May 31, 2014

Azden AZ-61 6m FM HT - Tip #2 - disabling "the beep"

This post is in a series regarding the 1990's vintage Azden AZ-61 6m FM HT.

Azden AZ-61 6m FM HT

So you have dusted off  your Azden AZ-61 6m FM HT and powered it back to life.  Congratulations for giving this neat old radio a go!  One of the things you may have noticed when pressing buttons is an annoying, "beep" after each key press.  The good news is that the beep noise can be toggled off and on easily (if you know the trick).

How to toggle off and on the key press beep

Step 1) Press and hold the "FUN" key while powering the radio on.


Yes, it is that simple.

Good DX and 73, NJ2X




© Michael W. Maher and NJ2X.COM, 2014. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Michael W. Maher and NJ2X.COM with appropriate and specific direction to the original content.

FCC Technician Exam Question Of The Day (T9B07)

B) Which of the following is true of PL-259 type coax connectors?

A) They are commonly used at HF frequencies

NJ2X Notes:
The PL-259 connector is the defacto standard on HF amateur radio equipment.  The type N connector is technical superior in everyway but is not commonly found on amateur radio equipment.


PL-259

May 30, 2014

Space Elevator...

The Space Elevator will be built about 50 years after everyone stops laughing -- Sir Arthur C. Clarke

Space Elevator

FCC Technician Exam Question Of The Day (T9B01)

Q) Why is it important to have a low SWR in an antenna system that uses coaxial cable feedline?

A) To allow the efficient transfer of power and reduce losses


NJ2X Notes:
A perfect standing wave ratio (SWR) is 1:1.  Higher SWR is the result of an antenna and feedline that do not have matching impedances.  Any SWR greater than 1:1 indicates some of the transmitted energy is being reflected back toward the transmitter.  This reflected energy results in RF energy being radiated from the feedline as heat (an efficiency loss).  In some cases, the reflected energy can even cause damage to the transmitter. 

May 29, 2014

FCC Technician Exam Question Of The Day (T9A11)

Q) What is meant by the gain of an antenna?

A) The increase in signal strength in a specified direction when compared to a reference antenna

NJ2X Notes:
Gain is often expressed in decibels (dB).  A theoretical antenna called an isotropic radiator is sometimes used as a reference.  An isotropic radiator is a point source located in free space and radiating equally in all directions.

May 28, 2014

FCC Technician Exam Question Of The Day (T9A10)

Q) In which direction is the radiation strongest from a half-wave dipole antenna in free space?

A) Broadside to the antenna

NJ2X Notes:
The strongest radiation from a half-wave dipole is at right angles to the antenna wire. For example, if the dipole wires are oriented so they run to the East and West then the antenna would radiate the strongest to the North and South.

May 27, 2014

FCC Technician Exam Question Of The Day (T8B05)

Q) What is a satellite beacon?

A) A transmission from a space station that contains information about a satellite

NJ2X Notes:
Satellite beacon frequencies


Beacon. An amateur station transmitting communications for the purposes of observation of propagation and reception or other related experimental activities.

May 26, 2014

FCC Technician Exam Question Of The Day (T8A02)

Q) What type of modulation is most commonly used for VHF packet radio transmissions?

A) FM


NJ2X Notes:
FM stands for Frequency Modulation.  FM is used extensively in VHF and UHF communications.

May 25, 2014

Camelopardalids Meteor Shower

Take a gander at the Camelopardalids meteor shower tonight.

Good DX and 73, NJ2X

FCC Technician Exam Question Of The Day (T9A09)

Q) What is the approximate length, in inches, of a 6 meter 1/2-wavelength wire dipole antenna?

A) 112


NJ2X Notes:
The easiest way to handle this question is to memorize the answer.

May 24, 2014

Azden AZ-61 6m FM HT - Tip #1 - How to program the radio

The Azden AZ-61 6m handi-talkie (HT) can be found from time-to-time at hamfests for a relatively low price.  Buying one without the manual; however, can be a rather frustrating experience since the radio's design is far from intuitive.  This isn't the kind of radio that you can put in your hand and program without looking at a manual.  Almost anyone who has owned one would agree that it is downright difficult to program the AZ-61 (even with the original manual).

