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Glossary

Short definitions of the radio and platform terms the manual uses. Each entry links to the page that explains it in full.

Radio and APRS

APRS
Automatic Packet Reporting System: amateur radio's shared channel for positions, short messages, weather and status. Each report is a small packet carrying the sender's callsign.
APRS-IS
The APRS Internet Service: a worldwide network of servers that carries APRS packets over the internet. Anything on it may never have been on the air, so it proves nothing about where a station was (Transport is not trust).
Passcode
The number an APRS-IS client logs in with. It is derived from the callsign by a public formula, so it proves nothing about who holds the call.
IGate
Internet gateway: a station that copies packets it hears on the air to APRS-IS, and optionally the other way (IGate).
Digipeater
A station that repeats packets on the air to extend their range (Digipeater).
q-construct
A tag APRS-IS servers add to a packet's path (qAR, qAC, …) naming how and where it entered APRS-IS. Anyone with a passcode can write one, so APRScaching never treats it as proof of a hearing.
Callsign and SSID
Your licence callsign identifies you on the air. An SSID is the suffix after a dash (OE8APR-7) that tells one operator's stations apart; every SSID belongs to the same base call (Several callsigns).
AX.25
The data-link protocol amateur packet radio runs on; every APRS packet is an AX.25 frame (Connected-mode AX.25).
TNC
Terminal node controller: the modem that turns radio audio into packets and back, either a box between computer and radio or software such as Direwolf.
KISS
The simple protocol a computer uses to exchange packets with a TNC, over USB, serial, Bluetooth or TCP (Your radio in the browser).
AFSK
Audio frequency-shift keying: how 1200-baud APRS sounds on the air. The browser can decode and send it through a sound card.
CAT and CI-V
CAT (computer-aided transceiver) is the serial control a computer uses to tune a radio; CI-V is Icom's version of it (Rig control & weather).
NET/ROM, BBS and FBB
Classic packet-radio services: a NET/ROM node routes connections between stations, a BBS stores mail and bulletins, and FBB is the protocol BBSes use to forward mail to each other (Packet BBS & node).
AXUDP and AXIP
AX.25 frames carried over the internet (in UDP, or directly in IP). Useful links between nodes, but internet traffic all the same (AXUDP and AXIP peering).
Mailbox
Holds a short message for a station until the instance hears it on the air, then sends it as an APRS message from the service call. Separate from the BBS (Leave a message in the Mailbox).
MeshCom
A LoRa mesh network for licensed amateurs. APRScaching listens to a MeshCom node on the operator's network through the node's ExtUDP interface (MeshCom).
MeshCom group
A MeshCom chat channel named by a number, such as 232; * reaches every node. A group message is addressed to the group, not to a station (Read MeshCom group chat).
Meshtastic
A LoRa mesh system; APRScaching shows only nodes in licensed mode, which carry a callsign.
44Net, AMPRNet and HAMNET
44Net (AMPRNet) is amateur IPv4 space administered by ARDC: 44.0.0.0/9 and 44.128.0.0/10; <call>.ampr.org names live in it (44Net address). The internet reaches a 44Net subnet when it is announced in BGP, served through 44Net Connect or reached over the IPIP mesh; most of 44Net is not on the internet. In this manual, a 44Net address is one the internet reaches. HAMNET is an amateur IP network that is not on the internet. It is reached over RF links, and licensed hams also reach it through HAMNET VPN access (HAMNET only). European HAMNET uses addresses from 44.128.0.0/10, so no address range tells a HAMNET address from an internet-reachable 44Net one: the sysop declares which it is. Having one says nothing about the other.
LoTW
Logbook of The World, ARRL's contest and award log. Its callsign certificate can prove you hold a call (LoTW certificate).
CWOP and PWS
A PWS is a personal weather station; CWOP (Citizen Weather Observer Program) collects their readings (Weather stations).
Maidenhead locator
A grid square such as JN77pb that names a location in a few characters; hams use it in place of coordinates.

