The AM Forum

"Space shuttle audio" has been mentioned many times usually in a negative context. We've all heard the real space shuttle signals - very intelligible but like a telephone in a box?

But has anyone actually tried to define the qualities of the sound? what level of clipping? Where are the low and high frequencies cut off? Any gating or other effects?

Somewhere there should be a spec, but nowhere it would be easy to find..

Anyone got a live recording/example of  'space shutle audio' quality coming from a ham?

The space Shuttle boom microphone was engineered to be a noise canceling design similar to aircraft headsets .... there should be design data available for those to help define response

From Collins history:


My info says they used SSB almost exclusively.

Phil

That was a term I thought came from a member here in the Forum.
Space Shuttle audio is basically telephone quality audio..........300 hz to 3000, Like the old Heathkit DX100, unmodified.
The Scratchy Apache might be another example with the clipper adjusted to cause distortion.

I don't think anyone really cares about it that much, Pat. It's more of a generic term used to describe very narrow, restricted, communications-grade audio. Trying to give it parameters in the ham world would be akin to trying to nail Jello to the wall - it means different things to different folks. The common thread being, most folks don't want to sound that way.

Think of piercing, noise-penetrating audio that gets through the static and interference, but gives you a headache if you listen for more than a few minutes. That'll get you in the ballpark. Great for comms work, annoying for the long exchanges often associated with AM.

Data parameters are not relevant. I know it when I hear it!

I agree, and with sharp roll off below 300 Hz and above 3K. Add a carbon mike to give it that true nasal quality. It can be heard frequently on SSB during contests where bandwidth is reduced to 2.1 or 1.8 KHz. Add a speech clipper or compressor to this mix and you have ear bleeding audio.

Plantronics used by NASA and commercial airlines for YEARS will produce that "Space Shuttle Sound"

Also used in Television control rooms, remotes, etc. especially in the 70's and 80's

 Plantronics MS 50/T30-1 - headset

•Product Type: Headset - wired
•Headphones Form Factor: On-ear
•Connectivity Technology: Wired
•Headphones Technology: Dynamic
•Sound Output Mode: Mono
•Audio Specifications: Frequency Response 300 - 3000 Hz
•Impedance: 600 Ohm
•Microphone: Boom
•Microphone Technology: Dynamic
•Microphone Operation Mode: Mono

And most likely triggered by our fine group here on the AMFORUM and our WIDE AM (well not THAT wide) signals and the creamy audio... Did ESSB have its roots from us?? Even the CBers (some ) have cleaned up their act and using, or adjusting transmitters for better audio, instead of the raspy, distorted sound I would hear out of my radio.

It occurred to me that the "thing" with the NASA and later the "Space Shuttle" sound was not the way it sounded but was the NASA beep!!

People were big into that for a while.

               _-_-

Yes, the Roger Beep.Big in the CB whirl...

I much prefer the Valiant thud.

That beep always sounded like it was anything but a sinewave.. maybe it went through a clipper as well.

Hey this old H-161 headset might get close to the proper sound - but the real reason may be the electronics it plugs into.  Right, the audio is not for long speeches but for cutting through.

Heavy, heavy clipping + breath popping + very restricted BW with greatly accentuated "presence" frequencies.

Another term I've heard was "ear bleed" audio.  Something to avoid, not emulate.  There's really no excuse for this audio for casual, enjoyable listening

Al

I agree, Al. I look at it this way: Restricted, clipped audio may have a slight advantage when in a QSO where signals are very marginal -- maybe ten per cent. of the time. The other 90 per cent. of the time it has no advantage whatsoever. And it is Hell to listen to.

So, to "get through" to ten per cent. or less of your listeners, you're supposed to make 90 per cent. of your listeners suffer? Idiotic.

Yet that is the philosophy that was pushed for years by major amateur radio publications. It is starting to lose some ground recently, though -- and about time.

73,

Kevin.

A lot depends on what you're trying to accomplish. If you're in a relatively local QSO, the typical "Barry White" audio is fine. If you're trying to work AM stations on the West coast, the Far East, or in Europe, conditions are marginal and you're only running 100 to 150 watts, running wide-body audio isn't going to help you. Throwing in some audio clipping and/or narrowing of the audio bandwidth can help make the contact. In this case, it makes no difference who else might be listening and causing their ears to bleed, you're not trying to work them. If you're only a listener and not participating in the contact, there is a use for the tuning knob.

ERRRRRRR! Sounds Hnyellowy!
Tim WA1HnyLR

That reminds me Tim, one night I heard you on the Hairwaves using a carbon mike.

What mike were you using and with what equipment?

Sounded, "interesting." :)

Phil - AC0OB

Completely agree.  

High fidelity is nice, but I don't mind listening to properly adjusted clipped audio in QSO or just reading the mail.  I guess my tastes are more utilitarian.

In regard to the NASA beep, in the 70s, I heard a few ham SSB operators using a beep at key up.  I'm not certain, but I think there was an article in Ham Radio or 73 describing how to build a transistor oscillator and connect it to the mic input to do that.

Brad

The NASA beep was actually developed by Quindar Electronics, formerly in Springfield NJ
https://en.wikipedia.org/wiki/Quindar_tones

Or the Browning Eagle "ping"

In some cases, that was due to the single pole/double throw contacts in the mike switch. When you released the mike button, if the transmit side didn't disconnect fast enough before the receive side connected, you would hear a ping or some type of short feedback. Sometimes the internal antenna change over relay with multiple contacts, caused a similar type of problem.

When I tuned across the guy in this screenshot he appeared to be doing an excellent job of emulating "space shuttle audio" with his tight 2.4k filter and restricted/clipped audio. He was boasting about how his penetrating audio setup has made him famous in various "DX windows" and I have no doubt that lots of stations will remember him as his "whirl-wide" signal appears to be approximately 20k wide. Sometimes narrower is not necessarily better!

Rob W1AEX

The Browning pings is due to a slow mute of the receiver. This can be extended or even made adjustable in duration by changing the value of an electrolytic on the receiver B+ line going thru the T/R relay. It occurs during Tx keying not at the end of transmission like a roger beep.

Deleted due to formatting completely blowing the message apart.

I can recall two Lafayette CB models we sold with the same unique mike, where the ping happened going from transmit back to receive. The fix was to adjust the spacing between the leaf spring contacts in the mike head. The leaf springs in this mike were extremely thin and easily bendable without too much pressure. About a year later, the mike was replaced with something a lot more durable.

Narrow audio does not equal narrow RF.   :o

Then there was the guy in Kansas wit a Tempo one blowing a cyclone whistle every time he keyed up on the local channel.