Block 2 Flashcards
What three things characterize a radio wave?
Amplitude, frequency and wavelength
The magnitude of change in the height of the radio wave is
Amplitude
Frequency and wavelength have what kind of relationship?
Inverse
The number of cycles completed by a periodic quantity in a unit of time is
Frequency
The distance between successive crests of waves is
Wavelength
The behavior of radio waves when they are transmitted from one point to another is
Radio Propagation
HF Sky Wave Propagation utilizes what to make beyond line of sight (BLOS) communication possible?
The ionosphere (the uppermost part of the atmosphere)
The process of combining two or more frequencies across a nonlinear device to produce a new frequency is
Heterodyning
The DIFF and SUM of frequencies are
Sidebands
How many layers does the Ionosphere have?
- D, E and F (F1 and F2)
Both LSB and USB are offset the same value from the carrier (T/F)
True
The amplitude of the RF Carrier changes to match the instantaneous amplitude changes of the modulating signal creates a
Composite Signal
When heterodyned the RF Carrier has a representation of the audio superimposed on it (T/F)
True
In amplitude modulation (AM) carrier is transmitted even when no modulating signal (intelligence) is present (T/F)
True
In amplitude modulation (AM) lower side band (LSB) and upper side band (USB) are transmitted - even though they contain the same intelligence (T/F)
True
A variant of AM that uses transmitter power and bandwidth more efficiently by suppressing the carrier and on of the side bands is
Single side band (SSB) transmission
Single side band (SSB) transmissions are primarily use for
Beyond line of sight (BLOS)
In single side band (SSB) if there is no signal in, what occurs?
No signal out (modulation doesn’t occur)
What are some advantages of single side band transmission?
- Spectrum conservation
- Power Efficiency
- Effective gain in transmit and receive
- Total effective gain
- Peak envelope power
- Better signal-noise ratio (SNR)
Decreasing bandwidth of each channel in a radio system to all for more channels in the overall radio spectrum is
Spectrum conservation
Total HF spectrum is smaller therefore channel spacing needs to be smaller (T/F)
True
Power output is only developed when carrier is modulated (T/F)
True
What can concentrate almost all available power into a single side band (making it more efficient?
Single side band (SSB)
A transmitter’s averaged power output during one RF cycle (or a sample) at the highest crest of the modulation envelope is
Peak envelope power (PEP)
What happens when a single side band (SSB) transmitter is keyed and un-modulated?
It will have virtually no power out
If no audio is applied, no side band is developed. (T/F)
True
Why is signal-noise ratio (SNR) better in single side band (SSB) transmissions?
Because the other side band is eliminated, decreasing the bandwidth.
A controlled cryptographic item (CCI) has the capability to do what?
Encrypt/decrypt radio signals
For a controlled cryptographic item (CCI) the guidance is somewhat vague, but …
It is generally understood that CCI equipment will never be left unattended
What are the frequency ranges for the AN/PRC-150(C)?
SSB - 1.6 t0 29.99 MHz (100 Hz steps)
FM - 20 to 59.99 MHz (100 Hz steps)
HF - 1.6 to 29.99 MHz
What are the modes for the AN/PRC-150(C)?
- Fix (single channel)
- HOP (frequency hopping)
- ALE (automatic link establishment)
- 3G (faster form of ALE)
- 3G (faster form of ALE)
What function of the the AN/PRC-150(C) results in transmitting a 1000 Hz tone?
Continuous wave (CW)
What are the the AN/PRC-150(C) power output options when functioning in FM modulation?
1W, 5W and 10W
What are the configurations for the AN/PRC-150(C)?
Manpack, vehicular and base station
What is the HF frequency band range?
3 MHz - 30 MHz
What type of transmitted or received signal has only one side band?
Single side band
What does a HF radio with automatic link establishment (ALE) create?
Link quality analysis (LQA) table, which scores the inherent quality levels of potential channels for communication on HF.
What is the standard bandwidth of a single side band (SSB) voice signal?
2.7 KHz
What is the effective dB gain of a single side band (SSB) receiver?
3 dB
What was developed to increase a HF operator’s chances of successful communications?
ALE
What are the two types of link quality analysis (LQA) scoring?
Sound and exchange
What is the maximum output power of the AN/PRC-150(C) when in FM mode?
20 W
Which switch position still provides secure communications with forces that may not be authorized for Type I Cipher Text?
Citadel Cover (CC)
What is the RF input impedance from the antenna?
50 ohms
What is the AN/PRC-150 frequency hopping frequency range?
2 MHz - 29.9999 MHz
What antenna kit is provided with the AN/PRC-150?
OE-505 manpack whip antenna
What can you do to reduce moisture damage to the AN/PRC-150 connectors?
Cover connectors with rubber boot covers
When installing batteries for the AN/PRC-150, you can use batteries of different chemistry. (T/F)
False
