IW5EDI Simone - Ham-Radio

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Cubical Quad Design

Posted: 30 Apr 2016 03:07 AM PDT
http://www.iw5edi.com/ham-radio/2122...al-quad-design


The frequency scaling formulas for Cubical Quad antennas are shown in this
picture.

Note that frequency is measured in Megahertz {MHz} and the total length of
each element is measured in feet {ft}.

The spacing of each element is the same and all directors are the same size.

The gamma match uses a small air variable capacitor approximately the value
given and an adjustable shorting bar at the end connected to the element.
The antenna is tuned by adjusting the length of the shorting bar on the
gamma match for minimum VSWR with the variable capacitor half engaged. Then
adjust the capacitor for minimum VSWR at the mid band frequency.

The enclosed EXCEL programs:Â*Â*CubQuad.zip (includes cubicalq.xls,
cubquad2.xls, cubqvswr.xls) can be used to determine the element lengths
and the gamma match values for different frequencies.

In general the design is robust and may be optimized for gain or front to
back by adjusting the spacing of the elements.
Figure 1. Cubical Quad Frequency Scaling Equations.

This antenna design has been built for both the ten and two meter versions
and I have used them for T-Hunting and in two CVARC Field Day events with
good results.

Figures 2 and 3 show the calculated antenna patterns and performance.

Table 1 shows an example output from the EXCEL Scaling program.

Figure 4. Shows VSWR vs. Frequency for three different 2 meter antennas, a
4 element Quad, a 6 and a 12 element Yagi.
Figure 2. Elevation Pattern for the 4 element Cubical Quad 36 above a
perfect ground




Figure 3. Azimuth Pattern for the 4 element Cubical Quad 36 above a perfect
ground


Figure 4. VSWR vs. Frequency for Three 2 Meter Antenna Designs.





CUBICAL QUAD
Scaling Formulas

3/19/97 22:24







Dr. Carl O. Jelinek
Total Length

All the same
All the same





N6VNG
Lr
Ldrv
Ldir
S
G
W
C


f=Frequency {MHz}
Reflector {ft}
Driven {ft}
Directors {ft}
Spacing {ft}
Gama {ft}
Width {ft}
Cap {pfd}



146.565


7.028


6.857


6.652


1.584


0.292


0.094


20.0




222


4.640


4.527


4.392


1.045


0.193


0.062


13.2




445


2.315


2.258


2.191


0.522


0.096


0.031


6.6




52


19.808


19.327


18.750


4.463


0.822


0.264


56.3




28.5


36.140


35.263


34.211


8.144


1.500


0.482


102.8













Notes: Scaling
Lr = 1030/f
Ldrv = 1005/f
Ldir = 975/f
S = 232.1/f
G = 42.75/f
W = 13.74/f
C = 2930/f




Table 1. Cubical Quad Scaling Relationships

The post Cubical Quad Design appeared first on IW5EDI Simone - Ham-Radio.


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Programming VHF/UHF Radios

Posted: 30 Apr 2016 02:01 AM PDT
http://www.iw5edi.com/ham-radio/2118...-vhfuhf-radios


The purpose of this article is to give you an idea of what you will need to
do to set up a new radio for basic Simplex, Repeater, and Memory operation
so that you will have an idea of what to look for and concentrate on in the
instruction manual for your radio.

Programming a new VHF/UHF radio usually proves to be a frustrating
experience for most new amateur radio operators. In the words of Helen
Tallen KG6DUK “I thought I could just buy a radio, turn it on, and it would
work�. Unfortunately a new radio must first be programmed for simplex and
repeater operation before it can be used to communicate with local hams.

Most VHF/UHF ham radios are packed with dozens of interesting features.
Only a small number of these features are actually used for normal
communications. The remainder are provided for special communication modes
occasionally used by experienced hams. The problem is that the few features
that you do need are usually imbedded in the complex menus used by the
radio to set up all its other advanced features. To make matters worse,
there are no standards for the set up menus. Each radio is different. Even
radios made by the same manufacturer differ in their set up menus.Â* This is
not only exasperating to new hams, it drives experienced amateur radio
operators crazy also. To program a radio you must read the radio’s
instruction manual to learn what the specific set up procedures are for
that radio. Â* Don’t every loose the radio’s instruction manual! Without it,
you will not be able to reprogram the radio.

While radio manuals are getting better, it is still very easy to get
totally confused the first time that you try to set up a radio. Again,
explanation of how to set up the basic functions that you need are mixed in
with the complex descriptions of the advanced features.

