MDC signalling on GMRS.

[KAF6045]

I don't have much reason to actually ask for general access. My home is just outside the current effective range of the repeater, so the only time I could make use is when going in for chemo sessions (four+ hours in a building with poor reception) followed by specialty shopping. Nearest "immediate family" is down the block from me -- and I really wouldn't trust my brother with even my cheapest HT (the nieces are some 30&60 miles south of GR, so way out of "immediate family" control range).

For those events where I needed a driver, using HTs on simplex to advise when I was leaving the hospital and ready to be picked up is sufficient (driver is usually my brother's wife).

 

[SteveShannon]

18 minutes ago, KAF6045 said:

I don't have much reason to actually ask for general access. My home is just outside the current effective range of the repeater, so the only time I could make use is when going in for chemo sessions (four+ hours in a building with poor reception) followed by specialty shopping. Nearest "immediate family" is down the block from me -- and I really wouldn't trust my brother with even my cheapest HT (the nieces are some 30&60 miles south of GR, so way out of "immediate family" control range).

For those events where I needed a driver, using HTs on simplex to advise when I was leaving the hospital and ready to be picked up is sufficient (driver is usually my brother's wife).

 

I wish you the best results possible with your chemo.

[Lscott]

I wish you the best as well. My sister and her husband both went through radiation treatments. Sister was breast cancer and her husband had prostate cancer. Both are doing good fortunately. I hope you're results a in positive outcome.  

[KAF6045]

7 hours ago, Sshannon said:

I wish you the best results possible with your chemo.

I've already gone a year past when the oncologists would have estimated when the cancer was first discovered... Though it does seem to be migrating to lymph nodes... so who knows where treatment goes next...

I do need to get off the Internet and inventory my crud in preparation of having a will made (I'm aiming for a trust -- especially with all the firearms, followed by all the musical instruments -- one may not care about what happens to a $350 flat-top mandolin, but a $2400 Taylor NS-72 is a different matter, along with all the radio gear [which is why I gave my nieces the Tech study guides, and as incentive Yaesu starter HTs]).

 

[DONE]

Didn't realize thread had changed and was old.  Never mind

 

 

[KAF6045]

17 hours ago, WRKC935 said:

Didn't realize thread had changed and was old.  Never mind

Apologies, the subject did wander off the trail in the last week or so.

[WQAI363]

I realize that my 2 or 5 cents is pointless now. However, I will my opinion on the use MDC signaling on GMRS Repeaters or simplex. Thinking about MDC signaling on GMRS, Mr. Shannon makes sense. MDC is forbidden on Amateur Radio and it's really unnecessary for GMRS, unless used in volunteer SAR or a CERT TEAM. Of course, I do enjoy the squawk sound of MDC tones, but MDC does have a purpose, just not for casual conversation or idle chat-chat.

[Lscott]

5 hours ago, WQAI363 said:

MDC is forbidden on Amateur Radio

Can you provide a definitive reference for the above comment?

[gortex2]

MDC isn't forbidden on Amateur Radio or GMRS. I use it on both. Done properly a user wouldn't even know its being used. And its great to keep CCRS off my sites. 

 

[OffRoaderX]

37 minutes ago, gortex2 said:

Done properly a user wouldn't even know its being used

How would you prevent me, as a user with a non-mdc capable radio, talking to you with your MDC enabled, prevent me from knowing its being used?

[nokones]

5 hours ago, gortex2 said:

MDC isn't forbidden on Amateur Radio or GMRS. I use it on both. Done properly a user wouldn't even know its being used. And its great to keep CCRS off my sites. 

 

One of my radio clubs in Arizona has issued every member a personal PT-T ID number for members only to have access to one of the Club's repeaters sites. The PT-T ID must be sent with the MDC signaling. Without the proper ID, the repeater will not open up.

[TrikeRadio]

10 minutes ago, nokones said:

One of my radio clubs in Arizona has issued every member a personal PT-T ID number for members only to have access to one of the Club's repeaters sites. The PT-T ID must be sent with the MDC signaling. Without the proper ID, the repeater will not open up.

Isn’t that a problem for people who are using radios that are not able to send that code?

[nokones]

2 minutes ago, TrikeRadio said:

Isn’t that a problem for people who are using radios that are not able to send that code?

The members with non-compatible radios had to buy a compatible radio in order to have access. The repeater owner was having a problem with a constant jammer so he took action to eliminate the problem by controlling who has access. 

[OffRoaderX]

7 minutes ago, nokones said:

so he took action to eliminate the problem by controlling who has access. 

That wont really eliminate the problem, but it will postpone the problem until the jammer gets an MDC compatible radio and the associated CPS OR until he figures out how to jam the input..

[marcspaz]

54 minutes ago, OffRoaderX said:

That wont really eliminate the problem, but it will postpone the problem until the jammer gets an MDC compatible radio and the associated CPS OR until he figures out how to jam the input..

 

The level of effort required to clone the ID of an authorized radio far outweighs the knowledge and stamina of the average jammer. LoL

[OffRoaderX]

1 hour ago, marcspaz said:

The level of effort required to clone the ID of an authorized radio far outweighs the knowledge and stamina of the average jammer.

This is true.. if they were smart/weren't losers, they would not be jamming...

[SteveShannon]

4 hours ago, nokones said:

The members with non-compatible radios had to buy a compatible radio in order to have access. The repeater owner was having a problem with a constant jammer so he took action to eliminate the problem by controlling who has access. 