Azden AZ-61 6m FM Transceiver
After searching the Internet, we discovered that there are rather few resources to guide the manual-less Azden AZ-61 owner in programming the radio.  As a consequence, there are probably more than a few fully functional units out there just sitting on a shelf collecting dust for lack of ability to program.  If you are one of those owners, we prepared this short tutorial on programming the Azden AZ-61 for you.  We hope it inspires you to dust-off your Azden AZ-61 (or snap one up at a hamfest), program a repeater or two, and get it back on the air.

How to program a repeater into the Azden AZ-61

In the following step-by-step example, we will program a local 6m repeater located in Ben Lomond, California (WR6AOK, output = 52.800 MHz, offset = -0.500 = 52.500 MHz, PL = 114.8) to the Azden AZ-61's memory address "MA0".

"MA0" is the main memory channel and can be recalled quickly via the dedicated MA0 button on the front left of the radio.  This is a pretty handy feature.

Step 1: Turn on the program mode

  • In order to program the radio you need to first enable the programming mode. 
  • Press "FUN" + "0" (at the same time) and hold for 1 second
  • The LCD display will show a blinking "PR"
  • Note: The programming mode is automatically turned off when the radio is left idle for 10 seconds or more.  This is an irritating "feature" since it forces you to repeatedly re-enable the programming mode (unless you are fast at going through the programming steps).  Be prepared to get a lot of practice on turning on the program mode.

Step 2: Select the memory address to program

  • For our example, we are going to program the memory address "MA0".
  • Using the up or down arrow buttons (located to the right of the LCD), select the memory address, "MA0".
  • "MA0" will appear in the upper left hand corner of the LCD when selected.
  • Press the "#" key

Step 3: Enter the receive frequency

  • For our example, we are going to program a receive frequency of 52.800 MHz.
  • Note: The AZ-61 does not have a decimal key.  Instead, use the "*" to denote the decimal when entering the frequency.  
  • Enter the frequency by pressing the keys, 52*800
  • Press the "#" key

Step 4: Enter a receive CTCSS frequency

  • For our example, we do not want to use a CTCSS frequency (not sure if the repeater transmits the CTCSS) so we are going to program this memory address to disable that feature.
  • Using the up and down arrow buttons (located to the right of the LCD), select "C00:"
  • Press the "#" key

Step 5: Enter transmit frequency

  • For our example, we are going to program a transmit frequency of 52.500 MHz.
  • Note: The AZ-61 does not have a decimal key.  Instead, use the "*" to denote the decimal when entering the frequency.  
  • Enter the frequency by pressing the keys, 52*500
  • Press the "#" key

Step 6: Enter transmit CTCSS frequency

  • For our example, we are going to program a transmit CTCSS frequency of 114.8 Hz.
  • Note: The CTCSS frequencies are stored in the AZ-61 in a table.
  • Using the up and down arrow buttons (located to the right of the LCD), select the "C16: 114.8"
  • Press the "#" key
Voila!  We have programmed a repeater into the Azden AZ-61 in just six easy steps.  Armed with these steps you can repeat the same procedure to program any of the other 40 memory addresses.  Hope this article has inspired you to put  your AZ-61 back on the air.

Considering its age, there are a surprising number of other features that can be programmed into the Azden AZ-61.  Perhaps this is a good example of how more can be less.  In the case of the AZ-61, more features seems to have led to less usability / programmability.  We may cover additional programming topics in a future article if there is interest.  Drop us a line and let us know.


