On a 150 watt marine SSB HF transceiver, what would be indicated by a steady output of 75 watts when keying the transmitter on?

There is probably a defect in the system causing the carrier to be transmitted.

There should always be fluctuations as the result of input, and single side band should have only what is being sent, so having a steady output is the indication of a problem.

For more information, please see W8JI site for the article on About Power

Also see Electronics Notes site for the article on Decibels

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The tachometer of a building’s elevator circuit experiences interference caused by the radio system nearby. What is a common potential “fix” for the problem?

Add a .01 µF capacitor across the motor/tachometer leads.

For explanation of capacitor in such circuits, please see Diesel Duck Info site for the article on Technical notes of interest to Marine Engineers Radio Frequency Interference

Also, Control Engineering site for the article Don’t be the victim of electrical noise and EMI

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A common method of programming portable or mobile radios is to use a:

A laptop computer.

From wp2ahg:

Many portable and mobile radios can be programmed by connecting them to a laptop computer using a serial or USB cable.

The other three choices are not used for programming radios:

• A dummy load is used to prevent propagation
      while testing a radio.
  
• A wattmeter measures signal wattage.
  
• A signal generator creates electronic signals.

See the Prepared site for the article on How to program a Ham radio with CHIRP software

Also, see the Ham Radio School for the article on Five Common Mistakes New Hams Make

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In a software-defined transceiver, what would be the best way for a technician to make a quick overall evaluation of the radio’s operational condition?

Use the built-in self-test feature.

From wp2ahg:

Built-in self-test features on radios are the quickest method of evaluating a radio's operational condition.

Setting up a spectrum analyzer and service monitor and manually verifying the manufacturer's specs is not a quick process as compared to using a self-test feature.

Using another radio on the same frequency to check the transmitter does not do a full test on the radio, nor is it as quick a process as using self-test feature.

The FCC does not prohibit the use of on-board self-test features on radios. It is not restricted to Amateur Radio use.

See Wikipedia's articles on:

• Software-defined radio
  
• Digital signal processing
  
• List of amateur radio software
• Digital radio
• List of software-defined radios

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How might an installer verify correct GPS sentence to marine DSC VHF radio?

Look for latitude and longitude on the display.

From wp2ahg:

If the latitude/longitude is correctly displayed on a marine DSC VHF radio, then the radio is interpreting the GPS sentence correctly.

You would not press and hold the red distress button as that would initiate a distress signal.

Unsure of what a 'GPS confirmation readout' is.

A VHF radio check position report would confirm a VHF radio's transmit/receive capabilities, but would not confirm the GPS system is working.

For more information, please see the GPS.gov site for the article on GPS Accuracy

Also, see the Lemberg Solutions site for the article on GPS Accuracy. A Complete Guide for Dummies

And, from the Skyhook site, please see the article on Best Practices to Measure Location Accuracy and Geo-Positioning Performance Metrics

For more details, please Naval Postgraduate site for the article on GPS Accuracy Levels

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What steps must be taken to activate the DSC emergency signaling function on a marine VHF?

Input of registered 9-digit MMSI.

From wp2ahg:

MMSI (Maritime Mobile Service Identity) is a 9-digit code that uniquely identifies ship stations, coast stations, ship & coast earth stations, and group calls.

This code must be entered into a marine VHF radio so that it can be transmitted with the DSC (Digital Selective Calling) emergency signal.

For more information, please see the US Coast Guard site Navigation Center for the article on Maritime Mobile Service Identity

"Maritime Mobile Service Identities (MMSIs) are nine-digit numbers used by maritime digital selective calling (DSC), automatic identification systems (AIS), and certain other equipment to uniquely identify a ship or a coast radio station.

MMSIs are regulated and managed internationally by the International Telecommunications Union in Geneva, Switzerland, just as radio call signs are regulated. The MMSI format and use is documented in Article 19 of the ITU Radio Regulations and ITU-R Recommendation M.585-6, available from the ITU."

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