Geocaching and locks

With Geocachers looking for ever more ways to make their caches challenging and individual, having a lock to open without a key is gaining popularity. This isn’t without controversy, even owning a set of Lock picking tools in some countries is illegal, however, in most countries this isn’t the case. ‘Lock-picking’ has an image problem in the general public’s mind, which is largely unfounded. Before we start, a large caveat, if it can be shown that the tools in your possession are intended for illegal purposes, then expect the full weight of the law. Being able to demonstrate permission to open a lock is everything here. All caches of this type should have the fact that “there is a lock to defeat (Pick, bump etc)” stated very clearly in the Geocache description, or else the act of opening it would stray into the grey area as to the legality of opening the lock (see lock sport rules at the end of this piece). There’s far more legal complexity that I can cover in this short article and.. I’m not a lawyer.

Given that defeating locks is a life skill that few of us possess, there is a hobby called Locksport where you can learn. Locksport is based around defeating locking system using a variety of skills traditionally known to a small group of people in the associated professions. Locksport has its roots in the broader field of lock defeating or picking, a skill that has been practiced since the very first lock was made. However, the organised and recreational aspect of lock picking, known as locksport, did not appear until the latter part of the 20th century.
The origins of locksport can be traced back to the hacker and computer security communities who regarded any closed system as a challenge. As computer enthusiasts explored the digital realm, many found a parallel interest in physical security, including the mechanisms that safeguarded valuable information. Lock picking became a hands-on extension of the broader ethos of exploring and understanding systems.

In the 1990s, groups like the MIT Lockpicking Club and the Open Organisation of Lockpickers (TOOOL) started formalising and popularising the recreational side of lock picking. TOOOL, an organisation from the Netherlands founded by Barry Wels and Deviant Ollam in 2002, played a significant role in promoting locksport globally. The organisation aimed to advance the public’s understanding of locks and security through educational initiatives, training, and organised events, constantly working with the public and manufacturers to highlight lock vulnerabilities.

Locksport events, often referred to as “lockpicking villages,” became a staple at hacker conferences and conventions. These gatherings provided a platform for enthusiasts to share knowledge, exchange techniques, and engage in friendly competitions. The focus was on education, ethical behaviour, and responsible use of lock-picking skills.
Locksport has evolved into a diverse and inclusive community that welcomes individuals with varied backgrounds, from hackers and security professionals to hobbyists and locksmiths. The emphasis remains on education, skill development, and fostering a sense of responsibility in using lock-picking knowledge.
In the past two decades, the popularity of locksport has grown, with local groups forming both offline and online, bringing together like-minded individuals who share a passion for this unique skill. The community continues to promote a positive and ethical approach to lock picking, emphasising the importance of understanding security systems to enhance overall safety and awareness.

To keep lock-picking skill away from those who would abuse it, members of locksport groups have zero tolerance for illegal or immoral lock picking, bypass, or other forms of entry.

Locksporters abide by the following rules, with no exceptions:

  • Locksporters may open only locks that belong to them. For other locks, they need express consent of the owner.
  • Locksporters may not open a lock that is in use.
  • Permanently removing (or relocating) the lock may be done only when lawfully and specifically sanctioned by an appropriate authority.
  • A lock which has been effectively abandoned by its owner and placed in a public place without securing anything (i.e., not “in use”, such as a lock placed on a “lovewall”) may ethically be picked by any locksporter, provided the lock is returned to its original locked position and state.
  • The security needs of others must be preserved.
  • All activities take place within boundaries of respectability, integrity and professionalism.

Ulefone Power Armor X11 Pro Rugged Smartphone: The Ultimate Outdoor Companion

If you’re an outdoor enthusiast, you know the importance of having a reliable and rugged smartphone by your side. The Ulefone Power Armor X11 Pro Rugged Smartphone is designed specifically with durability and versatility in mind, making it the perfect choice for anyone who loves to spend time in the great outdoors.