The Alinco radios installed at the East County Sheriff’s Station (ECSS)
ARES/RACES Emergency Communication Center will be used as an example. These
radios are fairly typical in their set up procedures. Also, by reading this
article you will know how to operate the radios in the comm. center should
it become necessary for you to do so during an emergency or to support one
of our many CVARC Thousand Oaks public service events.



SIMPLEX OPERATION: Simplex is the simplest mode of operation. Simplex does
not involve a repeater and is used to communicate with a “near by� ham who
is approximately in your line of sight. During a recent ARES/RACES simplex
test, Pete Heins N6ZE used a low power handheld radio to talk to hams
throughout Conejo Valley from the top of Tarantula Hill in central Thousand
Oaks. All of Conejo Valley was in Pete’s line of sight. In a similar test,
conducted in a hilly residential neighborhood near the Thousand Oaks
Library, myself and another amateur radio operator were able to communicate
only a half mile or less using handheld radios operating in the simplex
mode. Being on top of a high hill or having a tall antenna with a “clear
line of sight� is very important when using simplex communications!

To operate simplex you have to tune your radio to the frequency that you
and the ham that you want to talk to agree upon. In addition, you have to
turn off your radio’s repeater frequency shift function. Frequency shift is
utilized only when communicating through a repeater. It is not used for
simplex operation. Finally, set your radio’s output power to an appropriate
level (usually low or medium power), set the squelch control to eliminate
background noise, and turn the volume control to a comfortable listening
level. You are now ready to begin simplex communications. Â* These steps are
described in more detail below. For the Alinco radio, simplex set up
requires you to use a row of buttons located below its display as shown in
Figure 1.







The buttons are labled as follows:



SET
MW
SHIFT
LOCK
M/L
D


FUNC
V/M
MHz
TS/DCS
CALL
SQL




The pushbutton in the upper right hand corner of the radio is the power
on/off button. The small knob to the left of the power on/off button is the
volume control, and the larger knob below it is the frequency tuning knob.
Other radios will have similar controls, with the exception of the smallest
handheld radios which use push buttons instead of volume control and tuning
knobs.

Frequency Selection: Radios have two operating modes, VFO mode and memory
mode. To set the radio to the correct frequency you must be in the VFO
mode. If your radio is in the memory mode, there will be an M or a channel
number appearing somewhere on the radio’s display. For the Alinco, an M
appears on the left edge of the display when it is in the memory mode. If
you are in the memory mode, the V/M button must be pushed on the Alinco to
enter the VFO mode (the M will disappear from the display). The Variable
Frequency Oscillator (VFO) is the module that controls your radio’s
frequency. Turning the tuning knob causes the radio to change frequency in
very small steps. If the person that you want to talk to is on a frequency
of 147.555 MHz and your radio is tuned to 144.000 MHz, it will take you all
day to “crank� your tuning knob to a frequency of 147.555 MHz. To move
across the band quickly with the Alinco, push the MHz button. The display
will change to 144. Turn the tuning knob 3 clicks. The frequency display
will change from 144 to 145, then 146, and finally 147. Pushing the MHz
button again puts the radio back in the normal mode. Now turn the tuning
knob until you reach 147.555 MHz. Many radios operate in this manner.
Others allow you to enter the frequency that you want directly from the
radio’s key pad, in the case of a handheld, or from the key pad on the
microphone.

Turn Off Shift: When communicating through a repeater, the frequency that
you are listening to (the repeater output frequency) will be automatically
changed (shifted) by your radio to the repeater input frequency when you
begin to transmit. In simplex mode you do not want this to happen. In
simplex mode, the frequency that you are listening to is also the frequency
that you want to transmit on. To ensure that this happens, you must turn
off the shift function. On the Alinco you will notice the word SHIFT
displayed above the MHz key. Since SHIFT is written above the key, it means
that you activate the Shift function by first pushing the Function (FUNC)
key and then the MHz key. Repeating this two keystroke operation will cycle
you through three options, minus shift (a – appears on the display), plus
shift (a + appears on the display), no shift (no symbol appears on the
screen). It is this last option that you want for simplex operation.

As just described, the Alinco has one function engraved on each function
key and a second function, requiring the use of the Function key, displayed
above each key. On some radios, pushing the Function key causes the labels
displayed above the function keys to change, thus changing the function
performed by each key when it is pushed. Pushing and holding down the
Function key for 1 second causes a third set of labels to appear. Other
radios may show two functions above each key and differentiate them by
color, gray and blue for example. Gray colored functions are executed
directly by pushing the key under the label. Blue functions require you to
push the radio’s Function key and then the key under the blue label. Your
radio will likely use one of these approaches to select functions such as
turning off the frequency shift.

