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Apollo Discussions => The Hoax Theory => Topic started by: nickrulercreator on January 22, 2018, 12:54:09 PM

Title: Sound on the moon?
Post by: nickrulercreator on January 22, 2018, 12:54:09 PM
Note: Am not a HB. Just asking questions and looking for an answer. Pls. no hate, thanks. (also I'm typing quickly that's why my grammar sucks).

Came across this video:

Lot's of it is obviously explainable, usually just by the astronaut touching the object that's making the noise, but some of it is weird. Check out 1:48, for example. The object falls over and makes a metallic banging sound, but the astronaut doesn't appear to be touching it. There are some other noises like that, too, but not much. The footsteps are also explainable too because the feet act as a medium for the sound waves.

I have a few explanations, but they're not exactly solid.

1. The sound was caused by the astronaut touching the object. As for 1:48, for example, it may look like the astronaut's foot is touching the object, though that's iffy.

2. The sound travels through the ground. This is, IMHO, a more likely explanation for 1:48. Though, not for all the other parts.

3. Becuase there were 2 astronauts, it's possible the sound originated from whatever the other astronaut was doing too.

4. Because sound in mission control could also be picked up, it's possible that some sounds came from Houston.

and, lastly, i've seen another thread on this forum discussing the same ideas of sound. JayUtah had an excellent, and very technical explanation:

LM was mic'ed; it had a cabin recorder.  It was not "powered down" in the least; it was the relay for the suit circuit.  The suits used a sort of daisy-chained VHF circuit which was picked up by the VHF antennas on the LM and upconverted to the S-band to Earth.  Outside the range of the LM, the LRV played the role of VHF-USB relay.

Though I can't make any opinion on much of the technical aspects, this seems reasonable.

I also know that electronics and vacuum tubes can sometimes act as microphones and send any sound data too.

Is there any other explanation? Which of these is most likely?
Title: Re: Sound on the moon?
Post by: Apollo 957 on January 22, 2018, 05:50:35 PM
I assume someone, somewhere has gone to the original footage/soundtrack and verified that the sounds have not been added later by Team Hoax pranksters?

The internut is filled with Apollo stills which have been doctored by Team Hoax.
Title: Re: Sound on the moon?
Post by: nickrulercreator on January 22, 2018, 06:36:00 PM
I assume someone, somewhere has gone to the original footage/soundtrack and verified that the sounds have not been added later by Team Hoax pranksters?

The internut is filled with Apollo stills which have been doctored by Team Hoax.

Good point. Where would one find all the original tapes, though. Surely they must be in an archive if this video contains them, or scattered over the internet. I must look into this.
Title: Re: Sound on the moon?
Post by: Apollo 957 on January 22, 2018, 07:03:09 PM
https://www.hq.nasa.gov/alsj/a16/video16.html

Journal text links have the dialogue, so if this is present in the YT version, you can track the video clip to match
Title: Re: Sound on the moon?
Post by: nickrulercreator on January 22, 2018, 08:11:37 PM
https://www.hq.nasa.gov/alsj/a16/video16.html

Journal text links have the dialogue, so if this is present in the YT version, you can track the video clip to match

Found 1:48 here https://www.hq.nasa.gov/alsj/a16/a16.sta11.html#1670637 It begins around 1:55 in the video. A thud can be heard when the object drops, though I don't think it's the object. A soft, but high-pitched whirring noise also begins at the same time, so it's possible that the sound is either whatever the object is being picked up by the VHF signal as an electric current, or something else. It's weird, though.

If someone else with better knowledge on this than I would comment, that would be extremely helpful.
Title: Re: Sound on the moon?
Post by: smartcooky on January 23, 2018, 12:10:51 AM
Note: Am not a HB. Just asking questions

Just a word to the wise (no hate or anything like that) but "Just Asking Questions" is not a term you want to use around here... we call it JAQing-off, its a common tactic used by HB's before they show their true colours and start bringing up long debunked stuff.

To address your concerns, I would not take ANYTHING posted by HB's on Youtube at face value. They are not past editing videos to support their claims. You need to trace the original video.
Title: Re: Sound on the moon?
Post by: Apollo 957 on January 23, 2018, 03:58:54 AM
There's an open mic at CapCom, so is there any real proof the sound came from the Moon's end of the conversation? Mere coincidence that it was generated at the same time as the bag drops?

