Bidah
02-16-2007, 12:34 PM
There are a lot of options when it comes to communications. Some
require licenses, and some do not. I will briefly describe some of the
aspects here, but if you want more information, then I suggest that
you get one of the beginning radio books on the subject. These can be
found anywhere from your local library to websites ( www.aesham.com,
www.hamradio.com, www.arrl.org ) just to name a few.
Things to consider:
budget
distance
portable or base station
power supply
weight
usability
--- Communication options that do not require licenses
CB
Inexpensive and easy to obtain, but also crowded, and in the high
HF frequencies ( 27 MHz ). There are portable handhelds ( rather
large ), mobile, and desktop models. CB's have a decent range,
around 25 to 30 miles for a 4 watt model with a good antenna.
Handheld units will be less. With CB you also can get "skip",
which is a bounce of the signal off of the ionosphere. That means
that you can talk, or hear, stations many hundreds to thousands
of miles away. The amount of skip is cyclical, by about 11 years.
It also varies by time of day, usually starting around midday, and
lasting into the evening.
FRS
Inexpensive and easy to obtain. Low power, handheld with some base
style units. Due to the frequency range ( UHF 460 MHz ) they do not
have a lot of range. Depending on the terrian, up to 2 miles. In
hilly areas, expect a mile or less. What makes a big difference in
these radios ( or any radio for that matter ) is a good receiver.
My pair of Motorola can get more "range" than my bargain town radios.
The fact that they are of limited range can also be put to good use.
That means that the signals that you do transmit won't make it far,
and you have far less problems with "skip" from a long distance
interfereing with your local communications.
--- Communication options that do require licenses
GMRS ( business band )
GMRS is very similar to FRS as they are easy to obtain. They operate
on a different band, and most commonly employed by businesses. They
are usually handheld in nature, but you can also get base stations.
They use more power,have a 5 mile range, and may employ repeaters if
you are subscribed to one of the commercial ones. You are required
to have a license, but there are many operators that do not get the
license ( $70 fee ), and operate anyway. According to reports you
are not bothered unless you interfere with a business user who will
report the problem to the FCC.
Ham Radio ( HF VHF UHF )
Operation in this range requires an FCC license, which is easy to
obtain, and basically costs nothing beyond the testing. They are
monitored by the FCC, but mostly by the ham radio operators
themselves.
HF
This is long what has been thought of as where ham radio operator
reside, and to an extent that is true. The areas where you can
operate start just above the AM radio ( 160 meters or 1.8MHz )
section and continue to just above the CB band in what is known
as 10 meters ( 28 to 30MHz ). Each part of this section has it's own
abilities and detractions. The higher you go in frequency, the more
it tends to be only available during the day, and the lower in
frequency the more available during the night ( for long range
communications ). Of course you can reverse that for short comms and
security. The best all around, and most used segment, is that of 20
meters or 14MHz. You will notice that it falls in the middle of this
section. These bands, given that you use the correct band, mode of
communication, antennas and such, will give you comms around the
world, somtimes with very little power. I have a small home built
radio, that uses morse code, operates on a small battery pack, and is
able to communicate over a very long distance ( thousands of miles ).
It's power output is less than what would be used to power a maglight.
Most units here are of the base station type, although mobiles are
common. Most units manufactured in the last 20 years or so operate on
12v which makes our job much easier. My current radio, at full power
of 100 watts, needs 20 amps at 12 volts to function, so you must plan
accordingly. You can also build very simple, portable radios such as
those described above that can do a very good job.
VHF and UHF
These bands are very popular, and is the easiest to get licensed for.
All that is required is some basic electronic theory and regulations.
Average study time is about 8 hours, so can easily be done in a week.
There is no code requirement.
VHF
This band goes from 50MHz to approximately 220MHz. The relevant parts
for us is the 6M ( 50MHz ), 2M ( 144MHZ ), and 220MHz portions. There are a
lot of government use of this band, especially around the 50MHz
portion. For years the darling of this has been 2 meters for mobile
and handheld use. That has begun to change in recent years with the
addition of good cheap radios for the 6 meter portion of the band.
50MHz or 6 meters
Long considered the best of the VHF bands, there are a lot of
government use of the surrounding frequencies, including the military.
This band has good range, even for a handheld radio, and due to
increasing popularity, an increase in the types of radios that you can
get for a very resonable price. Since this band is very close to the
HF range, it does experience some 'skip' due to atmospheric and
sunspot conditions, so range will vary accordingly. Handheld units
are typically 5 watts, and range out to 30 or more miles. A mobile
unit at 25 watts and a good antenna can range out to the hundreds of
miles. This is currently seeing lots of activity within the patriot
community due to this fact, and the fact that it is widely used by the
military. Hence it is becoming a standard capability to posess. Base
station and mobile radios can be bought that will operate using all
the available modes ( AM, FM, CW, SSB, DATA ).
