Notify user of DUPE so they can send B4

[w7sst]

Summary

During a simulation, duplicate DX stations may occur. When this occurs, it would be nice if MRCE would display "DUPE" in the status area. This gives the user a chance to send "B4" using the F6 key. The sending station will then quietly go away.

Motivation

This will add realism to the simulation by providing feedback to the user whenever a duplicate QSO is about to occur.

Detailed Description

Additional context

• explore whether the status pane should be displayed all the time (it also displays errors).

Tasks

• Design
• Codimg

[w7sst]

Developer Notes

• add TDictionay to Log.pas
• save all entered callsigns into this dictionary
• after user enters callsign, check dictionary for duplicate entry

[w7sst]

This could be related to #274.