Analog scramblers

[brandon]

Anyone know who is running the analog scramblers on the 4 and 5 meg bands? I'm guessing they may be fishing vessels or perhaps even from the Mexican Military. Some frequencies include: 4700, 5460, 5520 and 5555. I receive them very strong during local daylight hours here in California.

Here is an audio clip to get an idea of what they sound like.

 

[kb2vxa]

Simple voice inversion, the least secure of all encryption. Once upon a time a local cop shop went "yellow" when they didn't want scanner buffs to know what they were saying but my tone generator, diode ring demodulator, amp and speaker fixed it right up. There used to be all sorts of schematics, kits and even assembled units available but they went the way of all primitive technology when it becomes obsolete.

To answer your question, they're anything but military. I'll go with fishing boat radio pirates, not only do they operate on oddball frequencies to avoid eavesdropping but a decades old "scrambler box" affords a bit of extra protection from competition in their fishing grounds.

A thought just hit me, they could be using LSB when normal communication is conducted on USB. Selecting the opposite sideband will give the same sounding result on a receiver. That's another way they may avoid detection, the "other guy" might not think of that.

 

[brandon]

More today on 5600 and 5620 kHz. I have tried both sidebands. These are definitely scrambled. I also notice some data bursts usually just after the QSO wraps up. It's in the above recording too.

 

[hfdxer]

nice catch I have heard this before. This is the Mexican government. I have heard some scrambled transmission but the interesting thing is that some of the Spanish words are comprehensible. Obviously it is scrambled but must not be very sofisticated as Im able to understand some of it. Not on this particular transmission though.

 

[E-Man]

Sounds like the voice inversion that works with the ctp descrambler.

 

[kb2vxa]

"I have tried both sidebands."
I never said anything about you directly as I expected you would try both sidebands, "the other guy" may not be quite so intelligent.

"This is the Mexican government."
I would have expected them to have at least cerebros pocos but I could be wrong. Voice frequency inversion is so easy to recognize by ear and just as easy to re-invert using less than a handful of components so they may as well be transmitting in the clear... nos cerebros a todos.

 

[ff-medic]

Anyone know who is running the analog scramblers on the 4 and 5 meg bands? I'm guessing they may be fishing vessels or perhaps even from the Mexican Military. Some frequencies include: 4700, 5460, 5520 and 5555. I receive them very strong during local daylight hours here in California.

Here is an audio clip to get an idea of what they sound like.

If, And I mean "IF" it is voice scrambling / inversion..most likely it can be descrambled. There are quite a number of voice descramblers on the market. Voice inversion was a big thing in the 80's with law enforcement. But, there were boxs..commerically sold , where you turned the box on...and adjusted a dial that made the voice " In the clear".

Now a days..If it is not some sort of unique digital or encrypted radio system...More than likely it is not secure. I prefer DES or AES , to most other encryptions. Agencys pay this and pay that for a complicated and secure radio system...when simple AES and DES has been used successfully by the U.S Govt for years..and to my knowledge ; and U.S Military experience..with no hasssles or complications.

FF - Medic !!!

 

[ff-medic]

Anyone know who is running the analog scramblers on the 4 and 5 meg bands? I'm guessing they may be fishing vessels or perhaps even from the Mexican Military. Some frequencies include: 4700, 5460, 5520 and 5555. I receive them very strong during local daylight hours here in California.

Here is an audio clip to get an idea of what they sound like.

A great source among many sources = Ramsey Electronics.


FF - Medic !!!

 

[Hooligan]

"Secure" or "Security" is a relative term. Whether or not something is "secure" depends on what the reasonable threat was at the time. Tactical security tries to protect the resource (person, information, facility, etc.) against a known or suspected threat for that particular moment and the forseeible future whereas strategic security is also concerned with long-term threats.

If these guys are simply fishermen, they're mostly trying to protect their comms from other fishing fleets, so they don't need a really sophisticated encryption system, and they're mostly trying to protect tactical information -- how the fishing is at certain locations at that very moment or that week.

Also, keep in mind that DES & DES-XL were never designed or supposed to be used by the US gov't for classified information, just some information that was tactically sensitive. To protect classified information, tactical or strategic, other encryption systems/comm networks were available to (most) users who had a need for it.


DES & AES are nice, but not always easy to use on what is otherwise an analog system, such as the comms heard by the OP.

 

[kb2vxa]

Gee Hooligan, I THOUGHT that sounded strangely familiar. (;->)

>To answer your question, they're anything but military. I'll go with fishing boat radio pirates, not only do they operate on oddball frequencies to avoid eavesdropping but a decades old "scrambler box" affords a bit of extra protection from competition in their fishing grounds.