End FunctionSelection : Usually, the radio will return you to the normal
radio display after selecting a function. Occasionally you can get stuck in
the function selection process. It is therefore important to know how to
terminate a function selection. On the Alinco, you push the V/M key to
terminate or close function selection. Find out how to do this on your
radio before you use the Function key to avoid getting stuck in the
function selection mode.

Power Level: Most radios have several transmit power levels, typically
High, Medium, and Low. Â* To minimize interference to others and to minimize
the drain on your batteries, set your radio to the lowest power level
needed to communicate with the person that you are talking to. Â*A good
level to start with is Medium. On the Alinco, H/L (High/Low power) is
displayed above the Call key. This means that power selection is a second
level function. Push the Function key followed by the Call key to select
power level. Â* Repeating this set of key strokes will cycle you through the
High (nothing displayed), Medium (Mi displayed), and Low (Lo displayed)
power levels of the radio. Stop at the setting that you want. Most radios
set the power level in a similar way.

Squelch: On many radios the squelch and volume are concentric controls (an
inner knob and a larger outer knob on the same shaft). For the Alinco there
is a Squelch key (SQL). For concentric controls, turn the squelch knob
(usually counter clockwise) until you hear continuous background noise
(hissing).Â* Now turn the knob the other direction until the hissing stops
and the radio is quiet. This sets the sensitivity of your radio so that you
can hear others without the nuisance of background noise. On the Alinco
this is done by pushing the SQL key and then turning the tuning knob in the
manner just described for concentric squelch controls.

Volume Control: Finally set the volume control to an audio level that is
comfortable.

Receiving: You should now be able to receive the transmissions from the
person that you want to talk with.

Transmit: To transmit, push the PTT (Push To Talk) key on your handheld
radio or on your microphone. Â* Wait a second after pushing the PTT key
before speaking to give your radio time to enter the transmit mode. If you
do not do this, the first word that you speak may not be clearly
transmitted. Speak in a normal voice. Speaking too loudly will distort your
transmission. Also, talk across your microphone, from the side, instead of
directly into it. Talking directly into the microphone can cause background
hissing.

EMERGENCY SIMPLEX OPERATION: Simplex operation is a very important mode
that everyone should know how to use. During a natural disaster, the local
repeaters may fail. If that occurs, amateur radio operators assisting with
emergency communications traffic must switch to the simplex mode to
continue emergency operations. This is done by setting up their radios for
simplex operation, using the procedures described above, and tuning their
radios to an agreed upon simplex frequency. Â* On Tuesday night May 18 at
7:00 PM we will be testing our emergency communications simplex operations
on 147.885 MHz. If you would like to be part of an important test, set up
your radio for simplex operation and check into the exercise following the
directions that will be transmitted to all participants that evening.

REPEATER OPERATION: Repeater operation permits communications over an
extended area, even with a handheld radio. A repeater located on a high
hill or mountain top has line of site coverage over a considerable area,
often 15 to 20 miles.

A repeater amplifies signals it receives on its input frequency and
retransmits them on its output frequency throughout its area of coverage.
As a repeater user, you will listens to others on the repeater output
frequency. This is the frequency that is listed for the repeater in
repeater directories. For example, the output frequency for the Bozo
Repeater is 147.885 MHz and the Grissom Repeater is 146.850 MHz. The
repeater input frequency, for 2 meter repeaters, is off set or shifted
either +600 KHz or -600 KHz from its output frequency. Â* When you transmit
to a repeater, the output of your radio must shift + or 600 KHz, as
appropriate, to the repeater’s input frequency. The off set for both Bozo
and Grissom is negative. The Bozo output frequency is 147.885 MHz. So when
you transmit to Bozo, your radio must transmit at a frequency of 147.285
MHz. You must program this + or off set into your radio in order to use
the repeater.

Most repeaters in metropolitan areas utilize an access tone to avoid
receiving and retransmitting signals actually intended for a different
repeater operating on the same frequency. This tone is known as a PL or
CTCSS tone. There are actually 39 tones available for use ranging in
frequency from 67.0 to 250.3 Hz. Â* A repeater will only retransmit signals
which contain its particular PL tone. For example, the PL for Bozo is 127.3
Hz while that for Grissom is 94.8 Hz. Â* To utilize a repeater, your radio
must be programmed to transmit the PL tone which the repeater is expecting.
If you don’t, the repeater will ignore your signals. In some cases a
repeater will not use a PL tone, for example the Ojai repeater does not use
a PL. In that case you will not program a PL tone into your radio for that
repeater.

