[Discuss-gnuradio] Signal Source - frequency control

[Gavin Jacobs]

I am building an application to send an APRS message. I have GRC 3.7.9.2 running on Windows 10, with a Hackrf as the radio. I have a kluge to transform the bits into an audio signal at 2200 Hz for a 0, and 1200 Hz for a 1. See the attached. But, on the Signal Source block, on the left hand side, is a grey attachment point that appears to be an input. If I hover the mouse over that, it says 'freq', but every time I attach something, it will attach but is always flagged in red (error). So, is there a way to attach a signal there and vary the frequency using the output of another block? i.e. instead of using Probe signal and Probe Function, just attach the output of the "Add Const" block to the input of the Signal Source block?

Thanks,

Gavin

aprs.grc.png
Description: aprs.grc.png