FRS/GMRS Frequencies Explained
How to get two different Walkie-Talkies
to communicate with each other
There are many different
makes and models of FRS and GMRS radios.
And - alas - many different
ways of numbering the different communication channels they
Part 5 of a 5 part series - click for Parts
A combination of confusing FCC
frequency allocations, different types of radio service,
nonstandard channel numbering, deceptive advertising by radio
manufacturers, and confusing features has made it extremely
difficult to get different makes and models of walkie-talkies to
work with each other.
Although these devil's brew of
different challenges would seem to make for a very daunting
task, if you separate out the nonsense from the relevant
reality, and do just a few simple things, you should have no
In other words, please read on.
A Modern Day Electronic Tower
With the proliferation of
remarkably inexpensive walkie-talkie radios, it is entirely likely
that you will find yourself with a Brand X Model 100 type radio
transceiver (walkie-talkie) and trying to communicate with your
friend who has a Brand Y Model 200 type unit.
You both turn to the same
channel number, but when you try and send him a message, nothing
happens. And when he sends back to you, again nothing
Or, even more confusing, one
of you can receive signals from the other, but not vice versa.
You know it isn't an
underlying problem with the radios, because you can talk just fine
to the other radio you have when you bought a pair of them, but
somehow, there is a problem when going from your radio to your
friend's different make/model radio.
There are four possible
issues interfering with your ability to send and receive messages.
CTCSS stands for Continuous
Tone Coded Squelch System, but for most non-technical people,
knowing the full glorious name of this system doesn't really aid
much in the understanding of it.
Many people completely
misunderstand what this is and does - including, unfortunately,
many people who describe and review these radios.
So let's first understand what
they don't do.
CTCSS does NOT give you
Using a CTCSS code on your
radio does not mean that other people can't hear what you
are saying. It means you can't hear what they are saying,
but it does not mean they can't hear what you are saying.
CTCSS does NOT give you more
We've seen people who multiple
the channels by the CTCSS codes (eg 22 x 38 = 836) and marvel at
the number of different 'channels' to choose from, saying words to
the effect 'With 836 different channels to choose from, you don't
need to worry about congestion or other users'.
This is nonsense. All
the other users are still sharing the same channel - just because
you can't hear them doesn't mean they're not there, and your
signals have no priority over theirs when you come to transmit.
So, having hopefully debunked these two
myths, let's now see what CTCSS does do.
What CTCSS does
When activated, CTCSS sends a
tone along with your voice whenever you send a transmissions.
This tone is not normally audible, but it is detected by the
If the receiving CTCSS is
switched on, it listens for the tone. If it is the tone that
it has been told to accept, it will then play the broadcast over
its speaker. But if the tone is a different frequency, it
will ignore the message.
This means that the person
listening to their receiver is not bothered by people who are not
intending to communicate with him, because they are either using
no tone at all (with CTCSS switched off) or a different tone.
However, there is still only
one channel, and only one person can broadcast on it at any one
time. The different tones don't enable multiple
transmissions to occur simultaneously, and if that should happen,
they will still interfere with each other, no matter if they are
using tones or not.
And if a person switches off
the CTCSS on their receiver, they can hear all transmissions, no
matter what the tone that might be used, on a given channel.
The problem with CTCSS
Different systems use
different sets of tone frequencies. The most common system
uses 38 tones, but there are a number of other 'standards' out
So there is the problem.
If your radio uses one set of tones, and the other radio you are
trying to communicate with uses a different set of tones, they are
probably not going to be able to talk to each other unless you
both switch off your CTCSS function.
DCS stands for Digital Coded
Squelch, and it can be thought of as being identical in function
to CTCSS, but using a slightly different method of signalling.
Instead of adding a tone to the transmission, DCS sends a digital
DCS blocking has exactly the
same limitations and challenges as CTCSS, and can be available in
over 100 different codings.
Making things even more
complex are some radios that have both CTCSS and DCS on them!
That starts to really make for complexities upon complexities.
Multiple perhaps 40 CTCSS codes with perhaps 100 DCS codes, and
that gives you 4,000 different ways to limit what you can hear on
each channel (but remember, although it limits what you
hear, it doesn't limit what other people can hear
if they have turned off their CTCSS and DCS controls).
Multiply that by perhaps 22 channels at you are at almost 100,000
different combinations of channel, CTCSS and DCS code.