Phone in bright sunlight

One of the standout features of the Ulefone Power Armor X11 Pro is its ruggedness. It’s built to withstand even the toughest conditions, with an IP68 rating for water and dust resistance. This means that it can be submerged in water up to 1.5 meters deep for up to 30 minutes without any damage. It’s also shockproof, able to withstand drops from up to 1.5 meters without any damage.

In addition to its rugged design, the Ulefone Power Armor X11 Pro is packed with features that make it perfect for outdoor activities. It has a large 5.5 inch HD display that’s perfect for viewing maps and other information, even in bright sunlight. It also has a powerful 8-core processor and 4GB of RAM, making it capable of handling even the most demanding apps and games.

Quick to obtain GPS lock and accurate

But where the Ulefone Power Armor X11 Pro really shines is in its GPS capabilities. It’s equipped with high-precision GPS, GLONASS, and BeiDou navigation systems, allowing you to track your location and movements with incredible accuracy. This is especially useful for activities like geocaching, where it’s important to get a quick lock onto your exact location and give exact readings to that elusive cache.

The Ulefone Power Armor X11 Pro also has a range of other features that make it perfect for outdoor adventures. It has a long-lasting 8150mAh battery, so you don’t have to worry about running out of power when you’re out in the wilderness, I got a day of heavy GPS usage without having to recharge the phone and never ran out of battery. It also has a 16MP rear camera and a 5MP front camera, allowing you to capture stunning photos and videos of your adventures.

Excellent camera

Overall, the Ulefone Power Armor X11 Pro is an excellent choice for anyone who loves spending time outdoors. Its rugged design, powerful specs, and advanced GPS capabilities make it a fantastic outdoor companion. Whether you’re hiking through the mountains or exploring the wilderness in search of that cache, the Ulefone Power Armor X11 Pro has you covered. The phone is priced at £155 but as can be found for less.

Our GPS history and why we still use them along with our phones

We have been using a GPS since we started Geocaching way back in 2010. Our first GPS was the eTrex 10 with no maps, we just ‘followed the arrow’, it did however support downloading Geocaching GPX files via USB which made it ideal for Geocaching. A testament to the eTrex’s toughness and simple design is that this model, although revised is still available today. It was bomb proof had no touch screen just a thumb-operated joystick, monochrome display and a pointer to where the destination was, and how far away it was. The eTrex has exceptional battery life but was slow to get a signal and its accuracy was truly hit or miss under tree canopies. This little unit spawned many adventures for us.

Garmin eTrex 10 Patche99z, CC BY-SA 3.0, via Wikimedia Commons

After a few years of finding ourselves on the wrong side of a river or having to make a long hike due to a dual carriageway or some other obstacle blocking our progress we decided on the Oregon 450T which had Ordnance Survey maps 1:50 k. This was a revelation and for the first time allowed us to see a map which allowed us to plot a route unhindered by obstructions. The Oregon 450t had a touch screen, a SD card slot for maps and extra data, an electronic compass, a barometric altimeter and could store thousands of Geocaches. We got about 6 years of use and abuse out of these units. Maintenance, mainly due to rough handling, resulted in screens being replaced, buttons fixed and other sundry parts replaced until they both were beyond repair. I recycled parts from both and with some bits off a Russian GPS breaker on eBay, a ‘Frankenstein’ Oregon 550 GPS was created, this had all the same features as the 450T it now sported a 3.2 megapixel geotagging camera. Although this unit has now slightly out of date OS maps it is still fully functional and in constant use to this day.

By Garmin -, CC BY-SA 3.0,
Garmin 450T By Garmin –, CC BY-SA 3.0,

I personally own a Garmin GPSMAP 64s now, I never liked the touchscreen which with my big hands didn’t work so well for me, I love the buttons and simple menu system. The unit has a good sized display that can be read in bright sunlight which was always a problem with the older models and mobile phones. The reception is great even under trees, and the unit is quick to get a GPS lock. The 64s uses GPS + GLONASS + WAAS although not Galileo. I also 3D printed a simple mod that allows rechargeable batteries to be used and charged in the unit whilst connected to USB. Bluetooth is available and in reality only useful for transferring Geocaches to another compatible unit, it’s a battery killing extra I don’t need and is designed for external sensors like heart rate, therefore remains switched off.

