What is mean by "motorboating"? I see it mentioned often, but cannot find a definition.
What is mean by "motorboating"?
- Thread starter sadatoni
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markbart
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Motorboating to me is digital trunking signals on a analog scanner.
Mark
Mark
DonS
Member
In my experience, when people complain about "motorboating", they're referring to a scanner receiving a digital voice transmission (e.g. P25 CAI voice) but not decoding it as "digital" - instead playing the undecoded digital noise as if it was an analog voice transmission.
For example, a Motorola trunked system (3600bps control channel) on which some or all of the voice transmissions are digital. Unless explicitly programmed otherwise, the scanner has to wait for a short time at the beginning of each voice transmission, in order to determine if that transmission is digital or analog. If it's really a digital transmission, but the scanner "misses" that fact, you'll hear the undecoded digital noise: "motorboating".
Another example: a non-trunked (conventional) P25 CAI voice frequency that isn't explicitly forced to digital mode (e.g. by telling the scanner, in some way, that it's digital - like programming a NAC value), or which is erroneously programmed as "analog" (e.g. by programming a DCS or CTCSS value). In the first case, the behavior would be like the trunking example above; in the second case, the scanner will always give you the digital noise, since you've told it it's "analog" (presuming the CTCSS / DCS programming doesn't "gate" the audio).
You'll always get this behavior on an analog scanner programmed with such systems or frequencies. It's possible to get it on a digital scanner, as well, depending on signal quality, scanner settings, etc.
For example, a Motorola trunked system (3600bps control channel) on which some or all of the voice transmissions are digital. Unless explicitly programmed otherwise, the scanner has to wait for a short time at the beginning of each voice transmission, in order to determine if that transmission is digital or analog. If it's really a digital transmission, but the scanner "misses" that fact, you'll hear the undecoded digital noise: "motorboating".
Another example: a non-trunked (conventional) P25 CAI voice frequency that isn't explicitly forced to digital mode (e.g. by telling the scanner, in some way, that it's digital - like programming a NAC value), or which is erroneously programmed as "analog" (e.g. by programming a DCS or CTCSS value). In the first case, the behavior would be like the trunking example above; in the second case, the scanner will always give you the digital noise, since you've told it it's "analog" (presuming the CTCSS / DCS programming doesn't "gate" the audio).
You'll always get this behavior on an analog scanner programmed with such systems or frequencies. It's possible to get it on a digital scanner, as well, depending on signal quality, scanner settings, etc.
Thanks. I kind of thought it was a digital signal showing up in an odd places.
cpsTN
Member
Did motorboating have the same meaning BEFORE digital, but not caused by digital apparatus?
As far as you sig, I now know why I keep running into buildings when I drive!
Comint
Member
One of the main examples of motorboating in days gone by (early 60's), was batteries in transistor radios going flat.
The battery voltage would get down to such a level, that the Local Oscillator would 'drop out' (stop oscillating). The battery voltage would then rise slightly because it no longer had the load on it, whereupon the oscillator would restart, and the cycle would repeat itself, resulting in 'chopped up' audio coming out the speaker (the putt-putt-putting).
Time to get new batteries.
Motorboating was also experienced in valve radios, in even earlier times.
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Comint
Yes. Motorboating, the low frequency oscillation that makes that noise, has nothing whatsoever to do with digital. It's generally a failure mode of an analog gain stage (amplifier) that's really not supposed to oscillate in the first place.
The guys that have been playing with radios since they had crystals and tubes would understand the term, and what the guys in this thread are refering to as 'motorboating', would probably be called something else.
As far as you sig, I now know why I keep running into buildings when I drive!
Yikes!
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