Dan and Dan,
I've read this thread with interest, and while I honestly don't have time - or the necessary access to my files, which I've stored offsite - I will try to assist (from memory, so some errors are inevitable for which I apologize in advance!) in some way with the issues you raise.
First, with reference to transcripts, there are many, many versions of the DPD radio transcripts, and probably all of them contain errors, omissions, etc., of one kind or another. For example, the Secret Service, the Dallas Police, and the FBI all made transcripts, in addition to private transcripts made by Jim Bowles, Arch Kimbrough, Dave Dix, Russ Sheerer and many others. Some of these purport to be "complete" transcripts, while even more are only partial transcripts.
Add to this the fact that there are numerous copies of the radio recordings themselves, too. Again, many of these are only partial copies which, like some of the transcripts, focus on segments of the recordings of particular interest to the author/originator. All of these recordings are many, many generations removed from the original recordings - the Channel 1 recordings were voice-activated, made in "real time" onto flimsy blue polyester dictabelts by means of a stylus cutting a continuous grove onto a blank belt, capable of holding up to 30 minutes worth of sound recordings. In order to ensure that no break in recording, the radio messages were recorded such that there was an "overlap" of about 15-20 seconds at the end of each belt and the start of the next belt. Similarly, Channel 2 (an auxiliary channel used to handle additional radio traffic generated by special events) was also a voice-activated recording, recorded onto flexible green plastic discs. On the day of the assassination, there were two dispatchers working together on Channel 1 at any one time (Officers Hulse and Jackson at the time of the assassination, if I remember correctly), while another dispatcher (Sgt. Henslee) was working Channel 2 on his own, so it is not really surprising that there are discrepancies between what was said (and when it was said) by the dispatcher on either channel.
Over time, both the channel 1 and 2 recordings were copied onto a variety of media, including reel-to-reel tapes, cassette tapes, PC diskettes, hard drives, etc. The quality of these copies varied immensely, as did the recording speeds of the devices on which they were copied. In addition, the physical location of the original recordings over the years was not always the best in terms of protecting the recordings - in envelopes in boxes, in drawers in filing cabinets, and other such places, and certainly not in ideal storage conditions in terms of temperature and humidity-controlled environments, either.
So, when we take all these factors into consideration, it is not really surprising that discrepancies will arise from one transcript to another, and from one recording to another. However, the "nearest to the original" recordings that currently exist are held in the National Archives, from whom copies can be purchased. Copies of these recordings can be purchased from NARA, but to the best of my recollection, they are quite pricey! The recordings obtainable from NARA (again, from memory) cover the time periods from around 10:00 am to 2:00 pm on Channel 1, and 11:00 am to 10:00 pm on Channel 2.
I apologize for this lengthy post, but I hope it will be of some help to you in explaining how and why some of the many discrepancies between the recordings and the transcripts could - and did - arise.