Also, the bag drop takes place as the boldened action in the transcript;

"167:08:00 Duke: Yeah, right. And it's really shocked, whatever it is. It looks like chalk, Tony, it's so shocked. It's about pebble size, and it's broken open. Oh, let's make it 5 centimeters long, broken open. John, could you bring me a...Let me get this one documented. (Pause)

[Charlie puts the SCB down on the ground and tries to stand it upright, but the weight of the 500-mm camera makes it fall over. In Houston, there is a discussion about having Charlie take the film magazine out of his Hasselblad and putting it in the 500-mm camera.]

167:08:37 Duke: Okay. The polarizing filter's coming off (the LMP Hasselblad he is wearing). I hope."

So we have a 500mm camera falling over on a layer of regolith, atop solid rock. The astronaut is standing right next to it. Sound transference through rock and suit to the mike, or is that too much of a stretch?
Title: Re: Sound on the moon?
Post by: raven on January 23, 2018, 10:44:44 AM
There's plenty of other evidence they're in hard vacuum, like the behaviour of the dust and the flag and an impromptu pendulum (https://www.youtube.com/watch?v=kojsfbN8ulc). What happened here? Sadly, we can't say for certain, I think. Information is limited. All we can do is conjecture. However, I will say, a non sound through air explanation fits the rest of the facts better.
Title: Re: Sound on the moon?
Post by: bknight on January 23, 2018, 03:49:58 PM
I reviewed one of the sounds occurring at 1:50 when a collection bag falls over.  The caption says that voice removed and slow removed.  The video A16v.16070637 has the same event at 1:56 and I hear no sound.  I suspect that a "sound" was dubbed in when the voice was removed either maliciously or legitimate error.  Slow removed?  The original was taped live in normal motion, too many corrections attempted on this video for it to be factual.
Title: Re: Sound on the moon?
Post by: nomuse on January 24, 2018, 10:08:33 AM
The possible identity of certain stray sounds is an interesting question, but it in my mind has nothing to do with a the possibility of a hoax.

Why? Because there's no reason for an open mic. None of the sound intended to be in the final production is available on the sound stage, after all. It is all suit mics and effects. MOS is practically industry standard anyhow and that's the only sensible way to film.

Okay...there is a bit of wriggle room. Over at the BBC they shot "Doctor Who" on such a short schedule all the dialog was captured on set. Mistakes and all, dropped props and all. Similarly, they might have had the voice actors sitting around in the booth doing dialog for an Apollo shoot and not had time to edit out when the director dropped his pencil or something.

So...okay, it's not quite as ludicrous as claiming live sound off the set in the era of FILM cameras, especially early ones. But when you add other Hoax Believer nonsense like a director talking out loud giving directions during the shot ("Talk!") and high-speed fans running to make the flags look right....well....
Title: Re: Sound on the moon?
Post by: AtomicDog on January 24, 2018, 07:26:47 PM
That's the same thing I said a few years ago. Why in the world would you have open microphones on a soundstage that is supposed to represent a VACUUM?
Title: Re: Sound on the moon?
Post by: smartcooky on January 24, 2018, 10:05:32 PM
...there's no reason for an open mic. None of the sound intended to be in the final production is available on the sound stage, after all. It is all suit mics and effects. MOS is practically industry standard anyhow and that's the only sensible way to film.

None of this matters to the stupid HB's though does it? Many of their whackadoo claims contradict each other... they simply see/hear something they are incapable of understanding and conclude suspicious anomaly = hoax because reasons!

Their ability to draw conclusions from evidence is about on par with that Greek/Swiss idiot with the bad hair...

I don't understand it.... therefore it must be aliens
I can't explain it.... therefore it must be aliens
I don't know.... therefore it must be aliens
Title: Re: Sound on the moon?
Post by: TexMex on April 24, 2018, 01:05:48 AM
The video here is from a video camera. The video camera does not record sound.

The audio is from the astronaut's communications radio.  Note, this is the astronaut in the video.  No astronaut is holding the camera.  The microphone for that system is inside the spacesuit, just in front of the astronaut's mouth.  So the microphone is not in a vacuum, and the sound has lots of air, water and solids to travel through.  Air in the spacesuit, water in the astronaut, and solids in the... well everything.  And as we all learned in 6th grade science sound travel better in liquids and solids than in gasses.  This is why deaf people "listen" to music by holding a loud audio speaker.

Close a box and the vibration travels from box to glove to astronaut, suit, and microphone.  Move quickly and the spacesuit itself is likely to make some noise.  It's 3 layers, not form fitting, and parts of it are going to slap against the astronaut, and other layers/parts.  Jump around in the dirt and your boots grinding into the dirt make vibrations that travel through you to your microphone.
Title: Re: Sound on the moon?
Post by: Dalhousie on May 24, 2018, 09:16:16 PM
The video here is from a video camera. The video camera does not record sound.