Good DX and 73, NJ2X


Other related articles on NJ2X.COM:
Azden AZ-61 6m FM HT - Tip #1 - How to program the radio
Azden AZ-61 6m FM HT - Tip #2 - disabling "the beep"
Azden AZ-61 6m FM HT - Tip #3 - 1993 review article
Azden AZ-61 6m FM HT - Tip #4 - rebuilding the battery pack
Azden AZ-61 6m FM HT - Tip #5 - how to reset the radio
Azden AZ-61 6m FM HT - Tip #6 - Automatic Power-Off
Azden AZ-61 6m FM HT - Tip #7 - VFO Mode
Azden AZ-61 6m FM HT - Tip #8 - Frequency Step
Azden AZ-61 6m FM HT - Tip #9 - Scanning
Azden AZ-61 6m FM HT - Tip #10 - Dual Watch



© Michael W. Maher and NJ2X.COM, 2014. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Michael W. Maher and NJ2X.COM with appropriate and specific direction to the original content.

FCC Technician Exam Question Of The Day (T9A08)

Q) What is the approximate length, in inches, of a quarter-wavelength vertical antenna for 146 MHz?

A) 19

NJ2X Notes:
Electromagnetic waves travel at the speed of light which is 299,792,458 meters per second or for the ease of calculation we can round up to 300,000,000 m/s.  Frequency and wavelength are related and can be determined by the formulas:

Frequency = Speed of Light / Wavelength

or

Wavelength = Speed of Light / Frequency


The easiest way to deal with this question is to simply memorize the answer



May 23, 2014

FCC Technician Exam Question Of The Day (T9A07)

Q) What is a good reason not to use a "rubber duck" antenna inside your car?

A) Signals can be significantly weaker than when it is outside of the vehicle

NJ2X Notes:
Using an antenna on the exterior of the vehicle will dramatically improve both reception and your transmitted signal.  Better to have all that RF outside the vehicle too.



Intelligence...

If the presence of electricity can be made visible in any part of the circuit, I see no reason why intelligence may not be transmitted instantaneously by electricity. -- Samuel Morse

May 22, 2014

FCC Technician Exam Question Of The Day (T9A05)

Q) How would you change a dipole antenna to make it resonant on a higher frequency?

A) Shorten it


NJ2X Notes:
The key to successfully answering this question is to remember that wavelength gets smaller as the frequency increases.  The physical dimensions of antenna correspond to the wavelength.  So to optimize an antenna for a higher frequency you need to shorten the antenna's size (and wavelength).

The old carpenter's adage, "measure twice, cut-once" doesn't quite work when shortening an antenna for a particular frequency.  That is because antennas are complex and cutting them exactly to spec or formula does not assure an antenna will behave at the desired frequency.  A more appropriate adage might be, "measure the length twice, trim a little, measure the resonance and SWR, repeat as necessary".

May 21, 2014

FCC Technician Exam Question Of The Day (T9A04)

Q) What is a disadvantage of the "rubber duck" antenna supplied with most handheld radio transceivers?

A) It does not transmit or receive as effectively as a full-sized antenna

NJ2X Notes:
Many hams upgrade their HT's rubber duck with a higher performance antenna.  The trade off is typically size for performance.  However, there are times when a full size antenna is needed to make the contact.  For example, Arrow have handheld 2m/440 Mhz Yagi's that work great with an HT and can be used for satellite communication.

Directional arrow antenna for 2m/440 MHz

May 20, 2014

FCC Technician Exam Question Of The Day (T8B07)

Q) With regard to satellite communications, what is Doppler shift?

A) An observed change in signal frequency caused by relative motion between the satellite and the earth station

NJ2X Notes:
The Doppler shift, named after the Austrian mathematician and physicist Christian Doppler, who proposed it in 1842, is the change in frequency for an observer moving relative to its source.  With respect to sound waves, it is commonly heard when a vehicle sounding a siren or horn approaches (rising pitch), passes (neutral), and recedes (falling pitch) from an observer.  A fast moving train blasting its horn while passing a stationary observer at a crossing is one of the more dramatic examples.

Doppler shift also occurs in radio communications with satellites.  When this happens the receives signal frequency appears to change (though the transmitted frequency remains constant).  The change is due to the satellite's high speed of motion relative to the ground station.

Christian Doppler


May 19, 2014

FCC Technician Exam Question Of The Day (T7D10)

Q) What is probably happening when an ohmmeter, connected across a circuit, initially indicates a low resistance and then shows increasing resistance with time?

