Initial commit

pages/T9B.md

@@ -0,0 +1,85 @@
+T9B – Feed lines: types, attenuation vs frequency, selecting; SWR concepts; Antenna tuners (couplers); RF Connectors: selecting, weather protection
+
+- [[T9B01]] (B)
+What is a benefit of low SWR? #card
+	- A. Reduced television interference 
+	- B. Reduced signal loss
+	- C. Less antenna wear
+	- D. All these choices are correct
+
+- [[T9B02]] (B)
+What is the most common impedance of coaxial cables used in amateur radio? #card
+	- A. 8 ohms
+	- B. 50 ohms
+	- C. 600 ohms
+	- D. 12 ohms
+
+- [[T9B03]] (A)
+Why is coaxial cable the most common feed line for amateur radio antenna systems? #card
+	- A. It is easy to use and requires few special installation considerations
+	- B. It has less loss than any other type of feed line
+	- C. It can handle more power than any other type of feed line
+	- D. It is less expensive than any other type of feed line
+
+- [[T9B04]] (A)
+What is the major function of an antenna tuner (antenna coupler)? #card
+	- A. It matches the antenna system impedance to the transceiver's output impedance
+	- B. It helps a receiver automatically tune in weak stations
+	- C. It allows an antenna to be used on both transmit and receive
+	- D. It automatically selects the proper antenna for the frequency band being used
+
+- [[T9B05]] (D)
+What happens as the frequency of a signal in coaxial cable is increased? #card
+	- A. The characteristic impedance decreases
+	- B. The loss decreases
+	- C. The characteristic impedance increases
+	- D. The loss increases
+
+- [[T9B06]] (B)
+Which of the following RF connector types is most suitable for frequencies above 400 MHz? #card
+	- A. UHF (PL-259/SO-239)
+	- B. Type N
+	- C. RS-213
+	- D. DB-25 
+
+- [[T9B07]] (C)
+Which of the following is true of PL-259 type coax connectors? #card
+	- A. They are preferred for microwave operation
+	- B. They are watertight
+	- C. They are commonly used at HF and VHF frequencies
+	- D. They are a bayonet-type connector
+
+- [[T9B08]] (D)
+Which of the following is a source of loss in coaxial feed line? #card
+	- A. Water intrusion into coaxial connectors
+	- B. High SWR 
+	- C. Multiple connectors in the line
+	- D. All these choices are correct
+
+- [[T9B09]] (B)
+What can cause erratic changes in SWR? #card
+	- A. Local thunderstorm
+	- B. Loose connection in the antenna or feed line
+	- C. Over-modulation
+	- D. Overload from a strong local station
+
+- [[T9B10]] (C)
+What is the electrical difference between RG-58 and RG-213 coaxial cable? #card
+	- A. There is no significant difference between the two types
+	- B. RG-58 cable has two shields
+	- C. RG-213 cable has less loss at a given frequency
+	- D. RG-58 cable can handle higher power levels
+
+- [[T9B11]] (C)
+Which of the following types of feed line has the lowest loss at VHF and UHF? #card
+	- A. 50-ohm flexible coax
+	- B. Multi-conductor unbalanced cable
+	- C. Air-insulated hardline
+	- D. 75-ohm flexible coax
+
+- [[T9B12]] (A)
+What is standing wave ratio (SWR)? #card
+	- A. A measure of how well a load is matched to a transmission line
+	- B. The ratio of amplifier power output to input
+	- C. The transmitter efficiency ratio
+	- D. An indication of the quality of your station’s ground connection