Channels VS Frequencies

[Jimru]

Hi all,

I ran across a fellow with AM BCB experience who asserts that using the term "channels" is interchangeable with "frequencies".

My assertion is that the word "frequency" is the common reference to where in the band a given station is located, be it AM BCB, FM BCB, or shortwave broadcasting.

Is he correct, or am I? Or, does it depend on certain circumstances?

Thanks!

Jim

 

[Voyager]

You're correct, but in the case of many services, they are interchangeable. For example, AM and FM Broadcast each frequency has a channel designation. CB, FRS, and GMRS is the same - each has a designation. Even some Land Mobile has channel designations (although many don't use them or realize they exist). Other services such as Amateur have 'bands', not channels, although some bands are divided into channels for repeaters and the like.

So, the correct answer as you put it is "it depend(s) on certain circumstances"

BTW, there can be many duplicate channel numbers, too. CB Channel 1 is not the same frequency as FRS Channel 1. Each service has their own list, so I would side with you more than the other guy. If he says they are interchangeable, ask him what frequency corresponds to "channel 1".

 

[DaveNF2G]

A channel is a pathway. A frequency is a rate of vibration. A channel includes a frequency, but unless the frequency is modulated in some way, it is not a channel.

 

[ka3jjz]

Well, if we push aside the philosophy, and omit the GMRS / FRS / FM stuff (since it's not germaine to a HF only forum) 'it depends' is only partially correct. Apart from the CB stuff, the only other place I can think of that uses channel designations - outside of any ITU publications - would be the maritime service, where assigning channel numbers is a fairly common practice. See these links for examples...

MF & HF Channel Information

eCFR — Code of Federal Regulations

eCFR — Code of Federal Regulations

eCFR — Code of Federal Regulations

It's worth noting that a lot of the activity on these bands has gone down drastically over the last few years due to the development of satellite tech, and even in the digital world, there are several stations using PACTOR type protocols that can't be read...even the number of these is really small compared to what it was several years ago.

As a practical matter, when folks report maritime activity, they usually talk frequencies, not channel numbers, as it's far clearer and easier to understand. I rather doubt you would see this in the aero service, and as for the feds or military, with them, anything goes....Mike

 

[Boombox]

Hi all,

I ran across a fellow with AM BCB experience who asserts that using the term "channels" is interchangeable with "frequencies".

My assertion is that the word "frequency" is the common reference to where in the band a given station is located, be it AM BCB, FM BCB, or shortwave broadcasting.

Is he correct, or am I? Or, does it depend on certain circumstances?

Thanks!

Jim

It depends on the type of radio hobby you're into, and how technical you want to get.

For MW DXing, "channels" is appropriate for generic reference, i.e. "I was tuning up the channels and..." Or "reception was great on this station except for adjacent channel interference."

But if you're telling someone else you heard a rare station, you give them the "frequency" where you heard it. To use the term channel in that instance would be sort of useless. I think it's much the same for FM DX.

On Shortwave, hobbyists tend to use the term "frequency" more, because even where there are SWBC bands (which you could say have 'channels'), the number of stations are low enough that frequencies are much more useful.

There are channels on HF, as has been mentioned. The HF Marine bands have channels, complete with channel numbers. But if I ever hear anything on them and report it anywhere, I give the frequency, and I think most HF listening hobbyists do that also.

 

[Jimru]

So, it depends is about right. I've been a radio hobbyist for many years and I've never heard a shortwave station say anything about channels mentioned by the broadcasters, only freqs.

The same is true for my experience with both AM and FM; for instance, when a station IDs, they don't say "you are tuned WXYZ channel 88.3".
I know that the professional equipment (such as military gear) my in fact have channel designations on the rigs, but in the hobbyist world, we use only frequencies as a reference. Same with the scanning hobby. The gear itself has channels and you'll hear PD/FD/EMS units specify "go to channel 8", but channel 8 is usually a different frequency for one dept to the next, so we, as hobbyists, use frequencies, once again.

I think from a hobbyists point of view, in my experience, frequencies trump channel designations in most instances.

Thanks for all of your input!

 

[KB7MIB]

The way I've seen it explained, is that a frequency is a specific point in the radio spectrum. A channel is a communications path that utilizes one or more frequencies. And channelization will vary amongst agencies and the radio service(s) they use.

John
Peoria, AZ

 

[majoco]

Hmmm. I think it depends on how the radio is to be used. Transmitter/receivers that are capable of transmitting on any frequency usually require a licensed operator who has shown by written exams and practical demonstration that he know what he is doing and is aware of the requirements not to cause interference with other stations and has the skills to ensure that it remains that way. Radios that are designed to be used by relatively unskilled operators are usually 'channelised' so that transmissions out of the allocated frequency band are impossible. Marine VHF is a prime example, the remote station on the bridge has a handset and a channel selector and that's all, apart from a volume control which usually cannot be turned right down to zero so that no calls are missed. Anyone on the bridge can use the radio. If long distance communication is required, then you use Satphone these days, but you used to have a Radio Officer to man the ships radio station - he was the licensed operator.

 

[SCPD]

I ran across a fellow with AM BCB experience who asserts that using the term "channels" is interchangeable with "frequencies."

Jim,

I'll shock you... he's actually right -- but it depends on the context. I'm only in my 40's but even I used CB radios where the "channels" were fixed frequencies by crystals. My stepdad had a couple of old 1970s Realistic CB radios that were 2-channel units but the channels were dependent upon which crystals you plunked into the unit.

Obviously, as technology advanced and radios (scanners) became more complex then the definition changed.

Radio shack also sold many scanners that used fixed crystals.

Are the terms interchangeable today? Not really -- but 30 years ago both terms were defined the same. (I don't know recall anyone ever using the word frequency. Perhaps only HAMs did at that time.)

