Emphasizing what Chris said.... China uses powerful SWBC transmissions to jam unwanted outside signals. One has to take a lot of care when identifying a station, especially if one isn't fluent in Mandarin. If you look up a transmission on a schedule and see SOH, RTI (Mandarin), RFA (Tibetan or Mandarin), VOA (Mandarin), or any broadcast in Tibetan, you're still much more likely to be copying CNR1 than any of those stations. I learned that well two summers ago when I used to listen to RTI in English at 1100 UTC, and hear it be dramatically drowned out at 1200 when it switched to Mandarin.
There are a few methods I use to determine which one I'm hearing. One of the best is to wait for :30 or :00 of the hour, because CNR1 has time pips while none of these other stations, RTI included, do. Another is to note if there's an echo reminiscent of short path/long path propagation. I believe China uses multiple transmitters at different locations when they jam and that that explains the echo, which does sound a bit closer than your usual long path signal from the same source does. Another is to look for either different stations that might be jammed (that is, if I've "found" RFA, then look for RTI or VOA or SOH in Mandarin) to compare audio, or a listed CNR1 broadcast that's not intended to jam.
Failing any of that, I will assume jamming just because in my routine listening I encounter it every morning while most of those other stations, especially at solar minimum, are challenging enough to copy.
Topic: Unid 6230 AM 2131 utc 01 Jun 2019 (Read 1020 times)
