k9rzz
Member
Hey that's cool !!
John K9RZZ
John K9RZZ
Weather balloon frequencies?
- Thread starter k9rzz
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iMONITOR
Silent Key
k9rzz said:
You'd be surprised! Most of the signals from space, satellites, etc are very low power. When you have unobstructed line-of-sight, it doesn't take much.
w0fg
Member
k9rzz said:
Why not? I've worked over 5000 miles on 500 mw and about 150 countries with less than 5 watts.
Rick, W0FG
KG9NZ
Member
Signals on 403 MHz
I have been trying to receive the weather balloons as well and ran across this forum topic.
I've tried scanning both the 400-406 MHz bands and 1675-1685 MHz evenings shortly after 00z (I have a NWS office that launches weather balloons about 10 miles from me). I'm not sure what these balloons should sound like if I receive them. The only signals I have heard are on 403.063, 403.312, and 403.665 MHz. These sound like data signals, but they are there constantly (i.e. I've been listening to them since Friday night). Based on the band, I'm assuming these are weather data signals of some type. But I'm sure the transmitter from a weather balloon would not remain active for days.
I am attaching a recording of the signal I am hearing on 403.063 (receiver set to NFM). The other two frequencies sound the same, but each appears to have different data (i.e. the pulses are not in sync with each other). Can anyone help me identify what these signals are? And does anyone have any recordings of actual weather balloons so I could tell what I am listening for?
Thanks,
Frank KG9NZ
I have been trying to receive the weather balloons as well and ran across this forum topic.
I've tried scanning both the 400-406 MHz bands and 1675-1685 MHz evenings shortly after 00z (I have a NWS office that launches weather balloons about 10 miles from me). I'm not sure what these balloons should sound like if I receive them. The only signals I have heard are on 403.063, 403.312, and 403.665 MHz. These sound like data signals, but they are there constantly (i.e. I've been listening to them since Friday night). Based on the band, I'm assuming these are weather data signals of some type. But I'm sure the transmitter from a weather balloon would not remain active for days.
I am attaching a recording of the signal I am hearing on 403.063 (receiver set to NFM). The other two frequencies sound the same, but each appears to have different data (i.e. the pulses are not in sync with each other). Can anyone help me identify what these signals are? And does anyone have any recordings of actual weather balloons so I could tell what I am listening for?
Thanks,
Frank KG9NZ
KG9NZ
Member
Weather Balloon heard - Audio sample attached
I managed to hear a weather balloon on 1676 MHz using my Icom PCR-1500. I stationed myself near the airport at launch time. Best reception was WFM 50kHz. Using a sub-optimal VHF/UHF ham antenna on the roof of my car, I received the signal for about 15 minutes before it faded out. Winds were light (less than 10 knots up to several thousand feet) so the balloon probably only traveled a few miles away during that time.
The data should be decodeable, but I have no idea how. I found out my local weather service uses a Sippican Mark IIA radiosonde, which provides GPS, temperature, humidity, pressure. There is a program that is supposed to decode radiosonde data at
http://www.coaa.co.uk/sondemonitor.htm
but apparently it does not recognize the data format for this radiosonde. Definitely digital data, spectrum analyzed with Audacity shows peaks at 960Hz and harmonics.
If you wish to try receiving weather balloons, they are launched from certain airports at 2300Z and 1100Z each day. You can see a map of airports that launch these here:
http://weather.unisys.com/upper_air/skew/index.html
Not sure that all use the same type of weather balloon or the same frequencies. Bands allocated for weather balloons are 1675 to 1685 MHz and 400 to 406 MHz, so they should be somewhere in one of those ranges. These devices put out anywhere from 60 to 250 mW, and most receivers are not very sensitive above 1GHz, so you will probably need to be within a few miles to hear one.
Frank
I managed to hear a weather balloon on 1676 MHz using my Icom PCR-1500. I stationed myself near the airport at launch time. Best reception was WFM 50kHz. Using a sub-optimal VHF/UHF ham antenna on the roof of my car, I received the signal for about 15 minutes before it faded out. Winds were light (less than 10 knots up to several thousand feet) so the balloon probably only traveled a few miles away during that time.
The data should be decodeable, but I have no idea how. I found out my local weather service uses a Sippican Mark IIA radiosonde, which provides GPS, temperature, humidity, pressure. There is a program that is supposed to decode radiosonde data at
http://www.coaa.co.uk/sondemonitor.htm
but apparently it does not recognize the data format for this radiosonde. Definitely digital data, spectrum analyzed with Audacity shows peaks at 960Hz and harmonics.
If you wish to try receiving weather balloons, they are launched from certain airports at 2300Z and 1100Z each day. You can see a map of airports that launch these here:
http://weather.unisys.com/upper_air/skew/index.html
Not sure that all use the same type of weather balloon or the same frequencies. Bands allocated for weather balloons are 1675 to 1685 MHz and 400 to 406 MHz, so they should be somewhere in one of those ranges. These devices put out anywhere from 60 to 250 mW, and most receivers are not very sensitive above 1GHz, so you will probably need to be within a few miles to hear one.
Frank
iMONITOR
Silent Key
I tried to decode it. It was either partly sunny, or partly cloudy, not sure which. 
Actually that's pretty cool that you were able to receive it so good! Interesting!
Actually that's pretty cool that you were able to receive it so good! Interesting!
So you are saying that if I would put my antron on it's side and transmit with four watts, it would go up and out of space?
The signal that doesn't bounce off the upper atmosphere already does. The 5 watts that my FT-60 and VX-5 do that's for sure.
Huhh?????
nd5y
Member
RF is just like light. It travels forever unless something blocks it and get 4 times weaker whenever the distance is doubled.
cpuerror
Member
Some of these units do have GPS receivers built in with NMEA output to the transmitter. So if you find one of those you scored big time.
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