APRS on aprs.fi

Analog vs digital APRS

There is actually no such thing as “analog” APRS. The traditional APRS over AX.25 on 144.800 MHz (or 145.390 MHz in other parts of the word) is actually defined as a digital mode.

However, Anytone has a possibility in their radios choose wether to send APRS over AX.25 or as position data over the DMR channel. This settings can be found in MENU -> APRS -> Upload Type, “A -Aprs” for APRS over AX.25 or “D – Aprs” for using the DMR. In Anytone they call these modes “Analog APRS” and “Digital APRS”.

APRS over AX.25 – “analog” APRS

In this mode positions are transmitted on a simplex channel (144.800 MHz in IARU region 1) and can be received by anyone in range. The packets can be repeated by digitpeaters (WIDE1 for local “fill in” digitpeaters and WIDE2 for wide coverage digipeaters). If the packet hits a digitpeater with an I-gate it is transported into the APRS-IS system and can be seen in aprs.fi.

The traditional APRS over AX.25 packet radio has many more functions than just position reporting, such as telemetry, weather reports, messaging etc etc. If your radio is capable of receiving APRS you can also see other hams in the area (position, distance, direction etc).

APRS over DMR – “digital” APRS

In this mode, the radio uses the built in function in the DMR specfication to transmit position data. When this position data reaches the Brandmeister servers it is converted to APRS and fed into the APRS-IS system and can be seen on aprs.fi.

APRS over DMR is limited to only position data so if your goal is to just show up on aprs.fi, this can be the mode of choice for you. You miss out on all other features of APRS when using DMR or “digital” APRS.

If you look at the APRS menu on the Anytone for example, the APRS SMS function is only availible for “Analog APRS”.

APRS SMS only in
APRS SMS not availible in “Digital APRS” (over DMR)

For me, I choose the “old school” APRS over AX.25 all days in the week 🙂

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