144MHz or 2 meters
Base station and mobile radios can be bought that will operate using all
the available modes ( AM, FM, CW, SSB, DATA ). Range for handhelds is
around 15 miles, less depending on terrain, mobiles have about 25 to 60
miles depending on the power of the unit. A good antenna, as
elsewhere, really helps your range. Most radiowaves here are
vertical, but a handheld beam can be used both ways. Since this is a
popular ham radio band, and has been for quite some time, there are
lots of repeaters to extend your range, and most have some backup
capability ( at least for a while anyway ). Equipment is common on
the used market as well.
220MHz
Not a lot of use on this band, and hence not a lot of equipment to
choose from. Range falls between 2 meters and 440MHz.
UHF
This band is primarily in use by amateurs in the 440MHz portion. This
is also where the FRS and GMRS users reside ( just above ). Less
users, and less crowded, this is a good band for limited range
commnuications, and mobile, base station, and handheld units can be
bought, some at a very resonable price. The primary users are
handheld or mobiles to repeaters, although this is where sattelite use
really comes into play. Handheld radios typically can output 5 watts,
and depending on terrain have a range to about 10 miles.
Base station and mobile radios can be bought that will operate using all
the available modes ( AM, FM, CW, SSB, DATA ).
Beyond
There are frequencies beyond the UHF spectrum that go will into the
microwave region ( above 1GHz ). They are very useful for point to
point communications, but usually it is line of sight. This range is
affected by such things as rain. It is not uncommon to use transverters
to gain access to this band, which will allow the use of your better
equipped VHF or UHF station ( the signal is converted up and down ).
You can get handhelds and mobiles for this band, but you are limited.
--- Equipment Options
There are several different types of radio selections, and the line is
blurred with the newer electronics. Some of the mobile radios will
boast features that were not long ago only available to base station
type radios.
Base Stations
These usually have more features, better filtering ( audio and
signal ), but are large and require a substantial amount of power to
run. Older, but very good radio's can be had on the used market for a
resonable price. Normally found for the HF spectrum, they can also be
found for VHF and UHF.
Handhelds
These are just what you think. Generally low power, and lacking base
station features. But, they are readily portable, which is nice when
you want to pack it around all day.
Portable (mobiles)
These have less power than base stations ( usually ), but more than
handhelds. They are larger than what a handheld would be, but can get
you a host of features above a handheld. Depending on the frequency,
this option can cost you some in weight and space, but give you a lot
more operational range. Of course you will have to lug around bigger
batteries.
--- Antennas
Antennas come in three basic configurations: vertical, dipole, and
beam. There are literally many variations of these antennas, but that
is beyond what is required knowledge at this time. There are some
very good books written on the subject, including design theory, or
just how to build them with dimensions and such.
Vertical
These antennas are what people are most familiar with. Car radio
antennas, CB antennas, your handheld radio, cellular phones. They can
be very tall, or short, depending on the frequency range. Easy to
deploy, but cumbersome due to materials. Generally good antennas for
use in the VHF and UHF bands, but quite large for HF work. There are
ones on the market for HF that will work quite well. Usually will
provide some signal gain.
Dipole
These are usually made of wire, and strung between to vertical points
( trees, houses, etc... ). Easy to make, can be concealed,
lightweight if needed, and normally used on HF, but could be used on
VHF and above. Most will provide no signal gain, and in fact a dipole
is used as a zero refernce. For portability these are an excellent
choice on HF and 6 meters. There are some models of wire antennas
that can provide gain, but they add weight, are not easy to make, and
are easier to see. This is the type of antenna that I primarily use
for HF.
Beam
These are usually made out of tubing, and put on top of a tower ( like
a TV antenna ). They provide gain, and can be used on all bands, but
the lower HF portion can be quite large and use tricks to electrically
make them larger. For VHF use, they can be quite small and portable.
For this band they are also a very good choice since you can get a
good boost by using them.
--- Modes of Communication
AM
This is the mode that standard CB uses, and some ham activity. This
mode uses more energy for a given amount of output power. AM uses a
continuous carrier that is modulated by voice. If you want to
conserve power, and get distance, this is not the mode to use.
SSB
Single Sideband is the stepchild of AM. What SSB does is eliminate the
continuous carrier, and then output one of the modulated sidebands (
hence the term Lower Sideband (LSB) and Upper Sideband (USB)). What
that means is that it uses less power, and gives you a greater range.