The best thing to do with
CTCSS, DCS, and any other similar features is to turn them off.
Maybe, once you've verified you can at least get to the same
channel, then you might experiment with one of these extra
features, but until you have regular communication going
conveniently, you shouldn't add extra wild cards to the mix.
Channel Selection and
This too is a bit confusing.
There are historical reasons for how things evolved, but to cut to
the chase, the reality is that there are 14 different frequencies
for the FRS radio service, and 23 different GMRS frequencies.
Sounds simple, right?
Well, sort of, yes.
But then it gets a bit more
complicated. The first complication is that seven of the 14
FRS frequencies are the same as seven of the GMRS frequencies.
So the 14 + 23 don't total 37.
They actually come to 30 different channels.
The second complication is
that few GMRS radios - and almost no consumer grade ones - use all
23 GMRS frequencies (most use only 15).
The third complication is that
there is a sort of crazy order to the frequencies and how they are
assigned, and no manufacturer provides a sensible sequential
series of channel numbers to the frequencies.
So what might appear to be
Channel 1 on one radio might be Channel 8 on another.
And, one of the channels on
one of your radios might not even be in use at all with the other
of your radios.
FRS and GMRS Issues
The fourth issue is whether
both radios are able to send/receive the same bands. Some
radios are only FRS. Some are only GMRS. Some are both
FRS and GMRS. In other words, even with the best will in the
world, maybe your radios don't have all the same frequencies in
them (but, don't despair - the chances are that they at least have
some overlap in frequencies, even if not all the same ones shared
Some explanation and
clarification may be in order! The FCC has allowed GMRS
(General Mobile Radio Service) type radio service to operate since
In 1988, the FCC slightly
changed the purpose of the GMRS service, allowing it to be used by
individuals for personal use, while still requiring people using
GMRS radios to buy a license from the FCC to be allowed to operate
the radios. Licenses are good for an entire family, and are
valid for five years. The current cost of a license is $85.
In 1996 the FCC came out with
a new type of radio service, FRS (Family Radio Service).
This used frequencies in the same area as the GMRS frequencies
(indeed, it shares seven frequencies and also uses another seven
frequencies in the same range).
The new FRS service had
slightly different rules. It was not as powerful as GMRS
service, but it was open to anyone, without the need to buy a
license or to register at all with the FCC.
There were presumably obscure
reasons that probably make sense to the FCC, but not to us, as to
why the FCC had FRS radios share some but not all frequencies with
This inevitably lead to radio
manufacturers selling combined FRS/GMRS radios on the 'honor'
system. You had to promise to not use the GMRS part of the
walkie-talkie unless you had a GMRS license.
Well, with these radios being
sold to anyone and everyone - children, adults, whoever, and with
few people bothering to read much more in the instructions than
how to turn the radio on, the GMRS frequencies were rapidly filled
with non-licensed users. This so overwhelmed the FCC
enforcement division that in 2010 the FCC sort of gave up
enforcing the need for licenses with GMRS radios.
Radios are sold with a strange
mix of 'on these frequencies you can only transmit on low power,
on these frequencies you can only transmit on high power if you
promise you have a GMRS license, and on these frequencies, you can
only use them if you have a GMRS license.
Some radios have some GMRS
frequencies, some have all of them.
This is very confusing for
users, who largely completely ignore such requirements.
Midland Invents New 'Channels'
But wait - there's more.
Alas. And it isn't good. It is bad.
Midland - a one time fine
company with excellent products has clearly let its marketeers run
They now offer radios that claim to have 50 different
channels. As you know from reading above, there are, in
total, only 30 channels permitted by the FCC. What are the other 20 channels
that Midland offers?
This is a mystery. Amazingly, when one visits their website and looks at the
specifications for these radios, there is a partial list showing
frequencies for the first 22 channels (a standard set of FRS and
GMRS frequencies) and then no details at all for the other 28
What are these channels?
We sent emails to two different parts of Midland, and got no reply
from either. Are they truly secret channels?
We did some more research, and
as best we can tell (and we invite Midland to break their
embarrassed silence and correct us) these new channels are
total marketing fictions. They are just repeating
the earlier 22 channels in their radios (so that some frequencies
end up being called three different channel numbers!) but with
hard-coded CTCSS and DCS settings.
