Technician Class Series – Talk to Outer Space

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Hello everybody and welcome back to Everything Hamradio! Today we are going to continue our series on the Technician Class License Question Pool! Today we will be talking about Talking to Outer Space.

As always, the correct answers will be in bold. I also recommend that you only read the correct answers when studying for your test. If you do this, when you take your test and you see a question, there will be a better chance that the correct answer will jump out at you easier. Some say that this approach is kind of like cheating, but the way that I see it, you will always be learning something in this hobby and you don’t have to know everything there is to know about the hobby to get your license.

If you would like to purchase a copy of the Technician Class study book, written by Gordon West, WB6NOA with Eric P. Nichols, KL7AJ, that this series is loosely based around, below is a link to it.

Let’s move on to the good stuff, shall we?


 

T8B04 Which amateur stations may make contact with an amateur station on the International Space Station using 2 meter and 70 cm band amateur radio frequencies?

  1. Only members of amateur radio clubs at NASA facilities
  2. Any amateur holding a Technician or higher class license
  3. Only the astronaut’s family members who are hams
  4. You cannot talk to the ISS on amateur radio frequencies

There is no restrictions as far as what license that you have in order to be able to talk to the ISS. So basically since a Technician class and above have full access to the 2m and 70 cm bands, any licensed operator can talk to it

97.207 Space station.

(c) The following frequency bands and segments are authorized to space stations:

(1) The 17 m, 15 m, 12 m, and 10 m bands, 6 mm, 4 mm, 2 mm and 1 mm bands; and
(2) The 7.0-7.1 MHz, 14.00-14.25 MHz, 144-146 MHz, 435-438 MHz, 2400-2450 MHz, 3.40-3.41 GHz, 5.83-5.85 GHz, 10.45-10.50 GHz, and
24.00-24.05 GHz segments.

 

T8B10 What do the initials LEO tell you about an amateur satellite?

  1. The satellite battery is in Low Energy Operation mode
  2. The satellite is performing a Lunar Ejection Orbit maneuver
  3. The satellite is in a Low Earth Orbit
  4. The satellite uses Light Emitting Optics

LEO stands for Low Earth Orbit. A low Earth orbit (LEO) is an orbit around Earth with an altitude between 160 kilometers (99 mi), with an orbital period of about 88 minutes, and 2,000 kilometers (1,200 mi), with an orbital period of about 127 minutes.

T8B03 Which of the following are provided by satellite tracking programs?

  1. Maps showing the real-time position of the satellite track over the earth
  2. The time, azimuth, and elevation of the start, maximum altitude, and end of a pass
  3. The apparent frequency of the satellite transmission, including effects of Doppler shift
  4. All of these answers are correct

Many factors come into play when you are trying to talk or track a satellite. You have to know the track of the satellite, the time it takes to go across the sky, the elevation from your location at the start and finish of the viewable window of the satellite and lastly what the apparent frequency is taking into account the effects of doppler shift. For those that doesn’t know what the doppler effect is, it that the signal is higher when an object is coming towards you and lower when it is going away. The best example of this is a train horn. When you are sitting at a crossing and the arms are down because a train is coming. When the trash is coming towards you the horn is higher and louder than it appears after the train has past. It seems quieter and lower after the train has past because the sound waves aren’t being compressed by the engine and/or the air displacement that the engine makes while in motion.

T8B06 Which of the following are inputs to a satellite tracking program?

  1. The weight of the satellite
  2. The Keplerian elements
  3. The last observed time of zero Doppler shift
  4. All of these answers are correct

The traditional orbital elements are the six Keplerian elements, after Johannes Kepler and hislaws of planetary motion. The main two elements that define the shape and size of the ellipse:

  • Eccentricity () – shape of the ellipse, describing how much it is elongated compared to a circle. (not marked in diagram)
  • Semimajor axis () – the sum of the periapsis and apoapsis distances divided by two. For circular orbits, the semimajor axis is the distance between the centers of the bodies, not the distance of the bodies from the center of mass.

