Hey there Lobster79,
Thanks for reaching out to Apple Support Communities. We understand you’re hearing a siren type noise and calls are dropping on your iPhone. We’ll be happy to help with this.
To verify, does this issue occur with every call? If not, that may help us understand what’s causing this so we can resolve the issue.
If restarting doesn’t permanently resolve the issue, see if this occurs when you use headphones or the loud speaker. Make sure your iPhone is up to date:
Update your iPhone, iPad, or iPod touch
Then go through the steps here and see if they help at all:
If you can’t make or receive calls on your iPhone
Disconnect any Bluetooth accessories or other devices you may have connected to your iPhone.
If these steps don’t help, let us know if this happens with every call and if it doesn’t, see if you can identify a common factor when this occurs and we’ll go from there.
Take care.