Keeping tones private

[VETCOMMS]

Question the the repeater experts.   How do I keep people from scanning my personal repeater tones and gaining access?   I do not own one yet but am looking at either a gr1225 or vxr=7000 but if other repeaters are more secure I'd welcome experienced suggestions. 

[nokones]

Why would it be a problem if someone use your repeater? Is there some harm to you or your repeater if someone does use the repeater?

It's like you setup the entire backyard for a BBQ  with all kinds of food and drinks and you only invite yourself to the party.

Owning a repeater and not allowing anyone else use it is like having a party for yourself only. So, what is the point of having a repeater and only you uses it. Who are you going to party with?

[kidphc]

Sadly. Don't use the repeater is the answer.

The only way to stop a tone decoder is to not have transmissions with the tone encoded.

Hell we have one local guy, sits in a tow truck between calls and tries to find repeaters. He is proud of finding hidden repeaters. He has every tone programmed on every repeater pair. Basically tried to brute force method to find repeaters. He gets a repeater tail and he is happy.

Just be prepared to change tones if someone starts interfering.



Sent from my SM-S901U using Tapatalk

[Sshannon]

3 minutes ago, WRTZ750 said:

Question the the repeater experts.   How do I keep people from scanning my personal repeater tones and gaining access?   I do not own one yet but am looking at either a gr1225 or vxr=7000 but if other repeaters are more secure I'd welcome experienced suggestions. 

Unless you never transmit to it you can’t because any transmission can be scanned.
That has nothing to do with the repeater brand or model. 

If you need security neither GMRS nor ham radio are appropriate. 

[WRXP381]

You don’t sorry.  They can hear everything said anyway so it’s not private in any way no matter the tones.  So I’d say just change them often if it becomes a problem with jerks scanning then harassing you.  

[Lscott]

1 hour ago, WRTZ750 said:

How do I keep people from scanning my personal repeater tones and gaining access?

Simple answer you can't can't.

Some people have toyed with the idea of using a single frequency "trunked" repeater where every radio has to be registered with the ESN, by using the internal Electronic Serial Number, to authorized access. As far as I know there isn't a way to change the radio's ESN.

The typical analog system is known as LTR, Logical Trunked Radio, and the variation using the radio's ESN called Passport.

Some people have bumped into used radios with the special Passport firmware loaded. When they try to reprogram the radio using the "normal" software the display shows SJ-180 and fails to load the code plug. I even had a used Kenwood TK-3180 HT with that firmware loaded. I managed to load the normal LTR firmware so I could use the regular radio programming software. I do have a copy of the special SJ-180 programming software too.

This is also fairly common on digital voice mode repeaters. The process to get a radio on one of those is a bit more complex requiring a "system key" file, licenses etc. just to program the radio. Normally with those radios you can't even read the radio without the system key file. There are hacked versions of the radio programming software out there that will read the radio and save the contents as a ".srv" service file without it. See attached screen shots of a used NXDN trunked radio I read with that software.

 

Understanding Passport Radio Systems App Note.pdf

[VETCOMMS]

Thx.   So if someone is keying up the repeater what controller do I need to remotely kill the repeater and shut it down?  I think I saw the Bridgecom repeater does this?

[OffRoaderX]

I have a $18 WiFi electric switch connected to my repeater so I can shut it down from my phone from anywhere (with internet connection).

[tweiss3]

7 minutes ago, OffRoaderX said:

I have a $18 WiFi electric switch connected to my repeater so I can shut it down from my phone from anywhere (with internet connection).

This x100

[WRYZ926]

About all you can do is change the tones. But that still won't stop people from scanning for the new tones. As mentioned, you can get a  remote switch to shut the repeater down or use a controller to remotely access the repeater to make changes.

We have tones set for transmit and receive on our GMRS repeater. People can still hear the repeater on the corresponding simplex channel without any tones set. And since they can hear the repeater, they can also scan for the PL tones.

[tweiss3]

Here is the thing, how often do you actually think you will need to use your repeater? Your actual need will be much less than you think. Most things times its used, simplex works just fine.

[VETCOMMS]

So would it be accurate to say charging a fee to use either a private repeater or a linked repeater system is likely to be complicated because tones are easy to scan for?

[Sshannon]

17 minutes ago, WRTZ750 said:

So would it be accurate to say charging a fee to use either a private repeater or a linked repeater system is likely to be complicated because tones are easy to scan for?

No, because scanning for the input tone isn’t as easy as scanning for the output tone. Make them different. 
Also, most people are honest and will honor your rules. 
But if you’re thinking about making your repeater a money making scheme beyond costs you might want to review the regulations. 

[marcspaz]

As others have mentioned, you really can't prevent someone from finding the tones or even testing their way through them.  Short of turning the repeater on and off depending on need, you can implement security through obscurity.  Though, the more obscure you get, the more likely you are to need a non-compliant repeater and mobile/portable user radios.

 

Split-tone is one means of obscurity.  Have the repeater transmit a tone that is different than what is used to unlock the squelch, or no transmit tone at all.  Use DCS in and CTCSS out.  This would make it much harder to guess... however, if someone is close enough to someone using the repeater, you can always scan the users transmission. 

Additionally, you can use what is known as "user defined CTCSS".  For example, I could use 300 Hz or 2.9 KHz.  If you want to get really extreme, you can also configure some units to require the presence of two tones or digital ID's at the same time, in order to open the repeater squelch, known as paging.