Did that actually work? I understand how that would prevent the jammer from initiating access, but isn’t the jammer able to get in as soon as someone else accesses the repeater? Or was the jammer a weaker signal?

[nokones]

4 hours ago, SteveShannon said:

Did that actually work? I understand how that would prevent the jammer from initiating access, but isn’t the jammer able to get in as soon as someone else accesses the repeater? Or was the jammer a weaker signal?

I don't know those details.  About a year ago when the PT-T ID was implemented, the repeater owner did change the input Tone and just recently, the input Tone was changed again.  

The MDC squawk does not repeat. I would think if the jammer wants to decipher a PT-T ID, he would need to be close or at a high elevation point to someone transmitting the ID. The repeater is not near a large population center but does have a large coverage area footprint.

[nokones]

9 minutes ago, nokones said:

I don't know those details.  About a year ago when the PT-T ID was implemented, the repeater owner did change the input Tone and just recently, the input Tone was changed again.  

The MDC squawk does not repeat. I would think if the jammer wants to decipher a PT-T ID, he would need to be close or at a high elevation point to someone transmitting the ID. The repeater is not near a large population center but does have a large coverage area footprint.

The Club believes the jammer was not a club member and probably not aware that the PT-T ID is needed for access because the MDC squawk is not repeated and that information was only provided to members through the website members only portion of the website and only the member can view their respective PT-T ID number.

There hasn't been a problem since or at least no one has said anything if it has continued. 

[DONE]

So are they using an MDC control list, or a RAC (repeater access code) to open the repeater?  Moto did support those on some of their repeaters.  I am not so much interested in locking people out of my repeater at present, but If I could figure out an MDC switch that would turn on such a filter switching the repeater to 'private use' when needed that might be something.

 

[gortex2]

14 hours ago, OffRoaderX said:

How would you prevent me, as a user with a non-mdc capable radio, talking to you with your MDC enabled, prevent me from knowing its being used?

Using MDC equiped equipment a user will not hear the MDC if setup properly. Yes others with non MDC capable radios would hear that. I never hear MDC on my repeater or console, just see the ID on my screen.

[gortex2]

25 minutes ago, WRKC935 said:

  I am not so much interested in locking people out of my repeater at present, but If I could figure out an MDC switch that would turn on such a filter switching the repeater to 'private use' when needed that might be something.

 

If you have Quantars you just need a SAM Module (Station Access Module). It requires software and will allow you to create a user list of approed users. Works well. Hard to find but they pop up online now and then. 

[JeepCrawler98]

That machine is one of mine - it's not well documented, but if you use app_rpt (asterisk/allstar/hamvoip/etc.) as the repeater controller it supports MDC decoding and can be configured to behave accordingly. The software can map MDC to DTMF instructions and macros, and DTMF codes can be used to establish an access table (dtmfkey=yes), so that's how you get the two systems to work together. It can also do things like automatically link or reconfigure based on MDC statusing, so it has use cases outside of access control.

Use of MDC was encouraged; the member website automatically generated random PTT ID codes for every member (existing and new), and automatically uploaded the keylist to the repeater system every 15 minutes. Users without MDC capable radios were able to use DTMF PTT-ID which worked too, just slower and not as reliable in noisier signals.

The area that machine covers had a lot of issues with bad behavior on high-profile repeaters, so this was our way to send a message and clean things up fast; it worked very well for that. We had it on for about a year, and its since been disabled to make programming easier for new users, its stayed relatively clean since. Once you have it configured it's really easy to turn on-and off, literally one line of code, we had considered propagating to the rest of the repeaters on our system but haven't had a real need to just yet so make life easy for the non-problem areas it was kept off.

The other benefit is that every user's keyup is logged; it made it really clear who some of the chronic kerchunkers were and they were contacted directly to knock it off (wait you can tell it was me?? :shockedpicachu:)

Edited December 16 by JeepCrawler98

[WQAI363]

On 5/7/2022 at 10:25 AM, WROZ250 said:

I feel kind of stupid asking this question, but I'm genuinely not sure of the answer.

I know MDC signalling is not legal on amateur radio, because it is a proprietary (Motorola) protocol (e.g. not an open 'standard'). 

However, I can't find anything in the rules that prohibits its use on GMRS.

Legal or not legal? (cause I'd really like to use it).  I'm leaning towards it being legal but I'd really like some feedback on the topic

Thanks!

There's a forum on RR on the exact same Topic. I say here what I have said over there, MDC has a purpose in the Business and Public Safey world, but it is unnecessary for Amateur Radio Service or the General Mobile Radio Service. I can certainly understand some folk's obsession with listening to the squawk coming from a radio, either before the user speaks or after they release the PTT. However, MDC signaling doesn't really have a purpose with most 2-way radio services available for average consumer and does not belong in the Amateur Radio Service. 

Besides, with APRS / GPS Amateur Radios and GMRS, you can know who's speaking and where.

 

[OffRoaderX]

5 minutes ago, WQAI363 said:

MDC has a purpose in the Business and Public Safey world, but it is unnecessary for Amateur Radio Service or the General Mobile Radio Service..... MDC signaling doesn't really have a purpose with most 2-way radio services available for average consumer

In my GMRS group it serves a very important purpose and is very necessary.
If that makes you sad, you are free to go listen to a different channel while we are all transmitting our MDC-squawks.