This is what most form of HF communications utilizes for voice, as
well as some CB's that have the capability.
CW
Continuous Wave is best known as Morse Code. This is sending a
carrier wave in bursts, long and short. The familiar dit dah's that
you hear. It is fairly easy to learn, uses very little power, easy
to build transmitters and receivers, and can go for a very long
distance. It is also easier to understand if there is a lot of
atmosphereic noise, far greater than that of SSB.
FM
Frequency Modulation is similar to AM, but uses a different method of
sending and interpreting the signal. This mode is most common on the
FRS, GMRS, handheld and mobile radios for ham use. Again it uses more
power, and will not get a signal as far, but when you do get a signal,
it will tend to be very clear.
DATA
Sending data via a radio is very similar to using your modem to
connect to the internet. The method of communication may use SSB or
FM, but then delves very deep from there as to how the communication
is sent and received. Depending on the mode used, this can go quite a
distance, but is generally about the same as voice.
Satellite
Similar to using a repeater situated on a mountain or building, you
are using a sattelite to repeat your signal within the path that it
can 'see'. So, you have to be able to get into it, and also the
person that you are trying to contact. There are also store and
forward types, that would be similar to a bulletin board, or email.
This can use some sophisticated equipment depending on which one you
are trying to use, but can be done with a dual band handheld unit.
Generally the use of FM ( which handhelds use ) is discouraged due to
the bandwidth of the signal, and how much power is used by the
sattelite to bring the signal back to earth.
---- Powering your Radio Setup
Oh, the choices that you can have. Depending on how much power is
required by your setup, and whether you want it to be portable,
luggable, or need a forklift and commercial power is up to you. For
portability the gel cell reigns king. They are usually inexpensive,
and provide a good power to weight ratio. Most of the batteries that
you would need can be found on the used market. Such places as phone
switching equipment swap out there batteries long before they are worn
out. Don't overlook a good marine battery either. You can use regular
automotive batteries but they will not last nearly as long since they
are not designed for deep discharge cycles. I also prefer batteries
that are sealed, but that does not limit what I could use. To charge,
you can make your own chargers, buy commercail ones, or setup some
solar panels and control unit. While solar panels are not quite there
in portability, they have come a long way in the last decade.
-bidah
require licenses, and some do not. I will briefly describe some of the
aspects here, but if you want more information, then I suggest that
you get one of the beginning radio books on the subject. These can be
found anywhere from your local library to websites ( www.aesham.com,
www.hamradio.com, www.arrl.org ) just to name a few.
Things to consider:
budget
distance
portable or base station
power supply
weight
usability
--- Communication options that do not require licenses
CB
Inexpensive and easy to obtain, but also crowded, and in the high
HF frequencies ( 27 MHz ). There are portable handhelds ( rather
large ), mobile, and desktop models. CB's have a decent range,
around 25 to 30 miles for a 4 watt model with a good antenna.
Handheld units will be less. With CB you also can get "skip",
which is a bounce of the signal off of the ionosphere. That means
that you can talk, or hear, stations many hundreds to thousands
of miles away. The amount of skip is cyclical, by about 11 years.
It also varies by time of day, usually starting around midday, and
lasting into the evening.
FRS
Inexpensive and easy to obtain. Low power, handheld with some base
style units. Due to the frequency range ( UHF 460 MHz ) they do not
have a lot of range. Depending on the terrian, up to 2 miles. In
hilly areas, expect a mile or less. What makes a big difference in
these radios ( or any radio for that matter ) is a good receiver.
My pair of Motorola can get more "range" than my bargain town radios.
The fact that they are of limited range can also be put to good use.
That means that the signals that you do transmit won't make it far,
and you have far less problems with "skip" from a long distance
interfereing with your local communications.
--- Communication options that do require licenses
GMRS ( business band )
GMRS is very similar to FRS as they are easy to obtain. They operate
on a different band, and most commonly employed by businesses. They
are usually handheld in nature, but you can also get base stations.
They use more power,have a 5 mile range, and may employ repeaters if
you are subscribed to one of the commercial ones. You are required
to have a license, but there are many operators that do not get the
license ( $70 fee ), and operate anyway. According to reports you
are not bothered unless you interfere with a business user who will
report the problem to the FCC.
Ham Radio ( HF VHF UHF )
Operation in this range requires an FCC license, which is easy to
obtain, and basically costs nothing beyond the testing. They are
monitored by the FCC, but mostly by the ham radio operators
themselves.
