RotA 2015

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

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 XP (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 wagon 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. Although the auto tuner would find some sort of match it wasn't stable, often re-tuning 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 of Contact Time Station Worked Band or Freq (MHz) Mode TX RX Operator’s Name QTH IARU Locator Distance (km) Notes
RST No. RST No.
26/09/2015 11:22 GB0SCR 40m SSB 59   59   Colin       RotA: Swindon and Cricklade Railway
26/09/2015 11:32 PA3EMN 40m SSB 59   59   Roel Amsterdam      
26/09/2015 11:34 GB6AR 40m SSB 59   59   Neville       RotA: Amerton Railway Allerton Staffordshire
26/09/2015 11:36 G8LJY 40m SSB 59   59   Alan Bath      
26/09/2015 11:40 PE2JB 40m SSB 46   44   Jace Netherlands      
26/09/2015 11:41 2E0IMI 40m SSB 59   59   Clive Windermere      
26/09/2015 12:02 GB0FLR 40m SSB 59   59   Ian       RotA: Foxfield Light Railway
26/09/2015 12:05 MM6RLL 40m SSB 59   59            
26/09/2015 12:07 G6FCH 40m SSB 59   59            
26/09/2015 12:11 G3XIV 40m SSB 59   59   Geoff        
26/09/2015 12:15 MI1AIB 40m SSB 59   59   Paul        
26/09/2015 12:22 2E0DAO 40m SSB 59   59   David        
26/09/2015 12:23 G1IZQ 40m SSB 59   59   Tom Northampton      
26/09/2015 12:25 EI5HIB 40m SSB 59   59   Noel Central Ireland      
26/09/2015 12:28 M6FPW 40m SSB 59   59   Steve Northamptonshire      
26/09/2015 12:29 G4STP 40m SSB 59   59   Tony County Durham      
26/09/2015 12:35 GB2WS 40m SSB 59   59   David       RotA: Princess Royal Class Locomotive Trust
26/09/2015 12:36 M0DFW 40m SSB 59   59   Dave Cambridge      
26/09/2015 12:47 M0ZAE/P 40m SSB 59   59   Henry Ranworth Norfolk Broads      
26/09/2015 12:50 G0STK 40m SSB 59   59   Allan York      
26/09/2015 12:53 G0KAF 40m SSB 59   59   Bryan Ellesmere Port      
26/09/2015 12:54 G3KKJ 40m SSB 59   59   Alex Dorset     Operating for 60 years
26/09/2015 12:56 GI6FHD 40m SSB 59   59   Alfred        
26/09/2015 12:59 G6GXE 40m SSB 47   58   Lance Folkstone     5W
26/09/2015 13:00 M3OZP 40m SSB 57   57   Chris Folkstone      
26/09/2015 13:04 MI6GGF 40m SSB 59   59   Andy Lisburn Northern Ireland      
26/09/2015 13:10 MX0PHX 40m SSB 59   59   Alan       RotA: Nottingham Transport Heritage Centre – Phoenix Radio Group
26/09/2015 13:13 G8RZ 40m SSB 59   59   Peter Workington     TS590D
26/09/2015 13:15 GI4SZW/M 40m SSB 59   58   Jim Newry      
26/09/2015 13:19 GB0ESR 40m SSB 47   59   Jeffry       RotA: East Somerset Railway
26/09/2015 13:23 G3RXA 40m SSB 59   59   John Norwich     13 miles South West of Norwich. TS830 Carolina Windom
26/09/2015 13:25 M3GJA 40m SSB 59   59   Trevor Kings Lynn     TF61
26/09/2015 13:28 M0PDG 40m SSB 59   59   John Arnold Nottingham      
26/09/2015 13:30 EI5DD 40m SSB 59   59   Steve Gallway     FTDX5000MP
26/09/2015 13:33 M0KRR 40m SSB 59   59   Alistair South East Cornwall      
26/09/2015 13:35 G4DUL 40m SSB 59   59   Martin Toddington South Bedfordshire      
26/09/2015 13:37 G0TRB 40m SSB 59   59   Roger Tamworth Staffordshire      
26/09/2015 13:39 G0JKY 40m SSB 59   59   Brian Dudley      
26/09/2015 13:42 DL1YAR 40m SSB 59   57   Willi        
26/09/2015 13:47 G3TGB 40m SSB 59   59   Brian Braintree      
26/09/2015 13:52 G8WPL 40m SSB 59   59   Don Manchester      
26/09/2015 13:54 GB2OCG 40m SSB 48   59   Tony       RotA: Eastbourne Miniature Steam Railway
26/09/2015 13:57 GB2RER 40m SSB 57   57           Special Event Station
26/09/2015 13:59 M0DMA 40m SSB 59   59   Derek        
26/09/2015 14:02 2M0JVR 40m SSB 59   59   Victor        
26/09/2015 14:06 G4GQL 40m SSB 59   59   Alan        