 

Some other obscure configurations could include non-standard splits.  There is nothing that says you have to use a +5 MHz split for your repeater.  There are specific frequencies that we can use, but no mandatory use of any given pair.  Meaning, you could have your repeater input on 467.650 and your repeater output on 462.550.

 

So, if you want to have a ton of fun, configure the input of the repeater to be on 467.700 MHz and have the squelch open with a paging tone group of 67.0Hz/1.9KHz, have the output on 462.575 MHz with a DSC of 754, and then use a voice scrambler.

[WRUE951]

4 hours ago, WRTZ750 said:

Thx.   So if someone is keying up the repeater what controller do I need to remotely kill the repeater and shut it down?  I think I saw the Bridgecom repeater does this?

ICS controller can be configured to turn up/down via HTML or DTMF.  The Bridgecom you refer to is most likely set up with an ICS controller they are plug an play for Bridgecom,,  Arcom may work as well but i don't think Arcom can switch via HTML  

[WRUE951]

50 minutes ago, marcspaz said:

use a voice scrambler.

Voice Scramblers works well, especially in the Hytera radios..  But problem with that, everyone needs a like radio.  Other problem, if anyone worries about it.  FCC Illegal for GMRS.  But still quite a few still use it.    

[VETCOMMS]

Thank you all for the information!

[gortex2]

5 minutes ago, nokones said:

Owning a repeater and not allowing anyone else use it is like having a party for yourself only. So, what is the point of having a repeater and only you uses it. Who are you going to party with?

I guess this really goes back to use case. Each use may be different. I own 6 repeaters. 1 is an open repeater although not listed here. All of mine are funded and maintained by myself. They are for my family and friends use only. Personally I dont want to wake up at 2am with 2 guys jabbering about his big toe that needs fungus removed. Between electric and tower fees its not a cheap endevor for some repeaters so thats my take. If someone wants a repeater to talk to there family I can see it being closed. Ive been doing this for ovder 30 years and while GMRS has changed I still use it for the same reason my parents used it for. Internal communications. 

Back to topic on hand. As said it can't be blocked but can be limited. All my repeaters used split DPL/CTCSS tones. Motorola offered RAS on some of the repeaters and has been used with great success. I've not needed to use it yet but if it gets to a point I may turn it on. 

[Borage257]

Is the RAS system like using the DTMF tones?

I suppose DTMF could be used in addition to the DPL and CTCSS tones for repeater control.

[WSAM454]

1 hour ago, nokones said:

Why would it be a problem if someone use your repeater? Is there some harm to you or your repeater if someone does use the repeater?

It's like you setup the entire backyard for a BBQ  with all kinds of food and drinks and you only invite yourself to the party.

Owning a repeater and not allowing anyone else use it is like having a party for yourself only. So, what is the point of having a repeater and only you uses it. Who are you going to party with?

If you have regularly have  backyard BBQs, I doubt that you will open them up to anyone who may be passing by, although you may be more generous than the average person.

As Gortex said, if you are spending the money to get the equipment in place, licensed, and maintained, then you should be able to have some control over who and how it is used.  

 

Bottom line is that  although years ago Motorola called CTCSS "Private Line" it really isn't totally private!

[tweiss3]

19 hours ago, WRUE951 said:

Voice Scramblers works well, especially in the Hytera radios..  But problem with that, everyone needs a like radio.  Other problem, if anyone worries about it.  FCC Illegal for GMRS.  But still quite a few still use it.    

Voice scramblers (inversion scrambling) won't prevent the tones from being scanned. Audio will just noise, but the tone still gets transmitted in the same place. 

[WRUE951]

53 minutes ago, tweiss3 said:

Voice scramblers (inversion scrambling) won't prevent the tones from being scanned. Audio will just noise, but the tone still gets transmitted in the same place. 

yup,  i just made the comment in relation to privacy (somewhat)  

[TechnoHam633]

Hi, I'm a Recycled Noob. Old Call expired, so I decided to license again. Just a suggestion, but has anyone experimented with Non-standard PL tones ?? Such as 71.3 ?

Some of the older Kenwood gear will let you program "odds" or non standard tones for repeater use. TK-805's will do this.  All the Newer china toys that can scan for tones, Can't scan for Non standard tones, essentially keeping your tone private{er} . In fact, I haven't found Any of the newer toys that can scan for Odd tones.

[Lscott]

4 hours ago, gortex2 said:

Motorola offered RAS on some of the repeaters and has been used with great success.

I believe that’s patented Motorola technology. In that case you’re limited to Motorola radios. I guess if it’s just for your family it’s likely no big deal. You can program the radios for them.

[Lscott]

4 minutes ago, TechnoHam633 said:

Some of the older Kenwood gear will let you program "odds" or non standard tones for repeater use.

That only works to the extent you can keep the tones secret. The weakest link in any security method are the people. Sooner or later someone is going to tell a buddy what the odd tone is so they can talk. Then you’re done.

[TechnoHam633]

2 minutes ago, Lscott said:

That only works to the extent you can keep the tones secret. The weakest link in any security method are the people. Sooner or later someone is going to tell a buddy what the odd tone is so they can talk. Then you’re done.

That's True and I guess go's along with the adage, Loose lips sink ships. I was just thinking that the "simpler minds" might not figure that tactic out and help keep Repeater Security. Someone mentioned Split tones which is a good idea too.