I am able to send messages from RF to SMS, but I can’t seem to receive messages. Why?
In order for messages to get from the SMS gateway to your RF station, you need to have a local bi-direction iGate. If you want to learn more about how messages move from the Internet into the RF space, there’s an excellent write-up here:
http://aprsisce.wikidot.com/doc:aprs-messaging-explained
In helping users troubleshoot this over the years, I have discovered that the most common issues are:
- The user has not enabled beacons on their APRS client. If the iGate hasn’t heard your (messages don’t seem to matter), it won’t gate your messages to RF.
- Unfortunately, many iGates are receive only. These iGates will gate messages from RF to the Internet, but not the other way around.
- The messages do get gated to RF, but fail to reach the intended target because the iGate is using too short a path to reach it.
- The messages do get gated to RF, but the iGate lacks the power to reach the intended target or a local digipeater.
- The messages do get gated to RF, but high APRS traffic in the area causes collisions, corrupting the packet.
- Incorrect tuning of radio with a software client using AFSK (volume too high or too low on radio ma prevent the AFSK software from demodulating the message)