Category Archives: Event

50 MHz RSGB Trophy Cup

Members of the SNBCG once again took part in the 50 MHz Trophy Cup. The contest runs for 24 hours from 3pm on Saturday. This year, the contest had been booked for one of the hottest days of the year, with temperatures reaching 30°C (around 220°F in old money).

We set up on Saturday morning, using a 5 element 50MHz beam and a 10m pump up mast.  A solid state amplifier provided 400W and a light weight tent to keep off the sun.

The most important issue throughout the weekend was trying to keep cool, with copious cold drinks from the fridge. Fred G3SVK was kind enough to lend us a fan and this became an essential item for the shack.

Fred spent some time operating on CW, working mostly EU with the odd notable exception.

In total, we worked 250 stations, with our best DX being 5B4AAB at 3161KM. You can view the claimed scores here and map here.

Upminster Windmill GB2UW 2017

We arrived at Upminster Windmill at 9am on Saturday 13th May 2017 to begin setting up. The local council allowed onto the grounds and opened up the visitors centre for us.

Within 10 minutes we had the VHF antenna assembled and up. The HF doublet followed shortly after.

Dave M0TAZ quickly got setup inside the staff room at the visitors centre.

1/4 wave on 80 meters

The plan was to put up an 18 meter (60 ft) spider beam roach pole and operate a 1/4 wave on 3.7 MHz. We have used both the 12 m and 18 m roach poles from Spiderbeam with the intention of using them to support inverted V antennas and verticals. Previously we used the 12 m on a number of occasions to support a doublet for portable operating, and the 18 m to make a top loaded vertical for 1.9 MHz with an inductor.

On this occasion, we wanted to try a 1/4 wave on 80 m and the 18 m is ideal for that purpose. The pole can be fully extended and then walked up from the ground, but you will often need to use jubilee clips around the poles to stop it collapsing under its own weight. Like the smaller poles the sections do pull out and lock, but in a breeze, the sections can often rock back and forward and then without notice concertina down. Here you can see the roach pole and me for scale.

Using 6 radials and a wire fence the antenna was ready for some testing. The VSWR was 1.1.5, I think with a larger ground plane this may have been lower, but it was acceptable for our purpose.

The antenna was guyed off at 4 and 12 meters, this is essential in even the lightest of winds.

With the addition of a IC-7600 and solid state amplifier, the station was ready to go.

Unfortunately, the bands have been suffering from disturbed conditions due to solar flares, so despite our best efforts, we were unable to work big DX. We did work quite a few European stations, and also a fair few UK and Irish stations.  The reports received from the antenna and the reception performance was very good, and I was able to receive stations from the USA later in the evening. Unfortunately, the USA stations were in a net, so I didn’t disturb them.

The weather also provided some anxiety, over the course of the weekend the wind picked up to a fairly constant 20 MPH breeze. Thankfully despite some groaning the guys held and the antenna came down without incident.

Over the course of the weekend, we worked 80 stations from 22 DXCC.

Easter Field Weekend

During the long Easter weekend members of the SNBCG came together for a radio weekend. Over the course of the four days, two HF stations were set up; one on 7 MHz and the other roaming between 1.8 and 28 MHz depending on propagation.

Dave M0TAZ decided he would try a 1/4 wave vertical on 7 MHz and use his recently purchased push-together fibreglass poles. These poles are often sold at radio rallies in packs of 5 (each pole 1.3 metres) to give an overall height of 6.5 meters. Using two packs of the poles, the required height of 10 metres was achieved.

Chris G8OCV had made some supporting guy rings, these provided anchor points for the guy lines at approximately 4 and 8 meters. The first attempt didn’t quite go to plan, it simply wasn’t possible to walk up the 10m pole, as we found out when we exceed the bend radius of one of the poles. Lesson learned it didn’t make any difference as the fracture was in the joining section that was simply moved to the first section. In the end, we used 9 poles, giving us a total height of 11 meters with a simple wire running down the side for the radiator.

Six 6 radials were cut, each around 10 meters in length, and the antenna was mounted at the base of a wire fence. The earthing system included the 6 radials and the wire fence, and this provided a reasonable match around 1.5:1 at 7.150 MHz. It would have been much easier to use a push-up fishing/roach style pole but experience has taught Dave that these can be tricky to keep up without guying and tapeing over the joints. As we wanted to run linear amplifiers this weekend, the prospect of the pole moving in the wind and/or falling down made, we made up our minds to use push together poles as the first choice. The antenna was fed with coax with a choke unun (or balun) at its base to stop the coax radiating, and this needed to be capable of high power.

