Rosmalen Radio Rally 2017


Once again I attended the radio rally in Rosmalen with George M1GEO, Chris G8OCV, Peter G0IAP and Dave M0MBD. We travelled 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 on-board 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 onsite, although you often find the walk can be 5 minutes or so to the conference centre. 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 (centre) 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 omni directional 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 short wave listeners are simply interested in identifying the signals and working out their location. The frequencies used 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 improvements 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 dont 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 anytime.

The expanded version shows just one NDB, located at Epsom and using the CW ident EPM. The AM carrier can be seen in the centre, 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 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

Ive 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 a 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 its 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 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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KiwiSDR 10 kHz to 30 MHz now online.

Listen to my SDR

Access other SDR from around the world.

Buy one online.


In April 2016 the KiwiSDR project was born on Kickstarter, the plan was to produce a software-defined radio (SDR) covering shortwave, the longwave & AM broadcast bands, various utility stations, and amateur radio transmissions, world-wide, in the spectrum from 10 kHz to 30 MHz.

Fast forward and the project has now been completed with the first units having been dispatched


The first time I used one was when Dave G7UVW added his to the website.

After using it for a few weeks via the web browser I was sold, it was ideal for HF monitoring, and with remote access with up to 4 independently tuneable receivers.

The idea of having your own web based SDR always online, and accessible from anywhere in the world was very appealing and coupled with an active antenna the performance if very good. The advantage of the active antenna is it works well over the entire HF spectrum, its especially good below 5 MHz.

I use the Wellbrook loop mounted outdoors at around 5m, but you may be interested in a much less expensive project version as detailed by George M1GEO.

The SDR software has a built in WSPR decoded that works really well, and with time they hope to add further features.

Ive been updating the station text, its work in progress but I’ve added quite a few of the medium wave station names.

Have a listen with the my SDR, I understand Safari, Firefox and Google browsers work best. The display is not mobile friendly at the moment, but it does seem to work OK on the IPad.

Be sure to let me know how it works, leave us a comment and don’t forget to include your town / country or callsign.

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MX0SNB Operating CQ WW WPX RTTY Contest

This weekend was the CQ WW World Prefix Contest (WPX) and RTTY has never been so popular. The bands were once again packed with RTTY, with most of the big contest stations making their mark. I used the Secret Nuclear Bunkers club call MX0SNB, as its quite rare and was more popular than a standard M0 call this weekend.

The basic setup is here.

The Expert 1.3k-FA purring along at 400w.

Using just a doublet antenna and a 10m vertical and I was active on 7, 14 and 21 MHz.

Its possible with a small antenna and some power to have some fun on the bands, here was a spot added to DX summit from DL2SAX “Big Pile up RTTY

7 MHz was mostly EU although the band can throw up the odd surprise later in the evening. Operating time was casual, just fitting in some RTTY in between other tasks. In total I managed to work 359 stations in 52 DXCC.

I used the Expert 1.3K-FA solid state linear amplifier, with around 5w drive and 400w out. This was the first time I had tried the linear with sustained contest style usage, and it coped very well. Even with frequent CQ calls the temperature never passed 43 C.

Most of my contacts were around EU, although a few DX did get worked.

Maps produced by SH5 contest log analyser

Enjoyable few hrs on the band, thanks to everyone we worked. The prefered QSL method for MX0SNB is LoTW and EQSL.CC, although we will reply to any cards via the bureau (VIA M1GEO).

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Canvey Radio Rally 2017

The first rally of the year Canvey, organised by SEARS can sometimes be snowy, cold and wet being in February. This year it was quite mild, so no need for the snow boots thankfully.

Transport was provided by Peter G0IAP, and we were joined by Dave G7UVW. We arrived in good time around 9.45 and noted people already starting to congregate outside the door, we opted to remain in the warm car and await the door opening. The doors opened shortly after 10, and just £2.50 provided you entrance to the multitude of lovingly used vintage items (OK junk) on display in 2 halls.

The main hall was busy with the usual mix of traders and Special Interest Groups. Peter M0PSX from Essex Ham had information and a display video showing 2016 events.  It was good to see Charlie M0PZT from Ham Goodies  both very busy, in fact I didnt really get a chance to chat with either Peter or Charlie as they we both so busy dealing with punters!

The RSGB has a book stand and this was well staffed with the usual helpful volunteers from team RSGB.

Walters and Stanton had a good display of items, giving Essex amateurs a chance to ask about the changes to their business model.

Tea, coffee and the infamous bacon rolls were on offer from the serving hatch in the main hall. I think we all remember the year Canvey rally didn’t serve any bacon, it almost caused a riot in the streets. Thankfully special attention has been give to catering, and further disasters has been averted.

Nice to catch up with so many friends from LEFARS, Secret Nuclear Bunker CG, Essex Ham and the RSGB. I has a nice catch up with Dave G4ZST and Riche M0TYA while browsing some junk.

Here you can see Dave G7UVW giving the sniff test to a recently acquired vintage light meter.

A chance to rest your feet.

So what bargains did I find ?

A couple of project boxes and some heat shrink, but rallies arent about the junk you buy more about the people you meet and a chance to chat.

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© 2015 Dave, M0TAZ