I recall a certain group mistakenly believing that same 1566 jammer was from
Yanbian too, until I notified that it most certainly was not since Yanbian
People's Radio could not broadcast from the same town as a high-powered
jammer. :o)
My recordings of 1566 while in Seoul in early November clearly show the
jammer is *exactly* as it was in the past, as 1467 is as well. Nothing has
changed with either of those signals (i.e. the actual jamming sound of them
as heard locally). 1467 is the same laser jammer at the moment as I listen
to it. 1566 is the same too as I'm listening to it right now.
However... with that said, North Korea does use a different type of jammer
than the south does, technology-wise. The 1584 jammer starts out low and
gradually sounds bigger before it eventually self-destructs (no better way
to put it) and starts over again. You can see the whole hilariously awkward
process on the SDR actually, as I have saved images of it.
It's possible that everyone is hearing this same process in the audio of the
1566 jammer but not hearing the actual laser-like sound as you seem to be
suggesting too. Jammers sound different from a distance, absolutely. The
signal sounds... wider somewhat, a lot like 1206 Yanbian... that loud hum
their signal has that shows as a really wide line on the SDR and kind of
kills the clearness of their audio. I hear that same sort of hum when the
jammer is behind Jeju and it's possible in coordination with the jamming
noise, it is cycling every 2 seconds, which is what you end up picking up
from it and may also explain why the sound sometimes peaks and gets louder
over Yanbian in my recordings of it.
Jeju is too strong on my friend's SDR to *clearly* hear the jammer, as
compared to the signals in the city, which usually heavily favor Pyongyang
and northeast China. And Yanbian is, as usual, interfering with it too.
That's the best explanation I can give (aside from a totally separate
north-aiming jammer I cannot receive in Seoul over a local south-aiming
one), because these jammers have not changed at all, not as heard locally
anyway. Mauno should always feel free to ask me about these things too. Even
if I'm not in Seoul, many of my radio friends are and I can access some of
their equipment online when needed. Just seemed silly to me to go through
asking people from other countries for help when you've got someone with
Pyongyang as daytime locals less than 100 miles away. :)
Those recordings are ... interesting though, although I'd never have the
patience to deal with a mere hum...
-Chris Kadlec
Seoul AM Radio Listening Guide
Date: Wed, 21 Dec 2016 00:28:31 +0000 (UTC)
From: [email protected]
Subject: Re: [IRCA] Puyallup, WA Ultralight TP's for 12-20
Hi Chris,
<<< I know from my own extensive experience that jammers change their
sound over
long distances (from my own words, as a matter of fact), but it doesn't
sound like the 1566 laser jammer. The sound is too... smooth, and the
pattern is too consistent and spread apart for it. It would be less
consistent as it tries to break through typical audio, as you can hear in
the clip below. But then again, I didn't hear any of your audio outside
this
clip, so it's hard to truly judge, and I don't know what the jammer would
sound like overseas where it would obviously be mixing with Jeju's
directional signal. I just feel it would be a hard time justifying this
one
as the jammer, in my opinion anyway, from someone who used to hear this
pain
in the ass every night. >>>
The 1566 pulse-type jammer was first noticed here in September, although
back then it had a simple, buzzing bee-sounding pulse very two seconds. An
MP3 of that jammer signal on HLAZ's Japanese service at 1254 UTC on
September 24, 2016 is at the following link
https://app.box.com/s/gm78l03yw105533ewwaocf42qzur08l9
That MP3 was forwarded to the Real DX Yahoo group, where Mauno Ritola
submitted it to Asian experts for investigation. They concluded that the
Jammer was from North Korea, based on its similarity to the 1467-Mokpo
Jammer.
The 1566- N.K. Jammer has been augmenting its jam signal since then,
however. In addition to the buzzing bee pulse every two seconds, in
October it added a pulsing tone of about 2 kHz every two seconds, in
cycles in between the buzzing bee pulse. The 2 kHz pulsing tone now seems
to be the primary noisemaker, although the buzzing bee tone can still be
heard in between the 2 kHz tones when the Jammer is strong. This is the
current 1566-Jammer signal, as recorded at 1315 on November 26th
https://app.box.com/s/gg15dn3r7k30hl9kjnif3zqs2ctgcmzq
On most days the 1566-jammer shows up along with HLAZ here, although in
the new sound format (like in the recording posted from this morning) it
typically is only audible with the 2 kHz pulsing tone every 2 seconds.
This would probably be the only weak indication of the Jammer for someone
who is struggling to hear it in North America under HLAZ for the first
time. Of course it is an independent TP station, so although it generally
follows the same propagation as HLAZ, it fades in and out at different
times than HLAZ. Rarely it is all by itself on the frequency.
Gary DeBock (in Puyallup, WA, USA)
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