Garmin GSMAP 64S By Virgilinojuca – Own work, CC BY-SA 4.0

So why do we still use this old tech? We get at least a couple of days battery life out of both the 550 and 64s which is a lot more than our mobile phones. If the battery runs out we just pop in another couple of AA batteries and off we go. They survive rough treatment much better than mobile phones. Detailed maps can be downloaded from sites like Open Street Maps and preloaded on SD Cards, these are always available even when there is no phone signal, this is also great for caching abroad where maps can be preloaded. They accurately track our route which can be examined in Garmin’s Basecamp software when we get home. I’m not saying GPS units are more useful than mobiles, but a phone with apps like Geocaching, C:geo, Looking 4 Cache is a perfect compliment to a GPS.

Numbers Stations, secrets hiding in plain sight

In the mid-late 20th century, before digital technologies, the radio was the easiest way to communicate over very long distances. The shortwave frequencies were crammed with pop stations, political propaganda and ham radio users. Jammed in between these transmissions, there were occasional unexplained broadcasts, some obvious analog data transmission and other unexplainable stations. Some of these broadcasts consisted of just a series of figures being read out in a mechanical voice, these often started with a short jingle beforehand to identify the station. Officially, no one knew what they were for, governments vehemently denied their existence, however, just about everybody knew these were spy communications. These mysterious transmissions were nicknamed numbers stations because of their transmissions consisting of apparently nothing else but sequences of numbers, and for want of a better name it stuck. I can vividly remember as a boy discovering these stations and being both puzzled and excited as I tried to decode them.

Antenna “G1” at Hörby Shortwave Station, near Hörby in the south of Sweden

Numbers stations were mysterious and suggested top secret agents, clandestine meetings, this was at the height of the cold war where the eastern bloc was the enemy from an unknown land and nuclear war was an ever present threat. They had names like the Linconshire Poacher, Cherry Ripe & The Russian man. It’s now certain these were transmitting codes using what’s called a One Way Voice Link (OWL) that required no response from the listener, apart from being tuned into a radio frequency at a given time along with their code book to decrypt the incoming message. The code was decrypted using One Time Pad (OTP), which at the time was considered completely unbreakable without the corresponding code book. The OTP was so called because the decoding sheet usually tiny was used just once then disposed of, each sheet had a random set of numbers which was used to decode the incoming message. There are 5 factors in using a OTP

The key must be as random as possible.
The key must be at least as long as the plaintext so it never repeats.
The key must never be reused even reusing part of the code would compromise the message.
The key must be a secret between the sender and receiver.
The key must be destroyed after use.

Using a one time pad

Every letter of the alphabet has its own number equivalent.


Convert letters to numbers

Replace letters with numbers from the table.

Replace letters with numbers

Now add the Numbers from the pad to our replacement numbers, if more than 100 use the last two digits only, then divide into groups of 5 and transmit


Encode using sender OTP

Our message becomes
79577 72928 96245 62806 09104 81713 76737 32342

To decode the message, the recipient uses the same page from his own one-time pad. Numbers are broken into pairs once again and subtracted, we will have to add 100 I the product of the 2 numbers is less than 0



Decoded message at numbers stage
Reconvert into the alphabet

Some OTP used X for spaces and punctuation and added an XX at the end of the code with padding letters after to make the code up to the required 5 letter blocks.

Copyright Mark Pitcher
Russian Shortwave Volna-K radio set

OTP is still in use today as a medium to send encoded messages that require little equipment to decrypt once received. Even using brute force methods on super computers isn’t thought to be able to crack the code and is as secure as when it was devised in 1882 by Frank Miller, although Quantum Computing will change this when they become large enough.

