The Power of SIGINT

As a youngish engineer in the 1980s I’d already had plenty of experience in exploiting the properties of communications signals to solve complex problems. I’d been responsible for planning and executing the in-orbit testing of the European Space Agency’s (ESA) first 3-axis stabilised Ku-Band communications satellites, OTS and ECS.

In-orbit testing is a very different game to just designing and using communications satellites on a day-to-day operational basis. The earth stations involved are actually precise, calibrated measuring instruments and one has to be very inventive about how one can exploit the signals and signal processing to understand what is going on, particularly during anomaly investigations.

The Scharnhorst at Sea

The Scharnhorst at Sea

So here was I in the 1980s working with a major UK defence contractor on a project. One member of this small team was a senior engineer, close to retirement, who had been heavily involved in signals intelligence (SIGINT) during WWII. It was he who conveyed to me the following account of his involvement in the fate of the German battleship, Scharnhorst, in WWII. It’s a fascinating story and despite some searching I haven’t been able to corroborate it nor find any reference to the specifics, so I’ll record it here as-told for posterity:

The Scharnhorst had been causing havoc on allied North Atlantic convoys in 1940 and 1941, and Wikipedia’s description The German Battleship Scharnhorst is very comprehensive. An RAF air raid on 24th July 1941 caused major bomb damage to the ship and it limped into the German-controlled French port of Brest on 25th July where it went into dry dock for extensive repairs.

Bletchley Park Mansion Today

Bletchley Park Mansion Today

The Scharnhorst and its state of readiness were obviously of intense interest to the allies and its communications were the subject of continuous monitoring. Most folks today will have heard of Bletchley Park and its role in breaking and exploiting the German (and other) encrypted communications. There are published reports of the Bletchley Park teams using the ENIGMA decrypts of the Scharnhorst’s communications (COMINT) to gather intelligence on the progress of the repairs. What are not reported are the other related activities of ELINT and SIGINT, and this is where my colleague comes in.

A Typical WWII HF Radio Monitoring Station

A Typical WWII HF Radio Monitoring Station

Bletchley Park carried out other functions in WWII and was but one of a number of related intelligence establishments. My colleague worked at a HF radio station outpost on a hilltop somewhere in England which was continuously monitoring the Scharnhorst’s radio transmissions.
One of the things he was monitoring was the close-to-carrier spectrum of the Scharnhorst’s transmissions. He wasn’t interested in the COMINT, but the deep behaviour of the RF signal itself.

Now for the techy bit: The RF carrier is not a perfectly clean CW signal by any means. It carries information about how the signal itself was generated, and what has happened to it during its generation, upconversion, transmission and downconversion by the monitoring station. What my colleague observed was that, in dry dock, the Scharnhorst was running on shore-based power – not its own generators. The phase noise / spurious signal sidebands were at 50Hz from the carrier signal. Lo and behold, one night some time before the 8th February 1942 these sidebands suddenly jumped in frequency to 400Hz. The Scharnhorst had switched to its own internal power, and was therefore in the water and preparing to leave Brest!

Scharnhorst and Gneisenau at Brest

Scharnhorst and Gneisenau at Brest

Obviously, this information was immediately fed into the system and resulted in a step up of activity by the allies. On 8th February 1942 a photo reconnaissance mission detected that the Scharnhorst plus two sister ships, the Gneisenau and the Prinz Eugen were in the Brest harbour area and preparing to leave. They left at 23:00 on 11th February 1942 (some reports state Scharnhorst cast off at 21:14 British time) to run the gauntlet of the English Channel (codename Operation Cerberus) and the rest is history.

That escape from Brest and the subsequent failure of allied electronic warfare (EW) systems to detect them is described in great detail in the book “Battle Scars of Military Electronics – The Scharnhorst Breakthrough” by Sir Robert Watson-Watt of Radar pioneering fame.

The Sinking of the Scharnhorst

Sinking of the Scharnhorst, 26 December 1943
by Charles E. Turner

The above painting is in the UK’s National Maritime Museum, here.

Relevance in Today’s World
Apart from this story being a record of a particular individual’s contribution in the SIGINT field over 70 years ago, there are lessons here for today. That very same technique can be employed to narrow down the geographical source of interfering signals in satellite communications systems. It is but one tool that can be used in the fight against the curse of satellite interference.

In financial terms alone satellite interference (intentional or otherwise) costs the industry many tens of millions of dollars each year and is the subject of a number of mitigation programmes by the major satellite operators, a major one being the Satellite Interference Reduction Group.

Satellite Interference Reduction GroupThe Satellite Interference Reduction Group (IRG) is the global industry organisation with the mission of combating and mitigating radio frequency interference (RFI) for an interference-free satellite frequency spectrum.