Programming your radio to work with a repeater is similar to programming it
for simplex operation with the addition of the +/- off set and the PL tone.
For the Alinco radio, the programming proceeds as follows:

Frequency Selection: If the radio is in the memory mode (there is an M
showing on the display indicating memory mode), then push the V/M key to
place the radio in the VFO mode. Tune the radio to the output frequency of
the repeater that you wish to use, 147.885 MHz for Bozo, using the same
tuning procedures that were used to select a simplex frequency.

Select +/- Shift: Â*Select the appropriate +/- off set for the repeater that
you plan to use. On the Alinco this is done with the SHIFT key. Â* The word
SHIFT appears above the MHz key which means that the FUNC key must be
pushed followed by pushing the MHz key to activate the Shift function.
Performing this two keystroke operation causes a – to be displayed
indicating that the radio is now set up for a negative off set. Performing
the two keystroke operation again causes a + to be displayed indicating a +
off set. Performing the operation again causes the – and + signs to
disappear, indicating that you are back in the Simplex mode. Perform the
operation as many times as needed to achieve either a – or a + off set, as
appropriate for the repeater that you will be using.

Select PL Tone: If the repeater that you will be using requires a PL tone,
then you must select the tone which the repeater expects. Tone is selected
on the Alinco radio by pushing the TS/DCS key. Pushing the key once will
cause a T to be displayed plus a tone frequency. Turn the tuning knob until
the tone frequency expected by the repeater is displayed.Â* Complete the
tone selection by pushing the V/M key to exit the selection process. The
normal display will return, except that a T is now showing on the display
indicating that a PL tone has been selected. Pushing the Alinco TS/DCS key
multiple times will cause other functions to appear on the display. If this
occurs, continue pushing the key until only a T accompanied by a tone
frequency is shown on the display and proceed as described above.

Power Level: Set the radio’s transmit power level to the lowest power
needed for the repeater to clearly receive your signal. A good level to
start with is Medium. Set this power level in the same way as was done for
simplex operation.

Squelch: Â*Set the squelch in the same manner as was done for simplex
operation.

Volume Control: Finally set the volume control to an audio level that is
comfortable.

Transmitting and Receiving: You are now ready to communicate with others
via the repeater. Before beginning to transmit, make sure that the person
that has been transmitting is really finished before starting your
transmission. Then delay a little longer so that if someone has emergency
traffic, they will be able to break in and use the repeater. If all is
quiet, then you may transmit by pushing the PTT key on your handheld radio
or microphone. Remember to wait a second after pushing the PTT key before
speaking to give your radio and the repeater time to enter the transmit
mode.

RADIO MEMORY OPERATION: Programming radio simplex and repeater frequencies
is a lot a work. After you have set up your radio for a particular simplex
frequency or repeater, you can store that information into your radio’s
memory so that you will not have to repeat the set up the next time that
you want to use that simplex frequency or repeater.

Writing to a Memory Channel: Storing the information that you have
programmed into the VFO is particularly easy on the Alinco radio. Push the
V/M key to place the radio in the memory mode. An M will appear on the
display. Turning the tuning knob will select different memory channels. The
number of each memory channel will appear on the display as it is selected.
Select an unused memory channel. The memory channel number will blink if
that memory channel is empty. Other radios tend to do the same for an empty
channel. Push the FUNC key followed by the V/M key to write the contents of
the VFO into the selected memory channel, ie to do a memory write function
(MW).

Memory Read: Â*Once you have stored all of your favorite repeater and
simplex frequencies into memory, all that you have to do is select the
appropriate memory channel to begin operating on that frequency. To do
this, you switch your radio from the VFO mode to the memory mode, pushing
the V/M key on the Alinco, select the appropriate memory channel, and begin
operating. For example, if operation on the Bozo repeater (memory channel
02) is desired, push the V/M key to place the radio in the memory mode (an
M appears on the display).Â* Turn the tuning knob until memory channel 02
appears on the display. Begin operating on Bozo. That is all there is too
it.





Article by Ken Larson, KJ6RZ

originally available at http://www.cvarc.org/tech/program_vhf_uhf.html

The post Programming VHF/UHF Radios appeared first on IW5EDI Simone -
Ham-Radio.