AIS: USB dongle or via integrated VHF radio?

[CapnKernel]

If you're like me and you're trying to save every dollar, a $30 RTL-SDR and some faffing around with software will pick up AIS:

 https://www.rtl-sdr.com/rtl-sdr-tutorial...-tracking/
 https://www.rtl-sdr.com/buy-rtl-sdr-dvb-t-dongles/
 
That comes with a telescopic antenna, and will receive AIS within about 5-10nm.

Another option for a few more $ is dAISy:

 https://shop.wegmatt.com/
 https://www.tindie.com/stores/astuder/
 https://pocketmariner.com/daisy-gives-bo...is-answer/

AIS integrated into your boat's VHF receiver sounds nice, especially if it will also double as an AIS transmitter.  But this is of course going to cost more, and AIS transmission is only useful if the "heavy" you hope won't run you over has someone at the helm taking notice.  It's not something I'd ever assume.  AIS transmit is also useful if you want your friends to know where you are, but the OnCourse app is also good for this, assuming you have mobile coverage where you're sailing:

 https://help.marinetraffic.com/hc/en-us/...h-OnCourse

I have an RTL-SDR and I've received AIS with it, but I haven't yet run OpenCPN and integrated it.  It's on my long TODO list :-)