With a decent size antenna, a low phase noise downconverter and a spectrum analyser one can easily determine the frequency of the power grid supplying the interfering transmitter. Is it in a 50Hz country, a 60Hz country, on a ship, on an aircraft or even space-based? One can glean even more information than this, but that is beyond the scope of this article.

And remember, you heard it here first!

Copyright 2015 Satellite Spy (Dr Bob Gough)

Put A Rocket Under Your Website

It’s taken a few years putting together this 40+ page website and carrying out ongoing site updates and maintenance. Gradually, the website became slower and slower to load and that fact didn’t really dawn on me until I recently received a tweet from a long-time tweep colleague, Cinnamon Carter (@Cinnamon_Carter). Always succinct and to the point she said something along the lines of “Hey, your website is really slow. You need to fix it up!”.

Now when Cinnamon speaks I listen. She has over 58,000 Twitter followers and with good reason. She’s heavily into the latest science and technology issues, with an emphasis on cybersecurity as well as tackling ‘rogues and charlatans’ head-on.

As a result of her wakeup call I started digging into the underlying reasons why websites were slow, and I learnt a lot of stuff I just didn’t know before. I confess to becoming a bit obsessive when faced with a new area of knowledge and a steep learning curve and this was one such situation. It resulted in me spending weeks digging deeper and trying out different approaches to speeding up websites in general and this website in particular.

This is not intended as an in-depth review and comparison of all the different speed-up techniques and products that are available – the use of Google search is much better at that and there are many excellent sites and blogs out there that cover such things in far more detail than I could. Rather, this is a summary of my conclusions and the specific things I did to try to speed up this (and in fact any) WordPress-based website.

WordPress websites rely on the use of a theme, and WordPress itself has its own free themes available. I investigated themes four years or so ago and I decided to use the family of themes from StudioPress, by CopyBlogger, which are based on their Genesis Framework. I’ve been very happy with this (I use their Corporate Theme here) and see no reason to change it. For those interested here’s a link to StudioPress Themes for WordPress.

Website Cache
Whichever theme one uses there are many plugins available to achieve almost anything you can imagine doing on a website. From the perspective of website loading speed the key thing to implement is the use of a cache, and there are free as well as paid alternatives. Two common free ones are called WP Super Cache and W3 Total Cache. Both receive good reviews and I implemented and investigated WP Super Cache. I also implemented a paid one called WP Rocket, which is in use on over 31,000 websites at the date of writing this. WP Rocket was definitely my preferred option and the one I’m using now. Hence the title of this blog post!

There’s a comparison of the features of these three alternatives here => Comparison of Features.

WP Rocket does much more than just caching and it requires zero setup and works right out-of-the-box. In addition there are lots of ‘fine-tuning’ options as well for those who want to squeeze even more speed out of their website. It’s very flexible and customisable and their documentation and support are excellent.

Content Delivery Networks
So you think you’ve got everything covered by using a caching plugin? Not quite. A caching plugin significantly improves the performance of your website on the server upon which it runs, but what about accessing that server from anywhere on the planet? If your server is in Hong Kong, for example, how long does it take when a user tries to access your website from, say Amsterdam?

This where a CDN or Content Delivery Network comes in. Broadly, a CDN takes your website content and places it on a number of very fast servers located at strategic internet nodes across the planet. This means that your website is very close to users anywhere in the world, making it very fast indeed for everyone, anywhere.

I chose a CDN called MaxCDN. It’s dead easy to set up and interfaces seamlessly with WP Rocket. MaxCDN’s documentation is very good indeed and their support, in my opinion, sets a gold standard for support from any software company.
( Note: MaxCDN has subsequently been taken over by StackPath).

In conclusion, after spending weeks digging into the ins and outs of improving my website’s speed I’m extremely happy with my choices. And if you think my website is still a bit slow please bear in mind that I’m still tinkering with some of the finer points of the setup …

What is 4G? Do you know?

It’s not often that I stray into the broader world of telecommunications, but I was so impressed with this article by Mark Gregory in “The Conversation” that I wanted to share it in its entirety.
For those of you who want a peek behind the ‘4G’ acronym without being sucked into a morass of technical detail, then this is the article to read.

Explainer: what is 4G?

By Mark Gregory, RMIT University

If you’re looking to buy a new smartphone or computer you’ve probably seen advertisements and offers for 4G-compatible devices. You might even own a 4G-compatible device already.

But just what is 4G? How does it compare to existing 3G networks? And what is the current availability of 4G networks in Australia?

[Read more…]