SIGINT: Cool things to do with just a WebSDR!
Note: If you are not a huge fan of perusing a long-form piece, an explanatory video will soon be out on my Youtube channel, so keep a watch :)
SIGINT is a multipurpose craft that you will always yearn for, doesn’t matter if your work is directly or indirectly linked to any form of investigation.
Well, if you haven’t yet… now is the time to experiment with online radios and eavesdrop on a frequency that fascinates you.
No, you don’t need an antenna or hardware if you are a dabbler and merely need a receiver to lurk into random stuff which could potentially be of your interest.
Just entering the term ‘WebSDR’ on a search engine is sure to provide you with innumerable results, comprising random websites to even portals and databases for searching any frequency from VLF to UHF.
Although won’t call this ‘DXing’ as that would be a shame to the actual community, haha!
WSPR/FT8/CW:
Let’s say you come across ham radio frequencies, which mostly use WSPR (Weak Signal Propagation Reporter) protocol and FT8 mode at present times. Historically, it used to be in the CW mode, which is encoded in Morse code.
A valid reason for amateur radio operators shifting to FT8 mode is thought out to be its much wider coverage than CW mode, which in turn makes contacting individuals from distant areas rather easier.
One of the key advantages of a WebSDR is the multiple options that we get for decoding numerous radio modes in a single window by just selecting from a drop-down menu.
Here’s an example of a decoded signal using FT8 mode:
For FT8, you get a character limit of 13 per message which requires 13 seconds to send. Always consider these conversations into 4 slots per minute, as your transmission will take 15 seconds, then replies will take another 15 seconds, thereafter you will transmit again for the next block, and so on…
A typical FT8 conversation:
– CQ + (call sign 1) + (4 character location 1)
– (call sign 1) + (call sign 2) + (4 character location 2)
– (call sign 2) + (call sign 1) + (signal report in numerals 1)
– (call sign 1) + (call sign 2) + R (signal report in numerals 2)
– (call sign 2) + (call sign 1) + RRR
– (call sign 1) + (call sign 2) + 73
– (call sign 2) + (call sign 1) + 73
The alien characters that you notice in the conversation are written in ‘wire signal’ which is a brevity code used by telegraphers and ham radio enthusiasts to convey their message in a few characters, examples of which you can find here. CQ is an exception which is often used by voice operators or those communicating in morse code to make a general call.
Along with that, you may check out PSK Reporter website to view till where your CQ calls are reaching by entering your call sign (if you are a licensed ham radio operator).
Regarding WSPR, a standard message using this mode compresses its content into 50 bits, containing the call sign, 4 character locator and dBm transmit power (E.g., K1ABC FN20 37). As for messages with a compound call sign and/or 6 digit locator, a two-transmission sequence is used.
The locator that is mentioned above (FN20) is a Maidenhead grid cell, based on the Maidenhead Locator System. This geocode system is used by amateur radio operators for describing their geographic coordinates in a concise manner.
After that, what you can do is to simply copy the call sign that you wish to know more about, and paste it in https://hamcall.net (or the likes of it) to gather the user’s name and location.
There are also a bunch of websites which allow you to analyse real time WSPR spot data, though this one is considered to be more accurate.
On a side note, WSPR is often used for tracking a certain ship’s path, provided that the vessel has been equipped with a WSPR system. Wondering if it could be used for Russian navy ships or polar expedition ships? Yes, it can be!
Pagers (mostly used in UK):
Next up is a pager, an antiquated technology which is often found to be employed in the UK hospitals during emergency cases.
From a 61-year-old man receiving CPR in a random hospital (which is also named) to a patient who wants someone to take care of his cat for the time being, it’s astonishing as well as extremely alarming to witness this extent of bizarre info that you would have probably never imagined.
Just turn on the page mode from where it is written ‘DIG’ and enter the frequency over which the pager is seemingly operating, or find it on the bandwidth by randomly tuning into possible pagers.
SSTV:
A slow-scan television (SSTV), reminding you of olden days, is used by amateur radio operators to either transmit or receive static pictures via radio. It could be both, monochrome or colour.
Just click on the SSTV decoder and see the magic over frequencies that apply.
IBP:
International Beacon Project (IBP), a network consisting of 18 continuous wave (CW) beacons which operate on five designated frequencies in the HF band, in order to provide a way for monitoring the prevailing ionospheric signal propagation characteristics to users with amateur or commercial high frequency radio.
Choose the IBP Scanner mode from the menu and watch the continuously changing beacon station names written over the ongoing signal.
TDoA:
Suppose a signal is transmitted from a station and is received by several other stations located far away at different time intervals as a result of varying distances, this is what we call time-difference-of-arrival (TDoA) using which the transmitter’s position is calculated.
You may also combine it with the triangulation method to get a more precise location if you are supported by the required equipment needed to do the same.
You will find the TDoA direction finding service option in some of the WebSDRs, which has just recently been added.
For all things maritime…
Navtex, DSC or random Navy stations – you’ll find it all here… which is scary enough if you understand its sensitivity. As for Navtex (abbreviation for navigational telex), it can also be found at http://navtex.lv, or you may check https://iho.int/navigation-warnings-on-the-web to access specific Navarea warnings.
