Clean Up The Shack – Part 3

So, the posts are coming thick and fast at the moment but, this won’t continue as there will be a wait for all the bits to arrive.

Having rifled through screen shots taken some months ago you can see the problem I was having with severe interference. These two powerful signals were generated by an LED security light which was quickly  removed and sent for recycling at the local tip

In my previous post, I stated that I wasn’t interested in the science around Amateur Radio. However without applying a bit of science I will not know if the changes I make are making a difference. OK, so the “opticians” approach – see if it works or not – is a form of a measure but I will see if I can actually put a figure on it.

Unfortunately, I have cocked up a little in that I did not take a screen grab of where I was before I removed a load of power bricks, so, you will have to take my word for it that I had S9 of noise on 40m

After removing the power bricks that has fallen to S7

It is well worth going through every word of GM3SEK’s presentation several times as there is always a possibility that you could miss something. I have now done this and learned something in the process so will be doing a couple more things than originally planned.

GM3SEK said in his presentation – words to the effect of – “you shouldn’t need to filter the DC after you have installed the mains filter”.

However, he clearly demonstrated that switch-mode power supplies can quite easily be a major source of interference. This got me thinking.

My main PSU is a switch-mode and, the PSU for the Loop Antenna tuner is a 24V brick PSU. I am assuming therefore, that there is the potential for these to be causing a problem – no matter how small – despite the hope that they should be excellent quality considering what they were designed for.

I have therefore produced 2 DC filters


The first is about 10 turns of 30A DC cable which comes from the back of the PSU and directly into the Flex 6400


The second is many many turns of the cable from the 24V PSU which feeds the Loop’s tuner.

To my unqualified eye, this PSU does not give me a lot of confidence so I plan to replace it for a decent variable voltage PSU at some point in the future

So, has adding these made a difference?

I would say so!

Clean Up The Shack – Part 2

Well, when I posted on Twitter that I had ordered all the bits to make a mains filter for the shack I did not realise what the response would be.

The tweet has generated more likes, retweets and comments than anything I have ever posted and I suddenly also have 1,200+ followers to the blog. I am not sure why, but hey, if folks are interested that can only be good!

However, let’s get a couple of things straight, building the mains filter and blogging about it is NOT because I am going to do anything different. I am simply following the instructions given in GM3SEK’s (Ian White) blog, presentation and diagrams.

My blog, is simply showing the processes of applying his knowledge and expertise and the challenges I will need to overcome in doing so.

As many of my Twitter followers already know, I am a white stick operator and, what is simple and straightforward for many, is not going to be for me. Again most will know that I have absolutely no interest in the science around Amateur Radio – I am simply an operator who is purely interested in the QSO and nothing else!

Many believe that I have a “duty” to understand the science behind it – sorry to disappoint but I have no interest whatsoever and only seek the LoTW confirmation of our QSO.

Primarily I operate on digital modes and hence weak signal modes such as JT65/9 and FT8/4.

I live in a very RF hostile environment with high density terraced houses and in the middle of a triangle of electrified rail lines. 12m away is a chapel that is full of fluorescent lighting and I have significant sources of interference with dozens of LED bulbs and more powerbrics than I can count in my own home. In addition, I live in very close proximity to 2 tower block which are covered with more antennas than I can count with paging systems, repeaters, broadcast radio transmitters and point to point, and, point to multipoint microwave systems – many of which I installed for commercial purposes!

About 40% of the power bricks have now been replaced with a single 12 volt supply but, I have not managed to replace them all – yet

Living in a small house with a small garden meant that I had to compromise on my choice of antenna and have a 1m diameter magnetic loop which is fed via Ultraflex 7 to a Flexradio 6400 connected to a dedicated “shack PC”

In the past 2 years – with a 12 month lay off – I have managed 136 confirmed DXCCs including VK and ZL so I know I have plenty of capability with the existing system.

What I am now trying to do is make as much improvement as I can as every db counts when working weak signals.

GM3SEK’s blog and presentation can be found here

Clean Up The Shack – Part 1

I have known for a long time that I am suffering from a lot of interference in the shack.

Some of it, I can do nothing or very little about quite simply because of where I live. However, like most, there is a lot of interference that I/we can do something about – it just needs sorting.

Well over 12 months ago I noticed – well it was staring me in the face – powerful signals on my waterfall.

A little bit of investigation showed that a power supply on my home’s CCTV system was causing the problem – so it was replaced.

Then other strong signals were noticed, then more and then even more.

Over the last 12 months I have removed a lot of “power bricks” replacing them with a single 12v power supply and now, have a 12V supply running throughout the house.

Once “lockdown” came into being, and, my wife and son started to work from home. more interference cropped up due to the power supplies on their respective laptop computers.

I have been aware for a long time that there is a solution to deal with this, but, being lazy, I have never got round to dealing with it!

As it now appears that I will be confined to home for some considerable time, coupled with other family members causing interference, I have decided to address the problem once and for all.

The solution is quite simple, just visit and all the information you need is there together with a very good presentation in video and PowerPoint formats.


I have to admit, when I received my letter from the NHS telling me that I had to be “shielded” from Coronavirus, I was somewhat shocked and quite upset.

Having dwelled on it for a couple of days, I realised that there was little point. It is what it is and I have no choice.

It didn’t take that long before I decided to make the effort and get back on the air and start to chase the DX.

But, first things first!

Having been off the air for 12 months I knew that a lot work had to be done and, once that had been done, I needed to address some known issues with the shack.

But first, I removed everything from the rack, cleaned it, put everything back and started to updae all the software.

Windows updates took a few hours followed by WSJT-X and then had to update the Flex 6400.

Thankfully all went well and I was quickly back on the air!

I’m back

It has been a very long 12 months since I last had a QSO.

I won’t go into the reason for the long layoff, surfice to say, it has been a difficult 12 months on a personal level.

The most important thing is that I am back and raring to go – but some work on the shack needs doing first.