What is a Radiosonde for?

[BoomboxDX]

Really dumb question I know, but what is the purpose of these radiosondes? Are they weather balloons? Are they used for a different scientific purpose?

And what are their primary frequencies? Does someone have to have a high gain antenna to hear them if they are in the vicinity?

The only VHF DXing I've done (aside from some scanning and PSB and Railroad band listening in the past) is when I heard some NOAA weather satellites in the 136 Mhz band, the beepbeepbeepbeep sound that would occur as they drifted over the area.

[ChrisSmolinski]

Yes, they are weather balloons. They are launched twice a day (just before 0000z and 1200z) from many locations across the US. If you search the web you can probably find the NWS map of sites, it may be given in an early message on this board as well.

They use 1676, 1678, 1680, and 1682 MHz.

If they pass close by (overhead), I can get reception with just a discone antenna. Otherwise I use a modified WiFi dish antenna for high gain.

[BoomboxDX]

Thanks for the info, Chris. Not sure I have a radio that goes that high... but it makes it easier understanding the posts on this section of the forum knowing what these radiosondes are.