Bandwidth Resolution and Filters
Examine the spectrum with the following BW resolutions/filters:
Utilize all BW resolutions/filters between 5 Hz - 200 MHz (depending on the band being checked)
For frequencies between 3 kHz and 13 GHz It's generally best to start with a 3 or 5 MHz IFBW for a "high speed moving" sweep, and to monitor the wideband spectrogram.
This makes the energy easy to spot, but tough to identify. The IFBW is then modified until it is roughly 80-85% of the signal bandwidth, the results are then sent through a vector analyzer to help with identification.
All IFBWs available on the analyzer are also cycled through and the results transferred into a matrix, a little vector analysis is applied, and the modulation parameters are easily extracted.
To handle the microwave bands IFBWs between 10 kHz and 200 MHz should be used.
The ideal spectrum analyzer used for TSCM will have resolution bandwidths available from 20 Hz to at least 100 MHz. The HP 8569B was/is very well known for its resolution bandwidths from 100 Hz to 22 GHz. Real World Example:
Frequency Hopping device, randomly hops between 530 MHz and 750 MHz, a IFBW of 3-70 MHz will allow the activity to be easily identified, but a narrower IFBW will make it much more difficult.
Hint: A programmable digital spectrum analyzer should be used!
(1/3/5/10/15/20/25/30/50/75/100/150/200... Sequence is preferred).
Here are a few of the suggested bandwidths that you should try for a "fit."
BW Res - Usage/Primary Function 100/200 MHz - Resonate Cavity Bugging Devices/SIGINT Devices 125/35/8 MHz - Resonate Cavity Bugging Devices/SIGINT Devices 50/20/10 MHz - Diplomatic Microwave Bugs 40/20/10 MHz - Diplomatic Microwave Bugs 13/16/20 MHz - Microwave Wideband 11/12/13 MHz - Microwave Wideband .5/1/2/5 MHz - Microwave Wideband (Burst Bugs) 18/26/36 MHz - Satellite Wideband (Video) 2/4/6/8 MHz - Microwave Wideband (Video) 3/6/12 MHz - Microwave Wideband (Video) - Common .5/1/3 MHz - Microwave Wideband (Video/Burst/Pulse) 1.5/.75 kHz - Frequency Hopping Bugs - VERY Common .4/.2/.1 kHz - Frequency Hopping Bugs - VERY Common 3.2/6.4 kHz - Frequency Hopping Bugs - VERY Common 10/20/25 kHz - Frequency Hopping Bugs - VERY Common 50/75 kHz - Frequency Hopping Bugs - VERY Common 100/250 kHz - Frequency Hopping Bugs 300/500 kHz - Frequency Hopping Bugs 1/2/4/8 MHz - Frequency Hopping Bugs 300/250 kHz - Regular Wide Band Broadcast FM 150 kHz - Narrowband Broadcast FM Audio, Television Audio 280 kHz - Narrowband Broadcast FM Audio, Television Audio 200/150 kHz - Commercial Wireless Microphone - High Grade 150/100 kHz - Commercial Wireless Microphone - Concert/Broadcast Grade 58/77/84 kHz - Commercial Wireless Microphone - Typical Body Wire 50/60/75 kHz - Commercial Wireless Microphone - Typical police device 8/25/50 kHz - European/Japanese Industrial Bugging Devices 50/30 kHz - Wideband FM two-way communications (i.e.: Cellular Telephone) 16/15/6 kHz - Normal FM two-way communications 3/6/8/12 kHz - Narrowband Commercial - Voice 1/3.2/6 kHz - Narrowband (Marine, HF, etc...) 120/9/1 kHz - Narrowband (Bias Osc./Video Cameras/SIGINT) 30/750/500 Hz- Narrowband (Bias Osc./Video Cameras/SIGINT) 56/75/100 Hz - Narrowband (Bias Osc./Video Cameras/SIGINT) 30/150/200 Hz- Narrowband (Bias Osc./Video Cameras/SIGINT) 250/300 Hz - Narrowband (Bias Osc./Video Cameras/SIGINT) 300/250 Hz - Narrowband OOK/FSK/Data, etc... 300/250 Hz - Narrowband OOK/FSK/Data, etc...
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