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T9 – ANTENNAS & FEEDLINES – the most powerful transmitter isn’t worth much without an antenna!

"Learn how to join Alachua County ARES and Gainesville Amateur Radio Society, two organizations that offer training and activities for emergency communication, skills development, and public service. Fill out the application form and attend meetings to become a member."

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T9 – ANTENNAS & FEEDLINES – the most powerful transmitter isn’t worth much without an antenna!

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  1. T9 – ANTENNAS & FEEDLINES – the most powerful transmitter isn’t worth much without an antenna!

  2. How do you join Alachua County ARES? 1. Fill out the form FSD-98 2. There are no dues. 3. We encourage Thursday night net 146.820, 8PM (but not required) 4. We encourage 2nd Wednesday night meeting Red Cross 7-9PM (but not reqd) http://www.arrl.org/files/file/Public%20Service/fsd98.pdf ARES ACTIVITIES: – TRAINING for emergencies – TRAINING for skills – TRAINING for higher license – 2 Full Scale Exercises / year

  3. How do you join the Gainesville Amateur Radio Society? To apply for membership to GARS or to update your membership information (mailing address, callsign, e-mail address), please complete the GARS application form (PDF). Family memberships are available, please complete the GARS family membership form (PDF). You may print the appropriate form and bring the completed form with $25 ($35 for family membership) to the next GARS general meeting, executive board meeting or mail to: P.O. Box 140383, Gainesville, FL 32614. GARS is more of a general purpose Ham radio club that maintains 3 Voice repeaters and has entertaining And educational programs and Participates in Field Day as well as Race events and other public service Every year in Gainesville. Many hams are members of both Clubs.

  4. What is a beam antenna? A. An antenna built from aluminum I-beams B. An omnidirectional antenna invented by Clarence Beam C. An antenna that concentrates signals in one direction D. An antenna that reverses the phase of received signals T9A01 HRLM (4 - 16)

  5. What is a beam antenna? A. An antenna built from aluminum I-beams B. An omnidirectional antenna invented by Clarence Beam C. An antenna that concentrates signals in one direction D. An antenna that reverses the phase of received signals (C) T9A01 HRLM (4 - 16) Nice article on antennas on wikipedia

  6. Which of the following describes a type of antenna loading? A. Inserting an inductor in the radiating portion of the antenna to make it electrically longer B. Inserting a resistor in the radiating portion of the antenna to make it resonant C. Installing a spring in the base of a mobile vertical antenna to make it more flexible D. Strengthening the radiating elements of a beam antenna to better resist wind damage T9A02 HRLM (4 - 13)

  7. Which of the following describes a type of antenna loading? A. Inserting an inductor in the radiating portion of the antenna to make it electrically longer B. Inserting a resistor in the radiating portion of the antenna to make it resonant C. Installing a spring in the base of a mobile vertical antenna to make it more flexible D. Strengthening the radiating elements of a beam antenna to better resist wind damage (A) T9A02 HRLM (4 - 13) Makes it work...just not WELL….

  8. Which of the following describes a simple dipole oriented parallel to the Earth's surface? A. A ground-wave antenna B. A horizontally polarized antenna C. A rhombic antenna D. A vertically polarized antenna T9A03 HRLM (4 - 12)

  9. Which of the following describes a simple dipole oriented parallel to the Earth's surface? A. A ground-wave antenna B. A horizontally polarized antenna C. A rhombic antenna D. A vertically polarized antenna (B) T9A03 HRLM (4 - 12) By Chetvorno - Own work, CC0, https://commons.wikimedia.org/w/index.php?curid=40789783

  10. What is a disadvantage of the “rubber duck” antenna supplied with most handheld radio transceivers when compared to a full-sized quarter-wave antenna? A. It does not transmit or receive as effectively B. It transmits only circularly polarized signals C. If the rubber end cap is lost, it will unravel very easily D. All of these choices are correct T9A04 HRLM (4 - 15)

  11. What is a disadvantage of the “rubber duck” antenna supplied with most handheld radio transceivers when compared to a full-sized quarter-wave antenna? A. It does not transmit or receive as effectively B. It transmits only circularly polarized signals C. If the rubber end cap is lost, it will unravel very easily D. All of these choices are correct (A) T9A04 HRLM (4 – 15) Very small “aperture” – and low radiation resistance….