The antenna provided reliable service all weekend, and with the addition of 400W yielded over 200 contacts in 40 DXCC countries. An enjoyable part of the weekend was working DX stations later in the evenings, including the USA, Chile, Mozambique, Guinea-Bissau, Israel, UAE, Armenia and Asiatic Russia all on the 40 metre vertical.

DXCC Breakdown on 40 metre vertical

George M1GEO, Fred G3SVK and others operated the other station. George chased some good DX and Fred worked several hundred stations as “GB0SNB” in CW.

Below we see the DXCC breakdown of the second station using the mast doublet on 160 and 80 metres, and the beam (pictured above) on the higher bands. Some of the DX on the doublet and beam included several QSOs into Japan, Fiji, Trinidad, Guinea-Bissau, Cayman Islands and Argentina.

DXCC Breakdown on 160m doublet and HF beam

We also had time for a BBQ and some excellent curries provided by Fred G3SVK. It was nice to see Camb Hams members Geoff G0DDX and Linda G0TPX, and LEFARS members Derek M0XDC, Dave M0MBD and Dave M0VID. RSGB regional man Peter G0DZB also joined us for the afternoon, making the most of the good weather for a ride on his motorbike, and Bill G0IQK popped in on the Sunday afternoon.

Dave M0YOL worked some data modes using his portable setup. All in all, a good weekend was had by all.

The first 50 MHz contest of the year

Members of the SNBCG took part in the first 50 MHz contest of the year at the Kelvedon Hatch  club call M0SNB. The contest ran from for 3 hrs on Sunday morning (10 till 1) the weather was forecast to be 23C and sunny. We opted to operate outdoors using a 5e beam on a 10m pump up mast. The radio was an Icom 7600 and Expert 1.3 K-FA provided 400w power was provided by a Honda EU20 generator.

The band seemed very busy, with lots of stations taking part, and I think the good weather helped encourage more portable operating. Over the course of the next 3 hrs we worked 63 Q with our best DX into EI at 585 KM. Conditions seemed average, but we did have some very rapid QSO on some of the longer paths, sounded very much like aircraft flutter.


A very enjoyable contest in the sun, thanks to everyone we worked.

You can find the claimed scores online.

You can view the RSGB VHF contest calendar online

 

 

 

You can read more about the Kelvedon Hatch Secret Nuclear Bunker and the SNBCG here.

 

SSB AFS Contest

With snow on the ground and the sun in the sky it must be time to do some winter contesting. This weekend members took part in the RSGB affiliated society SSB contest, this takes part on 7 and 3.5 MHz from 2 till 6 PM.

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With a small amount of snow on the ground, and ambient temperatures around +1C we opted for the inside operating position. The station comprised of an Icom 7600, Expert 1.3KFA solid state linear and a doublet antenna at 30m on the bunker tower.

Band conditions on 7 MHz only supported “long skip” with some good signals from Scotland and Ireland, although after a short while even these distances proved difficult. The maximum usable frequency had moved down to 4 MHz, and so a switch to 3.5 MHz was required.

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A look on the Hack Green SDR confirmed 3.5 MHz was very busy, and we soon realised it was hard to find a run frequency. We also noticed a large amount of rasping electrical noise on 3.5 MHz, and so decided to investigate further. At times the signal meter was reading S9 or s9+10dB and so hearing weaker signals was proving impossible.

We changed the mains supply over from fixed to generator, and the noise floor dropped by 3 to 5 S points, interestingly it would seem the noise was coming from the mains, and so this would require some further investigation and most likely a mains filter project for Chris G8OCV.

 

32160162702_84e7a7833e_kThe generator proved to be a little problematic, for some reason it was running a little lean, and so the engine was sounding rather more stressed than usual. This caused the generator to “brown out” a few times as it coughed, wheezed and spluttered in its attempt to generate circa 2KW at 240v.  As they often say if something could go wrong, then it most probably would while your out in the field.

Hopefully the generator will be a simple fix, probably just needing a clean to the carburetor and no doubt another job to be added to the “to do list” before our next event.

 

While we had some fun, drank some tea and generally worked a few people I think its safe to say our score wont be breaking any records. As always we learnt a bit, had fun and generally tried to stay warm.

RSGB Christmas Cumulative Contest

The RSGB have a series of Christmas Cumulative contests covering 50/70/144 and 433 MHz. The contest is a chance to put down that turkey sandwich and head out to play some radio in the winter sun. The contest run for 2 hrs, and activity is over 4 days. You can read the rules online, and activity is typically quite high.

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This year I joined George M1GEO at our contest site the Secret Nuclear Bunker

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The setup included.

Icom 7100, 9e Portable Tona and RF power was provided by a Linear Amp 300w solid state amplifier. The mast was a Racal PU 12 at 5m as the band was wide open with tropo propagation, this provided some interested DX. Mains power was provided by a silent running 2KW Honda generator.
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We managed to work 51 stations, with our best DX into Spain, EA1FDI in IN53 at 1143 KM.