APRScaching

Instance
One running APRScaching server, run by a ham or a club for their region. Instances link up and share caches and finds; the one your account lives on is your home instance (Getting to your instance).
Home instance and remote cache
Your home instance is the one your account lives on: you sign in and log there. A remote cache comes from another instance in the network; it shows mirrored from its home, and you log it there (Getting to your instance).
Sysop
The ham who runs an instance. They set it up, link it to others, and can verify a callsign by hand or offer a cache for adoption (Instance admin at a glance).
The Shack
The launcher for the ham-radio apps — packet terminal, BBS, decoder, rig control and more (The Shack at a glance).
Find, DNF and note
A find logs that you found a cache; DNF ("did not find") logs that you looked and did not; a note is a comment without either (Log a find).
Difficulty and terrain (D/T)
Two ratings from 1 to 5, in half steps, that the hider sets: how hard the cache is to find, and how hard the place is to reach. Both add to the points a find earns (Open the cache sheet).
Stage, unlock and NFC stage
A stage is one step of a multi-stage cache. You unlock the next stage at the current one: by standing there, by following a clue, or at an NFC stage by scanning the tag or typing the code printed on it (Multi-stage caches).
Radio-verified, Location-verified and Logged (Tier A, B and C)
How strongly a find is verified. Radio-verified (A): a receiving station that isn't yours heard your APRS position on the air near the cache. Location-verified (B): your phone's location matched the cache. Logged (C): nothing independent placed you there; the find is recorded but not verified (How finds are verified).
Minimum tier
The lowest tier a cache counts as verified, shown on the cache sheet as Verification · Location-verified or better. A find below it stays on record but does not count as verified (Open the cache sheet).
Verified callsign
Proof that you control the licence you signed in with, shown as ✓ you control this call. It is separate from a find's tier, and from the register badge, which only says a licence exists (Verify your callsign).
Attested site
A receiving station the sysop vouches for: one of their own, or the ingest box a member lends the instance once the sysop trusts its hearings. Only a direct hearing at an attested site can make a find Radio-verified (Receiving site and Tier A, Lend your receiver to an instance).
Ingest box
The program on the operator's own computer that connects their radios and APRS-IS to the instance (RF ingest & transports).
Provenance
The record of how a packet reached the instance, and whether one of the instance's own receiving stations heard it directly. Only that record, never the path a packet took, counts toward verification (Transport is not trust).
Corroboration
Asking other instances whether they independently heard a finder on the air near the cache; enough agreeing instances can lift a find to Tier A (Corroboration and quorum).
Federation and peer
Federation is how instances share caches, finds and keys as signed records; a peer is another instance yours exchanges them with (Join the network).
Peer trust level
How far your instance trusts a peer: trusted shows what it publishes and counts its corroboration, unvetted mirrors it but hides it by default, blocked ignores it (Peers and trust).
Key fingerprint
A short checksum of an instance's signing key. Two sysops compare their instances' fingerprints over a channel they already trust before either one trusts the other (Joining the network).
Discovered instance
An instance your instance heard of without you adding it: a trusted peer lists it, or it announces itself on your local network. It is listed switched off and unvetted, and nothing is pulled from it until you follow it (Discovery).
Federation over FBB
An experimental way to carry federation records as packet mail, through the forwarding partners a sysop marks for it, for instances with no internet path between them. Off unless the sysop turns it on; the mail takes hours to days (Federation over FBB).
Tombstone
A signed deletion record. It travels through federation so erased data is removed everywhere and never mirrored again.
Passkey
A sign-in key stored on your device, used instead of a password. Each device holds its own, or shares one through your password manager (How a passkey keeps your account yours).
One-time sign-in link
A link that signs you in once, within 15 minutes. You get it by email, or from the sysop where the instance has no https and no email, such as on HAMNET (Getting to your instance).
Living cache
A cache that moves with an APRS station: you find it by meeting the station (Cache types).
Rendezvous
A record made when two living caches meet: within 150 m of each other inside 15 minutes. It shows on both cache pages, with the time for the cache's owner and the day for everyone else, and earns no points (Living caches).
Heritage place
A summit, park, castle or other place from an award programme or open map data, imported by the sysop so it shows as a cache. You find and log it like any other cache (Heritage places).
Adoption
Handing a cache on when its owner leaves. The sysop offers it, a player with a verified callsign asks for it, and the cache changes hands with its finds and logbook (Cache adoption).
Needs maintenance
A flag on a cache that tells the owner to check it. A finder sets it by ticking The cache needs maintenance on a log or with Report a problem: needs maintenance, and the owner's next maintenance log clears it. The last three find or did-not-find logs all being DNFs set it too, and the next find clears that (Maintain your cache).
Favourite
A heart (♡) you give a cache you like. The cache sheet shows how many players gave it one (Favourites).
Badge
An award on your profile for verified finds and hides: your first find, 10 to 500 finds, a Radio-verified find, finds of some cache types, and hidden caches. A find's tier label is a different thing (Badges).
Watchlist
The callsigns you follow. When the network hears one of them, you get an alert in the app, by push or in the email digest (Alerts and the watchlist).
Offline pack
The caches of one Maidenhead square, saved on your phone for use without a signal: up to 5000 caches, with their hints, latest logs and, where the instance offers one, the map (Offline packs).
Service call
The callsign an instance listens on for APRS and MeshCom messages: the sysop's callsign with SSID 15, such as OE8APR-15, unless the instance names another. You send it FOUND, DNF, NOTE, MAIL, NEAR or VERIFY messages, and its acks, replies and near-cache messages come from it (Log from your radio).

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