Times have changed, with the opening up of the eastern bloc, greater knowledge of these places due to travel most of the mystery has gone. Now the internet is currently used for most of our day to day communications these transmissions are laborious and largely redundant, although a few number stations still exist because of their simplicity to operate in remote parts of the world.

GPS Systems

GPS is now a part of everyday life, the ability to know exactly where you are on the planet was the dream of every navigator for millennia, now this is available at the press of a button. GPS is widely used in a variety of technologies such as mobile phones apps, cars navigation for both mapping and incident reporting, wildlife tracking which has yielded some interesting results for migratory birds and mammals and preventing crime by tracking desirable objects. This tech has only been available to the public since the year 2000 and has since become the most popular method of accurately establishing a location within metres. 


A short history of GPS Systems

The first publicly available Global Navigation Satellite Systems (GNSS) was the USA’s Navstar GPS satellite constellation. This was a satellite-based radio navigation system owned by the United States government established in 1978 for the USA military and made public in the year 2000 by the Clinton administration. America’s newest GPS system is now just one of many that provide geolocation and time information to a GPS receiver anywhere on Earth where there is an unobstructed line of sight to four or more GPS satellites. Other GPS systems include Russia’s GLONASS, the European Union’s Galileo, and China’s Beidou Navigation Satellite System which offer varying degrees of accuracy, the Galileo system being the most accurate at less than 1 metre for public use and up to 20 cm accuracy for paying customers in 2021.

NAVSTAR Global Positioning System satellite
Artist’s concept of a NAVSTAR Global Positioning System satellite, a space-based radio navigation network.

How does a GPS work?

GPS systems use sets of dedicated satellites, called constellations, these are not stationary but are circling the earth so ‘rise and set’ twice a day, the satellites constantly send out signals, the GPS receiver listens for these signals they don’t transmit anything back to satellites. To determine the location of the GPS satellites two types of data are required by the GPS receiver: the almanac and the ephemeris. The almanac contains information about the status of the satellites and approximate orbital information allowing the receiver to see which satellites should be visible. After establishing what satellites should be available for you to get a fix, your GPS receiver requires additional data transmitted by each satellite, called the ephemeris, this data gives very precise information about the orbit and location of each individual satellite. The GPS receiver uses the ephemeris data to calculate the location of a satellite within a couple of metres and then by using the information that was transmitted to the GPS, your position can be calculated by triangulation using the delta in time signal transmitted and when it was received plus the location of the satellites. The ephemeris is updated every 2 hours and is usually valid for 4 hours, so If your GPS receiver has been off for a while, it may take up to several minutes to receive the ephemeris data from each satellite, before it can get a fix, this is known as a cold start. Obstacles such as mountains and buildings block the relatively weak GPS signals, this will ‘lengthen’ and therefore distort the time to receive the data or even give a false location. On a Mobile phone, there is an additional A-GPS mode which uses the cell towers to calculate the initial position of the user very quickly but with less accuracy, unlike pure GPS this may send information back to a server where that might be helpful to process position. Once the receiver calculates its distance from four or more GPS satellites, it can figure out where you are to approximately a 7.8-metre accuracy and depending on the system in use the accuracy might increase. Using GPS for locating a point of the earth is a key component for Geocachers in their quest to find caches, hence the saying follow the arrow.

Photo: ©GSA, ©European GNSS Agency
One of the Galileo Satellite Constellation

Tips and tricks
1 Having obstructions between the GPS and satellites causes issues where 3 – 4 satellites cannot be seen simultaneously, this is most often seen in cities and forests where accuracy quickly degrades.

2 Multi-path or Signal reflection occurs when the GPS signal is reflected off buildings or other objects, this can delay the time-clock signal sent out by satellite and cause a miscalculation again resulting in degradation of accuracy.

3 In the Northern Hemisphere Face the internal Antenna toward open Southern, SW, SE, in the Southern Hemisphere revers this, most of the satellites are clustered around the equator, this will make getting a fix and maintaining on easier.