A ship is not merely a hollow sea-going vessel. It comes equipped with proper security mechanisms – more the number of technologies installed, greater the chances for it to be tracked in some way or the other.
These maritime safety procedures are ensured by the GMDSS (Global Marine Distress and Safety System), an international system developed by the IMO for automated emergency signal communication for distressed ships, boats, and aircraft. All the GMDSS-regulated ships are bound to carry a Navtex receiver (if applicable for their sea route), an Inmarsat-C SafetyNet Receiver (if their sea route is not served by Navtex), satellite EPIRB, a DSC-equipped VHF radiotelephone, two or three VHF handhelds, and two 9 GHz SARTs (search-and-rescue radar transponders).
Navtex is essentially designed to send warnings or other significant messages for a bunch of vessels traversing a specified area. To keep it simple, maritime regions across the globe have been divided into Navarea and Metarea sections for sending out navigational as well as meteorological warnings.
However, SafetyNet replaces the functions of Navtex for a few regions which are devoid of Navtex service. These messages are sent using the Inmarsat C system to a group of ships or ships in a particular area via the Inmarsat satellites. SafetyNet along with FleetNet together constitute what we call the Enhanced Group Call (EGC) service.
Other than this, EPIRBs (Emergency Position Indicating Radio Beacons) transmit distress signals on 406 MHz to the Cospas-Sarsat satellite system, containing a unique 15-digit identifier or the vessel’s MMSI number depending on the place of registration. This makes it prone to false alerts which can be made even by a brief inadvertent signal.
Anyway, getting back on track… here’s a Navtex warning coming from the Istanbul Turk Radyo that I randomly stumbled upon.
On the other hand, DSC (Digital Selective Calling) messages are primarily used to send an automatically formatted distress alert to the Coast Guard or rescue authorities, and also other vessels in close proximity. These alerts are sent on VHF marine radios.
The DSC message given below is an acknowledgement of the initial safety test conducted between a vessel and the coast station.
For military vessels, click on the FSK (Frequent Shift Keying) decoder and choose a random frequency from the ‘Military’ drop-down menu. For this example, I have chosen a frequency used by the Dutch Navy via which it sends CARB (Channel Availability and Receipt Broadcast) transmissions.
Some naval stations employ both RTTY and STANAG-4285 for CARBs. You will mostly witness the use of STANAG-4285 in NATO bases.
The 3 characters often present in the end are call signs of Royal Netherlands Naval bases. Hence, ‘PBB’ in this case refers to Den Helder, the main Dutch naval base. Lastly, ‘the two numerals and one alphabet’ form (e.g., 04B) refers to the warship frequencies pertaining to the naval station.
To assess the above broadcasted message more properly, kindly go through this article.
Important sites and documents for world Navy frequencies:
- https://i56578-swl.blogspot.com/2014/08
- https://priyom.org/military-stations/russia
- http://www.numbersoddities.nl/MX-profile.pdf
I am yet to discover how to use ADS-B and HFDL for aircraft monitoring and similar VHF-based AIS/ACARS systems, however I can share with you some fascinating facts that I discovered as I was unceasingly curious about certain frequencies all this time.
First of all, you should check out this awesome site for weekly radio log roundups: http://worldofradio.com/Hauserlogs.html
Now back to our course, China's firedrake jammer was something out-of-the-ordinary which is said to be sourced from the ChinaSat 6B satellite and then transmitted by relay stations. The extent of radio censorship by the CCP for the Mandarin-speaking audience is crazy... you won't get to hear channels affiliated to Voice of Tibet, Radio Free Asia, Radio Taiwan International, Voice of America and BBC World Service on the SDR as a result of the Chinese jamming sound transmitted on the same frequencies used by the target stations, which is usually composed of Chinese folk music. This composition is called 'The Firedrake' which runs for over one hour and then checks on the target station (if it is still active), thereafter runs for another hour, and the cycle goes on. On certain occasions, the signals are silenced using China National Radio broadcasts.
Secondly, the Japanese Maritime Self Defence Force (JMSDF) has a transmitting station in Ichihara which is nicknamed as the Japanese Slot Machine (enigma designation: XSL). It transmits data in the form of QPSK (quadrature phase-shift keying) at 1500 Bd, and sometimes in USB mode. Usually working on several frequencies at the same time, some of these still remain constant since the radio station’s inception… these are – 4231.5 kHz, 4291 kHz, 6417 kHz, 6445.1 kHz, 8588 kHz, and 8704 kHz. With its idle traffic signal closely resembling slot machine sounds, XSL is apparently used by the JMSDF for transmitting signals to the nearby ships.
And an honorary mention to the spy numbers stations which are presumably active since World War I, you can find more about it here!
BONUS: Israeli navy Haifa port radio frequencies – https://fmscan.org/net.php?r=b&m=s&itu=ISR&pxf=4XZ
Dedicating this post to all the journalists situated anywhere on the globe, who should not be left out as they always have chunks of really important stuff to research on… for a good cause, obviously.