  12. How would you change a dipole antenna to make it resonant on a higher frequency? A. Lengthen it B. Insert coils in series with radiating wires C. Shorten it D. Add capacitive loading to the ends of the radiating wires T9A05 HRLM (4 - 13)

  13. How would you change a dipole antenna to make it resonant on a higher frequency? A. Lengthen it B. Insert coils in series with radiating wires C. Shorten it D. Add capacitive loading to the ends of the radiating wires (C) T9A05 HRLM (4 - 13)

  14. What type of antennas are the quad, Yagi, and dish? A. Non-resonant antennas B. Log periodic antennas C. Directional antennas D. Isotropic antennas T9A06 HRLM (4 - 16)

  15. What type of antennas are the quad, Yagi, and dish? A. Non-resonant antennas B. Log periodic antennas C. Directional antennas D. Isotropic antennas (C) T9A06 HRLM (4 - 16) QUAD antenna: https://commons.wikimedia.org/wiki/User:Dolledre

  16. What is a disadvantage of using a handheld VHF transceiver, with its integral antenna, inside a vehicle? A. Signals might not propagate well due to the shielding effect of the vehicle B. It might cause the transceiver to overheat C. The SWR might decrease, decreasing the signal strength D. All of these choices are correct T9A07 HRLM (4 - 15)

  17. What is a disadvantage of using a handheld VHF transceiver, with its integral antenna, inside a vehicle? A. Signals might not propagate well due to the shielding effect of the vehicle B. It might cause the transceiver to overheat C. The SWR might decrease, decreasing the signal strength D. All of these choices are correct (A) T9A07 HRLM (4 – 15) LOSSES due to buildings can be 30 db or more --- less than 1/10 of 1% of your signal gets out...

  18. What is the approximate length, in inches, of a quarter-wavelength vertical antenna for 146 MHz? A. 112 B. 50 C. 19 D. 12 T9A08 HRLM (4 - 13)

  19. What is the approximate length, in inches, of a quarter-wavelength vertical antenna for 146 MHz? A. 112 B. 50 C. 19 D. 12 (C) T9A08 HRLM (4 - 13) Memorize: antenna length for half wave is 468 / frequency in megahertz. You’ll use it many, many times….. “4, 6 , 8….who do we aPPreciate?”

  20. What is the approximate length, in inches, of a half-wavelength 6 meter dipole antenna? A. 6 B. 50 C. 112 D. 236 T9A09 HRLM (4 - 13)

  21. What is the approximate length, in inches, of a half-wavelength 6 meter dipole antenna? A. 6 B. 50 C. 112 D. 236 (C) T9A09 HRLM (4 - 13)

  22. In which direction does a half-wave dipole antenna radiate the strongest signal? A. Equally in all directions B. Off the ends of the antenna C. Broadside to the antenna D. In the direction of the feed line T9A10 HRLM (4 - 12)

  23. In which direction does a half-wave dipole antenna radiate the strongest signal? A. Equally in all directions B. Off the ends of the antenna C. Broadside to the antenna D. In the direction of the feed line (C) T9A10 HRLM (4 - 12) Think of a wire going through the hole in a doughnut

  24. What is the gain of an antenna? A. The additional power that is added to the transmitter power B. The additional power that is lost in the antenna when transmitting on a higher frequency C. The increase in signal strength in a specified direction compared to a reference antenna D. The increase in impedance on receive or transmit compared to a reference antenna T9A11 HRLM (4 - 7)

  25. What is the gain of an antenna? A. The additional power that is added to the transmitter power B. The additional power that is lost in the antenna when transmitting on a higher frequency C. The increase in signal strength in a specified direction compared to a reference antenna D. The increase in impedance on receive or transmit compared to a reference antenna (C) T9A11 HRLM (4 - 7)

  26. What is an advantage of using a properly mounted 5/8 wavelength antenna for VHF or UHF mobile service? A. It has a lower radiation angle and more gain than a 1/4 wavelength antenna B. It has very high angle radiation for better communicating through a repeater C. It eliminates distortion caused by reflected signals D. It has 10 times the power gain of a 1/4 wavelength design T9A12 HRLM (4 - 12)

  27. What is an advantage of using a properly mounted 5/8 wavelength antenna for VHF or UHF mobile service? A. It has a lower radiation angle and more gain than a 1/4 wavelength antenna B. It has very high angle radiation for better communicating through a repeater C. It eliminates distortion caused by reflected signals D. It has 10 times the power gain of a 1/4 wavelength design (A) T9A12 HRLM (4 - 12)

  28. Why is it important to have low SWR when using coaxial cable feed line? A. To reduce television interference B. To reduce signal loss C. To prolong antenna life D. All of these choices are correct T9B01 HRLM (4 - 11)

  29. Why is it important to have low SWR when using coaxial cable feed line? A. To reduce television interference B. To reduce signal loss C. To prolong antenna life D. All of these choices are correct (B) T9B01 HRLM (4 - 11) High swr results in “standing waves” of high voltage / low voltage, High current, low current --- and the losses go way up in coax…..which Already has pretty high losses at vhf/UHF. Coax is basically unusable at Microwave for more than a few inches.

