzig  
27/09/15 11:48 SP2HQP 14.068452 PSK31 599 599 Roman Pruszcz Gdanski  
27/09/15 11:55 EI2WSVR 40m LSB 59 59 Sean   RotA: Waterford and Suir Valley Railway
27/09/15 12:34 SQ3SKN 14.068464 PSK31 599 599 Jarek Sulechow (W/Poland)  
27/09/15 12:44 MX0NBC 40m LSB 59 59 Paul   RotA: Avon Valley Railway – North Bristol Amateur Radio Club
27/09/15 13:14 GB0AVR 40m LSB 59 59 Ray   RotA: Amman Valley Railway – booked call before Avon Valley Railway
27/09/15 13:23 GB6AR 40m LSB 59 59 Chris   RotA: Amerton Railway Staffordshire (Second Contact)
27/09/15 14:03 EW6FW 14.068404 PSK31 599 599 Sergej Vitebsk  
27/09/15 14:27 UA9APA 14.068492 PSK31 599 599 Yuri    
27/09/15 14:31 SQ1SNT 14.068339 PSK31 599 599 Piotr Szczecin  
27/09/15 14:37 SQ9ETN 14.068301 PSK31 599 599 Andy