HF
This is long what has been thought of as where ham radio operator
reside, and to an extent that is true. The areas where you can
operate start just above the AM radio ( 160 meters or 1.8MHz )
section and continue to just above the CB band in what is known
as 10 meters ( 28 to 30MHz ). Each part of this section has it's own
abilities and detractions. The higher you go in frequency, the more
it tends to be only available during the day, and the lower in
frequency the more available during the night ( for long range
communications ). Of course you can reverse that for short comms and
security. The best all around, and most used segment, is that of 20
meters or 14MHz. You will notice that it falls in the middle of this
section. These bands, given that you use the correct band, mode of
communication, antennas and such, will give you comms around the
world, somtimes with very little power. I have a small home built
radio, that uses morse code, operates on a small battery pack, and is
able to communicate over a very long distance ( thousands of miles ).
It's power output is less than what would be used to power a maglight.
Most units here are of the base station type, although mobiles are
common. Most units manufactured in the last 20 years or so operate on
12v which makes our job much easier. My current radio, at full power
of 100 watts, needs 20 amps at 12 volts to function, so you must plan
accordingly. You can also build very simple, portable radios such as
those described above that can do a very good job.
VHF and UHF
These bands are very popular, and is the easiest to get licensed for.
All that is required is some basic electronic theory and regulations.
Average study time is about 8 hours, so can easily be done in a week.
There is no code requirement.
VHF
This band goes from 50MHz to approximately 220MHz. The relevant parts
for us is the 6M ( 50MHz ), 2M ( 144MHZ ), and 220MHz portions. There are a
lot of government use of this band, especially around the 50MHz
portion. For years the darling of this has been 2 meters for mobile
and handheld use. That has begun to change in recent years with the
addition of good cheap radios for the 6 meter portion of the band.
50MHz or 6 meters
Long considered the best of the VHF bands, there are a lot of
government use of the surrounding frequencies, including the military.
This band has good range, even for a handheld radio, and due to
increasing popularity, an increase in the types of radios that you can
get for a very resonable price. Since this band is very close to the
HF range, it does experience some 'skip' due to atmospheric and
sunspot conditions, so range will vary accordingly. Handheld units
are typically 5 watts, and range out to 30 or more miles. A mobile
unit at 25 watts and a good antenna can range out to the hundreds of
miles. This is currently seeing lots of activity within the patriot
community due to this fact, and the fact that it is widely used by the
military. Hence it is becoming a standard capability to posess. Base
station and mobile radios can be bought that will operate using all
the available modes ( AM, FM, CW, SSB, DATA ).
144MHz or 2 meters
Base station and mobile radios can be bought that will operate using all
the available modes ( AM, FM, CW, SSB, DATA ). Range for handhelds is
around 15 miles, less depending on terrain, mobiles have about 25 to 60
miles depending on the power of the unit. A good antenna, as
elsewhere, really helps your range. Most radiowaves here are
vertical, but a handheld beam can be used both ways. Since this is a
popular ham radio band, and has been for quite some time, there are
lots of repeaters to extend your range, and most have some backup
capability ( at least for a while anyway ). Equipment is common on
the used market as well.
220MHz
Not a lot of use on this band, and hence not a lot of equipment to
choose from. Range falls between 2 meters and 440MHz.
UHF
This band is primarily in use by amateurs in the 440MHz portion. This
is also where the FRS and GMRS users reside ( just above ). Less
users, and less crowded, this is a good band for limited range
commnuications, and mobile, base station, and handheld units can be
bought, some at a very resonable price. The primary users are
handheld or mobiles to repeaters, although this is where sattelite use
really comes into play. Handheld radios typically can output 5 watts,
and depending on terrain have a range to about 10 miles.
Base station and mobile radios can be bought that will operate using all
the available modes ( AM, FM, CW, SSB, DATA ).
Beyond
There are frequencies beyond the UHF spectrum that go will into the
microwave region ( above 1GHz ). They are very useful for point to
point communications, but usually it is line of sight. This range is
affected by such things as rain. It is not uncommon to use transverters
to gain access to this band, which will allow the use of your better
equipped VHF or UHF station ( the signal is converted up and down ).
You can get handhelds and mobiles for this band, but you are limited.
--- Equipment Options
There are several different types of radio selections, and the line is
blurred with the newer electronics. Some of the mobile radios will
boast features that were not long ago only available to base station
type radios.
Base Stations
These usually have more features, better filtering ( audio and
signal ), but are large and require a substantial amount of power to
run. Older, but very good radio's can be had on the used market for a
resonable price. Normally found for the HF spectrum, they can also be
found for VHF and UHF.
