Batboard

Every once and awhile I always stumble across these whiny cry babies complaing about MDC on the ham freq's. Im sure most of you have run into this yourself, my question is for those of us who use it occasion, are we fully within the laws and guidelines of the FCC and the Amatuer radio rules n reg's ? Just something im curious about when i hear "blah blah blah who do they think they are.. the police.. i think its illegal for them to even use that on ham freq's blah blah blah".... Any feedback appreciated

I sure can't see anything wrong with it.

It's a standard digital signaling system, that can be decoded and monitored by anyone with the correct hardwrae, without the need for a decryption key, etc.

You're only in trouble with the FCC if you are using encryption, or some other means designed specifically to obscure the content of your communication.

Beyond that , the stated purpose of amateur radio is experimentation and the advancement of radio communications technology, so, IMHO, those who whine at the introduction of a new signalling / communications mode are doing just that- whining. (Although, if you don't have DOS in your radio that data burst does get irritating after a while!)

-Off my soap box, and back to my bench!

What is the point in using MDC unless it's part of a system that can decode it ?

A few guys use it because they think it sounds cool, but most use it for the PTT ID feature and also for the ability the call alert a friend who is away from the radio.

For the system control use, MDC can even restrict who can use the system or automatically set up wide area operation, links, remote bases, etc., all driven by the system receiving the correct MDC ID.

For the ultimate in MDC controlled ham systems see:

http://www.enteract.com/~toddm/STROKE/mdc1200.htm

RadioSouth wrote:What is the point in using MDC unless it's part of a system that can decode it ?

Watch what you say. Some newer /\/\ radios can decode unit ID's.

Just because it might "sound" annoying doesn't mean that it should BE annoying.

If you set up a TinyTrackerII APRS board to operate in MIC-E mode, sending out a quick little APRS burp after you release the mic PTT, then they would probably not get so annoyed over it. At least that is what I think.

I could think of things more annoying then MDC1200 "burps." Like hams that key up, then try to think of something smart to say (and don't) and continue on for a minute putzing around with the PTT down. Or, the folks that breath every breath into the mic. I'm sure we all could find more annoying things then a quick little data stream at the end of transmittion.

What would be more annoying?

1. People that THINK about what to say while keyed up, then say it. Key up AFTER you think of what to say.

2. MDC Pre-Amble with more than a 500ms pre-time. Wow.

3. I don't know how annoying MODAT would be, it is kinda different than MDC. MODAT is tones while MDC is more of a squawk.

4. I know what would be the MOST ANNOYING out of anything. Those damn echo mics the CB Radio nuts use!

I think I mentioned this in the last time this topic came up... I wish you could set a pre-time and sidetone without the MDC Burst.

Some of the RACES members in our area have radios that do not have channel specific MDC... If they have it on one, they have it on all... My EMA director has a Vertex that's set up that way... He can't turn it off on the channels he doesn't need it on..

It is legal on the ham bands

MDC1200 is a /\/\otorola proprietary signalling format. So, unless you use a /\/\otorola radio, chances are most likely that it won't have it. And if it does, then the manufacturer probably had to give /\/\otorola a large check. $$$

Luckily, there are after-market MDC-1200 add-on boards that fit into most portables and mobiles. But then you would have the same ID on every channel.

I really wish that an open signaling format would become popular. I've said this before.

For example, 5-tone isn't very complicated, and is fairly open source. Not much more complex then MODAT or QC-II really. I hear that 5-tone is quite popular across the lake in Europe.

Ham manufacturers need to start putting signaling formats into their radios.

There is always APCO-25, which is open format...

I'm trying to think of why I would need these signalling formats on the ham bands. The craziest thing I ever heard was trunking on ham repeaters. Imagine all those repeaters waiting for a user, waiting and waiting and waiting....... Heck I even detest talking repeater controllers, but it least gets some voices on the silent repeaters. grumble,grumble, whine.....

Chris

An APCO-25 Ham Radio repeater. That would be... interesting. Although, i would be willing to bet those in charge of it's install would be sure it worked had good coverage. Unlike some municipalities that feel it is ok to cut things out and save $$ at the cost of the radios not working worth a crap. You'd see the Fire Dept with disfuncitonal system begging the hams for use of their stuff.

Check a little while back here in batlabs, there was a link to a webpage for a ham group that setup some repeaters (out in AZ/CA area I think) that would allow IMBE transmissions..

N9LLO wrote:I'm trying to think of why I would need these signalling formats on the ham bands. The craziest thing I ever heard was trunking on ham repeaters. Imagine all those repeaters waiting for a user, waiting and waiting and waiting....... Heck I even detest talking repeater controllers, but it least gets some voices on the silent repeaters. grumble,grumble, whine.....

Chris

Actually, if a frequency coordinator could get all the repeaters on one band, in one county to go trunked, good things would happen. All of those 99% idle repeaters could create a massive trunking system using their old repeater pairs. I'm not suggesting this for out in the "sticks," but here in suburbia, the odds of getting a new coordination is next to nill. With a 18 channel trunked system, you could have a lot of fun.

Issue each old repeater it's own talkgroup on the trunked system.