4 Low batteries invariably cause issues with GPS systems, make sure that your batteries aren’t on their last legs.

5 When you switch on GPS after moving more than 25 miles or replacing batteries keep it in one position in the open air to allow the ephemeris data to update, it will get a fix far quicker than moving with it.

6 Keep firmware up to date, if there are any bugs in your GPS program an update will fix the issues. If there are more up-to-date base maps in GPS standalone system, an update will repair that, too. 

7 GPS systems are not infallible so use common sense and your Mk 1 eyeball to check what you are being told by the system matches reality, learn to read a map and research where you are going. Most Geocachers will have stories of reaching a river or cliff face and being just meters from a cache that could not be reached without retracing their steps and trying another path. 

Blue Switch Day

Global Positioning System (GPS) when first developed was only available to the US military. Later civilians were allowed access with Selective Availability (SA) but the GPS signal accuracy was greatly reduced.

May 2nd 2000, on the instructions of President Bill Clinton, the US government turned off its Selective Availability. By “flipping the switch” everyone had access to high accuracy GPS signal. Twenty-four satellites around the globe processed their new orders, and instantly the accuracy of GPS technology improved tenfold. Tens of thousands of GPS receivers around the world had an instant upgrade. Even though there was not a blue switch, for some unknown reason, geocachers refer to this day as Blue Switch Day.

With the availability of accurate GPS signal the world changed forever with the introduction of new technologies that today we take for granted. Gone are the days of the road atlas!

May 3rd 2000 saw the first geocache hidden by Dave Ulmer in Oregon and the beginning of the game that we know today.

2017 Souvenir

In celebration of this Blue Switch Day geocaching first introduced a souvenir in 2017. To obtain your Blue Switch Day 2021 souvenir simply find either a geocache, an Adventure Lab or attend an event anytime between May 2nd to December 31st.

Doogee S88 Pro

After years of quite breaking fragile phones whilst Geocaching, when it was time to renew my ageing iPhone I took a look at the market place. One other thing that had bugged me over the years is having to charge a phone daily and if GPS is used heavily having to cart a powerpack to top up the battery, I’m operating system agnostic so wasn’t too bothered the Android iOs ‘wars’. There was one phone brand that leapt out at me which was Doogee’ a Chinese phone brand that is focused on rugged designs. Doogee is part of KVD International Group Limited headquartered in Shenzhen, China, since 2013, which is a long time in the small player mobile-phone world. The phone has a military hardware styling and claims to meet military standards for ruggedness which I don’t doubt. The 10000mAh battery lasts about a week between charges and with heavy GPS use about 3 days and as a bonus can reverse wireless charge other phones to share the power. For positioning, it can utilise GPS, GPS-A, GLONASS & BeiDou and lock times are impressive, with surprising accuracy. It’s tough, heavy and reliable, but it’s not all roses, being a Chinese phone there’s little or no support if anything goes wrong so my tip is to buy off Amazon and use a credit card to have even any hope of warranty.

Update: The SIM card holder broke on the third time inserting. Despite repeated attempts to contact Doodee support, I got no reply. Amazon stepped in and refunded my money, it’s a shame that what was a promising phone was let down by non-existent support and a £2 sim holder .

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My verdict
On paper, the S88 Pro is astounding value. Plenty of CPU power, long battery life and fully-featured GPS, bulletproof construction but it is too big to fit in a normal-sized pocket and very heavy. Not my daily driver but, for long Geocaching adventures, it’s ideal.


Android 10

CPU: MTK6771T Helio P70 Octa Core up to 2.0GHz

GPU: ARM Mali-G72


Storage: 128GB

Screen size: 6.3-inch

Resolution: 2340 x 1080

Weight: 372g

Dimensions: 171.6 x 85.5 x 18.7mm

Rear camera: SONY IMX230 21.4 MP + 8 MP + 8 MP

Front camera: Samsung S5K3 16 MP

OS: Android 10

Battery: 10000mAh

Available from Amazon Doogee S88pro