Bart Sibrel's "Talk"

[ka9q]

If you listen very carefully you can make out sounds in the background (including dialogue) that have been picked up.

This is crosstalk in the analog telephone company circuits between the ground stations and Houston. These links carried many ordinary telephone calls as well as dedicated circuits such as those leased to NASA. Especially noticeable are the MF (multifrequency) tone sequences used to transmit dialed numbers between switches at the start of calls; they may be familiar to those of us old enough to have made long distance phone calls before the switch to digital fiber transmission in the mid 1980s. They are similar to, and sound much like, DTMF ("Touch Tone") though the actual frequencies are different.

MF tones were also generated by the legendary "blue boxes" used by some to make free phone calls at the expense of the phone company. For this reason, MF was phased out even before the switch to digital transmission.

[bknight]

If you listen very carefully you can make out sounds in the background (including dialogue) that have been picked up.

This is crosstalk in the analog telephone company circuits between the ground stations and Houston. These links carried many ordinary telephone calls as well as dedicated circuits such as those leased to NASA. Especially noticeable are the MF (multifrequency) tone sequences used to transmit dialed numbers between switches at the start of calls; they may be familiar to those of us old enough to have made long distance phone calls before the switch to digital fiber transmission in the mid 1980s. They are similar to, and sound much like, DTMF ("Touch Tone") though the actual frequencies are different.

MF tones were also generated by the legendary "blue boxes" used by some to make free phone calls at the expense of the phone company. For this reason, MF was phased out even before the switch to digital transmission.

Why would ground station crosstalk be recorded in transmission from/to the CSM?

[Allan F]

Because the recording took place at the end of a long chain, containing phone lines.

[bknight]

Because the recording took place at the end of a long chain, containing phone lines.

It doesn't make sense to me, if those cross talks were "in the loop" there might be a constant overriding/interference with more pertinent conversations. 

[Ishkabibble]

If I ever buy a T-shirt with a personalised slogan, I think it will have to be Oopie blorp, to remind me of the special insanity of hoax-promoters. 

[Allan F]

Because the recording took place at the end of a long chain, containing phone lines.

It doesn't make sense to me, if those cross talks were "in the loop" there might be a constant overriding/interference with more pertinent conversations.

It is not intern NASA communications, but spillover from the public phone lines. Quite common before everything went digital.

[bknight]

Because the recording took place at the end of a long chain, containing phone lines.

It doesn't make sense to me, if those cross talks were "in the loop" there might be a constant overriding/interference with more pertinent conversations.

It is not intern NASA communications, but spillover from the public phone lines. Quite common before everything went digital.

Ok, but those conversations seems to be a persistent nuisance to the "real" communications, I guess nothing could be helped since it is a by product of the analog systems themselves.

[ka9q]

Ok, but those conversations seems to be a persistent nuisance to the "real" communications, I guess nothing could be helped since it is a by product of the analog systems themselves.

Correct. The designers always tried to reduce all these sorts of problems, not just crosstalk but also noise, fading and distortion. But only so much could be done with the analog technology of the day. The paths from the ground stations (California, Spain and Australia) to Houston included many terrestrial microwave, satellite and submarine cable channels and their impairments would all add.