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Automatic stations on the air

This page is for the sysop of an instance that transmits: an IGate, a digipeater, a node or a BBS. Such an instance is an amateur station, and you are its control operator; this page covers what applies to automatic stations and what APRScaching does to keep them within the rules.

The rules every operator follows, attended or not, are under On-air etiquette and rules. This page is not legal advice: meeting the rules at your station, on your bands, under your licence, is your responsibility as control operator.

Automatic & unattended operation

A digipeater, an IGate, a NET/ROM node (whichever command style it presents: NET/ROM, FlexNet, TNN or BayCom), a BBS, a store-and-forward mail path and any automatic federation-over-RF relay are automatically controlled stations. National rules restrict where and how these run: permitted band segments, power, occupied bandwidth, and a control operator who can be reached. APRScaching's part:

  • Automatic transmit (digipeat, beacon, forward, relay) is opt-in per port, never implicit.
  • Every RF transmit port of the ingest box (a KISS TNC, a soundcard port) transmits only under calls the gateway confirms for that box: control-verified, and held by the box's operator.
  • A port that keys the radio itself, the soundcard port, caps its airtime (SOUNDCARD_DUTY_PCT, 20 % of any minute by default), and a watchdog releases its PTT after SOUNDCARD_PTT_MAX_MS (10 s by default). Keep the radio's own transmit time-out on as well: it is the only release when the box is killed outright.
  • Every unattended transmit path is paced by a token bucket with a hard ceiling (Transmit pacing).
  • The digipeater drops a duplicate frame for 30 s, and DIGI_VISCOUS_MS holds a repeat back so a better-placed digipeater goes first. There is no airtime duty-cycle setting.
  • The federation-over-RF carriers choose only the record encoding and batch size for a link, never a band, segment or power level (Federation wire format).

Transmit pacing

Each unattended path draws from its own token bucket: burst transmits at once, then one more every refill seconds. Separate buckets keep a busy path (IGate traffic) from starving another (an answer to a radio command). You can tighten any bucket. A looser value is clamped to the ceiling with a warning at startup, so a typo never turns an unattended station into a channel hog.

Path Unit Settings Default Ceiling
Remote box (beacons, messages, answers) frame BOX_TX_BURST, BOX_TX_REFILL_SEC 3, then 1 per 60 s 10, then 1 per 6 s
MeshCom sends message MESHCOM_TX_BURST, MESHCOM_TX_REFILL_SEC 3, then 1 per 60 s 10, then 1 per 6 s
TX-IGate (APRS-IS to RF) message IGATE_TX_BURST, IGATE_TX_REFILL_SEC 6, then 1 per 10 s 10, then 1 per 6 s
FBB forwarding session BBS_FORWARD_BURST, BBS_FORWARD_REFILL_SEC 4, then 1 per 300 s 10, then 1 per 60 s

A refused transmit is always logged:

  • a refused remote-box command fails with the wait time;
  • a refused IGate message is not gated, and the sender's own retry carries it once a token is back;
  • a refused FBB session waits for the next scheduler poll.

Forwarding is paced per session, never per frame: throttling frames inside an open AX.25 link would stall it into retries.

What the station puts on the air

  • Identification. Every APRS and AX.25 frame the station sends carries its source callsign. The NET/ROM node identifies through its NODES broadcast, every NETROM_BROADCAST_MS (default one hour, at least 5 minutes). The digipeater and the IGate have no separate identification timer: they transmit only when relaying, under the station's callsign. Check that this meets your national identification rule.
  • Third-party traffic. A message the instance sends for a user puts the licensed user's callsign as the on-air source (}USERCALL>APZACG,…), with your station as the sender. When you forward other operators' BBS mail, or carry federation records that started at their stations, you remain responsible for your country's third-party rules and any international agreements.
  • No ciphertext. An RF binding never carries ciphertext. A field withheld for privacy, such as a cache owner's details under its federation scope, is dropped before it reaches the air, never encrypted onto it.
  • No secrets. The ingest secret, the session key, per-operator peer keys and the push (VAPID) keys authenticate on the internet side only. No radio path carries credential material.

Bandwidth, band plans and high-speed modes

APRScaching runs over whatever modem your TNC provides: typically 1200-baud AFSK or 9600-baud G3RUH on VHF/UHF, and 300 baud on HF. It also runs over the ingest box's and the browser's own 1200-baud soundcard AFSK, and over IP links (HAMNET microwave, and AXIP/AXUDP on the internet side). Symbol-rate, occupied-bandwidth and band-segment rules for these differ widely by country and band. You decide which ports and bands are enabled; the platform adapts its encoding to the link you turn on, but it does not choose the RF parameters for you.

44Net (AMPRNet) and HAMNET

44Net is amateur IP address space reachable from the internet, through 44Net Connect or BGP. HAMNET is an amateur IP network reached over RF links, and by licensed hams through HAMNET VPN access. They are separate networks, and the rules follow the path the traffic takes:

  • HAMNET traffic crosses amateur RF, so it is amateur radio: no content encryption, and callsign identification and control-operator rules apply, as on a 1200-baud packet channel. Where a HAMNET segment has a gateway to the internet, the amateur-service boundary sits at that gateway. You are responsible for what crosses it in each direction.
  • 44Net traffic between internet hosts, such as two 44Net Connect addresses, travels over the internet, not over amateur RF; ARDC's terms for the address still apply. Where it continues onto an RF link of yours, that leg is amateur radio, with the same rules.

What APRScaching enforces, and what stays yours

APRScaching provides You own
Signs, never encrypts; confidentiality degrades to field-drop Confirming that satisfies your regulator
Transmit off by default, gated on control-verification Being the reachable, responsible control operator
Per-port opt-in for automatic TX; token-bucket pacing on unattended TX, with a ceiling Choosing enabled bands, ports, power and segments; tightening the pacing to any duty-cycle limit your rules set
Callsign in every frame; NODES broadcast interval (NETROM_BROADCAST_MS, default 3600000 ms) Meeting your national ID rule
Third-party encapsulation preserving the originating callsign Meeting third-party and international-traffic rules
Recognition-only donations; no commercial payloads Keeping your on-air content non-commercial

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