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. & Msrmnts

Modes & Equipment

Antennas/ Propagation

100 100 100 100

200 200 200 200

300 300 300 300

400 400 400 400

500 500 500 500 FJ

E2C06 During a VHF-UHF contest, in which band segment would you expect to find the

highest level of activity?

The weak-signal segment of the

band, with most of the activity near the

calling frequencyback

E2C07

What is the Cabrillo format?

A standard for submission of

electronic contest logs

back

E2D07 Which digital protocol is used by

APRS: PACTOR, 802.11, AX.25, or

AMTOR?

AX.25

back

E2A02 What is the direction of a

descending pass for an amateur

satellite?

From north to south

back

E2A09 What do the terms L band and S band specify with regard to satellite communications?

The 23-cm and 13-cm bands

back

E1A05 What is the maximum power output permitted on the 60 meter

band?

100 watts PEP effective radiated power relative to the gain of a half-

wave dipole back

E1C01 What is a remotely

controlled station?

A station controlled indirectly through a

control linkback

E1D08 Which VHF amateur-service

bands have frequencies available

for space stations?

2 meters

back

E1F14 When/why might the FCC issue "Special Temporary Authority" (STA) to

an amateur station?

To provide for experimental

amateur communications

back

E1B05 What is the maximum

bandwidth for a data emission on

60 meters?

2.8 kHz

back

E6D08 Why use powdered-iron

toroids rather than ferrite ones in an

inductor?

Powdered-iron toroids generally

maintain their characteristics at higher currents back

E5B04 What is the time constant of a circuit having two 220-μF caps and two 1-MΩ res., all in parallel?

220 seconds

back

E5A08 What is the phase between the I through and the v across a series resonant circuit?

The voltage and current are in

phaseback

E5C04 Expressed in polar, what is the z of

a 400-Ω reactance cap in series with a

300-Ω resistor?

500 ohms at an angle of -53.1

degreesback

E5D12 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?

80 watts

back

E6A08 What do we call the freq. at which the grounded-base cur-

rent gain of a transis-tor is .7 X the gain at

1 kHz?

alpha cutoff frequency

back

E6E06 What charac-teristics of the MMIC

make it a good choice for VHF-

through-microwave circuits?

Controlled gain, low noise figure, &

constant in and out Z’s over a given frequency rangeback

E6D13 What type of CRT deflection is best

when high-frequency waveforms are to be

displayed?

Electrostatic

back

E6B04 What type of semiconductor

device is used as a voltage-controlled

capacitor?

Varactor diode

back

E6D06 What property of the core material determines the inductance of a

toroidal inductor?

Permeability

back

E7B12

What is this?

Figure E7-1

Common emitter amplifier

back

E6E10 What is the equivalent circuit

of a quartz crystal?

Motional C, motional L, and loss R all in

series; with a shunt C representing elect-rode and stray C back

E7H13 Define “capture range”

of a phase-locked loop circuit?

The frequency range over which

the circuit can lockback

E7C07 What kind of filter would attenuate an interfering signal as you are receiving an SSB transmission?

A notch filter

back

E7D13 Purpose of D1?

Figure E7- 3

C1 C3

+25 +12

R2R1

C2 D14000

4000 0.01

Q1

To provide a voltage reference

back

E8D15 What is the typ-ical nominal value for the RMS voltage at a standard household a.c. power outlet?

120V

back

E8A06 What is the approximate ratio of PEP-to-average power in a typical SSB phone signal?

2.5 to 1

back

E4A03 Which would a spectrum analyzer

display on the vertical axis: Amplitude,

Duration, SWR, or Q?

Amplitude

back

E8B08 What parameter is varied by the

modulating signal in a pulse-position

modulation system?

The time at which each pulse occurs

back

E4E07 How can you determine if line-

noise interference is being generated

within your home?

By turning off the AC-power main

breaker and listen-ing on a battery operated radio back

E2D12 How does JT65 improve EME

communications?

It can decode signals many dB below the noise floor using FEC

back

E8C05 What is the necessary bandwidth

of a 13-WPM international Morse code transmission?

Approximately 52 Hz

back

E2B09 What hardware, besides a receiver & computer, is needed to decode SSTV using

Digital Radio Mondiale

(DRM)?

No other hardware is

needed

back

E4C04 What is the definition of the “noise figure” of

a receiver?

The ratio of the noise generated by the receiver to the theoretical mini-mum noise (in dB)

back

E6E05 What noise figure value might

be typical of a low-noise UHF

preamplifier?

2 dB

back

E9A09 What is meant by antenna bandwidth?

The frequency range over which

an antenna satisfies a performance requirement

back

E9D13 What happens to Z at the feed point of a fixed-length ant. as

the frequency of operation is lowered?

The radiation resis-tance decreases &

the capacitive reactance increases. back

E9F06 What is the approx. length of an air-insulated parallel conductor xmission

line that is λ/2 long at 14.1 MHz?

10 meters

back

E3B02 What is the approx. maximum range for signals

using transequatorial propagation?

5000 miles

back

E0A07 How may dan-gerous levels of car-bon monoxide from

an emergency gener-ator be detected?

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

ORVrms = .707 X Vpeak

(to second game board)

Final Jepperdee

topic:hazardous materials

E0A09 Which insulating material used as a

thermal conductor is extremely toxic if

broken or crushed and accidentally inhaled?

Beryllium Oxide

Thanks for playingExam-prep Jepperdee:Extra-class

Edition