Cool find! S&F to the OP.
For many years I have been fascinated by Numbers Stations and have done a considerable amount of research into them, and the philosophies behind them
as well. Even without knowing what they're saying, it's still a quite interesting area of research.
Here are ten interesting facts for those interested...
1. As another poster noted, the reason you can receive the signal one hour and not the next is because of the way High Frequency, or "HF", broadcast
signals propagate through the atmosphere. It is for this same reason these stations are difficult if not impossible to accurately locate. The
signals from these HF stations bounce ("skip") off different portions of the atmosphere so reception is not a matter of line of sight. An HF signal
can be heard anywhere in the world. Sometimes, a signal originating on the other side of Earth can be heard better than one originating just 50 miles
2. Through the use of a 'One Time Pad' on the remote end, the same numbers can be broadcast over and over again for years, but mean something
completely different each time they are broadcast. There are slight variations in the number sequences on some stations which just heighten the
intrigue. If implemented correctly, the code associated with a true One Time Pad cannot be deciphered, not even by the multi-billion dollar code
cracking computers of the NSA and MI-6. Each pad is different, and is never repeated (ever).
3. Numbers Stations are as much 'mind games' as they are official communications mediums, and this is part of the strategy using them. The listener
has no idea how many people the number sequences are being broadcast to. It could be thousands, or none at all, but the numbers just keep on
going...forever. Today the numbers could be being broadcast to 200 people, tonight just 5 people, tomorrow morning none at all and that afternoon to
3,000 people. You can't tell from just listening.
4. Numbers stations can be used to play mind games on an adversary. Let's say I start broadcasting sequences of numbers which can be heard in your
country, does that mean I now have spies deployed there...or is it that I just want you to think I do?
5. Consequently, I can make my adversary spend time, resources and money on trying to figure out what I'm up to, when I might be up to nothing at all
other than trying to distract my adversary...and make him spend time, resources and money. However, because I keep doing broadcasting, relentlessly,
day after day, month after month and year after year I might equally be saying something really important. I might be setting up an elaborate
underground network for an uprising, an attack, an assassination or a coup d'etat...and because you don't know, you can't ignore it.
6. As Numbers Stations evolved most countries employing them moved to automated voice generators. These remove any potential for unintended give
aways like having a sense of urgency in your voice, etc. The numbers are just an endless string of monotone sequences of usually (5) numbers, but
sometimes (4) or (3). Generally never more than (5) numbers at a time though.
7. Numbers Stations don't turn on when there's a message and then turn off when there isn't a message because this would be a dead giveaway.
8. Numbers Stations many times do broadcast other things like music and sounds (the buzzer in the OP's example etc.). More recently there are also
squeeks and squawks which are clearly bursts of digital data (but for what?).
9. Strangley, most Numbers Stations are broadcast in English. There are some in other languages like Spanish and Chinese, but the vast majority are
10. There are other mysterious radio stations out there which broadcast all sorts of other weird stuff like odd sounds over and over again. They have
some purpose, but no one really knows for sure what that purpose is...only the originator knows the purpose and the audience. The rest of us just
have to sit and wonder.
edit...BTW, there are lots of resources out there on the Interwebz where you can find out more about these mysterious radio stations. It's a very fun
and intriguing thing to look into.
edit on 3/19/2014 by Flyingclaydisk because: (no reason given)