Band Police

This afternoon, some steady signal strength CW appeared within the 2500Hz normal operating width for FT8 on the 12m band.

Initially, I was surprised but not irritated by the CW - there's plenty of room for everyone.

Then I noticed the CW was repeating at regular intervals.  Below is the message being sent, which has a peak strength from somewhere on a bearing of about 120-130 degrees from north Wales. It seems someone has a bee in their bonnet, in that this is a 'warning' that the message frequency is the lower border for digimode operation.

Whilst the irritated operator may have some degree of argument that narrow band modes in IARU Region 1 are usually meant to run from 24.915 upwards, he has absolutely no leg to stand on.  In fact, he shoots himself in the foot.

Firstly, his CW transmission is at 24.915.467 - within the section where all narrow band modes are permitted.  The operator, as well as being an irritating fool, seems unable to understand what frequency his transmission is going out on!

Secondly, his own transmissions, which contain no identifying information as to the sender or his location, are entirely unlawful, no matter what band, mode, frequency or licencing authority!


Interestingly, I worked a EB4 station on CW yesterday on 12m - the first time I've heard CW on this band for some time.  Given the bearing, and that this operator has no QRZ.com presence, I'm beginning to wonder if it was that station who is the irritant...

Antenna towers: don't forget drainage!

Back in 2013, I found a cheap retractable lattice tower for my 12m LFA beam.  The drawback was I had to travel eight hours to very nearly Land's End, and then eight hours back again!

Installation of the tower was, as tends to be the case, slightly hurried.  Concrete comes on the hour it is ordered, and nobody will stop it setting if you're not ready!

So it was here, cutting the last bits of metal to prepare the mount above the hole at 10pm before the 8am concrete delivery the following morning.

Base concrete pouring, back in summer 2013.

Whilst I managed to get the concrete to flood the point where it met the bottom of the metal base, it's never easy to make sure that voids haven't formed, especially with today's accelerated-setting concrete.

So, if you are going to install a tower, make sure you think of drainage.  There was a small void, maybe about 200ml in volume, beneath my tower base, which wasn't able to drain away properly.  I think it formed because the two bolts that keep the winch section in place are quite close together, so they prevented proper concrete levelling underneath the base.

Drainage channel.  No more water accumulation.

After a lot of careful cutting with a pointing chisel to make a deep channel, I then broke through a small 'dam' that was preventing most of the water from getting out.  Iron-stained bacterial mats revealed this water had been in place for some time.

Now, when water seeps beneath the tower base, it instantly drains out again. 

Grey line to K4COD

Beautiful examples of propagation enhancements are always worthy of a write-up, no matter how many times I cover them.

Last evening, K4COD's 2W signal from Concord, GA, showed just how much the grey line period can enhance the chances of a DX contact.  In this case, the signal enhancement at peak grey line is +27dB (a factor of 500 times) over the pre-grey line period!

To put that into practical context, if you are using the highest, 200 milliwatt setting on a WSPRlite, the propagation enhancement magically gives you 100 Watts effective output!

Note, though, that the definition of the grey line period is certainly not always between two stations mutually lying within the grey line region, which is how the phenomenon is usually explained.

Here's the situation at 23:04UT, the start of the peak strength, about 90 minutes before K4COD enters the greyline.  You can see that the first part of the peak propagation started around 21:45UT, which is when my station was about half way into my local greyline.

23:04UT

Towards the end of the peak propagation (about 01:10UT), the greyline was situated like this.  The drop in propagation from this point on is a product both of my station lying towards the deepest part of the greyline (within which I remain all night during midsummer), and K4COD passing into his, deeper parts of the greyline.

01:10UT

Wake up, tune in!

You might be surprised if you get up fairly early and tune up on 12m these days.  A couple of days ago, I received T88T at +0dB SNR, although he seemed not to have  had enough faith in the band, as he didn't wait for a reply, and vanished from the band immediately!

All the same, signals are getting to central Asia quite regularly, and out to Japan on occasion.

This was the band here in Wales early this morning, at 06:49UT:

New internet connection - no copper!

For many years, my QTH, being very rural and yet not exactly far from civilisation, has suffered from terrible internet connectivity.

In the years 2008-2010, we had nothing but dial-up speeds, mostly due to the distance from the exchange (about 2km or more).

We then acquired a microwave internet link paid for by the Welsh Government.  In fairness, the Government did what they could to solve a country-wide problem.  But they and the taxpayer simply ended up being ripped off: grants to installers were a maximum of £1000 for equipment, and so, as was entirely predictable, most charged the Welsh Government £999.99!

Free equipment from the Welsh Government - but it was not very good.

This really didn't work very well at all, although when it did work, speeds were reasonable (about 8Mbps).  The service was up and down, and often off altogether.  Worse, the connection from router  to the rooftop antenna generated terrible RFI, which I recorded at the time. The company, having now made its directors a lot of money, was sold off and service standards dropped off a cliff.

We got rid of that system about 2015.

We then bought a mobile wi-fi box from 'EE'.  This worked very well until near the end of the contract, when we suddenly found unusual transactions that we hadn't agreed to.  They tried to take a large amount of money from us, but we complained and eventually recovered all of it.