The audio is from the astronaut's communications radio.  Note, this is the astronaut in the video.  No astronaut is holding the camera.  The microphone for that system is inside the spacesuit, just in front of the astronaut's mouth.  So the microphone is not in a vacuum, and the sound has lots of air, water and solids to travel through.  Air in the spacesuit, water in the astronaut, and solids in the... well everything.  And as we all learned in 6th grade science sound travel better in liquids and solids than in gasses.  This is why deaf people "listen" to music by holding a loud audio speaker.

Close a box and the vibration travels from box to glove to astronaut, suit, and microphone.  Move quickly and the spacesuit itself is likely to make some noise.  It's 3 layers, not form fitting, and parts of it are going to slap against the astronaut, and other layers/parts.  Jump around in the dirt and your boots grinding into the dirt make vibrations that travel through you to your microphone.

Aren't the astronaut radios on VOX?  If so, how much extraneous noise is needed before the Vox starts picking it up?
Title: Re: Sound on the moon?
Post by: bknight on May 25, 2018, 07:02:59 AM
The video here is from a video camera. The video camera does not record sound.

The audio is from the astronaut's communications radio.  Note, this is the astronaut in the video.  No astronaut is holding the camera.  The microphone for that system is inside the spacesuit, just in front of the astronaut's mouth.  So the microphone is not in a vacuum, and the sound has lots of air, water and solids to travel through.  Air in the spacesuit, water in the astronaut, and solids in the... well everything.  And as we all learned in 6th grade science sound travel better in liquids and solids than in gasses.  This is why deaf people "listen" to music by holding a loud audio speaker.

Close a box and the vibration travels from box to glove to astronaut, suit, and microphone.  Move quickly and the spacesuit itself is likely to make some noise.  It's 3 layers, not form fitting, and parts of it are going to slap against the astronaut, and other layers/parts.  Jump around in the dirt and your boots grinding into the dirt make vibrations that travel through you to your microphone.

Aren't the astronaut radios on VOX?  If so, how much extraneous noise is needed before the Vox starts picking it up?

I can't tell you the exact amount of sound energy that must be present for the Vox to "engage", but I can tell you that commercial models a few years ago and used extensively in and out of my profession differs dramatically.  I'm not sure if it is the brand of mic or the amount of use.  There were times that I had to "blow" into the mic to get it to engage or the first word likely never got transmitted, at the very least the first syllable. NASA may have had top line equipment for Apollo and thus you might have a "whack" when hammering in core tubes etc.
Title: Re: Sound on the moon?
Post by: Count Zero on May 25, 2018, 09:38:18 AM
Aren't the astronaut radios on VOX?  If so, how much extraneous noise is needed before the Vox starts picking it up?

I can't tell you the exact amount of sound energy that must be present for the Vox to "engage", but I can tell you that commercial models a few years ago and used extensively in and out of my profession differs dramatically.  I'm not sure if it is the brand of mic or the amount of use.  There were times that I had to "blow" into the mic to get it to engage or the first word likely never got transmitted, at the very least the first syllable. NASA may have had top line equipment for Apollo and thus you might have a "whack" when hammering in core tubes etc.

Many times when I hear the CapCom say something to the astronauts, I hear it repeated 3 seconds later.  I assume that I'm hearing the received audio coming from the speakers inside the astronaut's helmet, and getting re-transmitted by the helmet mike..  If that's loud enough to trigger the vox, I have no trouble believing that raps from a hammer can too.
Title: Re: Sound on the moon?
Post by: MBDK on May 25, 2018, 11:36:18 AM
Many times when I hear the CapCom say something to the astronauts, I hear it repeated 3 seconds later.  I assume that I'm hearing the received audio coming from the speakers inside the astronaut's helmet, and getting re-transmitted by the helmet mike..  If that's loud enough to trigger the vox, I have no trouble believing that raps from a hammer can too.

