To Split or not to Split… Tones? That is the question.

[djxs]

Hi all! I’m on a mission to fully understand what split tones are. I know there are many here with the knowledge that I am seeking. 
 

1. What are Split Tones?

2. Are split tones only used while working with a repeater?

3. Is “Split Toning” for everyone?

4. What are the benefits of split tones?

 

[BoxCar]

Split tones means there are different tones used for transmit and receive. It is one method of keeping the use of a repeater down as some radios are not capable of transmitting one tone to trigger the repeater receiver and another tone to unlock your receiver.

[axorlov]

I'll continue.

Split tones are for everyone! As long as your equipment allows to use them.
Benefits are abundant! Well, for the repeater owners. They can keep people with wrong equipment, or without the right knowledge, off the repeater. Low plank to pass, but nevertheless, filters problematic audience. It also challenges a _very_ problematic audience, they take it as a personal affront and make themselves a bigger problem.

[wayoverthere]

23 minutes ago, djxs said:

Are travel tones different from that of split tones?

 

Split tones refers to using two different tones for input/output, but isn't specific to a tone. Travel tone is specific, referring to 141.3, usually both input and output.

[djxs]

Are travel tones different from that of split tones?

[seanriddle]

 Is “Split Toning” for everyone?

4. What are the benefits of split tones?

Sure if it works for you. Me? I was running split tones for a good wile, do to guys 50+ miles away claiming my system was interfering with theirs..., But all is did was allow me to make sure my TX's were not on the same PLs as theirs and that the 50w mobiles were not keying the other system.. I have since moved away to help with radio compatibility. A large handful of radios lack the ability to do them, especially some of the basic GMRS radios. I'm currently running a DTS and it has allowed a larger group of users to access my system.

[WRNA710AZ]

Split tones are just as described above. Unless it is DCS, which is really not a tone, it's a digital code. Those codes can run normal polarity (N) or, reverse polarity (R) on either transmit or, receive. We have a repeater in Phoenix that runs split DCS,  (programing = CROSS, 071N, 225N, CROSS -> CROSS) as well as travel tone. The DCS (or DTCS as it may be referred to when programing) is used for normal everyday traffic and, as a means of keeping the repeater private for members only. The travel tone is programed into a separate channel (same repeater frequencies) in the radio and used for weekly nets, another set of tones is for tactical (emergency services), and so on. This way, members that don't want to listen to the net can stay on their "home" channel with the DCS, and not hear the net traffic.

Radios that are capable of using distinct, different, DCS codes are not that easy to find. Most times you have to ask the manufacturer the specific question. That said, most commercial radios (part 90), should be able to handle it. The Baofeng UV82C is one such handheld.

Hope this helps!

[djxs]

On 7/27/2021 at 5:36 PM, WRNA710AZ said:

Split tones are just as described above. Unless it is DCS, which is really not a tone, it's a digital code. Those codes can run normal polarity (N) or, reverse polarity (R) on either transmit or, receive. We have a repeater in Phoenix that runs split DCS,  (programing = CROSS, 071N, 225N, CROSS -> CROSS) as well as travel tone. The DCS (or DTCS as it may be referred to when programing) is used for normal everyday traffic and, as a means of keeping the repeater private for members only. The travel tone is programed into a separate channel (same repeater frequencies) in the radio and used for weekly nets, another set of tones is for tactical (emergency services), and so on. This way, members that don't want to listen to the net can stay on their "home" channel with the DCS, and not hear the net traffic.

Radios that are capable of using distinct, different, DCS codes are not that easy to find. Most times you have to ask the manufacturer the specific question. That said, most commercial radios (part 90), should be able to handle it. The Baofeng UV82C is one such handheld.

Hope this helps!

Clear as mud @WRNA710AZ I clearly have a lot of brushing up to do. It seems evident that the Bachelors degree I hold is not serving me well at the moment. I have so much learning to do. I'll keep at it. I appreciate your assistance. 