Good, until we were landed with some mysterious service charges we never used!

That was the end of 'EE' mobile broadband.

We then tried Vodafone.  This worked very well until last month, when the transceiver failed.  During those years of mobile data boxes, the infrastructure locally has improved dramatically.  We now have super-high speed fixed broadband fibre passing in front of our house, and so I decided to connect to this, to end our internet woes.

There was a lot of misunderstanding about the role of copper wires.  When you buy a package of phone and broadband, the network operator insists on copper cable for the phone.  That's OK, so long as no data is transmitted along it, potentially - and as widely reported across the UK - creating RFI.  The main problem is imbalanced line conditions with VDSL2, which causes very wideband RFI, leading to some very sad stories of operators who have operated successfully in urban areas for decades now being wiped out.

The first engineer told me that, despite a fibre connection being fixed to my house last week, all my services would be along copper wire.  "No way!" said I.  "You can take your services and stick them where the sun don't shine!"

Then, later the same day, and entirely unexpectedly, a fibre engineer arrived.  Being female, she was much more helpful!  She installed everything via fibre, with the only wires being power (12V, easily converted to linear PSUs if needed), and a very short WAN cable.

In total, the system, including the two SMPSUs, generates no detectable RFI on any amateur band.

At last, broadband connected by fibre - with no RFI!

So, if you are in the UK and thinking of a broadband package from BT, it is often now available all the way to your indoor connection via fibre alone - no copper wires at all!  Just make sure to bring the engineer in for a cup of coffee as soon as they arrive, and tell them about your radios and ask exactly how the services arrive at your home.  If you don't like what you hear, put a hold on the installation. 

It's also an idea, if you want to be treated like a new build home that will tend to get fibre-for-everything, that any existing copper wire you may have could have 'come down in a storm', if you catch my drift...

VHF/UHF Switch Problem.

I had a rare listen to 2m and 70cm FM last evening.  Here in North Wales, there is essentially zero 2m activity, even on repeaters, and those few who remain operational are generally not worth having a QSO with.

I noticed that, as I turned the antenna switch to its end-stop, the signal on 2m suddenly increased - by about 4 'S' points.  How strange!

On opening the VHF/UHF switch, I was firstly surprised to see how little I had received for the quite large amount of money paid for it! 

As you can see, it's just a shim of brass moving between the outputs!

How much did I pay for this?

Clearly, there's not an awful lot that can go wrong with such a simple switch.  Because more pressure on the switch brought about the improved signal, I thought this was probably corrosion on the brass metal knife.

After applying some metal polish with a ear-cleaning stick, it was obvious that there was quite a lot of surface corrosion to be cleaned away.  If you do this cleaning, please make sure you remove all traces of the metal polish, because if you don't, when it dries, it forms a non-conductive powder.

Quite a lot of surface corrosion on that kife switch!

After this simple treatment, the fluctuating signal problem had disappeared and full strength reception was restored!

24MHz - Some analysis (updated)

The latest 'HF' section of the RSGB's magazine, RadCom, invited reports this month from those who have recently completed QSOs on the upper HF bands of 24 and 28MHz.

The assumption of the author was that these bands are only open at the moment due to Es propagation.  It's not an altogether incorrect assumption, although the impression I get from regularly operating 24MHz is that the band is doing pretty well for the depths of solar minimum.

I decided to quickly plot the total fraction of each month where I completed a 24MHz QSO, together with the fraction of the month with DX activity on the same band, and it looks like this:

Certainly, the recent past seems to indicate Es is the major player in propagation at the moment.  Meteoric inputs - and thus Es propagation - are greater from roughly the end of October to December, but there is not really the peak in propagation one might expect at 24MHz.

UPDATE:

I spent some hours dragging out all the 24MHz QSOs from my LoTW log today, and the results are very interesting.

Looking at the plot below, you can see that the peak month, or even season for 24MHz activity moves around a lot.  In the past couple of years, the pattern of activity has inverted compared to earlier years (the plot is based on QSOs with the same 3-ele LFA Yagi throughout).  Again, blue is fraction of each month with any activity, and orange the fraction of each month with DX (>2500 miles).

The polynomial trend line tends to show a slight increase in 24MHz activity, perhaps consistent with a slow upward trend in solar activity evident at the moment.  DX activity continues at fairly low levels compared to previous years, and the improvement on these longer paths is much slower to take place, and indeed is either still declining or just reaching a plateau at the moment.

Blog in hiatus: a death in the family.

Sadly, after a brief and mercifully suffering-free battle against a cancerous brain tumour, my father-in-law passed away this morning.

Grandad Keith and my kids on a model train, in April 2009.

Keith, born in the railway-dominated area of Crewe in England, spent most of his life amongst wires and computers.  His early career was as a telecommunications engineer, which later changed to a computer technician at Bangor University.  Post-retirement, Keith spent some time running his own computer programming business, which included some work at the local nuclear power station.

Keith was a talented mechanical engineer, as well.  He spent many years building his own scale-model, working steam engine, and ran the North Wales Model Engineering Society.

Keith leaves behind a wife, three children and three grandchildren.

The blog will return to normal service after a period of mourning.