Year: 2019

RSGB Intruder Watch

The radio amateur community have always been vocal, that’s not a bad thing and has been very successful in allowing us to have very privileged access to the radio spectrum from DC to daylight.

On some bands, we enjoy primary access and should be free from other users sometimes called intruders. Other parts of the bands are shared and used on a secondary non-interference basis, we amateurs must not interfere with the primary users.

The RSGB provides a number of services, one is called Intruder Watch. Volunteers take reports and will complete some initial investigation and correlation of the data. The data is then red into OFCOM the national regulator, and the will take steps to report the problem to the national regulator in the country of origin.

The issues are often international problems, and so require evidence and sometimes weeks or months of data collection.

The RSGB intruder watch team can be contacted on they ask you to provide the following information. Date, Time, Frequency, Modulation type.

If you wanted to check the latest news from the IARU, you can read their newsletter online look for the latest news.

I often report a military station on 7 MHz, today I noticed an FSK station centred on 7.193 it was 200 Hz wide and using encryption.

The Kiwi SDR network can be very helpful in providing a TDoA service

Most likely Russian Naval FSK

I think it is very important to report these issues to the IW team, in the past, OFCOM have asked for evidence they intruder is causing an issue and that can be hard to demonstrate if 1 report has been received from 50,000 amateur radio operators.

The IW team ask you to report every occasion direct to their email address, even if its the same station on successive days. This helps to build a body of evidence and hopefully results in the station being encouraged to move away from our primary allocations.

12 into 5 doesn’t go

A couple of months ago I demonstrated to myself just how 12 into 5 doesn’t go, yes I know maths (or math if you speak American).

Unfortunately for me, this was more of an electrical disaster, putting 12v into my 5v QRP Labs Ultimate 3s transmitter. The display glowed unsurprisingly bright, and then blank.

At the time I wasn’t sure why, so in true fault finding tradition I turned it off and on again, several times in fact. It then clicked, or probably more precisely popped and the damage was done.

Looking on the QRP labs help file, I found a section that dealt with “Ive put 12v on my …” I guess I’am not alone, and to be honest I really cant see why this devices wasn’t designed as a 12v native power supply and then regulated to 5v.

Part 1 involved buying a new processor, these can be purchased for a few pounds online or by speaking with Hans and buying one at one of the rallies he attends.

Here is my rather sad v3.09c with burn mark!

Part 2 in my case indicated that there was an issue with the clock. I had to re-build the Si5351A Synthesizer, again available for a few pounds. The FAQ indicates this is probably OK, but in my case it wasnt and needed replacing.

Here is the new one ready to be fitted. It just needed the header pins, but I found this really difficult as my eyes dont seem to focus on anything close these days.

Once this was installed it sprang back into life, and is currently purring away at 200 mW on 7 MHz. I have been told on occasions the display can be damaged, but despite my best efforts this survived.

Zwolle Radio Rally – Netherlands

On the 2nd November 2019 we completed a new amateur radio rally / convention in Zwollle in the Netherlands.

Travel was via the Hook of Holland Ferry, and the fun began right from the start. I collected Dave G7UVW and we headed up the A12 towards Harwich, leaving a lot of time for any unforeseen issues. That was rather fortunate, as the first issues was a 4 car accident on the A12, a 45 minute delay.

Once cleared we made good progress, right up until some clown decided to close the A120, the main route into the Harwich port from the A12 for roadworks. They had organised a diversion, although it soon became apparent the route was long, complicated and involved country lanes!

Not such a problem in your SUV, but try that in a 60 ft articulated lorry, what could possibly go wrong. Well it did, one of the lorries became stuck in a country lane, and the queue of lorries and cars soon backed up. Now we were stuck in a country lane, Google was trying to take us back onto the A120 (closed) and the diversion was unusable.

The only thing to do, find that Carpenters album on the music system and try and relax. Very, very stressful, and we had left lots of time and we now only had 45 minutes to make the port before boarding closed.

GPS Track from the car

It should be easy to spot on the map the point that the A120 stopped and the diversion began.

Honestly, who in their right mind would close the main route into one of the largest ports in Essex! The journey should have taken 75 minutes, but was more like 2.5 Hrs.


We made it onto the ship, and decide to head down to the bar for a well deserved beer. The crossing was an overnight sailing, getting into Holland around 8 am the next morning.

Time for a Beer

The drive from the Hook of Holland to Zwolle was completed by George M1GEO, and was around 1hr 30 (around 100 miles) and traffic was light.

The queue to gain entry

The rally was well attended, we arrived around 1030 am and needed to queue for around 15 minutes for entry. Entrance was 9 EU, and the hall was large and stalls well spaced to avoid congestion.