The DOD ones I used during my career would not pick up the noisy ventilation system(s) around us, but a heavy breath, or the brush of your face against the mouth piece, could often make some peculiar sounds that would sometimes be reminiscent of a thud or thwack type of noise.
Title: Re: Sound on the moon?
Post by: MBDK on May 25, 2018, 11:40:52 AM
I should add that they did occasionally have to be adjusted by technicians to provide the preferred background/communications balance.  I am certain such adjustments, if they used a similar system, for Apollo could have been accomplished by the flight crew, mission control, or both.
Title: Re: Sound on the moon?
Post by: JayUtah on May 30, 2018, 09:50:42 AM
The maker is Plantronics, a name still very much known today in the field of headsets.
Title: Re: Sound on the moon?
Post by: Glom on June 27, 2018, 08:13:34 PM
Did the mics have a squelch?
Title: Re: Sound on the moon?
Post by: ka9q on June 27, 2018, 08:52:51 PM
A "squelch" is a receiver feature, not a transmitter feature. There's VOX (voice activated switching) which I believe was actually in the LM (or LRV) relay system, not in the PLSS -- but I'll have to check this. If that's the case then the two astronauts heard each other continuously, and only the signal to earth required the level to exceed a threshold. That threshold was set by a knob in the LM (or LRV).

There's a fair amount of cabling inside the suit between the PLSS and headset; I believe there were at least two microphones for redundancy. There had to be a preamplifier somewhere; at least the cabling between the microphone and preamp would be somewhat sensitive to electrical noise.
Title: Re: Sound on the moon?
Post by: ka9q on June 27, 2018, 09:50:39 PM
OK, I've looked through the handbook again. As far as I can tell, there is a VOX circuit on the inputs to the S-band and VHF transmitters on the LM and in the LCRU, but not in the PLSS. So the astronauts heard each other continuously during an EVA.

Note: in space and mobile communications where relays are involved, we comm engineers use the term "forward link" to refer to the entire signal path to the mobile station and "return link" (or "reverse link") to the entire signal path from the mobile station. This is distinct from "uplink" and "downlink" that refer specifically to unidirectional satellite relay links. The forward and return links would each consist of their own uplinks and downlinks.

Here's how the return link worked:

The LMP transmitted audio to the CDR (only) by VHF FM on 279.0 MHz. Their audio was combined in the CDR's PLSS and transmitted by VHF AM on 259.7 MHz to the LMP's PLSS (so he could hear the CDR) and to the LM or LCRU so it could be relayed to earth on 2282.5 MHz (LM) or 2265.5 MHz (LCRU). The relay in the LM or LCRU had a VOX in the line between the 259.7 VHF receiver and the S-band transmitter so we'd hear dead air unless one of them spoke loudly enough to trip it. But the astronauts could in principle whisper to each other and we wouldn't necessarily hear it. During the Apollo 11 EVA this return link VOX in the LM was set too low and that's why their voices often broke up. But they could hear each other fine.

The forward link from the LM or LCRU was VHF AM on 296.8 MHz to separate receivers in the astronauts' PLSSes (they each had separate volume controls). There was also VOX in this path between the S-band uplink receiver and the forward VHF transmitter in the LM or LCRU, plus squelches in those PLSS AM receivers so that the astronauts would not be bothered by uplink noise when Capcom wasn't talking (or if the relay link to the PLSSes was weak).

When I figured this part out a while ago this resolved a question I'd had for some time, which was how interference was avoided between the two VHF AM forward link transmitters on the LM and LCRU, both of which transmitted on 296.8 MHz. The two S-band uplink receivers heard the same signal from earth on 2101.8 MHz (=221/240 * 2282.5 MHz), but Capcom could choose which of two subcarriers to use for forward link voice. The LM listened to 30 kHz, the LCRU to 124 kHz. Since their VHF AM forward link transmitters were VOX keyed, they wouldn't both transmit at the same time (unless Capcom transmitted on both subcarriers at the same time, but they wouldn't have any reason to.)
Title: Re: Sound on the moon?
Post by: ka9q on June 28, 2018, 12:48:29 AM
Many times when I hear the CapCom say something to the astronauts, I hear it repeated 3 seconds later.  I assume that I'm hearing the received audio coming from the speakers inside the astronaut's helmet, and getting re-transmitted by the helmet mike..
That's correct. It was written up as an anomaly in one of the mission reports but I don't think there was anything that could be done about it.

