Term
| How do we measure wavelength |
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Definition
| Measure from one crest to another |
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Term
| Unit of measure for wavelength |
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Definition
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Term
Definition of frequency
Measured in:
Unit of measure |
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Definition
how many cycles per second
Cycles per second
Hertz |
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Term
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Definition
| 300 million meters per second |
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Term
1000 hertz:
1,000,000 hertz:
1,000,000,000 hertz: |
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Definition
kilohertz
mega hertz
giga hertz |
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Term
| Relationship of frequency and wavelength |
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Definition
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Term
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Definition
| the process of the wave building to a crest, then collapsing to a trough |
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Term
| Definition of Constructive interference |
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Definition
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Term
| Definition of destructive interference |
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Definition
| waves 180 degrees out of phase eliminate each other |
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Term
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Definition
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Term
Define Horizontal polarity
What is it used for? |
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Definition
e field parallel to the horizon
Low-level aircraft detection |
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Term
Define Vertical polarity
What is it used for? |
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Definition
e field perpendicular to horizon
Used to decluttering |
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Term
Define Circular polarity
What is it used for? |
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Definition
e field constantly shifts from vertical to horizontal
Weather penetration |
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Term
| What is the HF frequency band? |
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Definition
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Term
| What is HF frequency generally used for? |
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Definition
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Term
| How many types of frequency classification systems are there? |
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Definition
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Term
| The L-Band cover's what frequencies? |
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Definition
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Term
| The following defines? Pitch (freq) of an audio tone is higher when the source is moving toward the listener? |
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Definition
| Doppler Shift (Radar reflected from an object approaching the tx'er will be at a slightly higher freq, from a receding object a lower freq.) |
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Term
| Solar and cosmic noise rapidly drop off at what freq? |
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Definition
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Term
| True or False? Waves attenuate (lose strength) as they travel any distance? |
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Definition
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Term
| Atmospheric Attenuation is negligible at low freq, but begins to assert itself as what freq is approached? |
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Definition
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Term
| At 22.24 GHz, we can reach a resonant freq called the? |
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Definition
| Water line, at this freq water vapor attenuation becomes severe. |
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Term
| ____________ is the bending of electromagnetic energy? |
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Definition
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Term
| Freq & Refraction are related how? |
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Definition
| Inversely proportional (When Frequency increases, Refraction decreases and visa versa.) |
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Term
| Where is refraction often times the worst? |
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Definition
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Term
| HF spans what portion of the spectrum? Characteristics of HF? |
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Definition
| 2-30 MHz / Long Haul Comm / Noisy |
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Term
| VHF FM spans what portion of the spectrum? Characteristics of VHF FM? |
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Definition
| 30-80 MHz / Used by ground troops |
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Term
| VHF AM spans what portion of the spectrum? Channels are spaced every ______ MHz? |
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Definition
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Term
| UHF spans what portion of the spectrum? Characteristics and channel spacing? |
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Definition
| 225-400 MHz / Military Aircraft Use / 0.025 |
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Term
| Two different types of Communication Electronic attack? |
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Definition
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Term
| ________________ denies the use of freq by saturating it with a powerful radio signal? |
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Definition
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Term
| ________________ attempts to deceive or confuse a radio listener by broadcasting contradictory commands or bewildering information? |
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Definition
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Term
| 1st 2 lines of defense against jamming are? |
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Definition
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Term
| This is a anti-jamming frequency hopping system used for communications usually in the UHF spectrum? |
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Definition
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Term
| The Army's version of HAVE QUICK is called? |
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Definition
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Term
| ABC / KMT / JRF / RIT / WIF Answer using challenge and reply ? |
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Definition
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Term
| 2301 / 1938 / 0234 Answer using Transmission Authentication? |
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Definition
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Term
| EW stands for what? What type of radar system was an EW? What does EW provide? |
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Definition
| Early Warning / CHAIN HOME / low freq's which provide enemy's position, speed and heading, lacks precision. |
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Term
| AI stands for what? What does AI sacrifices _________ for light weight and close-in precision? |
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Definition
| Airborne Incecept / Long Range |
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Term
| GCI stands for what? What does GCI combine? |
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Definition
