MDC in Amateur Radio

[N3KGD]

Hello everyone. Just out of common couriosity to all those Amateur Radio operators out there. Under Part 97 rules, is the form of MDC-1200 or 600 allowable under the 2M and 70cm band. MDC is a form of signalling, however, I do not see any non-signalling laws that apply to the illgeal transmitting. So, a good question is, is MDC allowable in 2 Meters / 70 Centimeters. I've wondered this for a while.

 

[N3KGD]

Actually - I've come under the assumption that it is legal - because MCD is considered a form of data, and data transmissions are allowed within these bands. Selective calling is also considered "phone" communications when toning out.

 

[Grog]

It's used by some and hated by the old farts, sounds like a good enough reason to use it :lol:

 

[n2nov]

While not an "old fart", I look at it as useful for what it was designed for and a nuisance when used in another scenario. For example, any signalling scheme on pushing the PTT or releasing it is transparent when used with a repeater system designed for it so that users do not hear the brapping sound. Signalling on a repeater system is designed for the dispatcher to know who is keying up. On an amateur repeater that is not designed for using data signalling schemes, everyone hears the digital sounds and it can be quite harsh to listen to with the human ear. That is the reason that it is discouraged on amateur repeaters, eventhough it is not specifically banned by the FCC. We all need to be mindful of other users of the frequency and not just taking the stance that there's no law against making specific noises and tough if they can't take it. Let's lighten up and be cooperative with all users.

 

[N3KGD]

It's not actually me doing so however - I was just wondering upon the case. I know what MDC is and what it is made to and not to do. I understand that it can be an extremley annoying sound and not many enjoy it. I don't use it. I was just wondering in perspective because I didn't even see an exact rule under Part 97 about it.

Thanks for clarifying.

 

[kb2vxa]

Just because it's data doesn't mean it's an FCC approved Amateur transmission mode. As far as I know without further research into what sort of data is being transmitted and how I can't answer that question. If you want to transmit text, image or audio why not use an established conventional mode or are you looking for some sort of private communications system? That's the bit I don't understand, just what are you up to OM? You could run afoul of the "no encryption, ciphers or obscuring the meaning thereof" rule you know.

Now before comments fly due to misinterpretation I suggest the armchair lawyers and RF engineers refrain and rather the question redirected to the ARRL and someone who knows what they're talking about. A member can easily inquire of Chris Imlay the council for the League inasmuch as his firm of communications attorneys are best qualified given the proper information regarding that mode is supplied. Is it legal or not, that is the real question.

 

[MTS2000des]

While not an "old fart", I look at it as useful for what it was designed for and a nuisance when used in another scenario. For example, any signalling scheme on pushing the PTT or releasing it is transparent when used with a repeater system designed for it so that users do not hear the brapping sound. Signalling on a repeater system is designed for the dispatcher to know who is keying up. On an amateur repeater that is not designed for using data signalling schemes, everyone hears the digital sounds and it can be quite harsh to listen to with the human ear. That is the reason that it is discouraged on amateur repeaters, eventhough it is not specifically banned by the FCC. We all need to be mindful of other users of the frequency and not just taking the stance that there's no law against making specific noises and tough if they can't take it. Let's lighten up and be cooperative with all users.

This is not always true. Some of us use MDC as selective calling because we don't want to hear hour long conversations about bowel movements, who someone talked on HF, ten thousand kerchunks, CB sounding speak and spell repeater ID's, etc.

When someone in our group keys up, my radio unmutes- and I see the alias text (call sign) of the station I want to speak with and I have the option of answering or going back to keeping quiet. I can keep my radio on at work, or in a public place, and not subject people to constant chatter (as if we don't have enough rude cellphone turds and Nexhell users blasting their conversations for all to hear).

You can always get a "real" radio and enable data mute, and you won't hear them.

 

[frankblues]

(snip)If you want to transmit text, image or audio why not use an established conventional mode or are you looking for some sort of private communications system?

I thought amateur radio operators were supposed to be innovative, and abreast of technology. Why use PSK31 when Packet will do? Why use Packet when Amtor does the same sort of thing? Moving forward, trying new things.

That's the bit I don't understand, just what are you up to OM? You could run afoul of the "no encryption, ciphers or obscuring the meaning thereof" rule you know.

I really doubt that. MDC seems to be an open protocol; Vertex Standard, Motorola, Kenwood, and Icom all use it in their LTR radios. As long as it is openly documented, it should be allowed. There have been other selcal systems used in Ham Radio, I remember one being used by Kenwood in the late 80's / early 90's that required an extra display for the rig to read the callsign.

Now before comments fly due to misinterpretation I suggest the armchair lawyers and RF engineers refrain and rather the question redirected to the ARRL and someone who knows what they're talking about.

Part 97 isn't really hard to read. If it is not obscuring, if it is not encrypted, and if it is an openly documented standard, it is allowed. The ARRL is not the interpretive arm of the FCC, and I'm sick of being told that they are the only ones who understand what Part 97 says. It is required reading, folks.

 

[KC8RFE]

Dstar offers a high speed data transmission mode. Well it's not so high speed but it's better than nothing. 128kbs i think. It is only available on 1.2ghz though and requires some expensive gear.

I like the fact when using Dstar the other users call sign is displayed along with the optional message feature. However Dstar is a bit different than what your talking about here.

 

[DaveNF2G]

As long as it fits within the bandwidth specified in the regulations, it should be legal.

 

[N3KGD]

This is not always true. Some of us use MDC as selective calling because we don't want to hear hour long conversations about bowel movements, who someone talked on HF, ten thousand kerchunks, CB sounding speak and spell repeater ID's, etc.

When someone in our group keys up, my radio unmutes- and I see the alias text (call sign) of the station I want to speak with and I have the option of answering or going back to keeping quiet. I can keep my radio on at work, or in a public place, and not subject people to constant chatter (as if we don't have enough rude cellphone turds and Nexhell users blasting their conversations for all to hear).

You can always get a "real" radio and enable data mute, and you won't hear them.

And selective calling is recognized as phone communications under Part 97. Selective calling sends out a burst at the beginning of each transmission - the same as MDC.

 

[searchrescueff]

my $0.02

As far as I know without further research into what sort of data is being transmitted and how...

MDC utilizes data transmissions to send out: 1. the users identification AND/OR 2. short messages. If they are only using it to notify of who is talking, then I don't think that would violate FCC rules.

I really doubt that. MDC seems to be an open protocol; Vertex Standard, Motorola, Kenwood, and Icom all use it in their LTR radios. As long as it is openly documented, it should be allowed. There have been other selcal systems used in Ham Radio, I remember one being used by Kenwood in the late 80's / early 90's that required an extra display for the rig to read the callsign.

Vertex and Kenwood use MDC ONLY when equipped with an extra module. Kenwood uses it's own protocol, Fleetsync. I know cause I had to install a MDC board in my TK-2180 portable and TK-7180 mobile. And I'm not sure about Vertex, but do know it must be equipped with an extra module to enable MDC encoding.

 

[N3KGD]

To make this interesting - who could we actually contact by email to find out?