  30. What is the impedance of most coaxial cables used in amateur radio installations? A. 8 ohms B. 50 ohms C. 600 ohms D. 12 ohms T9B02 HRLM (4 - 9)

  31. What is the impedance of most coaxial cables used in amateur radio installations? A. 8 ohms B. 50 ohms C. 600 ohms D. 12 ohms (B) T9B02 HRLM (4 - 9)

  32. Why is coaxial cable the most common feed line selected for amateur radio antenna systems? 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 T9B03 HRLM (4 - 9)

  33. Why is coaxial cable the most common feed line selected for amateur radio antenna systems? A. It is easy to use and requires few special installation considerations B. It has less loss than any other type of feed line – wrong! C. It can handle more power than any other type of feed line—wrong! D. It is less expensive than any other type of feed line—wrong! (A) T9B03 HRLM (4 - 9)

  34. What is the major function of an antenna tuner (antenna coupler)? 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 T9B04 HRLM (4 - 19)

  35. What is the major function of an antenna tuner (antenna coupler)? 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 (A) T9B04 HRLM (4 - 19) Maximum power transfer occurs with Matched impedances….

  36. In general, what happens as the frequency of a signal passing through coaxial cable is increased? A. The characteristic impedance decreases B. The loss decreases C. The characteristic impedance increases D. The loss increases T9B05 HRLM (4 - 9)

  37. In general, what happens as the frequency of a signal passing through coaxial cable is increased? A. The characteristic impedance decreases B. The loss decreases C. The characteristic impedance increases D. The loss increases (D) T9B05 HRLM (4 - 9)

  38. Which of the following connectors is most suitable for frequencies above 400 MHz? A. A UHF (PL-259/SO-239) connector B. A Type N connector C. An RS-213 connector D. A DB-25 connector T9B06 HRLM (4 - 18)

  39. Which of the following connectors is most suitable for frequencies above 400 MHz? A. A UHF (PL-259/SO-239) connector B. A Type N connector C. An RS-213 connector D. A DB-25 connector (B) T9B06 HRLM (4 - 18)

  40. Which of the following is true of PL-259 type coax connectors? A. They are preferred for microwave operation B. They are watertight C. They are commonly used at HF frequencies D. They are a bayonet type connector T9B07 HRLM (4 - 18)

  41. Which of the following is true of PL-259 type coax connectors? A. They are preferred for microwave operation B. They are watertight C. They are commonly used at HF frequencies D. They are a bayonet type connector (C) T9B07 HRLM (4 - 18) Don’t work well at microwave. Don’t keep water out Cheap and common….usable…

  42. Why should coax connectors exposed to the weather be sealed against water intrusion? A. To prevent an increase in feed line loss B. To prevent interference to telephones C. To keep the jacket from becoming loose D. All of these choices are correct T9B08 HRLM (4 - 18)

  43. Why should coax connectors exposed to the weather be sealed against water intrusion? A. To prevent an increase in feed line loss B. To prevent interference to telephones C. To keep the jacket from becoming loose D. All of these choices are correct (A) T9B08 HRLM (4 - 18)

  44. What can cause erratic changes in SWR readings? A. The transmitter is being modulated B. A loose connection in an antenna or a feed line C. The transmitter is being over-modulated D. Interference from other stations is distorting your signal T9B09 HRLM (4 - 11)

  45. What can cause erratic changes in SWR readings? A. The transmitter is being modulated B. A loose connection in an antenna or a feed line C. The transmitter is being over-modulated D. Interference from other stations is distorting your signal (B) T9B09 HRLM (4 - 11)

  46. What is the electrical difference between RG-58 and RG-8 coaxial cable? A. There is no significant difference between the two types B. RG-58 cable has two shields C. RG-8 cable has less loss at a given frequency D. RG-58 cable can handle higher power levels T9B10 HRLM (4 - 17)

  47. What is the electrical difference between RG-58 and RG-8 coaxial cable? A. There is no significant difference between the two types B. RG-58 cable has two shields C. RG-8 cable has less loss at a given frequency D. RG-58 cable can handle higher power levels (C) T9B10 HRLM (4 - 17)

  48. Which of the following types of feed line has the lowest loss at VHF and UHF? A. 50-ohm flexible coax B. Multi-conductor unbalanced cable C. Air-insulated hard line D. 75-ohm flexible coax T9B11 HRLM (4 - 9)

  49. Which of the following types of feed line has the lowest loss at VHF and UHF? A. 50-ohm flexible coax B. Multi-conductor unbalanced cable C. Air-insulated hard line D. 75-ohm flexible coax (C) T9B11 HRLM (4 - 9)

  50. An article that can help you avoid a lot of MYTHs about antennas and feedlines: https://www.arrl.org/files/file/Technology/tis/info/pdf/q1106037.pdf Helps explain why 40 feet of coax used inappropriately…..can cut your signal by over 90% compared to using window line…. Most people do NOT understand “reflected” power and think (Incorrectly) that it “goes back into the transmitter and heats up the power amplifier”.

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