Sequence diagram - how to realize signal that needs to be send every 10ms

iam new to uml and working on a hobby RC helicopter where i have a sender (my remote control) and a receiver(the receiver board on the Heli).

the sender needs to send a message every 10ms to the receiver to make sure that it is still in range.

if the message is not received on the receiver after 10ms, the receiver will go into stand by and will allow no other signals to be performed.
whenever the receiver get the message again from the sender, it will start again and initialize all the other devices connected to it (the motor speed will be set to 0)

now i need to draw the sequence diagram
since iam new to uml, iam not sure how to realize this.

do i need to use the loop operator to show that the message is being transfered from the sender every 10ms? or can someone do that in other ways ?
how can i say in sd that iam not receiving the signal anymore?

any help is really appreciated…
i cant find anything useful about looping and time.

Thanks in advance

Keep in mind that sequence diagrams are intended to illustrate the sequence of events from an action.

In your example, that action seems to be the heartbeat message from the sender.

Therefore, I think your sequence diagram should really be about what happens when a single heartbeat message is sent from the sender to the receiver.

From your description, the receiving end would have alternative flows depending on whether the receiver is on a stand by or ready state and act accordingly:

If you want to capture the idea of the receiver in various states given the situation of whether it received a heartbeat signal or not, perhaps a state machine or activity diagram is what you want: