• Effective immediately we will be deleting, without notice, any negative threads or posts that deal with the use of encryption and streaming of scanner audio.

    We've noticed a huge increase in rants and negative posts that revolve around agencies going to encryption due to the broadcasting of scanner audio on the internet. It's now worn out and continues to be the same recycled rants. These rants hijack the threads and derail the conversation. They no longer have a place anywhere on this forum other than in the designated threads in the Rants forum in the Tavern.

    If you violate these guidelines your post will be deleted without notice and an infraction will be issued. We are not against discussion of this issue. You just need to do it in the right place. For example:
    https://forums.radioreference.com/rants/224104-official-thread-live-audio-feeds-scanners-wait-encryption.html

military seeking tech to override am/fm broadcsts

Status
Not open for further replies.

screenersam

Member
Premium Subscriber
Joined
Jan 29, 2006
Messages
559
Location
Somerset County, MD
#1
Special Operations seeks way to override broadcasters

***The U.S. Special Operations Command wants to find technology that would allow it to locate AM and FM radio signals in a specific area and then override those signals to send propaganda messages.
The SOCOM solicitation, posted Monday afternoon, calls for "sources to provide a radio broadcast system capable of searching for and acquiring every AM and FM radio station in a specific area and then broadcasting a message(s) in the target area on all acquired AM and FM radio station frequencies." The command, which is playing a larger role in military propaganda, is contemplating doing foreign comparative testing, which examines foreign technology to see if it's capable of doing the job, as it examines potential options, the solicitation said.***

just as long as they don't use it domestically
 
Joined
Feb 10, 2005
Messages
899
Location
Northern Alabama
#3
1) Transmit on the same frequency with considerably more power than the BC station.
2) Take down the power to the BC transmitter and then transmit on the frequency.
3) If the BC station is using a STL radio link, find the frequency of the link and take over the frequency.

Doesn't seem that hard to do, or am I missing something?
 
Joined
Jul 28, 2008
Messages
555
#5
I think the technology has been in existance forever. Come to think of it, IMHO I may be inclined to actually switch over to the FM band if I knew that the military was going to broadcast some messages to displace the usual lousy music and childish announcers.
 

Token

Member
Premium Subscriber
Joined
Jun 18, 2010
Messages
2,014
Location
Mojave Desert, California, USA
#6
I would have figured that could have been done long ago.

Possibly it could have technically been done in the past, however the specification as loosely described in the market survey inquiry are quite ambitious, particularly if the platform must be airborne as it sounds it might be. Depending on what they define as “a specific area” and the technology density in that area it might not be a really achievable goal.

If such a single integrated system exists today I have not heard of it.

T!
 

Token

Member
Premium Subscriber
Joined
Jun 18, 2010
Messages
2,014
Location
Mojave Desert, California, USA
#7
Bando Solo has been doing this for years. This does not seem like anything new.

I assume you mean Commando Solo?

And no, Commando Solo has not been doing this for years. Commando Solo does do AM, FM, TV, and military Psyops transmissions, however it really does not have the ability to jam and override an existing station unless that station is pretty limited.

To achieve the ability very loosely defined in the market survey (take over multiple broadcast sources) in the past has taken a combination of efforts. Target a transmitter facility or its power source to take it off the air and then transmit your own information on the now vacant frequency.

This market survey sounds something like a combination of some of the Compass Call capability (automatically detect and then respond to transmissions) with a new enhanced version of Commando Solo.

T!
 

Token

Member
Premium Subscriber
Joined
Jun 18, 2010
Messages
2,014
Location
Mojave Desert, California, USA
#8
1) Transmit on the same frequency with considerably more power than the BC station.
2) Take down the power to the BC transmitter and then transmit on the frequency.
3) If the BC station is using a STL radio link, find the frequency of the link and take over the frequency.

Doesn't seem that hard to do, or am I missing something?
To do as you describe in 1) might be beyond the ability of an airborne platform with its limited power budget. To do this against any one station requires the jammer to achieve a specific (defined by the information of the transmission) J/S (jam to signal) ratio. This ratio can be achieved by either the jammer having a higher ERP (by the desried J/S) than the target signal, or the jammer source being closer to the receiving station. The geometry of getting your jammer closer to the receive stations results in a small affective footprint.

To achieve a higher ERP than a single 25 kW (25,000 Watts) FM broadcast station plus a 10+ dB J/S might require something on the order of more than 60 dBW. Call it 100 kW and a 10 dB antenna gain…from an airborne platform…to defeat a single station. And you have to work similar things out for each and every FM BC stations in the “specific area”. Just as an example there are 23 FM stations in the Cairo, Egypt, area. Most of them are less than 25 kW, but most are also more than 2.5 kW. To jam and take over the broadcast of all of those stations might well require more than 1 MW (one million Watts) of power.

And that is just the FM BC band, TV would be a similar issue (if required, Commando Solo addresses TV, but the survey does not mention TV), but the AM band would be even tougher, because I doubt you would get the antenna efficiency of a land station from an airborne platform (I am assuming airborne platform, if you already have boots on the ground just take over the station). What you cannot do in antenna gain you must do in raw transmitter power.

You might end up needing a 10 Megawatt power source just to supply the jammers.

So I assume someone will propose something a bit more sexy and bit less brute force.

What you describe in 2) is already done using a few low cost LGBs and the afore mentioned Commando Solo aircraft.

What you describe in 3) is not very practical. It would work for relatively few stations and then all the station owners have to do is kill the link and feed the audio via a different source.

To do the tasking described in the market survey is not a trivial matter. Note that the survey is clearly defined as not being a request for proposal. They only want to find out who in industry might think they have the necessary hardware, skill set, and past performance, to take on such a task. It would be a pretty fun project to be involved with, I can think of a couple of approaches that might apply. But, more data would be needed to down select to a set of options.

Also notice the survey also specifies that they are looking for “a non-developmental light-weight, multi-frequency, simultaneous over-broadcast system that has demonstrated a Technology Readiness Level of 8 or higher”. This sounds like they have specific hardware in mind. If I was a betting man I would say they already know who and what they want, or at least have it narrowed down quite a bit, but they are starting the process of acquisition now. They probably have a pretty good idea who is going to respond, and with what information.

T!
 
Status
Not open for further replies.
Top