With the full duplex hot mike (non-VOX) link between the two astronauts, I did think about the possibility of a mutual feedback loop. Only the acoustic path through the LMP's headset would be required to complete a loop since the CDR's PLSS electronically mixed the LMP's voice with his own and transmitted it the LM or LCRU -- and back to the LMP so the LMP could hear the CDR. I guess the round trip gain was kept low enough to prevent that.
Title: Re: Sound on the moon?
Post by: raven on June 29, 2018, 01:34:48 AM
This phenomena (https://arxiv.org/abs/0903.3367)  was used by Italian high school students (https://www.technologyreview.com/s/412697/school-kids-measure-distance-to-the-moon/) to measure the distance to the moon, fascinatingly enough, including measuring its eccentricity.
Title: Re: Sound on the moon?
Post by: ka9q on June 29, 2018, 07:34:47 AM
I'm surprised they could do this, since the path between Houston and the moon wasn't direct but went by way of one of the ground stations, usually by satellite, which would add its own delay.
Title: Re: Sound on the moon?
Post by: raven on June 29, 2018, 03:43:27 PM
I'm surprised they could do this, since the path between Houston and the moon wasn't direct but went by way of one of the ground stations, usually by satellite, which would add its own delay.
Yeah, they mention those delays in the paper.
Title: Re: Sound on the moon?
Post by: BDL on October 27, 2018, 08:33:34 PM
Revisiting this one for a bit, I’m still not sure what happened or what may have made those noises at 1:42-1:51 or with the lid closing/opening. Everything else is easily explainable to me.
I wonder if there’s any way to know? I’m having a little bit of trouble understanding. I hope I’m not asking for too much.

I think it’s likely just a coincidence and those sounds were just the coming from inside the EVA suit itself, but I’m not really sure. Thanks.
Title: Re: Sound on the moon?
Post by: MBDK on October 27, 2018, 09:48:05 PM
Revisiting this one for a bit, I’m still not sure what happened or what may have made those noises at 1:42-1:51 or with the lid closing/opening. Everything else is easily explainable to me.
I wonder if there’s any way to know? I’m having a little bit of trouble understanding. I hope I’m not asking for too much.

I think it’s likely just a coincidence and those sounds were just the coming from inside the EVA suit itself, but I’m not really sure. Thanks.

Noises in the VOX microphones can be made by even slightly harder breaths, such as any extra exertion, like hammering - it all depends on the astronaut's mouth proximity to the mic, and it WOULD be closer when he leans forward in his suit to observe some of the tasks he was working on.  Also, the mics at Houston control were open and could make similar sounds just by being adjusted, tapped with a pen, or exhaling close to the mic.  As they were voice activated, and designed to filter out background noise, close proximity of the mouth was also required in order to be clear and audible, and often resulted in inadvertent brushing of the lips or chin up against the mic, causing all sorts of odd sounds.  I know because I used those type of systems for years during nuclear refueling operations.
Title: Re: Sound on the moon?
Post by: BDL on October 28, 2018, 05:03:16 PM
Revisiting this one for a bit, I’m still not sure what happened or what may have made those noises at 1:42-1:51 or with the lid closing/opening. Everything else is easily explainable to me.
I wonder if there’s any way to know? I’m having a little bit of trouble understanding. I hope I’m not asking for too much.

I think it’s likely just a coincidence and those sounds were just the coming from inside the EVA suit itself, but I’m not really sure. Thanks.

Noises in the VOX microphones can be made by even slightly harder breaths, such as any extra exertion, like hammering - it all depends on the astronaut's mouth proximity to the mic, and it WOULD be closer when he leans forward in his suit to observe some of the tasks he was working on.  Also, the mics at Houston control were open and could make similar sounds just by being adjusted, tapped with a pen, or exhaling close to the mic.  As they were voice activated, and designed to filter out background noise, close proximity of the mouth was also required in order to be clear and audible, and often resulted in inadvertent brushing of the lips or chin up against the mic, causing all sorts of odd sounds.  I know because I used those type of systems for years during nuclear refueling operations.
Thank you very much. I guess those sounds were just coincidence. Did these sound happen often throughout the Apollo missions? It seems like they would, but I haven’t watched a lot of the Apollo footage (which I’m ashamed to admit).
Title: Re: Sound on the moon?
Post by: MBDK on October 28, 2018, 06:38:53 PM
Thank you very much. I guess those sounds were just coincidence. Did these sound happen often throughout the Apollo missions? It seems like they would, but I haven’t watched a lot of the Apollo footage (which I’m ashamed to admit).

Absolutely.  Here is the first random video I looked at -


Just going halfway through it, and only noting discernibly audible sounds distinctly apart from the voices, I heard noises at 0:14, 0:55, 0:59, 1:16, 1:20, 1:30, 1:35, and 1:40.  That is where I stopped, as you get my drift.  Better ears than mine may hear more.