 

[KC4RAF]

Back in the late '50s thro the '60s,

I had no idea what a channel was. It was always referred to as "frequency", then in the late '60s found out about CB and what channels was about. And that was the only time any of us referred to channels, CB.
Channel is referenced to certain frequencies assigned to a given license, such as police, marine, frs, gmrs, etc.
Has any one ever heard of 3.7Mhz as channel 2 or channel 3?
How about 14.20Mhz as channel 4 or channel 5?
Frequency is the intellectual id of a radio wave.
Channel is the, well, channel; doesn't tell you anything.

 

[Jimru]

Right. CB was and is "channelized", I believe for the reasons you state, Nickcarr. The same would be true also for public service comms, marine and other services that Majoco states, so basically anyone can use it. The same is true for Family Radio Service (FRS, an unlicensed service, with designated frequencies) and also General Mobile Radio Service (GMRS, a licensed service, but also designated frequencies) these two services also refer generally to channels, as their radios are at fixed frequencies.

However, I know that hams the world around use the term frequency. Especially since we, as hams also often transmit in various modes, with different bandwidths as well as "splitting" frequencies, most often done during things like DXpeditions, so that the hams at the DX site are not smothered in calls from dozens (hundreds?) of anxious callers trying to get through. They'll say things like "go up five" or however many kHz they determine to split.

Anyway, again it seems that it can depend. However, as a listener to AM and FM and SW broadcasting, I never heard anyone refer to "channels", although technicians and engineers might use that term.

Interesting food for thought!

 

[KB7MIB]

Right. CB was and is "channelized", I believe for the reasons you state, Nickcarr. The same would be true also for public service comms, marine and other services that Majoco states, so basically anyone can use it. The same is true for Family Radio Service (FRS, an unlicensed service, with designated frequencies) and also General Mobile Radio Service (GMRS, a licensed service, but also designated frequencies) these two services also refer generally to channels, as their radios are at fixed frequencies.

Years ago, licensees in the GMRS could only select up to 2 channel pairs on their license. This was before all channel licensing was allowed. At that time, the GMRS channels were referred to by the actual frequency (usually the 3 digits after the decimal, such as 550, 575, etc), and channel 1 in one licensee's radio didn't always match up with channel 1 in another licensee's radio, depending on which channel(s) each licensee was authorized, and how they chose to program their radio(s). I originally picked the 650 and 675 channel pairs, myself.

It wasn't untill after all channel GMRS licensing, the establishment of the FRS, and the introduction of the 22 channel hybrid FRS/GMRS bubblepack radios, that 550 became channel 15, and 725 became channel 22, etc.

John
Peoria, AZ

 

[n2nov]

The reference to "channels" in LW/MW/SW/FM broadcasting comes from standardization of the spectrum so that broadcasters are placed on a known frequency spot so that they do not interfere with each other. As stated previously, it is also done in HF marine, aviation & government use spectrum as well as the public service and television bands.

 

[SCPD]

The reference to "channels" in LW/MW/SW/FM broadcasting comes from standardization of the spectrum so that broadcasters are placed on a known frequency spot so that they do not interfere with each other. As stated previously, it is also done in HF marine, aviation & government use spectrum as well as the public service and television bands.

Yes no one is disputing that fact -- the question is whether or not the terms are still interchangeable. IMHO, they are no longer interchangeable -- since a "channel" can now be comprised of mode, ctcss codes, repeater shifts, and many other custom variables.

 

[ka3jjz]

All of which are common references on frequencies above 30 Mhz.

A gentle reminder - this forum is for frequencies below 30 Mhz. If you wish to discuss this topic as it pertains to VHF and above, please take it elsewhere.

Mike

 

[Voyager]

As I said earlier... for ANYONE who thinks they are interchangeable, just answer one question: What is the frequency of "channel 1"?

They are, of course, not interchangeable. If they were, there would be a 1:1 relationship and not 1:many as exists.

 

[majoco]

Well, it's not quite a simple as that. Having served on a fishing trawler around the north of Iceland as a licenced Radio Officer ( a legal requirement ) the fishing company didn't want anyone listening to know what frequencies they were using - so the company had a guide book which gave company 'channel numbers' and I had to tune the transmitter to 'this' frequency and the receiver to 'that' frequency and the luxury of a second receiver to listen to the original 'call' frequency so that any chat that went on about "I caught a gazillion herrings at position so-and-so" was not intercepted by another company. When you went back to base you got another list of frequencies vs channels to be used after such-and-such dates....

I was instructed by the Skipper to scan around the band (the MF radio band around 2182kHz) and listen to what I could get any info from.....

Trouble is most trawlers had names or dodgy positions for where they caught the catch.....

 

[Jimru]

Majoco, it sounds like you were using tunable rigs, as opposed to fixed channels, such as on marine VHF rigs. But that the "channelization" was an unofficial use of the word for your trawler or company, yes?

 

[DaveNF2G]

The technical answer can be found in posts 3 and 7 in this thread.

The philosphical "answer" is in the OP - it depends.

Do we still need to debate this?

 

[majoco]

But that the "channelization" was an unofficial use of the word for your trawler or company, yes?

Certainly the channels were an 'unofficial' scheme that was thought up by the office people. The radio room transmitter had all the crystals for the MF band and I tuned the receiver to what the scheme said went with that transmit frequency for that particular month or voyage - a sort of 'half-duplex'. The other ship had the reverse frequencies of course - if I went to say channel 23 he might go to 32. It wouldn't take a rocket scientist to find both frequencies but the messages were so short and 'coded' that the chances of getting both of them were slim indeed. There was a general simplex chat frequency but nothing of any importance was said on that frequency.

( "half-duplex"...oh, no, not again...... )