OSINT people don't
know when an attack will happen or even if one will happen. What we can do is look for clues, perhaps I should've been more clear in my message, I'm not telling you that if these things happen it means nukes are going to fly. I shouldn't have used the wording
"there are ways of telling whether nukes are about to fly", instead I should've said "gauge the possibility that serious events are happening behind the scenes, whether a false alarm is happening or a realistic drill is going on or something serious" (although drills are usually announced to minimise the likelihood of Able Archer incidents happening). However I stand by wording of the rest of that statement.
A lot of the time in OSINT we don't have a clear picture of what's going on, instead we piece together evidence and come up with likely scenarios. Now, if you pieced together signs and signals that you've been gathering with inside information (rare but valuable when verified), global tensions at that time, recent sabre rattling then you can have a good guess as to what's happening.
Now, referring to your individual points about my statement:
1 - If you're going to start important military campaigns, you know that the enemy has been listening to your encrypted stuff for a while now, and its possible that they may have broken your code. It is therefore logical to change your frequencies and encryption to something completely different to make it harder for the enemy to know what you're saying.
It is documented from the Warsaw pact's Operation RYaN, I refer you to the following declassified Soviet document pertaining to Operation RYaN: " Committee for State Security (KGB), 'Indicators to Recognize Adversarial Preparations for a Surprise Nuclear Missile Attack'," November 26, 1984, History and Public Policy Program Digital Archive, BStU, MfS, HA II, Nr. 11792, S. 25-38. Translated by Bernd Schaefer.
https://digitalarchive.wilsoncenter.org/document/119338 "
I refer you to the following points:
2.1. Significant modifications in operation of military communication networks of the United States and NATO (putting reserve channels into operation; launch of the mode “Minimize”).
2.1.5 Restriction of work with means of communication and introduction of “Minimize” mode in national communication networks and in NATO communication networks
2.4.1. Change of secret codes and ciphers of government and military institutions, in NATO staff, and in the armed forces; introduction of additional measures to protect communication lines from eavesdropping.
2 - See following points in linked document:
1.2.7. Rushed preparations and departure of nuclear missile submarines from rearward bases and into forward deployment areas (in this context: working intensity increases concerning these aspects, daily routines are changing, and security gets tightened).
1.3.10. Start of nuclear ballistic missile submarines from their base Holy Loch in Great Britain – 2 to 3 nuclear submarines with ballistic missiles.
1.3.15. Preparation of warships for going to sea
3 - Operation RYAN doesn't discuss troop movements as it focused on indicators of nuclear warhead use, but if you're going to war its generally advisable to have your troops lined up on the enemy's border ready to go.
4 - I refer you to the following points in the linked document:
2. Uncovering the implementation of mobilization measures to secure operations of the US leadership under conditions of a nuclear war.
2.2. Evacuation of people close to the highest political leadership of the United States from areas of increased risk on US territory and in foreign countries.
4.3. Relocation of the highest political leadership and leading people from government institutions of the NATO states to protected command centers to continue government.
For more, I refer you to the points under section
Special indicators of immediate preparations for a nuclear missile attack in the political area:
1.1.3, 1.1.4, 1.1.5, 1.1.7, 1.2.1. There are more points on this subject, but you can sift through RYAN documents and find them if you want.
Please bear in mind Operation RYaN was made by the Soviet Union to predict when/if the US was going to initiate a first strike. Now, some of the assumptions made for a first-strike scenario don't ring true for a retaliatory strike, but a lot do. Mainly the ones I've listed.