This does not do anything of
any benefit to users at all, and we repeat our earlier
recommendation that the best use of these radios is usually with
no DCS and CTCSS enabled at all (see below for a discussion on
when and how to use DCS/CTCSS).
The only beneficiary of this
50 channel claim is Midland, enabling them to sell walkie-talkies
claiming to have more channels than their competitors.
Shame on Midland for inventing
the 50 channel nonsense. Let's hope the other manufacturers
don't respond, by offering radios with 100 'channels' and so on,
How to Match Channel Numbers and
Okay, after all that preamble,
now for the meaty part.
The following table can be
used to help you understand the different frequencies and also to
match the channel numbers on one walkie-talkie with the channel
numbers on another walkie-talkie.
To match channel numbers,
simply look up the frequencies of the channels for the first
radio, and write the channel numbers alongside the frequencies in
the Radio 1 column. Next, do the same for the second radio
in its column.
Every walkie-talkie we've
found (apart from the Midland '50 channel' monstrosities) have a
chart listing the frequencies and assigned channel numbers in
their documentation. Use that to fill out the form below.
If you've lost the manual, the
chances are you can download a copy from the manufacturer's
After having done this
exercise for both radios, you have an easy
conversion chart, showing the channel numbers on the first radio
and the corresponding channel numbers on the second radio.
of Frequencies and Typical Uses
Frequency in MHz
GMRS-S & FRS
GMRS-S & FRS
GMRS-S & FRS
GMRS-S & FRS
GMRS-S & FRS
GMRS-S & FRS
GMRS-S & FRS
Note on Table Data
For the GMRS frequencies, we
specify them as either output from repeater frequencies (with the
letter 'O'), or input to repeater frequencies (with the letter
'I'), and we number them to show which input frequencies are
matched by which output frequencies.
GMRS frequencies not intended
to be used with repeaters are marked with the letter 'S' (for
You don't really need to
understand what these mean, the main thing to do is simply to
match the frequencies to your channel numbers on your radios.
The One Time it Makes Sense to
Use CTCSS or DCS
If you find that all the
channels on your radios are being used by many other people at the
same time, and if that means you are being plagued by lots of
annoying radio transmissions, none of which are intended for you,
then you can buy yourself some peace and quiet by activating a
CTCSS or DCS blocking tone so that only transmissions from the
other people in your group (who will be using the identical tone
of course) will cause your radio to actually broadcast the
received message over its speaker.
If you do this, there is a
very important thing you must do.
Any time you want to send a
message yourself, you should turn off the blocking first to check
that no-one else is currently transmitting. All
walkie-talkies are required to have a button, usually right next
to the push-to-talk button, that will 'open' the squelch (ie turn
off the CTCSS/DCS blocking) and enable you to hear if anyone else
is transmitting at all on the channel, but without your specific
If you don't do this check,
then when you do transmit, two things might happen.
The first is that your
transmission would scramble the transmission of any other person
who is currently in the middle of their transmission.
The second is that your
transmission would also be scrambled by the other person's
But you won't know this, and
you'll be wondering why the message you just transmitted hasn't
been responded to by the person in your group you were sending the
The person you were hoping to
send a message to might send a message saying 'Did you just try to
say something, please repeat it'. The person the other
person was sending to will do the same. Other people on the
channel might also say 'Was that a message for me?'. You'll
end up retransmitting. The other person who had been sending
at the same time will end up retransmitting. The net result
- massive more congestion, confusion, and traffic than if you just
pause and check before then transmitting.
So, please, if using these
tone controls, be sure to check that no-one else is using the
channel before you start your own transmission.
Of course, if you have your
CTCSS/DCS switched off, there is not so much need to open the
squelch before sending your message.
Sometimes more is less, and in
the case of walkie-talkie radios, more options for limiting the
transmissions you here, and more channels to choose from, can
sometimes result in less readily understood radios and much more
Use the conversion table above
to enable you to equate the different channel numbers in different
radios, and in general, avoid using the CTCSS and/or DCS
functions, which most of the time make things more complicated
rather than more convenient.
See also Parts 1, 2, 3 & 4
Part 1 we explain the different types of personal radio
services available to you, and what they variously mean.
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.
Part 3 we give you real world test results of 'consumer
grade' radios and help you
choose which is the best system for your needs.
Part 4 we do a second round of testing, comparing professional
grade GMRS radios and antennas to consumer grade radios.
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1 June 2012, last update
02 Jul 2017
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.