Ambient noise charts

[Roberto]

Hello,
I just received this weather fax chart from Northwood, the title says "Ambient noise"; not having a clue about what it might be I googled and found it's the output of a model of sea ambient noise, mainly in use by military and research people using underwater sound techniques (seismic, oceanographic, etc). Given that these end users possibly have no problem at all with high speed communications by satellite, is there a reason this data is also broadcast with this rather old technology?
Also, haven't they better ways of computing the level of this ambient noise locally, rather than relying on model output?
r.

 

[Buck Turgidson]

Hello,
I just received this weather fax chart from Northwood, the title says "Ambient noise"; not having a clue about what it might be I googled and found it's the output of a model of sea ambient noise, mainly in use by military and research people using underwater sound techniques (seismic, oceanographic, etc). Given that these end users possibly have no problem at all with high speed communications by satellite, is there a reason this data is also broadcast with this rather old technology?
Also, haven't they better ways of computing the level of this ambient noise locally, rather than relying on model output?
r.


View attachment 179625

I would imagine that anyone who knows why also knows it's not for public consumption.

 

[zoidberg]

"Give me a ping, Vassily. One ping only...."

 

[GHA]

Nice image -

Is that on the schedule?
https://www.weather.gov/media/marine/rfax.pdf
GYA Northwood – WEATHERFAX

Quick google couldn't find "ANPS PROGNOSIS", wonder what that is, ambient noise?

edit - found it > "24 H ANPS Ambient Noise Prediction System PROGNOSIS 00"
https://www.hisse-et-oh.com/store/medias/sailing/5dd/218/693/original/5dd2186939819f3668e08456.pdf

For those without a receiver curious to have a play, Fldigi software can be set to listen to stereo mix & use someone else's receiver on websdr
http://websdr.ewi.utwente.nl:8901/
On a windows laptop anyway.

Nice that GYA is transmitting, the schedule is actually more useful on passage than DWD.

And just thought as there isn't enough on the to-do list already, every single usb, computer, phone charger, buck/boost should be on one circuit so they can all be turned off at the flick of a switch, even the victron smartshunt is a bit noisy on RF

 

[RobbieW]

It's cosmic, man...
Glast-ambient – Electronic Sound

 

[Roberto]

And just thought as there isn't enough on the to-do list already, every single usb, computer, phone charger, buck/boost should be on one circuit so they can all be turned off at the flick of a switch, even the victron smartshunt is a bit noisy on RF

I bought this timer switch to stop the fridge at the crucial hours and avoid to blur half a chart, good for the IT impaired like myself The number of times I manually switched the fridge off while receiving and then forgot to put it back on until the following day...
https://www.amazon.fr/dp/B06ZYYG3W1?psc=1&ref=ppx_yo2ov_dt_b_product_details

 

[GHA]

I bought this timer switch to stop the fridge at the crucial hours and avoid to blur half a chart, good for the IT impaired like myself The number of times I manually switched the fridge off while receiving and then forgot to put it back on until the following day...
https://www.amazon.fr/dp/B06ZYYG3W1?psc=1&ref=ppx_yo2ov_dt_b_product_details

Same here!!!! Fridge now talks to the raspberry pi so click of a mouse can turn it off for 15 minutes

 

[zoidberg]

If I made a guess.... relating to the pre-deployment settings for air-dropped passive sonobuoys.... could I expect a visit from a wee humourless man in a grubby trenchcoat asking me to stop making wild guesses..?

 

[capnsensible]

If I made a guess.... relating to the pre-deployment settings for air-dropped passive sonobuoys.... could I expect a visit from a wee humourless man in a grubby trenchcoat asking me to stop making wild guesses..?

Dread nought. That will not compromise our sleek underwater deliverers of megadeath....

 

[zoidberg]

Dread nought. That will not compromise our sleek underwater deliverers of megadeath....

...If the boogers can find their way out of the Clyde!

And I still find myself chuckling over the scurrilous old tale of the Silent Routine and the CPO's Cufflinks....

 

[GHA]

View attachment 179625

What do you use to receive such good images? I can get readable & useful images but not sure if the noise is from the boat or just because it's a long way from the south of Portugal to northwood or Germany.
Using an Icom ic7000 through a signalink into fldigi running on a Pi 4


Fitting the post the raspberry pi right now is playing Hania Rani from a random ambient mix

 

[wonkywinch]

Beats listening to the squeaky wheel.

 

[Roberto]

What do you use to receive such good images? I can get readable & useful images but not sure if the noise is from the boat or just because it's a long way from the south of Portugal to northwood or Germany.

My apologies I forgot to answer.
That is a very good image indeed (albeit useless to us), on average I have no such luck they come with all types of small disturbances, greyed like yours, tiny spots sprinkled everywhere, except the fridge which wipes out almost everything.
That one was with a WIBE (Wetterinfobox, Morer electronics), sort of programmable SDR receiver for Fax, Navtex, Rtty etc, very nice piece of kit I acquired SH recently, once configured it tunes to the best frequency and saves the broadcast, it has its own active antenna on the stern gantry. Otherwise during the past years I mainly used an Icom 706, or the Degen 1103. Quality of images more or less comparable, ferrites everywhere help but I think the boat EMI environment is the main determinant, the quality of the receiver/antenna coming second.