GB1STG Special call for St Georges Day

Sunday 23rd April St Georges Day provided a good excuse to play some radio with Essex Ham. Charlie M0PZT had once again applied for the special call GB0 ST Georges day, and the location was Gallywood common just South of Chelmsford.

The weather was better than expected, and this encouraged lots of Essex Ham members to attend and play radio. I counted 7 active stations, these included at various times 144 MHz FM and SSB, 70 MHz, 18 MHz, 14 MHz, 7 MHz 5 MHz, and 3.5MHz So you could say we had most bands covered.

 

I opted to start on 70 MHz using a 1/2 wave and some push-up poles. The furthest distance on 70 MHz was down into the Gatwick area around 50 Miles. Once I had worked everyone I could hear I then migrated to 5 Mhz using a low doublet antenna.

With the assistance of G8OCV Chris and George M1GEO, we soon had the doublet supported in a local
tree and ready to work some inter G. The band conditions were a little depressed, once again a solar flare had caused some disturbances, but 5 Mhz did provide reliable contacts as far north as Scotland and all over the UK. Signals were especially strong from Devon and the South Coast.

It was nice to see so many people operating portable, every station battery powered. I operated from 1130 to 5 PM using a lead acid leisure battery and the Icom 7100. Special thanks to Peter M0PSX and Charlie M0PZT for organising the event once again.

You can follow Essex Ham on twitter or their website.

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HF Easter Weekend

During the long Easter weekend members of the SNBCG came together for a radio weekend. Over the course of the weekend, we had two HF stations set up one on 7 MHz and the other roaming between 1.8 and 21 Mhz depending on propagation.

 

I decided this weekend I would like to try a 1/4 wave vertical on 7 MHz and utilise my recently purchased push together plastic poles. The push together green poles are often sold at radio rallies and come in packs of 5 (each pole 1.3 meters) to give you an overall height of 6.5 meters. Using two packs of the poles I could achieve the required 10 meters.

 

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.

I also cut 6 radials, 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 told me these can be tricky to keep up without guying and some tape over the joints. I wanted to use the linear amplifier this weekend, and the prospect of the pole moving in the wind and or falling down made up my mind to use the push together poles as the first choice.

The antenna was fed with coax with a 1:1 balun (FT240-31) at its base to stop the coax radiating, and this needed to be capable of high power. John M0UKD made up the balun a couple of years ago after sourcing the parts online. I understand the RG400 coax can be quite expensive and difficult to obtain in small quantities, although any PTFE coax will suffice.

 

The antenna provided reliable service all weekend, and with the addition of 400w provided over 200 contacts in 40 DXCC countries. The highlight for me was working DX stations later in the evening, these included the USA, Chile, Mozambique, Guinea-Bissau, Israel, UAE, Armenia and Asiatic Russia.

George M1GEO and Fred G3SVK operated the other station, George chased some good DX and Fred worked several hundred stations as GB0SNB in his mode of choice CW.

Dave M0YOL worked some data modes using his portable setup.

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. Peter Onion G0DZB also joined us for the afternoon, making the most of the good weather for a ride on his motorbike.

 

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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 SNB using the 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.

 

 

 

 

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Rosmalen Radio Rally 2017

 

Once again I attended the radio rally in Rosmalen with George M1GEO, Chris G8OCV, Peter G0IAP and Dave M0MBD. We traveled up from Essex to meet George and Chris in Norfolk and then to Harwich to meet the boat.We boarded the overnight ferry from Harwich to Hook of Holland at around 8pm, and this left us a little time to chat and sample some of the onboard facilities. The boat sailed around 11 pm and arrived in Holland about 6 am the next morning.

 

The trip includes your own cabin, and breakfast the next morning with an “eat as much as you can buffet”. We always like to take this literally, and with carefully planning the breakfast can include toast, jam, bacon, eggs, beans, cereal, and fruit.  Once arrived at the Hook of Holland you leave the boat around 8 am local time, and the drive to Rosmalen is around 50 minutes.

 

The rally was held once again at Autotron, Graafsebaan 133, 5284 NL Rosmalen.

 

 

 

 

 

Ample parking is provided on site, although you often find the walk can be 5 minutes or so to the conference center. I assume they have more local parking for mobility impaired guests, but this is something to consider if you purchase anything large and heavy.

The selection of previously owned equipment was immense, covering everything from old army surplus equipment to modern computer spares and most things in-between. Some of the main dealers did attend, so it was possible to purchase new equipment as well as old.

It was also nice to meet up with other amateurs from around Europe, here you can see (center) George M1GEO chatting to (Left) Neils PA1DSP and Pieter-Tjerk de Boer PA3FWM

We left the venue around 4 pm and headed back to the hook of Holland. The trip home was equally enjoyable, with a 3-course evening meal on the boat and time to relax after a busy day searching for bargains.

 

 

 

 

 

We car shared with George M1GEO who provided all of the motor vehicle transportation, and the cost for the ferry, breakfast on both mornings, 2 nights cabin and a 3-course evening meal was around £160. Altogether great value, and a very enjoyable weekend.

