I'm assuming Day is going by his watch, if so we have some kind of synchronisation between "real" time and "tape" time.
Obviously there are issues with the accuracy of Day's timekeeping and the dispatcher clocks but it's a start.
I would agree if it wasn't for this from Bowles, the DPD radio dispatcher's chief;
There is no way to connect "police time" with "real time." The Committee Report stated that the Dallas Police Communications system was recorded by continuously operating recorders. That statement is incorrect. Channel 1 was recorded on a Dictaphone A2TC, Model 5, belt or loop recorder. Channel 2 was recorded on a Gray "Audograph" flat disk recorder. Both were duplex units with one recording and one on standby for when the other unit contained a full recording. Both units were sound activated. It is important to note "sound" rather than "voice" because either sound or noise from any source, received through the transmission line, would activate the recorders. Once activated, the recorders remained "on" for the duration of the activating sound plus 4 seconds. The four second delay permitted brief pauses or answers to questions without the relay mechanism being overworked. On occasion, the recorders would operate almost continuously because rapid radio traffic kept them operating. On November 22, 1963, the Channel 1 recorders became, for practical purposes, continuous recorders for just over five minutes starting at approximately 12:29 pm (Channel 1 time) because the microphone on a police motorcycle stuck in the "on" position. The resulting continuous transmission kept the Channel 1 recorders operating for just over five minutes thus giving us a real-time recording for that period. The only problem was determining a basis for an accurate time reference during that period.
“There is no way to connect "police time" with "real time."Bowles is referring to the dispatcher set-up when he is making this statement but I don't agree with it as some kind of fundamental pronouncement.
A thought experiment - imagine an officer was stood next to a reliable time source (let's say the Hertz clock on top of the TSBD). The dispatcher asks the officer what time the Hertz clock says and compares it to his own clock. In this way "real" time and "police" time have been connected.
Can this thought experiment be reproduced in reality?
The answer is "Yes".
The above picture is taken seconds after the assassination. The Hertz clock can be clearly seen showing 12:30.
When we look at the DPD tape transcripts we see that the very first call after the 12:30 timestamp is Chief Curry stating:
“Go to the hospital - Parkland Hospital. Have them stand by.”This is clearly a reference to the assassination.
So, here we have an example of "real" time being connected to "police" time. Maybe not to the second but certainly to the minute.
"Real" time (the Hertz clock) says the assassination occurred at 12:30pm.
"Police" time (the tapes) says the assassination occurred at 12:30pm
This could be a coincidence.
Also, just because both "times" seem connected at 12:30pm doesn't mean they can't be 6 minutes out 40 minutes later.
And who's to say the Hertz clock represents "real" time.
The example I gave in my previous post about Day arriving at 1:12pm and Sawyer's call between 1:11 and 1:12pm appears to another coincidence at first glance but actually suggests there is a slight discrepency between the two "times".
There is also motorcycle cop E. D. Brewer. Between 12:37 and 12:38pm "tape" time Brewer is dealing with a witness on the west side of the underpass. He is told to get to the TSBD and rides the wrong way up Elm Street to get there.
The Murray pic below shows 12:39pm on the Hertz clock:
A closer inspection of the pic reveals Brewer riding the wrong way up Elm:
Once again, this demonstrates a very close synchronisation between "real" time and "police" time.