26/09/2015 14:08 G3OKA 40m SSB 59   59   John Wirral Liverpool      
26/09/2015 14:10 G0JNT 40m SSB 59   59   Les Grimsby      
26/09/2015 14:12 G4GTX 40m SSB 59   59   Stewart Sunderland      
26/09/2015 14:19 G4KEE 40m SSB 59   59   Victor Exeter      
26/09/2015 14:21 2E0TGL 40m SSB 59   58   Andy Liskard      
26/09/2015 14:23 GM4JPI 40m SSB 59   57   Pete Shetland Isles      
26/09/2015 14:27 G4BHD 40m SSB 59   59   Trevor Camborne Cornwall      
26/09/2015 14:29 G4AWJ 40m SSB 59   59   Gordon Heathfield East Sussex      
26/09/2015 14:31 G1PIR 40m SSB 59   59   Dave Cheadle      
26/09/2015 14:33 2E0MDM 40m SSB 59   59   Steve Windsor      
26/09/2015 14:35 GW6TYJ 40m SSB 59   59   Jeff Swansea      
26/09/2015 14:40 G3KAG 40m SSB 59   59   Tony Royston Derbyshire      
26/09/2015 14:45 G0WFH/P 40m SSB 59   59   Chris Bletchley Park     10w
26/09/2015 14:48 G0OLZ 40m SSB 59   59   Roy March Cambridgeshire      
26/09/2015 14:51 M0WID 40m SSB 59   59   David Redhill Surrey      
26/09/2015 14:56 G3SCZ 40m SSB 59   59   Ray        
26/09/2015 14:59 G0CTR 40m SSB 59   59   Peter Ellesmere Port      
26/09/2015 15:01 G0SYF 40m SSB 59   59   Bob Wotton Under Edge     No QSL cards
26/09/2015 15:05 GB0DR 40m SSB 59   58   John       RotA: Dartmoor Railway Okehampton Station
26/09/2015 15:10 2W0MCB 40m SSB 59   59   Mike Brecon Beacons      
26/09/2015 15:13 M3DMV 40m SSB 59   59   John Grantham      
26/09/2015 15:16 MWVJN 40m SSB 59   59   Tristan        
27/09/2015 09:34 GB0HBL 40m SSB 59   59           RotA: Helston Railway
27/09/2015 09:38 GB0BR 40m SSB 59   59   Gavin       RotA: Bluebell Railway
27/09/2015 10:11 GB0DRC 40m SSB 59   59   Dave       RotA: Didcot Railway Centre
27/09/2015 10:22 SQ6PLE 14.068419 PSK31 599   599   Irek Grzybowo JO74rd 1245  
27/09/2015 10:29 GB2LHR 40m SSB 59   59   Bill       RotA: Lakeside and Haverthwaite Railway
27/09/2015 10:38 GB2MGN 40m SSB 59   59   Linda       RotA: Whitewell and Reepham Railway
27/09/2015 10:57 GB0EOR 40m SSB 59   59   Sid       RotA: Epping and Ongar Railway
27/09/2015 11:07 GB0SCR 40m SSB 59   59   Collin       RotA: Swindon Cricklade Railway (Second Contact)
27/09/2015 11:08 SA4AZC 14.068507 PSK31 599   599   Christer Norsbron JO74rd 1245  
27/09/2015 11:16 EA7HGX 14.068508 PSK31 599   599   Salvador La Canada – Almeria IM86tu 1602  
27/09/2015 11:17 GB0HBL 40m SSB 59   59   Cliff       RotA: Helston Railway (Second Contact)
27/09/2015 11:20 EA7GTJ 14.068512 PSK31 599   599   Jose Bentarique (Almeria) – Spain IM86tu 1602  
27/09/2015 11:31 DL2UWL 14.068506 PSK31 599   599   Manfred Munich      
27/09/2015 11:40 GB2RER 40m SSB 59   59   Peter Cumbria     Special Event Station
27/09/2015 11:45 DL4LTM 14.068445 PSK31 599   599   Gerd Leipzig JO61ei 1029  
27/09/2015 11:48 SP2HQP 14.068452 PSK31 599   599   Roman Pruszcz Gdanski JO94hg 1451  
27/09/2015 11:55 EI2WSVR 40m SSB 59   59   Sean       RotA: Waterford and Suir Valley Railway
27/09/2015 12:03 GB4GNW 40m SSB 59   59   Ian       Special Event Station
27/09/2015 12:34 SQ3SKN 14.068464 PSK31 599   599   Jarek Sulechow (W/Poland) JO72tb 1247  
27/09/2015 12:44 MX0NBC 40m SSB 59   59   Paul       RotA: Avon Valley Railway – North Bristol Amateur Radio Club
27/09/2015 13:14 GB0AVR 40m SSB 59   59   Ray       RotA: Amman Valley Railway – booked call before Avon Valley Railway
27/09/2015 13:23 GB6AR 40m SSB 59   59   Chris       RotA: Amerton Railway Staffordshire (Second Contact)
27/09/2015 14:03 EW6FW 14.068404 PSK31 599   599   Sergej Vitebsk KO55be 2191  
27/09/2015 14:27 UA9APA 14.068492 PSK31 599   599   Yuri   MO05qh 4116  
27/09/2015 14:31 SQ1SNT 14.068339 PSK31 599   599   Piotr Szczecin JO73gk 1176  
27/09/2015 14:37 SQ9ETN 14.068301 PSK31 599   599   Andy   JN99mt 1522