Geocaching – 5 things you need to know

Geocaching HQ, Seattle

Geocaching is both a game and a business
 Groundspeak who manage Geocaching are a business. Groundspeak shows adverts on their website if you are not a premium member but this is minimal and restricted to a couple of small ones in your sidebar. They don’t get into big contracts to promote other people’s wares, so the money has to come from somewhere! Premium membership is their primary source for funds and about 7p a day, it isn’t a bad deal for Website in 26 languages, iPhone and Android Geocaching App, Adventure labs & Wherigo. Hours of fun for a few pence a day!

The orginal design of a Geocache

Play Fair
Don’t be a Geocaching tyrant, it’s a game played by many people most of whom you will never meet or know anything about. When Caching, it’s helpful to remember that the cache belongs to the owner, and if they say no photos of logs, signatures required, they are perfectly within their rights to delete your log if it doesn’t live up to the requirements set out in the geocaching page. If you don’t like this, then avoid that users caches, there are millions more out there. While there are rules, people’s interpretation of them may differ from your own. Rules like leaving a throw down when the cache is obviously there goes without saying, but deleting someone’s log for not signing because it’s too wet isn’t fair play IMHO.If you are a cache owner, please try to be understanding. People from all walks of life and all abilities cache, not everyone is as perfect as you might like. When submitting a new cache remember that reviewers are people, volunteers, and fit Geocaching in around their lives. Reviewers try to be objective and ensure everyone follows the same rules, but they are Cachers, like you and I, work with them to get your caches published. Check what is required before you submit a cache and make sure all the required information is on your submission, missing information is the largest cause of rejected caches. It’s not the reviewers job to do the leg work for you when you submit your new entry, if a reviewer rejects a cache and you don’t understand why, ask them.

Damp conditions at Cwmorthin

Go equipped
Having the right equipment makes for a great day of geocaching running out of battery or getting soaked is not. The primary item of course is a pen or pencil, and maybe a spare or two, there must be thousands of ‘lost’ writing implements left by Caches each week. Spare batteries or a power bank is essential for a day’s intensive caching, constantly using the GPS on your device is a heavy drain on batteries, and there’s nothing more infuriating than coming towards the end of lengthy series, only to have your phone die on you.
If you are heading up to the moors or into the mountains, appropriate footwear and waterproofs are the absolute minimum, snacks, water and a whistle should be carried as well. There are many articles on what to carry in your day bag online that can help you better than I can. Check the weather before you set out, because in the UK, it’s not unusual to have 3 seasons in one day. If venturing up a mountain or moors, it is worth noting as you gain altitude, the temperature drops surprisingly fast, around 1°C for every 100m, cold, wet and miserable isn’t a great day and possibly the quickest way to put someone off caching. If you are going into the wild and off the paths for a day hike, tell someone where you are going and when you expect to be back, it might just save your life, and don’t forget to let them know you are back at the end of the day.
Carry extra logbooks and pencils. We all know that it’s the Cache Owners’ responsibility to keep caches maintained, but sometimes life gets in the way, if you discover a cache with a full or wet log, please be kind and drop a new log in for them, don’t forget to message the cache owner and let them know what you have done. Please don’t slap a “Needs Archiving” on straight away, a simple message to the cache owner or a “Needs Maintenance” log is sufficient.

Ready for any weather

Get Social and meet other Cachers
Geocaching can be a lonely game, it is usually played in secret, and that’s half the fun. There are lots of events where Cachers gather and share stories of their adventures and great finds. There’s all sorts of social events from Cache In Trash Out which could be a litter pick or working with an environmental group to remove an invasive species from an area to a get together for a chat. It’s a great way to make new friends and catch up with old ones.

SWAG
People who cache with kids love SWAG (Stuff we all get), it makes the day more exciting searching for treasure and primes the next generation of Cachers. The golden rule about SWAG: if you take something, leave something of equal or higher value. Kids and some adults love to find treasure, and it’s so much better if they can take a new toy away and leave something behind for others. If we want to keep the sport alive and growing, it’s our responsibility to pass our enthusiasm to the next generation.
Ideas for what to put in: Small toys, Key Rings, souvenirs like woodies or path tags, Trading cards (in a waterproof seal easy bag), foreign coins, rain ponchos
Do not put in: Perishables, e.g. sweets that go horrible quickly and mess up a cache, non family friendly items, fireworks, lighters, drugs, alcohol and any illegal materials should also not be placed in a cache, although if someone is considering placing any of the above items they really need to have a word with themselves.

A well stocked Cache

Lastly it’s a game have fun and help each other, it’s not that difficult 🙂

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.

ABCDEFGHIJKLMNOPQRSTUVWXYZ
0102030405060708091011121314151617181920212223242526


























Convert letters to numbers

Replace letters with numbers from the table.

GO
TO
CLOCK
TOWER
FRIDAY
0715
2015
0312150311
2015230518
061809040125
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

GOTOCLOCKTOWERFRIDAY
0715201503121503112015230518061809040125
7242571425840953178694874399075864692217




















7957772928962456280609104817137673732342
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

Code7957772928962456280609104817137673732342
OTP7242571425840953178694874399075864692217
Add?








100100100
100






0715201503121503112015230518061809040125
Decoded message at numbers stage
0715201503121503112015230518061809040125
GOTOCLOCKTOWERFRIDAY
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. 

Introduction

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. 


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