Real
World Ranges for CB, FRS, GMRS and MURS Radios
Testing Results Part One :
Consumer Grade Radios
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If you're relying on the claims of the manufacturers,
you'll probably be very disappointed.
Here's a realistic
look at the true distance you can expect from your radios.
Part 3 of a 5 part series - click for Parts
One
Two Three
Four
Five |
Going to the shopping mall?
Expect your radios to have as little as a 100 yd range!
Wanting to keep in touch
between two cars driving on the freeway? Expect as little as a 1
mile range.
Wanting to stay in touch with
family at home while you drive to the shops? You'll be lucky to
get 1 mile of communications, and in some conditions, less than
1/4 mile.
CB Radio Range
CB radios have the longest
range of any of the different types of radio services considered
in these articles but only
if used with a good antenna. And that presents as the major
weakness of CB radios for most casual applications - the ideal
length for a CB radio antenna is about 15 feet!
CB radios can be a sensible
solution for communications between two cars (with external
antennas), or for communications between a 'base station' at
home or work (with a big high antenna) and a car. Expect two to
five miles range between two cars, and as many as ten or more
miles between a base station and a car. You might get twenty or
more miles range between two base stations.
But CB radios are probably
your worst solution for communications between two people using
hand-held portable radios with short antennas. They are not
nearly as small in size as the FRS/GMRS radios, they are much
more expensive. Because of the very inefficient antennas
in such units, their range is probably inferior to
the FRS/GMRS radios too.
Note that although their
range is the longest of any of the four radio services discussed
in this article series, their range is trivially short compared
to the range of transmissions at lower frequencies in the High
Frequency, Medium Frequency and Low Frequency radio bands.
Unfortunately, you need to pass various tests and be licensed by
the FCC in order to operate radio transmitters in these
frequency bands, making it impractical for casual use.
MURS Radio Range
I have not tested any MURS
radios and so can't comment specifically on them. However, I
guess that they will perform very much the same as FRS/GMRS
radios.
MURS radios are not on the
mass-market yet and so are the most expensive solution. On the
other hand, the 'commercial' grade of MURS radios that are on
sale are often made to a higher quality and with better
performance than the cheap 'consumer' grade FRS/GMRS radios, and
if you can find such radios and are willing to pay the price,
you will definitely get better performance than from FRS/GMRS
radios.
FRS Radio Range
FRS radios will give you as
little as 100 yds or less in office buildings and shopping malls
(less if no line of sight and you're on two different floors,
more if you are more or less in line of sight and on the same
floor).
In semi-open ground, you'll
get about half a mile of range, sometimes less (especially if
things block the line of sight between you), and seldom more
(mainly if you can have direct visual contact).
You'll get similar or
sometimes slightly better range if you are both in your cars,
but if the road you're on turns a corner, and the line of sight
disappears, the range will of course reduce again.
FRS radios are not allowed
to have external antennas, and their maximum power is limited to
half a watt.
GMRS Radio Range
A GMRS radio is identical to
an FRS radio - it uses the same frequencies. But it might have
two important differences.
The first difference is that
it might be higher powered than the FRS radio. As discussed in
part two and four of this series, extra power does not always
automatically mean extra range, so don't be too excited by the
extra power that a GMRS radio offers. All that extra power really
means is your batteries won't last as long!!!
The second difference is
that the GMRS radio can have an external antenna. As also
discussed in parts two and four, the quality of your
antenna is one of the most important factors in determining your
range.
So, in theory, a higher
powered GMRS radio with external antenna should outperform a
lower powered built-in antenna FRS radio.
Generally it seems that
manufacturers claim an 'up to 2 mile' range for FRS radios and
an 'up to 5-7 mile' range for GMRS radios (with built in
antennas) and then claim 'boosts range by up to 75%' for an
external antenna add-on. So, this would suggest a best case
range of about 12.25 miles for a moderately low powered GMRS
radio with a 'normal' non-directional antenna.
These theoretical ranges
were never experienced in actual testing conditions.
Testing Part One
See part four for a
second series of tests using 'professional grade' radios and
antennas.