Special thanks to Lin (George mum) for organising us all and sorting out all our travel arrangements 🙂

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Receiving Non Directional Beacons (NDB)

NDB are low power beacons in the 250 to 550 KHz range. The beacons are usually situated at a landing strip/airfield / oil platform to aid navigation. They are non-directional so use a vertical omnidirectional antenna, and reasonably low power. The ERP is very low, as the physical size of the antenna restricts the efficiency and the desired range is usually not more than a few tens of miles.

Photo credit Original uploader (and claimed/alleged photographer) was Mintaka10.

The beacons transmit in double sideband AM, so you can often see the carrier AM frequency and then on both the upper and lower side of the carrier the CW ident. The CW consists of one, two or three letters, and the morse ident is unique so can be used to geolocate the beacon.

Wikipedia contains further information on how these are used by pilots to navigate, although most shortwave listeners are simply interested in identifying the signals and working out their location. The frequencies used to lend itself to some considerable distances at night, although its often the noise floor of the local area in this bands that limits the receiver. I found my doublet antenna was poor to useless at these frequencies, and it was the Wellbrook Loop that provided a significant improvement on this and other LF, MW bands. George M1GEO has also provided some details of a homebrew version of the loop, and details can be found on his site.

If you don’t have a suitable HF receiver and aerial a good way to start is by utilising one of the online SDR receivers.  Some have a text above the receiver window showing the name/location of any beacons received. You can often click on this text and the receiver will set the correct frequency and mode.

Keep in mind that local conditions and time of day will as it does on other HF bands influence the stations that can be received at any time.

The expanded version shows just one NDB, located at Epsom and using the CW ident EPM. The AM carrier can be seen in the center, with the morse ident either side. Its helpful to be able to look up any decoded and confirm the location, the simple ident EPM does not provide you with much of a clue to its location. I found Sean G4UCJ website very helpful as it contained a list of his received beacons.

On occasions, the received signal is very weak, and local noise can often obscure the signal. In some circumstances, it can be helpful to use software to enhance the signal. The software is often used in QRSS very slow/low power CW, and works be building up a number of samples of the signal as we know the same information is repeated time and time again.

NDB finder is another excellent choice for finding the hard to detect signals, you can try that for free for 21 days.

If you like exploring the HF bands below 500 kHz the world of NDB can provide some interesting conditions. If you enjoy NDB or you want to share any further information please get in touch.

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Interesting Signals on HF

Sony Pro80 Receiver

I’ve always been interested in listening to the short wave bands, with my first receiver being the Sony Pro80 receiver. The Sony was a portable HF receiver that covered from 150 kHz to 223 MHz and was powered by 4x AA batteries. The receiver was excellent on the HF bands, and this receiver provided many years of reliable service.  I quickly realised that most of the interesting signals were outside of the broadcast bands, in the early days listening to the phone patch signals from troops in the Gulf war talking to their loved ones back home. Many of the signals were in the clear, simple analogue SSB signals.

 

HF Path Sounder

 

The advent of SDR receivers has allowed you to visualize and listen to signals, providing a unique view into how signals are modulated and propagate on the air. One such signal that caught my eye was this one seen on 11.14 MHz. It looked a little like OTHR, but was far too narrow and the way it increased and decreased its frequency did not look like anything I had seen before.  I checked with  Peter Martinez G3PLX (inventor of Amtor and PSK) who is world renowned for his technical expertise in these matters and he suggested an HF path sounder. A device that tests the HF propagation conditions, in some cases jumping around the HF spectrum. Something that I’ve never seen before, but without a spectrum display I may have never been able to identify this type of signal. Thanks to Peter for his assistance.

Sounds Like a Numbers Station

Much speculation has been published about HF number stations, one thing is for sure they have declined in popularity somewhat since the 1990’s. They were often found in the HF bands, 5 to 10 MHz being the most popular, and it’s now quite rare to find one on the bands without a little preparation. I was interested to see a station that sounded like a traditional numbers station on 6.739 MHz USB the other evening. It turns out this is not a traditional number station but generated by the USA military.

 

 

Firsttoken a youtube users suggests

This is not a “numbers station” (but calling it one is a common mistake). This is a transmission of the US Military HF-GCS network. These messages are called “EAMs”, or Emergency Action Messages as rangers199487 points out, in the hobby community. There is some question as to if all such messages are truly EAMs or not. These transmissions happen daily, many times a day. Common frequencies are 4724, 6739, 8992, 11175, 13200 and 15016 kHz. Many other types of signals are heard on the HF-GCS.

Numbers Station

Number stations are still around, and by checking the schedule at Priyom.org you can simply look up and listen to the next scheduled transmission. This example is broadcast on 8157 kHz USB.

Viewing the Bands in a Contest

 

 

 

 

 

The Kiwi SDR enables you to view to view up to 30 MHz of spectrum at one time. This can help identify areas of activity and provides a unique insight into how the HF bands are used.

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© 2015 Dave, M0TAZ