The QSO map showed some great openings to the South and East.

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The temperature dropped quickly once the sun set, providing a spectacular sunset and the motivation to pack away quickly. Altogether a great afternoon playing radio, with some great propagation for a change.

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Thanks to everyone we worked, and all the best in 2017.

EME and MS Weekend

Members of the Secret Nuclear Bunker Contest Group (SNBCG) assembled at Kelvendon Hatch to try 144 MHz (Earth Moon Earth) EME and MS (Meteor Scatter) over the weekend of the ARRL EME event As a group we have tried with some success MS QSO and this helped lay the foundation for this weekend’s EME event.

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EME is particularly challenging due to the great distances involved and extreme path loss of the signal after its travelled close on 500,000 miles! The equipment and format of the QSO is similar to MS, we used the WSJT-X 1.7 (currently in Alpha) and  WSJT provided free from Joe Taylor K1JT website.

The weekend of the ARRL EME event was selected as it provided the best chance of working some of the EME “big guns”. Our equipment was quite modest by comparison, but included a

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9 Element LFA antenna designed by Justin G0KSC,

DG8 masthead preamp as designed by Ian GM3SEK with the kit available to order from hupRF.

Linear amp UK  Gemini 2 VHF amplifier delivering 300w.

Low loss LBC600 / LMR600 coax.

Icom 9100.

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We found we could often decode signals, and even the thrill of decoding signals from the K2VEE in EM79 via the moon was incredible…then it happened.

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We answered a CQ call by HB9Q and to our surprise they replied. This was our first and it turned out only EME QSO that weekend.

We continued to have quite a few MS QSO working Italy, Slovenia, Denmark and Norway and also a number of SSB contacts with 30 or so UK stations over the course of the weekend.

It is always nice to try a new mode and to succeed, you must never underestimate how difficult it is to achieve a QSO over that incredible distance. We achieved our goal of making an EME QSO, and regular decoding of signals via the moon. If this has inspired you to have a go I would encourage you to check out  K4MSG guide to small station EME. Also have a look at W5UN monster EME array that has bagged him over 11,000 EME QSO !

QST also published an interesting article “A Basic Approach to Moonbounce” that you may find interesting.

Plans are already being made for the next EME event in November…

RSGB IOTA contest

Members of the SNB Contest Group came together to play some radio in the RSGB IOTA Contest. Some stations make the trek to far flung Islands in exotic parts of the world, we opted for the contest site close to Kelvedon Hatch in Essex.

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The SNB contest site has the added bonus of a 50m onsite mast, making an ideal platform to hang dipoles. George M1GEO and myself decided to operate or respective calls from the two radio setup, using 3.5, 14, 21 and 28 MHz. George also added his 50/70 MHz beam on the mast, and this provided some interesting contacts using MS and JT65.

With the able assistance of Dave G7UVW, Chris G8OCV, Peter G0IAP we soon had the antenna ready.

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Two pump up masts provided the following setup.

Clark 12m: Tri-band Beam A-3S covering 14, 21 and 28 MHz, with a 50/70 MHz beam.

Clark 10m : 15m 4e homebrew monobander.

Bunker: 3.5 MHz dipole at 30m centre

At various times we added some RF power from either the solid state Expert 1.3KFA or the HAL1200_Atlantic amplifier. We had some interaction between the close sited antennas, and at times this dictated the operating modes/times.

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Fred G3SVK provided joined us as our CW operator, Fred can often be found in the lower pasts of the bands chasing big DX.

No sign of the great man this weekend, but, we live in hope.

70 MHz Trophy Contest and CW QRP HF

George M1GEO and Dave M0TAZ took part in the RSGB 70 MHz trophy contest this weekend at the Kelvedon hatch Secret Nuclear Bunker contest site. The weather was ideal for alfresco operating, using the Icom IC-7100 and homebrew 6e beam at 10m on the Racal PU12 mast. Using 50W and a 85Ah leisure battery we operated from 11am till 4 am.

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Here you can see the PU12 and home-brew 6e 70 MHz beam. Operating from the base of the mast provided quick access to turn the beam. We managed to work 59 QSO with best DX into Scotland at 518 KM. The QSO map is shown here.

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Meanwhile Rob M0VFC was operating QRP HF on 3.5, 7 and 14 MHz using a range of dipoles. Unfortunately the HF bands have been a challenge at the best of times during the day, and QRP provided to be interesting. After a few hrs operating Rob had completed 30 QSO, and under the conditions that counts as a sterling effort! Here you can see Rob operating from the boot of his car. No appearance from the great man.

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Altogether another great weekend of alfresco operating in the sunshine.