General: Peak Inverse Voltage

What is the peak-inverse-voltage across the rectifier in a half-wave power supply? [G7A04]

A. One-half the normal peak output voltage of the power supply
B. One-half the normal output voltage of the power supply
C. Equal to the normal output voltage of the power supply
D. Two times the normal peak output voltage of the power supply

To answer this we must know what is going on in a half wave power supply.

A half-wave rectifier takes, as you might suspect, only half of a given alternating current (AC) input voltage, and turns that into (alright, well, sort of) direct current (DC.)  The above image shows what that basically looks like.  In this instance, it takes the positive voltage and discards the negative voltage.

The peak inverse voltage is the maximum input AC voltage that the device can withstand before it is operating outside of specifications, possibly even to the point of damage.  In a half-wave power supply, we are discarding one half of the wave, so it must be able to take a peak-to-peak input voltage of at least twice its output.

The answer then, is D. Two times the normal peak output voltage of the power supply.

 

General: Station Log Information

What information is traditionally contained in a station log? [G2D09]

A. Date and time of contact
B. Band and/or frequency of the contact
C. Call sign of station contacted and the signal report given
D. All of these choices are correct

When keeping logs for your station, you need certain pieces of information for the contact, or QSO to be considered valid.  If you don’t have the correct information in your log, when you go to confirm this contact with the other party, the information may not match, and the QSO might not be confirmed.  In a contest this can cost you points, or you might miss out on an award, or even something as simple as a QSL card.

At a bare minimum, you need the date and time of the contact, in UTC or “zulu” time.  This is also known as Greenwich Mean Time (GMT) and is basically the “world reference” for time.  You need the band, preferably the exact frequency (from which you can infer what band it was.)  You also need the call sign of the operator you contacted, and an additional piece of information that you (and they) can confirm as having been received (and sent.)  In contest settings this is usually a signal report.  Often times it will include other information relevant to the contest, like a location or sequence number.

Therefore, the answer is D. All of these choices are correct.  Now obviously you can record as much information about a QSO as you’d like, including recording the whole thing(!) But at a minimum you need the information outlined above.

Technician: Amplifier Components

Which of the following electronic components can amplify signals? [T6B05]

A. Transistor
B. Variable resistor
C. Electrolytic capacitor
D. Multi-cell battery

The answer is, as luck would have it, A. Transistor.  The transistor is probably the miracle of 20th century technology.  It’s an amplifier, a switch, and so much more.

None of the other components listed have the ability to amplify a signal.

General: Schottky Diodes

Which of the following is an advantage of using a Schottky diode in an RF switching circuit rather than a standard silicon diode? [G6A06]

A. Lower capacitance
B. Lower inductance
C. Longer switching times
D. Higher breakdown voltage

I know what you’re thinking.  Where did this bit of word soup come from, right?

First off, we need to know the difference between a Schottky diode and a standard silicon diode.  To start, they have a much lower breakdown voltage than a regular diode, which makes them generally better in high speed applications.

Since they aren’t capable of storing as much electric potential, and therefore electric charge, (which is the definition of a capacitor,) we can deduce that it would also have a A. Lower capacitance than a standard silicon diode.  This could make it quite useful in high frequency RF applications.

Technician: Electric Field

What is the ability to store energy in an electric field called? [T5C01]

A. Inductance
B. Resistance
C. Tolerance
D. Capacitance

Hate to say it, but this is basically a definition question.  The answer is D. Capacitance.  The easy way to remember this is just think about capacitors, the devices that actually store the electric field.  The next closest answer might be A. Inductance, which is the ability to store energy in a magnetic field, using (wait for it) an inductor.

(photo: https://commons.wikimedia.org/wiki/File:Capacitance_Meter_with_Popular_Electronics_Article.jpg)

Amateur Extra: Distance From Monitoring Facilities

Within what distance must an amateur station protect an FCC monitoring facility from harmful interference? [E1B03, 97.13]

A. 1 mile
B. 3 miles
C. 10 miles
D. 30 miles

The answer is: A. 1 mile.

Why? Because the FCC has said so, basically.  In section 13 of Part 97.

(b) A station within 1600 m (1 mile) of an FCC monitoring facility must protect that facility from harmful interference. Failure to do so could result in imposition of operating restrictions upon the amateur station by a District Director pursuant to §97.121 of this part. Geographical coordinates of the facilities that require protection are listed in §0.121(c) of this chapter.

 

General: Serial Port Connector

Which of the following connectors would be a good choice for a serial data port? [G6B12]

A. PL-259
B. Type N
C. Type SMA
D. DE-9

The answer is D. DE-9.  Now, wait a minute! I thought those were DB-9 connectors! Well, technically no.  The “B” refers to the size of the shell, so the older style 25-pin DB-25 connectors could be called that.  The DB designator just followed along, because they’re used so often for serial ports also.  The connector in the above image is an example of the DE-9 connector.

The remaining three connectors in the question, PL-259, N-Type, and SMA are all center-pin/outer-shield 2 conductor style connectors, specifically made for coaxial cables, like your radio-antenna feed line.  A serial port requires at minimum four conductors, two for transmit, and two for receive.

Technician: Ammeter Current Display

If an ammeter calibrated in amperes is used to measure a 3000-milliampere current, what reading would it show? [T5B06]

A. 0.003 amperes
B. 0.3 amperes
C. 3 amperes
D. 3,000,000 amperes

Don’t panic! This is a simple question about unit conversions, nothing more.

Remember your definitions of metric prefixes.  Milli means one one-thousandth, or 0.001.  Therefore, one milliampere is one one-thousandth of an ampere, or amp.  We can just multiply like this (and also remember to bring your calculator with you to the test!)

3000 x 0.001 = ?

and our answer is then C. 3 amperes.

Amateur Extra: Toxic Materials

Which insulating material commonly used as a thermal conductor for some types of electronic devices is extremely toxic if broken or crushed and the particles are accidentally inhaled? [E0A09]

A. Mica
B. Zinc oxide
C. Beryllium Oxide
D. Uranium Hexaflouride

The answer is C. Beryllium Oxide.  One of the hazards we face as radio enthusiasts is dealing with technology, and quite often the very materials we gain enjoyment from are also toxic if not handled with respect.  Beryllium Oxide is one of those.  So long as you don’t crush or cut the material, its pretty harmless.  The dust is what gets you.

I have run into a similar problem in antique radios I restore.  Occasionally I will run into a sheet of material acting as a vacuum tube heat shield.  You guessed it, its asbestos.  I simply remove the piece of material, very carefully, place it into a plastic zipper bag, and put it in the trash, taking great pains not to tear or crumple it.  It, too, is harmless if intact, but broken or torn it can release particles that could be inhaled and cause problems.

 

General: QRV

What does the Q signal “QRV” mean? [G2C11]

A. You are sending too fast
B. There is interference on the frequency
C. I am quitting for the day
D. I am ready to receive messages

Q-codes are one of those things you just have to memorize. There’s no good way around it.  I keep a list posted near my station, because there’s no way to remember all of them.  There are several that are used often, and this isn’t really one of them. Unless you’re really into CW and digital modes, you probably wouldn’t even think to use it at all.

The answer is D. I am ready to receive messages.  You can also add a “?” to the message, to turn it into the question: “Are you ready to receive messages?” That might actually get used more….

I’ve put a list of Q-codes in the Resources section of the website for your reference.