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Serious ‘XM (That’s W2XM) presents Exam-prep Jepperdee: Extra-class Edition Announcements Introduction of presenter Operation of the game is almost intuitive, and you can make up your own rules. Each numeric point value on either game board is a hyperlink which reveals a question. Advancing the game one slide past the question (by clicking the screen) displays the answer. “Back” on the answer slide returns you to the game board. “SFJ” stands for “semi-final jepperdee” and “FJ” means “final jepperdee;” proceed from SFJ or FJ by clicking screen until you see the next hyperlink. There is one daily double on each board; click on “Here’s the question.” For most fun, appropriate hardware (lights, push-buttons, sounder, lockout circuitry) should be used. A diagram is available from the author. OPERATING PRACTICES RULES AND REGULATIONS ELECTRICAL PRINCIPALS COMPONENTS & BLDG BLOCKS 100 100 100 100 200 200 200 200 300 300 300 300 400 400 400 400 500 500 500 500 SFJ Electronic Circuits Radio Sigs. Modes & Antennas/ & Msrmnts Equipment Propagation 100 100 100 100 200 200 200 200 300 300 300 300 400 400 400 400 500 500 500 500 FJ During a VHFUHF contest, in which band segment would you expect to find the highest level of activity? E2C06 The weak-signal segment of the band, with most of the activity near the calling frequency back E2C07 What is the Cabrillo format? A standard for submission of electronic contest logs back Which digital protocol is used by APRS: PACTOR, E2D07 802.11, AX.25, or AMTOR? AX.25 back What is the direction of a descending pass for an amateur satellite? E2A02 From north to south back What do the terms L band and S band specify with regard to satellite communications? E2A09 The 23-cm and 13-cm bands back What is the maximum power output permitted on the 60 meter band? E1A05 100 watts PEP effective radiated power relative to the gain of a halfwave dipole back What is a remotely controlled station? E1C01 A station controlled indirectly through a control link back Which VHF amateur-service bands have frequencies available for space stations? E1D08 2 meters back When/why might the FCC issue "Special Temporary Authority" (STA) to an amateur station? E1F14 To provide for experimental amateur communications back What is the maximum bandwidth for a data emission on 60 meters? E1B05 2.8 kHz back Why use powdered-iron toroids rather than ferrite ones in an inductor? E6D08 Powdered-iron toroids generally maintain their characteristics at higher currents back What is the time constant of a circuit having two 220-μF caps and two 1-MΩ res., all in parallel? E5B04 220 seconds back What is the phase between the I through and the v across a series resonant circuit? E5A08 The voltage and current are in phase back Expressed in polar, what is the z of a 400-Ω reactance cap in series with a 300-Ω resistor? E5C04 500 ohms at an angle of -53.1 degrees back How many watts are consumed in a circuit having a p.f. of 0.2 if the input is 100-V AC at 4 A? E5D12 80 watts back What do we call the freq. at which the grounded-base current gain of a transistor is .7 X the gain at 1 kHz? E6A08 alpha cutoff frequency back What characteristics of the MMIC make it a good choice for VHF-throughmicrowave circuits? E6E06 Controlled gain, low noise figure, & constant in and out Z’s over a given frequency range back What type of CRT deflection is best when high-frequency waveforms are to be displayed? E6D13 Electrostatic back What type of semiconductor device is used as a voltage-controlled capacitor? E6B04 Varactor diode back What property of the core material determines the inductance of a toroidal inductor? E6D06 Permeability back E7B12 What is this? Figure E7-1 Common emitter amplifier back What is the equivalent circuit of a quartz crystal? E6E10 Motional C, motional L, and loss R all in series; with a shunt C representing electrode and stray C back Define “capture range” of a phase-locked loop circuit? E7H13 The frequency range over which the circuit can lock back What kind of filter would attenuate an interfering signal as you are receiving an SSB transmission? E7C07 A notch filter back Purpose of D1? E7D13 Figure E7- 3 Q1 +25 C1 4000 C2 4000 +12 C3 0.01 R1 D1 R2 To provide a voltage reference back What is the typical nominal value for the RMS voltage at a standard household a.c. power outlet? E8D15 120V back What is the approximate ratio of PEP-to-average power in a typical SSB phone signal? E8A06 2.5 to 1 back Which would a spectrum analyzer display on the vertical axis: Amplitude, E4A03 Duration, SWR, or Q? Amplitude back What parameter is varied by the modulating signal in a pulse-position modulation system? E8B08 The time at which each pulse occurs back How can you determine if linenoise interference is being generated within your home? E4E07 By turning off the AC-power main breaker and listening on a battery operated radio back How does JT65 improve EME communications? E2D12 It can decode signals many dB below the noise floor using FEC back What is the necessary bandwidth of a 13-WPM international Morse code transmission? E8C05 Approximately 52 Hz back What hardware, besides a receiver & computer, is needed to decode SSTV using E2B09 Digital Radio Mondiale (DRM)? No other hardware is needed back What is the definition of the “noise figure” of a receiver? E4C04 The ratio of the noise generated by the receiver to the theoretical minimum noise (in dB) back What noise figure value might be typical of a lownoise UHF preamplifier? E6E05 2 dB back E9A09 What is meant by antenna bandwidth? The frequency range over which an antenna satisfies a performance requirement back What happens to Z at the feed point of a fixed-length ant. as the frequency of operation is lowered? E9D13 The radiation resistance decreases & the capacitive reactance increases. back What is the approx. length of an air-insulated parallel conductor xmission line that is λ/2 long at 14.1 MHz? E9F06 10 meters back What is the approx. maximum range for signals using transequatorial propagation? E3B02 5000 miles back How may dangerous levels of carbon monoxide from an emergency generator be detected? E0A07 Only with a carbon monoxide detector back Semi-final Jepperdee topic: A.C. waveform For a sinusoidal voltage, how do the peak and rms values compare? peak voltage = 1.414 X rms voltage OR Vrms = .707 X Vpeak (to second game board) Final Jepperdee topic: hazardous materials Which insulating material used as a thermal conductor is extremely toxic if broken or crushed and accidentally inhaled? E0A09 Beryllium Oxide Thanks for playing Exam-prep Jepperdee: Extra-class Edition