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Amateur Radio Quiz: Specs or Pepper?

12/06/2012

By H. Ward Silver, N0AX
n0ax@arrl.net

Pondering a possible purchase puts the potential pocketbook provider in a pickle! Unless, that is, they are a savvy savant of specifications. This quiz will lead you through a jumbled jam of jargon to see how well you speak the language of the specification!

1) Which one of these units is used to describe a receiver’s sensitivity?
a. decibels
b. microamps
c. volts/meter
d. microvolts

2) What does “TOI” stand for?
a. threshold of instability
b. third-order intermodulation
c. total overload immunity
d. tested omnidirectional insubordination

3) Which of the following is a method of specifying transmitter output power?
a. DTMF
b. IMD
c. PEP
d. CCITT

4) What is measured by a two-tone test?
a. a transmitter’s linearity
b. power dissipation by a transceiver
c. cabinet finish quality
d. phase noise in an oscillator

5) An antenna’s SWR bandwidth is the frequency range over which its...
a. SWR can be reduced to unity by an antenna tuner.
b. feed point impedance equals 50 ohms.
c. SWR is less than 2:1.
d. SWR causes transmitter output to be reduced by1 dB or less.

6) Which of the following is used to specify antenna gain?
a. dBV
b. dBW
c. dBd
d. dBm

7) How is an antenna’s wind load specified?
a. in-lb
b. square feet
c. acre feet
d. kg/m

8) Insertion loss is used to measure the performance of what equipment?
a. dummy load
b. audio recorders
c. low-pass filter
d. high voltage power connectors

9) Which parameter describes a preamp’s contribution to received noise?
a. noise figure
b. noise gain
c. noise bandwidth
d. shot noise

10) Which of the following is another way of specifying SWR?
a. peaking factor
b. return loss
c. rise time
d. standoff voltage

11) Which of the following is a unit for specifying feed line loss?
a. percent shield coverage
b. characteristic impedance
c. nepers
d. dB/meter

12) A receiver’s blocking dynamic range (BDR) measures its ability to respond linearly in the presence of what type of signals?
a. image
b. off-mode
c. multi-path
d. strong

13) Which is used to evaluate a band-pass filter’s ability to reject undesired signals?
a. Q
b. notch depth
c. pass-band ripple
d. ultimate attenuation

14) How is a digital voltmeter’s precision specified?
a. accuracy
b. resolution
c. input impedance
d. jitter

15) Duplexers use this parameter to show how well they prevent signals from coupling between bands:
a. insulation
b. insurrection
c. isolation
d. deviation

Bonus: What kind of a device could be characterized as having steep skirts?

 

Answers

1) d -- Sensitivity is a measurement of a receiver’s response to input signals, measured in microvolts
2) b
3) c -- Peak Envelope Power is a measurement of instantaneous power output at the peak of an SSB or AM signal.
4) a -- By inputting two closely spaced audio tones, distortion in the transmitter’s amplifier stages can be observed as spurious output signals.
5) c
6) c -- The “d” after “dB” stands for “with respect to a dipole” -- gain must be specified with respect to some reference.
7) b -- At a given wind speed, a towers are rated for a maximum amount of antenna area.
8) c -- The loss encountered by a signal in the signals passband.
9) a -- Noise figure is a “figure of merit,” measured in dB, that gauges the noise added by a circuit.
10) b -- Higher return loss indicates less signal is reflected by a load.
11) d -- Loss is frequency-dependent and must also be specified at a specific frequency.
12) d -- Excessively strong signals can cause a receiver’s gain to drop, “blocking” other signals.
13) d -- This is the attenuation of the filter outside the filter’s rolloff or transition region.
14) b -- But don’t confuse precision with accuracy!
15) c -- High isolation is better.

Bonus Answer: A band-pass filter – “steep skirts” means the filter’s attenuation increases very quickly outside the passband.



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