Handhelds
These are just what you think. Generally low power, and lacking base
station features. But, they are readily portable, which is nice when
you want to pack it around all day.
Portable (mobiles)
These have less power than base stations ( usually ), but more than
handhelds. They are larger than what a handheld would be, but can get
you a host of features above a handheld. Depending on the frequency,
this option can cost you some in weight and space, but give you a lot
more operational range. Of course you will have to lug around bigger
batteries.
--- Antennas
Antennas come in three basic configurations: vertical, dipole, and
beam. There are literally many variations of these antennas, but that
is beyond what is required knowledge at this time. There are some
very good books written on the subject, including design theory, or
just how to build them with dimensions and such.
Vertical
These antennas are what people are most familiar with. Car radio
antennas, CB antennas, your handheld radio, cellular phones. They can
be very tall, or short, depending on the frequency range. Easy to
deploy, but cumbersome due to materials. Generally good antennas for
use in the VHF and UHF bands, but quite large for HF work. There are
ones on the market for HF that will work quite well. Usually will
provide some signal gain.
Dipole
These are usually made of wire, and strung between to vertical points
( trees, houses, etc... ). Easy to make, can be concealed,
lightweight if needed, and normally used on HF, but could be used on
VHF and above. Most will provide no signal gain, and in fact a dipole
is used as a zero refernce. For portability these are an excellent
choice on HF and 6 meters. There are some models of wire antennas
that can provide gain, but they add weight, are not easy to make, and
are easier to see. This is the type of antenna that I primarily use
for HF.
Beam
These are usually made out of tubing, and put on top of a tower ( like
a TV antenna ). They provide gain, and can be used on all bands, but
the lower HF portion can be quite large and use tricks to electrically
make them larger. For VHF use, they can be quite small and portable.
For this band they are also a very good choice since you can get a
good boost by using them.
--- Modes of Communication
AM
This is the mode that standard CB uses, and some ham activity. This
mode uses more energy for a given amount of output power. AM uses a
continuous carrier that is modulated by voice. If you want to
conserve power, and get distance, this is not the mode to use.
SSB
Single Sideband is the stepchild of AM. What SSB does is eliminate the
continuous carrier, and then output one of the modulated sidebands (
hence the term Lower Sideband (LSB) and Upper Sideband (USB)). What
that means is that it uses less power, and gives you a greater range.
This is what most form of HF communications utilizes for voice, as
well as some CB's that have the capability.
CW
Continuous Wave is best known as Morse Code. This is sending a
carrier wave in bursts, long and short. The familiar dit dah's that
you hear. It is fairly easy to learn, uses very little power, easy
to build transmitters and receivers, and can go for a very long
distance. It is also easier to understand if there is a lot of
atmosphereic noise, far greater than that of SSB.
FM
Frequency Modulation is similar to AM, but uses a different method of
sending and interpreting the signal. This mode is most common on the
FRS, GMRS, handheld and mobile radios for ham use. Again it uses more
power, and will not get a signal as far, but when you do get a signal,
it will tend to be very clear.
DATA
Sending data via a radio is very similar to using your modem to
connect to the internet. The method of communication may use SSB or
FM, but then delves very deep from there as to how the communication
is sent and received. Depending on the mode used, this can go quite a
distance, but is generally about the same as voice.
Satellite
Similar to using a repeater situated on a mountain or building, you
are using a sattelite to repeat your signal within the path that it
can 'see'. So, you have to be able to get into it, and also the
person that you are trying to contact. There are also store and
forward types, that would be similar to a bulletin board, or email.
This can use some sophisticated equipment depending on which one you
are trying to use, but can be done with a dual band handheld unit.
Generally the use of FM ( which handhelds use ) is discouraged due to
the bandwidth of the signal, and how much power is used by the
sattelite to bring the signal back to earth.
---- Powering your Radio Setup
Oh, the choices that you can have. Depending on how much power is
required by your setup, and whether you want it to be portable,
luggable, or need a forklift and commercial power is up to you. For
portability the gel cell reigns king. They are usually inexpensive,
and provide a good power to weight ratio. Most of the batteries that
you would need can be found on the used market. Such places as phone
switching equipment swap out there batteries long before they are worn
out. Don't overlook a good marine battery either. You can use regular
automotive batteries but they will not last nearly as long since they
are not designed for deep discharge cycles. I also prefer batteries
that are sealed, but that does not limit what I could use. To charge,
you can make your own chargers, buy commercail ones, or setup some
solar panels and control unit. While solar panels are not quite there
in portability, they have come a long way in the last decade.
-bidah