NOTE:  Edited to remove extra "may" in last sentence.
Title: Re: Sound on the moon?
Post by: BDL on November 01, 2018, 10:28:16 PM
I’ve decided to watch a bunch more footage from Apollo 17 and I have indeed noticed very many of those same sounds. The audio is riddled with it.
Title: Re: Sound on the moon?
Post by: ka9q on November 15, 2018, 07:39:58 AM
These were analog radio systems, with plenty of potential noise sources of all kinds. Radio hams (like me) are very familiar with them. One possibility not yet mentioned is physical contact with or possibly even mere movement of the VHF antennas on the OPS or the LCRU (the Lunar Communications Relay Unit on the rover).

All of the Apollo radios were full duplex, so these noises could be generated even when an astronaut was not talking or his VOX was tripped.

The astronaut radios were in the PLSS but their antennas were physically mounted on the top of the OPS that sat on each PLSS; they were connected by a cable whose connectors could easily have gotten a little gritty in the lunar environment. This too could have generated noise when the cables were moved.

In the Apollo 17 video just posted I heard intriguing "chirping" sounds similar to the sound of ham slow-scan TV. From my knowledge of Apollo communications, I wonder if these could be crosstalk from the PLSS analog telemetry encoders. A commutator continuously walked through a series of analog signals, frequency-modulating the selected channel on a carrier tone above the normal voice range (but within the audible range) and added to the voice signals before transmission to the LCRU for relay to earth.

It sure would be fun to redo all this with modern digital technology...

Title: Re: Sound on the moon?
Post by: bknight on November 15, 2018, 08:10:54 AM
<snip>

All of the Apollo radios were full duplex, so these noises could be generated even when an astronaut was not talking or his VOX was tripped.

<snip>

Did you mean VOX was NOT tripped?
Not being a ham operator or an electronics expert, I have deferred to you for many of the electronics "anomalies" discussed in Apollo.  Do the "chirps" exist because of the internals of each components of the system, then? 
Title: Re: Sound on the moon?
Post by: ka9q on November 15, 2018, 03:29:03 PM
<snip>

All of the Apollo radios were full duplex, so these noises could be generated even when an astronaut was not talking or his VOX was tripped.

<snip>

Did you mean VOX was NOT tripped?
Yeah. Poor grammatical framing. I mean to say NOT (talking OR vox_tripped). The astronaut's transmitter stays on the air, and the ground continues to listen, even when the path between the microphone and transmitter is not active at the moment.
Quote
Not being a ham operator or an electronics expert, I have deferred to you for many of the electronics "anomalies" discussed in Apollo.  Do the "chirps" exist because of the internals of each components of the system, then?
I can't say what the exact mechanism is in this exact case, but it is common in analog radio and audio systems to have nonlinear distortion. When you sum two signals A and B, the output of the system is supposed to be simply A+B. With nonlinear distortion, the output is something else; it may be "clipped" to some limit, or it may be something else (usually less) than the actual sum. There can be any number of causes: poor design, excessive signal amplitudes, component degradation or failure, etc. Even a loose or dirty connector. This could happen anywhere along the signal chain, including in the receiver. I haven't watched a lot of the video but it did seem that it happens when the astronauts are very close to the rover camera so it could be overloading of the LCRU VHF receiver.

If you work out the math (Fourier transforms), nonlinear distortion produces frequencies not present in the original signal. If you put frequencies F1 and F2 into the system, the output may contain not only the original frequencies  F1 and F2, but also n*F1+m*F2.  If n and m are nonzero, including negative values, you get "intermodulation distortion". This is intentionally done in 'mixers', devices widely used in radio receives and transmitters to shift the frequency of a signal.

Each PLSS generates two telemetry subcarriers: the LMP at 3.9 and 7.35 kHz and the CMP at 5.4 and 10.5 kHz. Remember that the CMP receives the LMP's signal on an FM link at 279 MHz, adds his own, and transmits the sum to the LCRU (or LM) for relay to earth. Intermodulation distortion could easily produce difference frequencies between the various telemetry carriers falling into the audible range (300 to 2300 Hz). As I said before, the effect seems to happen when the astronauts are very close to the TV camera and LCRU so the commander's AM transmitter could be overloading the LCRU's receiver. You probably wouldn't get this effect on earlier (pre-J) missions using the LM for communications relay since the LM's EVA relay antenna is mounted on the top of the LM, away from the astronauts on the surface.


Title: Re: Sound on the moon?
Post by: Northern Lurker on November 15, 2018, 03:34:55 PM
Do the "chirps" exist because of the internals of each components of the system, then?