| Ground Controlled Incercept / Long Range and Precision |
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Term
| AEW stands for what? What problem did AEW overcome and how? |
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Definition
| Airborne Early Warning / Detecting low flying targets by elevating the radar. |
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Term
| 4 different types of radio freq generators used what are they? |
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Definition
| Klystron, Twystron, Magnetron, Microwave Transistors |
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Term
| 3 drawbacks of Klystrons? |
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Definition
| 5-50 minute warm up period, heavy, and produced X-rays. |
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Term
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Definition
| Very powerful and extremely stable |
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Term
| Difference between Twystron and Klystron? |
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Definition
| Twystron has advantage of "freq agility" |
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Term
| What are some benefits of Magnetron? |
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Definition
| Small, light, inexpensive |
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Term
| What's the major drawback of a Magnetron? |
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Definition
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Term
| What is the greatest strength of Microwave Transistors? |
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Definition
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Term
| Super Heterodyne Rx'er does what? |
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Definition
| Mixed the faint signals w/ a strong, stable, known freq. This produced two harmonic freq's that cloned the original signal of interest, and did so w/o adding noise or distortion. |
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Term
| What determines range resolution? |
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Definition
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Term
| What could possible occur if we increase PRF? |
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Definition
| Potential exists for 2x bang targets |
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Term
| As far as PRF is concerned what is required for two planes to be seen as two planes? |
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Definition
| Planes must be at least 1/2 a pulse width behind the lead target |
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Term
| Ghost image's on a radar scope are AKA? |
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Definition
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Term
| Doppler blind speeds exist, if a certain part of the signal hits the target the radar won't recognize it. |
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Definition
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Term
| If PRF increases what is more likely to occur? |
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Definition
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Term
| What shape is a Parabolic Reflector? What type of beam does it produce? |
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Definition
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Term
| What is one way pencil beams search for targets? |
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Definition
| Raster Scan (adjusts azimuth and elevation coverage to cover more or less territory depending on the situation) |
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Term
| What are Fan Beams useful for? What is the signal's trajectory from a fan beam? |
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Definition
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Term
| What can Fan Beams not do accurately? |
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Definition
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Term
| A radar with a vertical aparatus will have a beam with what trajectory? |
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Definition
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Term
| What can a horizontal beam measure accurately? |
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Definition
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Term
| With GCI and AEW radars, fan shaped beams have to estimate target height, what is the common error rate in feet? |
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Definition
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Term
| What is widely used by GCI radars to find altitude? |
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Definition
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Term
| What is the preferred height finding method of AEW platforms when working over water? |
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Definition
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Term
| What did the planar array signifcantly reduce? |
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Definition
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Term
| What was the biggest drawback to the planar array? |
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Definition
| Mass, typically 5 to 10x that of a relector w/ the same aperture (rx sz) |
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Term
| What type of radar is rigidly mounted; with no gimbal and no physical movement of the antenna? |
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Definition
| AESA - Active electronically scanned arrays |
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Term
| What are three things that the AESA is proficient at? |
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Definition
| Can change beam shape, can rx and process multiple signals, can be used as an aux intel asset |
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Term
| The Tall King and FPS-24 were what? |
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Definition
| Big heavy GCI radars, that used low freq's to extend range. They were inflexable and hard to mx. The weight of the antenna was the biggest problem. |
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Term
| Pulse compression increases our likelyhood of detecting an object at a given range by how much? |
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Definition
| 4x; Pulse compression factor of four. |
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Term
| Increasing our average power by turning on the tx more often which in turn increases the PRF increases the possiblity of what occuring? |
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Definition
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Term
| By increasing to medium PRF what is the primary benefits? |
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Definition
| Significant increase in range as well as a true look-down doppler capablity. (bottom line, increases our ability to detect targets) |
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Term
| What is the fix for second bang targets? |
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Definition
| Staggered PRF - rx'er only reports targets that both PRF's agree on, we will have defeated the 2nd bang problem |
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Term
| By increasing to High PRF what is the primary benefits? |
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Definition
| Greatly increases our range and gives us unambiguous Doppler processing. |
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Term
| In High PRF when the target drops from our display what has the target gone into? |
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Definition
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Term
| What PRF is being utilized when invisibility to targets crossing our path or running away from us is granted? |
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Definition
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Term