[Sshannon]

4 minutes ago, djxs said:

Clear as mud @WRNA710AZ I clearly have a lot of brushing up to do. It seems evident that the Bachelors degree I hold is not serving me well at the moment. I have so much learning to do. I'll keep at it. I appreciate your assistance. 

Don’t feel bad.  Lots of people like to do a data dump when asked a question (myself included!)  Let me see if I can avoid over complicating it.

I’m only going to concentrate on CTCSS tones. These tones just work as a way to avoid audibly hearing (in the case of a simple radio user) or retransmitting (in the case of a repeater) a received signal.  If you transmit with a tone of 87.5 Hz, that tone is added to your audio.  If I set my receive tone to 87.5 Hz, my receiver will allow your audio to be reproduced by my speaker, after filtering out the low frequency 87.5 Hz tone.  My receiver receives other transmissions but doesn’t audibly reproduce them unless they contain the correct tone.  If I want to hear everything I just remove the receive tones and it’ll audibly reproduce everything.

Similarly repeater owners program their repeaters to listen for one specific tone.  That’s the uplink tone, “up” meaning transmissions to the repeater, “down” meaning transmissions from the repeater to others.  Any transmissions on the same uplink channel which don’t include that specific tone will be ignored and not retransmitted by the repeater. The repeater operator can limit who knows what the uplink tone is in order to reduce what the repeater retransmits. That’s about the only access control a repeater operator has in GMRS.

Many repeaters also use a downlink tone.  That is simply to provide a convenient way for people to hear the repeater transmissions without hearing other transmissions on that channel.  There could be casual users who are simply using the same channel as the repeater transmits upon. Repeater users may not want to hear their chatter.  In most cases the repeater operator uses the same downlink tone as the uplink tone.

When someone chooses a different receive tone than the tone used for transmit, that’s called a split tone.  Honestly, I’m not convinced it accomplishes much.  It really doesn’t limit who can use a repeater as others have claimed, because a person can simply clear out the CTCSS receive tone and hear everything that’s transmitted.  

The only legal way to limit who can use a GMRS repeater is to try and keep people from learning the uplink tone.  Because there’s a limited number of tones and because they can can be guessed or easily scanned if you’re near the repeater, that’s only a temporary limitation. 

[wrci350]

1 hour ago, Sshannon said:

When someone chooses a different receive tone than the tone used for transmit, that’s called a split tone.  Honestly, I’m not convinced it accomplishes much.  It really doesn’t limit who can use a repeater as others have claimed, because a person can simply clear out the CTCSS receive tone and hear everything that’s transmitted.  

The only legal way to limit who can use a GMRS repeater is to try and keep people from learning the uplink tone.  Because there’s a limited number of tones and because they can can be guessed or easily scanned if you’re near the repeater, that’s only a temporary limitation. 

Well, that's the strategy, faulty or not.

You can very easily use a scanner or a radio that allows tone scanning to find the output tone (if there is one) from a repeater.  Unless the repeater is using split tones, you've found the input tone too.

With split tones, you have to be close enough to *someone who is transmitting* to monitor the input channel in order to scan for the input tone.  It's not a matter of being close to the repeater, since the repeater can 'hear' better than you can, even if you are standing next to it.

Not advocating at all, just expounding.

[Sshannon]

2 minutes ago, wrci350 said:

With split tones, you have to be close enough to *someone who is transmitting* to monitor the input channel in order to scan for the input tone.  It's not a matter of being close to the repeater, since the repeater can 'hear' better than you can, even if you are standing next to it.

I agree. That is more accurate.  It’s almost certain that the repeater has a higher and better antenna and possibly even a better receiver, but it’s much easier to physically find the repeater, which has a chance of eventually putting you within range of someone who is transmitting, than it is to find *someone who is transmitting* without approaching the repeater. Gotta start somewhere.