Chirps? Did you mean Quindar tones? https://en.wikipedia.org/wiki/Quindar_tones (https://en.wikipedia.org/wiki/Quindar_tones)

Lurky
Title: Re: Sound on the moon?
Post by: bknight on November 15, 2018, 03:42:57 PM
Do the "chirps" exist because of the internals of each components of the system, then?

Chirps? Did you mean Quindar tones? https://en.wikipedia.org/wiki/Quindar_tones (https://en.wikipedia.org/wiki/Quindar_tones)

Lurky

My description of what all have been talking about in the video.
Title: Re: Sound on the moon?
Post by: ka9q on November 15, 2018, 03:46:33 PM
No, these are different from the Quindar tones. The Quindar tones are generated by the Capcom's console when he starts and finishes talking. I'm referring to some artifacts that are clearly on the downlink. They start around 14:25 in BDL's video and continues at varying levels for some time. It starts while somebody is cleaning the camera lens, so it's possible he bumped into a cable connector and moved it slightly. Apollo 17 was especially plagued by lunar dust getting into everything, and I wouldn't be at all surprised if it had a role here.

I might be completely wrong about all this, but I can't think of any other potential source. Maybe they added some experiment that I simply don't know about. I should probably look at the telemetry system a little more closely to see if intermodulation distortion should in fact sound like what we hear.
Title: Re: Sound on the moon?
Post by: Northern Lurker on November 15, 2018, 04:00:17 PM
Oh that chirping. No idea here.

Funny how perception of a video changes depending on what you are looking or listening for. First time I watched the video, I followed the action on screen and listened to conversations and didn't notice any voice artifacts except quindar tones. On second try I ignored those and listened for thuds, I heard many of those, regardless of whether an astronaut was hammering something or not. On third try I again ignored all of those and listened to chips instead. Intresting that whining chirp that didn't distort the astronauts voice.

Lurky
Title: Re: Sound on the moon?
Post by: ka9q on November 15, 2018, 04:00:39 PM
I'm looking at the PLSS telemetry system in some more detail (Apollo Operations Handbook Extravehicular Mobility Unit - Vol I System Description Apollo 15-17, section 2.5.6, Extravehicular Communication System).

There are two telemetry subcarriers from each PLSS. One appears to be dedicated to an astronaut EKG. The other carries 30 telemetry channels at a sample rate of 1.5 Hz, with 26 of those channels usable for information (the other four are for synchronization and calibration). That implies a commutation rate of 45 Hz, which to my ear is not far from the rate at which the crosstalk tone signal varies.

I'm going to search the anomaly section of the mission report to see if anything like this is mentioned. They still analyzed Apollo 17 anomalies even though they didn't fix them unless they could conceivably appear in a Skylab mission.
Title: Re: Sound on the moon?
Post by: ka9q on November 16, 2018, 05:10:20 AM
I went through the mission reports for Apollos 15, 16 and 17 and I didn't see anything in the anomaly reports sections about telemetry crosstalk into the mission audio. It might have had a different source, or maybe it wasn't considered bad enough to rate a mention.
Title: Re: Sound on the moon?
Post by: BDL on November 27, 2018, 09:20:02 PM
I want to actually find the clips that are in the video that this thread is based on, but I’m not sure where to find it. I’ve tried going through the Apollo Lunar Surface Journal but I’m not really sure how to use it. Can someone help?
Title: Re: Sound on the moon?
Post by: BDL on November 27, 2018, 09:33:17 PM
More specifically, I’m looking for clips of 0:28, 0:34, 1:05, 1:12, 1:40, and 1:44 in any authentic Apollo archive. These timestamps are referring to the initial video this thread was made about on page 1.

These clips are all from Apollo 16.
0:28 and 0:34 were not given by the creator(s) of the video.
1:05 - a16v.1431336
1:12 - a16v.1655407
1:40 - a16v.1244215
1:44 - a16v.1684045
Title: Re: Sound on the moon?
Post by: ajv on November 27, 2018, 10:59:10 PM
The page you want is probably the Apollo 16 Video Library page: https://www.hq.nasa.gov/alsj/a16/video16.html

The Ken Glover clips match the names you listed. There is a link to the mission transcript next to each clip.
Title: Re: Sound on the moon?
Post by: BDL on November 29, 2018, 11:45:28 PM
So I went through the video archive and it turns out the noises weren’t actually in the original audio.
Any noise that can be heard can be explained by the astronaut simply breathing, stepping, or coming in contact with something - which can be proven. So, yeah. A large portion of their sounds are not actually in the original audio clips,

