From 81447ed49ffab88be2932c1db30a8538b54f69dd Mon Sep 17 00:00:00 2001 From: wb2osz Date: Fri, 1 Jan 2021 21:12:07 -0500 Subject: [PATCH] Comments about units. --- src/decode_aprs.h | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/src/decode_aprs.h b/src/decode_aprs.h index cdbb167..7ff3e87 100644 --- a/src/decode_aprs.h +++ b/src/decode_aprs.h @@ -80,6 +80,8 @@ typedef struct decode_aprs_s { char g_message_number[8]; /* Message number. Should be 1 - 5 characters if used. */ float g_speed_mph; /* Speed in MPH. */ + /* The APRS transmission uses knots so watch out for */ + /* conversions when sending and receiving APRS packets. */ float g_course; /* 0 = North, 90 = East, etc. */ @@ -94,6 +96,9 @@ typedef struct decode_aprs_s { float g_range; /* Precomputed radio range in miles. */ float g_altitude_ft; /* Feet above median sea level. */ + /* I used feet here because the APRS specification */ + /* has units of feet for alititude. Meters would be */ + /* more natural to the other 96% of the world. */ char g_mfr[80]; /* Manufacturer or application. */