| What is the most widely used jamming device? |
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Definition
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Term
| _____ is designed to match half the wavelength of the victim's radar RF? |
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Definition
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Term
| What is the EP (electronic protection) against chaff? |
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Definition
| Doppler processing at med or high PRF. |
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Term
| What are the three mechanical methods for radar jamming? |
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Definition
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Term
| What are the three electronic jamming methods? |
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Definition
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Term
| What jamming technique attempts to "fool all of the people all of the time"? |
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Definition
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Term
| "fool some of the people all of the time"? |
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Definition
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Term
| "fool all of the people some of the time"? |
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Definition
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Term
| What is the EP (electronic protection) against spot jamming? |
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Definition
| Frequency agility, the ability to switch to another frequency outside the jamming. |
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Term
| What is the EP (electronic protection) against sweep jamming? |
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Definition
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Term
| What is the EP (electronic protection) against Barrage jamming? |
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Definition
| Pulse compression Techniques - increase avg power to blow through jamming levels. |
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Term
| What is the best EP (electronic protection) to defeat range deception? |
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Definition
| Staggered PRF - true target will remain in the same range bin for pulse after pulse, but the recoreded and repeated pulses will fill diff range bins depending on the PRF in use at the time. |
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Term
| How does the repeater jammer decieve in azimuth? |
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Definition
| By exploiting the victim radar's side and back lobes. |
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Term
| What is the EP (electronic protection) of choice to defeat the azimuth deception jammer? |
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Definition
| Ultra-low side lobes or active side lobe blanking |
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Term
| What does deception jamming cause? |
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Definition
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Term
| What frequency is used to interogate a ship or aircraft's IFF? What Freq is used to reply with? |
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Definition
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Term
| Mode 1 is used by whom and for what? How many digits make up Mode 1? Is it manageable? |
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Definition
| Military / Mission ID / 2 digits, 1st is 0-7, second is 0-3 / Manageable |
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Term
| Mode 2 is used by whom and for what? How many digits make up Mode 2? Is it manageable? |
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Definition
| Military / Personal ID / 4 digits, all 0-7 / none Manageable |
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Term
| Mode 3 is used by whom and for what? How many digits make up Mode 3? Is it manageable? |
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Definition
| Military & Civilian / Selective ID / 4 digits, all 0-7 / Manageable |
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Term
| Mode 3C used by whom and for what? How many digits make up Mode 3C? |
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Definition
| Military & Civilian / 3 Digit altitude readout / Hooked to altimeter |
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Term
| Mode 4 is used by whom and for what? |
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Definition
| Military / Positive electronic ID , Encrypted |
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Term
| Mode S is used by whom and for what? How many digits make up Mode S? |
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Definition
| Civil / 24 digits 0-7 plus altitude, heading & speed / Not manageable |
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Term
| Mode 5 is used by whom and for what? Is it manageable? Is it redundant? |
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Definition
| Military / Encyrypted version of Mode S. / Not manageable / Yes, redundant with link 16 (JTIDS) provides the same caps, adds jam-resistant freq-hopping and is already a fully funded system. |
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Term
| What is the USAF IFF system? |
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Definition
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Term
| What type of radar is used by J-stars? |
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Definition
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Term
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Definition
| Makes use of shorter pulse widths and extreme pulse compression to achieve the necessary range resolution. |
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Term
| What is the size of resolution cell that has been achieved by SAR? |
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Definition
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Term
| How will a moving train appear on a SAR display? |
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Definition
| It will appear parallel to, but some distance from the tracks. Show's the way things were, not the way they are. |
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Term
| How does structural attenuation work? |
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Definition
a. By carefully arranging the AC’s internal structures, the radio frequencies can be attenuated as much as RAM
b. Effectiveness decreases as wavelength increases |
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Term
| What is impedance matching and how does it work? |
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Definition
| Use of materials in aircraft construction that don't reflect radio waves very well. |
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Term
| What types of high-tech application of impedance matching is currently in use? |
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Definition
| Plastics such as fiberglass or carbon-fiber and ceramics. |
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Term
| How does faceted surfaces work? |
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Definition
| Deflect radar beams in every direction except back to the Tx'ing radar, this is called diffusion. |
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Term
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Definition
| Make electronic signals quieter |
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Term
| Over the horizon radar might detect objects at what distance? |
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Definition
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Term
| Over the horizon radar tells us where something was like SAR, it is not very acurate range resolution becomes a problem, what is the typical resolution of OTH? |
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Definition
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