Makers section
View around the hall.

Lots to see, and a good selection of pre-loved equipment, and some new items. The catering on site was good, if a little expensive, I did see quite a few people well prepared with flasks and sandwiches in true radio amateur style.

The Dutch version of Raynet (DARES) had a nice vehicle on display, complete with a telescopic mast.

The return journey was back onto via the Hook of Holland and onto the ship. We had a 3 course meal book, and the standard of food online was excellent once again.

A very busy, but great fun weekend. Its always nice to catch up with radio friends and the rally is a great way to do that.

Decoding 433 MHz Signals with RTL SDR

One of the members at the radio club Merlin suggested trying out this sensor decoding program for the RTL SDR receiver. You can view and order one online for just a few pounds.

The software RTL 433 is a generic sensor decoder, and it will decode and display a variety of environmental data. Despite its name the frequency can be defined in the setup, and sensors can be found on 315, 433, 868 and 915 MHz depending on your location.

In the UK 433.92 is the most popular, and so this is a good place to start. Firstly you will need to install and have run the RTL SDR, you can do this by plugging it into the USB port on your computer and waiting. Windows will helpfully install the incorrect drivers, and this can be resolved by running Zadig. Follow the instructions here. The Quickstart guide is also online.

If your running Pi, Linux or Mac then you will need to look up the instructions on the link given for installation instructions.

Once the RTL dongle is installed, then the addition of a good 433 MHz antenna will allow the reception of some interesting signals, even if you just have the default magnetic antenna the chances are you will pick up some local traffic.

It will of course work much better with an external antenna, and these handy adaptors may help with connectivity.

The RTL has lots of diverse supported software, you can find a list available at

Merlin also pointed out that while the program will run from the windows explorer it is best to create a .bat file in notepad.

Mine looks something like this

mode 800
rtl_433_64bit_static.exe -f 433.4M -s 1024k

Useful resources for the beginner

Cheap Starter USB SDR

SDR Receivers

Scanner Antennas

Coax Cable

Coax Adaptors for SDR receivers

Bank Holiday Radio Weekend

August is the last Bank Holiday of the year, and with the weather set to be 30c+, it provided the ideal weekend to play some radio.

Sunset over SNBCG

Members of LEFARS and SNBCG came together at Kelvedon Hatch Secret Nuclear bunker for a 3 day radio weekend, including BBQ and camping. Some members of the advanced party arrived on Friday evening helping to set up the operating tents.

The 40m vertical was the first antenna to go up, this included 4 elevated radials.

7 MHz vertical antenna

The next antenna was the 3e 18 MHz beam, this was fitted onto the 12m SCAM mast.

18 MHz 3e homebrew beam

The operating tent was completed with the IC7300 and IC7610 and Expert 1.3K solid-state amplifier.

Peter M0PSX enjoying some DX

Peter was delighted to use the 7 MHz vertical and linear, commenting on how much fun it was to run a pile-up! The weekend was all about having fun and trying out new things, Dick G4DDP completed a number of QSO on 50 and 70 MHz working SPe all over EU.

John M0IDA working some DX

Special thanks to John who repaired my headset with a mono jack plug he desoldered from his own headset. Thanks, John!

Vintage Dave also decide to operate in period costume, adding to the nostalgia of his vintage wireless experience.

Dave M0IDF

The BBQ provided by some excellent food, thanks to Ron and Karen for setting this up and Dave M0MDB for his Chillie.

Thanks to Piotr for this clip, it gives you some idea how busy 7 MHz can be on a field day.

Dave M0TAZ working a busy 7MHz

We put 1030 QSO in the log, in 52 DXCC from both 7 and 18 MHz, thanks to everyone who took part and made the weekend a success.

70 MHz Cumulative #4

Portable operating in the summer can be one of the main attractions of contesting. Not only do you get the chance to enjoy the summer, but a chance to try things you cant do at home.

Like many, home comes with a considerable amount of man made noise, operating in the middle of a field solves that!

M0XTA Selim setting up the beam on the mast.

On this occasion we had setup around 1hr before the contest, so had enough time to call CQ and have a chat with other stations setting up for the contest.

Selim having a chat with some station on 4m

The contest lasted 2 hrs, and the first 60 minutes provided close on 40 QSO. The second hr wasn’t so busy, I guess we had worked most of the stations taking part.

We worked 48 stations in total, best DX was MM0CEZ at 554 KM.

The QSO map can be found here. The claimed scores can be seen here.

70 MHz providing QSO over most of mainland GB

Thanks to Selim M0XTA and Dave M0YOL for their help in the contest.