A) The circuit contains a large capacitor



NJ2X Notes:
When a voltage is connected to a resistor and capacitor in series, the initial current is high as the battery transports charge from one plate of the capacitor to the other. The charging current approaches zero through time as the capacitor becomes charged.  Charging the capacitor stores energy.




May 18, 2014

FCC Technician Exam Question Of The Day (T8B11)

Q) What is a commonly used method of sending signals to and from a digital satellite?

A) FM Packet


NJ2X Notes:
FM Packet

Packet radio is a digital mode of Amateur Radio communications which is similar to computer telecommunications employing modems. The telephone modem is replaced by a "magic" box called a TNC (terminal node controller) while the telephone system is replaced by amateur radio transceivers and amateur radio waves.   Packet radio transmits a stream of data from a computer via radio to another amateur radio station.  FM packet radio transmits using frequency modulation.

May 17, 2014

FCC Technician Exam Question Of The Day (T9A03)

Q) Which of the following describes a simple dipole mounted so the conductor is parallel to the Earth's surface?

A) A horizontally polarized antenna


NJ2X Notes:
Horizontal polarization is typically used communicating in HF using.  The simple dipole is the most popular is most easily mounted so the conductors are parallel to the Earth.  Vertical polarization is typically used in VHF and UHF communication applications.

May 15, 2014

Newton of electricity...

Ampere was the Newton of electricity. -- James C. Maxwell

FCC Technician Exam Question Of The Day (T9B02)

Q) What is the impedance of the most commonly used coaxial cable in typical amateur radio installations?

A) 50 ohms

NJ2X Notes:
50 ohm coaxial cable is the defacto standard used in amateur radio applications.  It is important that all the elements in the chain have matching impedance (radio, feedline, antenna, ...).  If there is a mismatch of impedance then SWR will be affected.

May 14, 2014

FCC Technician Exam Question Of The Day (T9A06)

Q) What type of antennas are the quad, Yagi, and dish?

A) Directional antennas

NJ2X Notes:
It helpful to think visualize a directional antenna like a magnifying glass.  A directional antenna "focuses" radio energy in a particular direction.  Directional antennas include the quad, Yagi, dish, and log periodic.

May 13, 2014

May 12, 2014

FCC Technician Exam Question Of The Day (T9A01)

Q) What is a beam antenna?

A) An antenna that concentrates signals in one direction


NJ2X Notes:
A beam antenna is a directional antenna.  Common beam antennas include:

- Yagi
- Quad
- Log periodic

Portable Yagi, elements made from metal tape measure

May 11, 2014

FCC Technician Exam Question Of The Day (T7C11)

Q) What is a disadvantage of "air core" coaxial cable when compared to foam or solid dielectric types?

A) It requires special techniques to prevent water absorption


NJ2X Notes:
A coaxial design in which a monofilament of plastic holds the center conductor in place in a hollow plastic tube allowing the remainder of the dielectric to be air. Typical velocities of up to 84% can be achieved in this design.

RG-59 air core coaxial cable


May 10, 2014

FCC Technician Exam Question Of The Day (T7C04)

Q) What reading on an SWR meter indicates a perfect impedance match between the antenna and the feedline?

A) 1 to 1

NJ2X Notes:
A one-to-one, 1-to-1, or 1:1 standing wave ratio (SWR) indicates a perfect impedance match between the antenna and feedline.  It also indicates that no RF is being reflected back toward the transmitter (not a good thing).  Yes, RF does travel in both directions through coaxial cable.



May 9, 2014

FCC Technician Exam Question Of The Day (T7B11)

Q) What is a symptom of RF feedback in a transmitter or transceiver?

A) Reports of garbled, distorted, or unintelligible transmissions

NJ2X Notes:
RF feedback is caused when RF finds its way back into the shack and into the audio circuit.  Under ideal conditions, all RF is radiated from the antenna (not from the chassis or coax).  RF feedback can be a problem with end-fed antennas, poor grounding, poor match between antenna and feed line impedance, and random wire antennas.  There are several effective techniques for eliminating or reducing RF feedback including: improving your station grounding, improving your antenna counterpoise, improving the match between your feed line and antenna, and using a common-mode RF isolation choke (also known as a current balun).