Two elements define the orientation of the orbital plane in which the ellipse is embedded:

  • Inclination – vertical tilt of the ellipse with respect to the reference plane, measured at theascending node (where the orbit passes upward through the reference plane) (green angle iin diagram).
  • Longitude of the ascending node – horizontally orients the ascending node of the ellipse (where the orbit passes upward through the reference plane) with respect to the reference frame’s vernal point (green angle Ω in diagram).

And finally:

  • Argument of periapsis defines the orientation of the ellipse in the orbital plane, as an angle measured from the ascending node to the periapsis (the closest point the second body comes to the first during an orbit). (blue angle  in diagram)
  • Mean anomaly at epoch () defines the position of the orbiting body along the ellipse at a specific time (the “epoch”).

T8B05 What is a satellite beacon?

  1. The primary transmit antenna on the satellite
  2. An indicator light that that shows where to point your antenna
  3. A reflective surface on the satellite
  4. A transmission from a space station that contains information about a satellite

Just like beacons in other areas of amateur radio, the transmission contains information about itself, in this instance it contains information about the satellite.

T8B09 What causes spin fading when referring to satellite signals?

  1. Circular polarized noise interference radiated from the sun
  2. Rotation of the satellite and its antennas
  3. Doppler shift of the received signal
  4. Interfering signals within the satellite uplink band

As a satellite flies across the sky, it rotate s. Because it rotates, part of the time the satellite is between you and the antenna. In the beginning days of services like dish network and direct TV, the dishes were small and maybe even the signal wasn’t as strong as it is now. In those early days, if someone were to walk directly in front of the satellite dish, you could actually see the shape of them go across your TV screen. The same principle applies to the signal when the satellite itself is between you and the antenna.

T8B07 With regard to satellite communications, what is Doppler shift?

  1. A change in the satellite orbit
  2. A mode where the satellite receives signals on one band and transmits on another
  3. An observed change in signal frequency caused by relative motion between the satellite and the earth station
  4. A special digital communications mode for some satellites

We touched on this a little bit a few questions ago but let’s dive a little deeper into what exactly the Doppler Effect is. The Doppler Effect is the effect that motion has radio frequencies due to the motion of the object transmitting the frequency in relation to the receiving station.  When the transmitting object is coming towards you the radio transmission is compressed because of the motion, once the transmitter passes the receiving station, the frequency waves expand and seems to go lower. Probably the easiest way to explain what the Doppler effect really is it to imagine yourself sitting at train crossing with a train coming. The horn is blowing warning people that a train is coming. The sound of the horn when it is coming towards you is loud and relatively high. Once the train passes you, the sound of the horn drops significantly as well as the volume.

Doppler Effect

T8B08 What is meant by the statement that a satellite is operating in mode U/V?

  1. The satellite uplink is in the 15 meter band and the downlink is in the 10 meter band
  2. The satellite uplink is in the 70 cm band and the downlink is in the 2 meter band
  3. The satellite operates using ultraviolet frequencies
  4. The satellite frequencies are usually variable

A satellite repeater is much like what is called cross-band repeating using your dual band radio. Using cross-band repeat on your dual band radio, you talk on one band and receive on another band and your dual band radio will transmit on the opposite band than what the transmission was received on. For example, if you transmit on 70cm, your dual band radio will receive it on 70cm and will retransmit it on 2m or 1.25m or whatever your dual band radio is. With satellites, it is basically the same except for that the uplink band will always be 70cm and the downlink will always be 2m.

T8B02 How much transmitter power should be used on the uplink frequency of an amateur satellite or space station?

  1. The maximum power of your transmitter
  2. The minimum amount of power needed to complete the contact
  3. No more than half the rating of your linear amplifier
  4. Never more than 1 watt

Just like with any amateur radio transmission you make, you should ALWAYS use the minimum amount of power need to complete the contact.

§97.313 Transmitter power standards.

(a) An amateur station must use the minimum transmitter power necessary to carry out the desired communications.

(b) No station may transmit with a transmitter power exceeding 1.5 kW PEP.