Conspiracy theorists are a really odd type of people, huh? But I genuinely didn’t know they’d go as far as faking their own evidence...
Title: Re: Sound on the moon?
Post by: Allan F on November 30, 2018, 12:13:04 AM
But that is the mainstay of the hoax business. Inventing and fabricating "evidence".
Title: Re: Sound on the moon?
Post by: JayUtah on November 30, 2018, 09:21:39 AM
I've encountered very few examples of outright deliberate fabrication of evidence.  That isn't to say hoax claimants are universally honest.  They aren't.  You have, for example, Sibrel deliberately cherry-picking the evidence, and you have Sam Colby deliberately misrepresenting it.  You have David Percy pretending to be an expert and then misinterpreting it.  And at the most innocent end of the spectrum you have people defaulting to nefarious explanations for unexpected things that creep into the record.  As illustrated here, often you can solve the problem by going to the original (or a better) source.  Most of what we use today for evidence are convenience samples and sources.  They're easy to obtain, but not always the best kept.  Audio recordings will acquire glitches from copies through multiple formats, some of them lossy or prone to artifacts.  Video recordings lose resolution and time stability.  Photographs lose resolution.

Regarding the latter, I remind you about the reseau fiducials.  When I shot using a reseau plate, I tested several hypotheses.  The first was saturation and halation.  No dice; the fiducials remained clear.  Then I tried scanning, both with commercial transparency scanners and consumer-grade.  Again, no luck.  It wasn't until I compressed the images with a lossy compression algorithm and shrank them to web-distributable sizes that the fiducials disappeared "behind" bright patches.  Over the years we've listened to, and debunked, countless theories for how the fiducials got lost.  We could have cut to the chase.  When I was finally able to get my hands on 4,000 dpi scans of the camera originals, the fiducials were not missing from them.

Logically we call this "subversion of support."  If possible, it's the best way to refute a hoax theory -- or any theory based on alternate explanations for allegedly anomalous data.  To subvert support means to point out that the thing being explained doesn't really exist and therefore requires no explanation.
Title: Re: Sound on the moon?
Post by: Allan F on November 30, 2018, 12:04:15 PM
I've seen plenty of obviously fabricated composite pictures, which show some impossible artefacts, like the Earth low on the horizon behind the LM, or videos with elements added or removed. Maybe they are originally meant to be jokes, but the hoax crowd suck them up and parade them as evidence for their claims.
Title: Re: Sound on the moon?
Post by: JayUtah on November 30, 2018, 02:24:14 PM
I've seen those too.  The ones I'm most familiar with are composites and panoramas made by people for innocent reasons and then misinterpreted or misrepresented by others for nefarious purposes.  I suppose that picking something you know has been fabricated and knowingly representing it as unaltered is tantamount to having fabricated it yourself.  I tend to think those people are mistaken or misled until I have evidence of malice.  It's still irresponsible as far as scholarship goes, but not everyone is a professional historian.
Title: Re: Sound on the moon?
Post by: bknight on November 30, 2018, 04:15:22 PM
IIRC, hunchbacked(?) claimed there was a third astronaut on the Moon in a panorama since (Schimitt, Duke, or Irwin was in one of the stills making up the panorama, but not in others) They lie about the panaorama, since they can't fathom that it was spliced together here on Earth out of images taken on the Moon.  And those individuals chose were to splice.  I think another instance involved tire marks being "absent", again by the person splicing the images.
Title: Re: Sound on the moon?
Post by: JayUtah on December 01, 2018, 11:48:30 AM
Well, what Hunchbacked doesn't understand could fill the VAB, but that's a different matter.  There's a whole genre of comical photography out there these days based on panoramas gone wrong.  And this is actually nothing new.  In the slit-scan style of panoramas that was used in box cameras, it was possible to be on one end of a panoramic group shot and then run around to the other side and be at the other end.  People's intelligence and competence vary.  That's just a fact of life.  Consequently you'll run across arguments that make you say, "That's just stupid."  That's not the same as deliberate fabrication.
Title: Re: Sound on the moon?
Post by: bknight on December 01, 2018, 01:58:51 PM
I do understand that hunchback is weak in many areas, but his comments in review of aerospace degree concepts belays his knowledge/ training .  k9aq has demonstrated many times his misunderstanding of electrical issues and many others have pointed out his poor visual abilities.  I'm ashamed to call him an fellow engineer.