I built electronics...

Other kids went out and beat each other up or played baseball, and I built electronics. -- Robert Moog


Bob Moog



May 8, 2014

FCC Technician Exam Question Of The Day (T9B09)

Q) What might cause erratic changes in SWR readings?



A) A loose connection in an antenna or a feedline



NJ2X Notes:
Loose connections can cause erratic changes in SWR.  Check your connections and secure cables mechanically.

May 7, 2014

FCC Technician Exam Question Of The Day (T7C08)

Q) What instrument other than an SWR meter could you use to determine if a feedline and antenna are properly matched?

A) Directional wattmeter


NJ2X Notes:
One of the most popular directional watt meters is the Bird Watt Meter.




May 6, 2014

FCC Technician Exam Question Of The Day (T7C06)

Q) What does an SWR reading of 4:1 mean?

A) An impedance mismatch


NJ2X Notes:
Amateur radios require an impedance match of 50-ohms in the coaxial cable, antenna, or any other device connected.  A mismatch between the radio and any of the devices in the chain will cause a greater than 1:1 (perfect match) SWR.

SWR is an abbreviation of standing-wave ratio.   SWR on a transmission line in an antenna system represents the the ratio of forward to reflected voltage on the line.  A perfect 1:1 ration occurs when all parts of the antenna system are matched correctly to one another.

May 5, 2014

FCC Technician Exam Question Of The Day (T7D01)

Q) Which instrument would you use to measure electric potential or electromotive force?

A) A voltmeter

NJ2X Notes:
A volt meter is a basic must-have piece of equipment for the ham.  There are very inexpensive volt meters and multi-meters available.

Multimeter





May 4, 2014

FCC Technician Exam Question Of The Day (T7C05)

Q) What is the approximate SWR value above which the protection circuits in most solid-state transmitters begin to reduce transmitter power?

A) 2 to 1

NJ2X Notes:
Remember, high SWR is something to be avoided.  Your equipment can be damaged while operating under high SWR conditions.  Automatic power reduction circuits are helpful; however, they do not cure the root cause.

May 3, 2014

FCC Technician Exam Question Of The Day (T8C06)

Q) For what purpose is a temporary "1 by 1" format (letter-number-letter) call sign assigned?



A) For operations in conjunction with an activity of special significance to the amateur community



NJ2X Notes:
Part 97
§97.3 Definitions.
(iii) Special event call sign system. The call sign is selected by the station licensee from a list of call signs shown on a common data base coordinated, maintained and disseminated by the amateur station special event call sign data base coordinators. The call sign must have the single letter prefix K, N or W, followed by a single numeral 0 through 9, followed by a single letter A through W or Y or Z (for example K1A). The special event call sign is substituted for the call sign shown on the station license grant while the station is transmitting. The FCC will issue public announcements detailing the procedures of the special event call sign system.

May 2, 2014

FCC Technician Exam Question Of The Day (T7C02)

Q) Which of the following instruments can be used to determine if an antenna is resonant at the desired operating frequency?

A) An antenna analyzer


NJ2X Notes:
An antenna analyzer is an extremely useful device for amateur radio. We use the MFJ-269 - HF/VHF/UHF SWR ANALYZER, COUNTER.  We have used it to identifying problems with our coaxial cables as well as designing and building antennas.  There are all kinds of interesting things you can do with it beyond these basic uses.


May 1, 2014

Madness....

Though this be madness, yet there is method in't. -- Hamlet, Act 2, scene 2, William Shakespeare

William Shakespeare

FCC Technician Exam Question Of The Day (T7D09)

Q) What is the characteristic appearance of a "cold" solder joint?



A) A grainy or dull surface



NJ2X Notes:
When soldering, failure to properly flux and bring the leads to melting temperature of the solder can result will be an unreliable "cold solder joint".

Checkout our soldering related articles on NJ2X.com.