(c) No station may transmit with a transmitter power output exceeding 200 W PEP:

(1) On the 10.10-10.15 MHz segment;

(2) On the 3.525-3.60 MHz, 7.025-7.125 MHz, 21.025-21.20 MHz, and 28.0-28.5 MHz segment when the control operator is a Novice Class operator or a Technician Class operator; or

(3) The 7.050-7.075 MHz segment when the station is within ITU Regions 1 or 3.

(d) No station may transmit with a transmitter power exceeding 25 W PEP on the VHF 1.25 m band when the control operator is a Novice operator.

(e) No station may transmit with a transmitter power exceeding 5 W PEP on the UHF 23 cm band when the control operator is a Novice operator.

(f) No station may transmit with a transmitter power exceeding 50 W PEP on the UHF 70 cm band from an area specified in paragraph (a) of footnote US270 in §2.106, unless expressly authorized by the FCC after mutual agreement, on a case-by-case basis, between the District Director of the applicable field facility and the military area frequency coordinator at the applicable military base. An Earth station or telecommand station, however, may transmit on the 435-438 MHz segment with a maximum of 611 W effective radiated power (1 kW equivalent isotropically radiated power) without the authorization otherwise required. The transmitting antenna elevation angle between the lower half-power (−3 dB relative to the peak or antenna bore sight) point and the horizon must always be greater than 10°.

(g) No station may transmit with a transmitter power exceeding 50 W PEP on the 33 cm band from within 241 km of the boundaries of the White Sands Missile Range. Its boundaries are those portions of Texas and New Mexico bounded on the south by latitude 31°41  North, on the east by longitude 104°11West, on the north by latitude 34°30North, and on the west by longitude 107°30West.

(h) No station may transmit with a transmitter power exceeding 50 W PEP on the 219-220 MHz segment of the 1.25 m band.

(i) No station may transmit with an effective radiated power (ERP) exceeding 100 W PEP on the 60 m band. For the purpose of computing ERP, the transmitter PEP will be multiplied by the antenna gain relative to a half-wave dipole antenna. A half-wave dipole antenna will be presumed to have a gain of 1 (0 dBd). Licensees using other antennas must maintain in their station records either the antenna manufacturer’s data on the antenna gain or calculations of the antenna gain.

(j) No station may transmit with a transmitter output exceeding 10 W PEP when the station is transmitting a SS emission type.

 

T8B11 What is a commonly used method of sending signals to and from a digital satellite?

  1. USB AFSK
  2. PSK31
  3. FM Packet
  4. WSJT

 

T1A07 What is the FCC Part 97 definition of telemetry?

  1. An information bulletin issued by the FCC
  2. A one-way transmission to initiate, modify or terminate functions of a device at a distance
  3. A one-way transmission of measurements at a distance from the measuring instrument
  4. An information bulletin from a VEC

97.3 Definitions.

(a) The definitions of terms used in part 97 are:

(46) Telemetry. A one-way transmission of measurements at a distance from the measuring instrument.

 

T1A13 What is the FCC Part 97 definition of telecommand?

  1. An instruction bulletin issued by the FCC
  2. A one-way radio transmission of measurements at a distance from the measuring instrument
  3. A one-way transmission to initiate, modify or terminate functions of a device at a distance
  4. An instruction from a VEC

 

97.3 Definitions.

(a) The definitions of terms used in part 97 are:

(45) Telecommand station. An amateur station that transmits communications to initiate, modify or terminate functions of a space station.


 

So that brings us to the end of this section. Next week we will be talking about Your Computer Goes Ham Digital! Please share my blog with your friends and if you have not done so already, please subscribe to my email list to get the latest and quickest notifications of any new post that I publish. You can sign up in the box on the sidebar. If you would rather, you can also sign up for my RSS feed. Please Like me on Facebook, and follow me on Twitter, Google+, LinkedIn and StumbledUpon. Links to all of these can be found under social on the menu.

Thanks for stopping by. If you have any questions or comments about today’s post, please leave them in the comments below or shoot me an email a k5clm@everythinghamradio.com.

Until next time…

73 de Curtis, K5CLM

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