Welcome, Guest. Please login or register.
Did you miss your activation email?
September 21, 2014, 12:06:35 AM
Home Help Login Register      
News: LiveATC.net Flyers Released!  Please click here to download & print a copy and be sure to post at an airport near you!


+  LiveATC Discussion Forums
|-+  Air Traffic Monitoring
| |-+  Aviation Audio Clips (Moderators: dave, RonR)
| | |-+  SuperDARN, HFDL or what?
« previous next »
Pages: [1] Go Down Print
Author Topic: SuperDARN, HFDL or what?  (Read 5873 times)
InterpreDemon
Sr. Member
****
Offline Offline

Posts: 420



« on: May 24, 2013, 11:01:37 PM »

I hear these sets of four zipping type pulses every two minutes (like clockwork) on the HF frequencies, not just my feed but some of the others as well. The infamous Russian "Woodpecker" died with Chernobyl, but I really don't know what this is. It never really bothered me before (have heard it for years) and I just assumed it was something wideband that was hitting me... until I began listening to two frequencies at the same time in stereo on the feed and noticed that it hits them (in this case 5550 on the left and 6577 on the right) at different times, but still on a precise interval of two minutes. I have listened to SuperDARN before and that is usually just above 10mHz, plus it only has a 40kc bandwidth, and though I have not listened to HFDL this does not sound like modulated sub-carrier to me, nor is it on the HFDL frequencies... these are voice. If it is a sweeper, I don't know how it could move up a full mHz from 5550 to 6577 in five seconds and still land four pulses on each frequency in between, which suggests to me that it must be something ARINC is doing either for an HFDL squitter or perhaps some propagation monitor or beacon. I have not been able to find anything about it or anything that sounds like it on the web.
Logged

Feed Purveyor:
KJFK ARINC
KHPN ATIS
(KJFK) NY DEP Liberty East
HF CAR-A  3455/5550/6577/8846/11396
HF ARINC LDOC  6640/8933
HF NY VOLMET  6604

Complaints should be addressed to: City Hall
Jetblast1
Full Member
***
Offline Offline

Posts: 113



« Reply #1 on: May 25, 2013, 02:48:41 PM »

I am not for sure, but I found this on the web:

Double Second Time Markers
Other International time and frequency standard stations share 2500, 5000, 10000, and 15000 kHz. Sometimes they can be heard from Salt Lake City when the skip distance is long. One of those stations is BPM in Pucheng, China, which is operated by the Chinese National Time Service Center (NTSC) (Shaanxi Astronomical Observatory, Chinese Academy of Sciences). BPM usually broadcasts Coordinated Universal Time (UTC) like WWV and WWVH do, but during minutes 25 through 29 and 55 through 59 of each hour BPM transmits UT1 instead. UT1 varies up to 0.9 second from UTC and the time difference can be either positive or negative. As a result, BPM’s time blips during those minutes normally lead or lag WWV and WWVH time ticks. BPM uses Chinese female voice identification during the last minute of each hour.

And on the google page I found an explanation that would fit the sound, it says:

"HF Time and Frequency Standard Stations - The S-Meter Site
www.smeter.net/stations/hf-time-frequency.php

The signal strength is typically about S7 in Salt Lake City during winter nights when ... to hear because of strong interference from U.S. Amateur Radio stations. 4996 kHz, RWM, Unknown, 5550 Miles, Institute of Metrology for Time and Space"

So again I am not realy sure, but it sounds likely to be from another frequency, the time marker on 5000 KHz seems to be strong enough during calm nghts....
Logged
InterpreDemon
Sr. Member
****
Offline Offline

Posts: 420



« Reply #2 on: May 25, 2013, 03:15:00 PM »

It would have to be pretty strong harmonics because I pick them up with the R-390's too, and they are bleed-proof. I think I might not have been clear... that recording is edited and has multiple sets of the pulses over a eight or ten minute period. Each set, left (5550) then right (6557) five seconds later, repeats every two minutes precisely and signal strength varies by band, in other words you don't always hear it on both, but in the early evening when both 5550 and 6577 are alive you can often hear it on both, never simultaneously but usually one leads or lags the other by between five and fifteen seconds. You can hear it on 6577 pretty much all the time. Like I said, I've heard this for years but always assumed it was something broad-band or the electric meter calling mommy or something, and it was only after spending time listening to my stereo feed that I realized it was occurring asynchronously on two different bands. I suspect it could be the SuperDARN radar network, but that is only supposed to be operating between 8-20 mHz and recordings I have heard are not like this at all... same goes for the HFDL, which sounds more like PSK.

I thought it was probably local until I heard it on Dave's feed up in NH, so that makes it a real puzzler.
Logged

Feed Purveyor:
KJFK ARINC
KHPN ATIS
(KJFK) NY DEP Liberty East
HF CAR-A  3455/5550/6577/8846/11396
HF ARINC LDOC  6640/8933
HF NY VOLMET  6604

Complaints should be addressed to: City Hall
Pages: [1] Go Up Print 
« previous next »
Jump to:  


Login with username, password and session length

Powered by MySQL Powered by PHP Powered by SMF 1.1.19 | SMF © 2011, Simple Machines Valid XHTML 1.0! Valid CSS!