I tested three radios in my
car - a 0.5 watt FRS radio (see left column), a 2 watt GMRS
radio with built-in antenna (Unit A in the middle column), and a
2 watt GMRS radio with both an internal antenna (Unit B in the
middle result column) and with an external roof mounted antenna
(right column), and matched them against another 0.5 watt FRS
radio and a 2 watt built-in antenna GMRS radio at home.
I drove in a spiral
sort of pattern around my house, and tested the quality of all
four different radio/antenna combinations from various places.
Here is a table showing the
quality ('recognizability' more than signal strength) of
reception on a 0-5 scale (5 is best).
No results are shown for
greater than 0.8 miles because none of the radios would receive
signals at these greater ranges. Distances are direct 'as the
crow flies' distances as measured by GPS.
Distance
(tenths of a mile) |
FRS |
GMRS
int antenna
(Units A - B) |
GMRS
ext antenna
(Unit B) |
1 |
5 |
5 - 5 |
5 |
2 |
3 |
2 - 3 |
4 |
3
(place 1) |
0 |
1 - 1 |
2 |
3
(place 2) |
3 |
2 - 3 |
4 |
3
(place 3) |
4 |
3 - 4 |
5 |
4
(place 1) |
0 |
3 - 3 |
4 |
4
(place 2) |
3 |
2 - 3 |
4 |
4
(place 3) |
2 |
1 - 3 |
3 |
5
(place 1) |
0 |
0 - 0 |
0 |
5
(place 2) |
2 |
0 - 1 |
3 |
5
(place 3) |
3 |
2 - 3 |
4 |
5
(place 4) |
3 |
2 - 2 |
4 |
6 |
2 |
1 - 2 |
3 |
6 |
1 |
3 - 3 |
4 |
7 |
0 |
1 - 0 |
1 |
7 |
0 |
0 - 0 |
0 |
8 |
0 |
0 - 0 |
0 |
8 |
0 |
0 - 0 |
1 |
Analysis
1. |
Many times the old low
powered FRS radio outperformed one of the new high powered GMRS radios
and sometimes it even outperformed both of them. This shows that
radio design is more important than power. |
2. |
There was a surprising
difference between the two different models of GMRS radio. This
again confirms that radio design is more important than power. |
3. |
Adding an external
antenna did improve the quality of the signal quite noticeably, but
did not give a big increase in range. |
4. |
The biggest factor on
range was the topography between the two units, with maximum range
varying up to two-fold depending on the conditions. |
5. |
You will get better
results in a flat open space where you can see the person you're
talking with, and you will get worse results within buildings. |
Summary
In the real world, range
experienced with generic consumer grade low cost FRS/GMRS radios
seems to vary from a low of under 100 yds (this happened in a shopping mall)
to a maximum of 0.8 miles.
This distance may stretch
out to a mile or two, and possibly more if you can both actually
see each other, with no obstructions between you.
For longer range between
cars, CB radios with good (ie large!) external antennas are your
best solution.
In general, the best way for
most people to stay in touch is simply to use a cell phone.
Especially if you never use all the included minutes in your
monthly plan, using your cell phone is probably the best
solution.
See also Parts 1, 2 4 & 5
In
Part 1 we explain the different types of personal radio
services available to you, and what they variously mean.
In
Part 2 we discuss how it is that manufacturers can claim
ranges of 'up to seven miles' when the effective range - as
tested by us - is sometimes as little as one twentieth the
claimed range. Many factors influence maximum range - some we
can influence, most we can not. In particular, read the
startling truth about the importance of transmitter power to
give you more range.
In
Part 4 we
repeat the testing, this time using 'professional grade' radios
to determine just how much more performance you get from these
much more expensive radios.
In
Part 5 we
explain the confusing mismatch of channel number allocations to
different FRS/GMRS radios.
Related Articles, etc
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Originally published
15 August 2003, last update
20 Jul 2020
You may freely reproduce or distribute this article for noncommercial purposes as long as you give credit to me
(David Rowell - KF7VVM) as original writer.
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