It would take some work to coordinate which callsign has which ID. I think a Type II SmartNet UHF system (on 70cm) would be great.

Clubs wouldn't be starting repeaters, they would be starting a talkgroup.

I'm sure the clubs wouldn't like this idea. The truth is, without a repeater, most clubs will wither away, because the repeater was the only thing that they really offered their members.

Here in Oakland County, Michigan, I found 2,470 hams in all of the counties zipcodes. Surely that number could support a county-wide SmartNet system.

SmartNet can have up to 28 system channels, up to 65535 unique radio ids, and up to 4000 talkgroups.

In Isabella County, MI (where my college is) there are 99 hams listed in the zipcodes in that county. And 50 of those live in the county seat city where Central Michigan U is. This would NOT be a canidate for trunking.

The trouble is getting gear CHEAP. It doesn't help much that /\/\otorola charges $$$$$ for the gear new.

You took the words right out of my mouth. I think linking together all the unused repeaters into a large trunked system would make a LOT of sense. I live in the D.C. area, and there are countless repeaters (VHF and UHF) that go unused for days. I think that a trunked system could really give ham radio the push it needs as far as the advancement of Ham technology. The only drawback is $$$$.

Actually, if a frequency coordinator could get all the repeaters on one band, in one county to go trunked, good things would happen. All of those 99% idle repeaters could create a massive trunking system using their old repeater pairs. I'm not suggesting this for out in the "sticks," but here in suburbia, the odds of getting a new coordination is next to nill. With a 18 channel trunked system, you could have a lot of fun.

Issue each old repeater it's own talkgroup on the trunked system.

It would take some work to coordinate which callsign has which ID. I think a Type II SmartNet UHF system (on 70cm) would be great.

Clubs wouldn't be starting repeaters, they would be starting a talkgroup.

I'm sure the clubs wouldn't like this idea. The truth is, without a repeater, most clubs will wither away, because the repeater was the only thing that they really offered their members.

Here in Oakland County, Michigan, I found 2,470 hams in all of the counties zipcodes. Surely that number could support a county-wide SmartNet system.

SmartNet can have up to 28 system channels, up to 65535 unique radio ids, and up to 4000 talkgroups.

In Isabella County, MI (where my college is) there are 99 hams listed in the zipcodes in that county. And 50 of those live in the county seat city where Central Michigan U is. This would NOT be a canidate for trunking.

The trouble is getting gear CHEAP. It doesn't help much that /\/\otorola charges $$$$$ for the gear new.

The idea is great guys, but there is one MAJOR point to consider. The smartnet controllers are only one part of the equation. The other part is the radios themselves. Generally speaking, the only radios out there that do MDC are Motorola. Aside from the Motorola buffs, there aren't a whole hell of a lot of them in use. There are even fewer in use that support any type of trunking, let alone smartnet. It certainly wouldn't be good for the spirit of the hobby to force all of the hams in any given area to get trunking compatible radios just to shoot the BS with a friend on the other side of town. And it certainly wouldn't be good for a ham who is passing through town and needs to use the patch to make a 911 call.

Think of this... Would Motorola be in business if my TMD700a or my VX5R had even half the features of an MCS2000 or MTS2000?

But that would mean the channels I want to have MDC on wouldn't work, right?

re-233431

N9LLO wrote:I'm trying to think of why I would need these signalling formats on the ham bands. The craziest thing I ever heard was trunking on ham repeaters. Imagine all those repeaters waiting for a user, waiting and waiting and waiting....... Heck I even detest talking repeater controllers, but it least gets some voices on the silent repeaters. grumble,grumble, whine.....

Chris

Because MDC allows you to do selective calling...passes thru most repeaters unlike DTMF calling, offers more advanced capability (like the ability to do aliasing so you can see who is xmitting). Most Motorola radios can be set for Data operated squelch which will mute most of the MDC sound itself. I use MDC radios to keep my radios quiet and free of the old fart rambling on and on about topics that don't interest me.

During public service work, MDC equipped radios can tell you who is transmitting...great for finding open mikes, clowns, etc. Also saves time you don't have give your friggin call every transmission. Too bad more ham radios don't use real digital signalling like MDC instead of this ancient DTMF crap- but then most ham radios are cheap junk anyway.

Whenever I encounter some mouth breather who wants to debate about the legality of MDC on ham bands I make reference to this point. usually the moron will say something lame like "well I don't know what data you are sending cause I can't decode it". 1)-Well get a real radio and you could. 2)-MDC is an accpeted signalling format, because you can't decode it doesn't make it any less legitamate, it is not to obscure the meaning of any traffic. 3)- Saying that MDC is illegal because the plain ear can't decode it would be akin to saying that packet radio or P25 is illegal because the plain ear can't decode it. Get real.

Many amateurs are using MDC in the my area, especially since there are a few repeater systems in the area that require you to use a MDC-1200 burst just to open the repeater.

Whenever I encounter some mouth breather who wants to debate about the legality of MDC on ham bands I make reference to this point. usually the moron will say something lame like "well I don't know what data you are sending cause I can't decode it". 1)-Well get a real radio and you could. 2)-MDC is an accpeted signalling format, because you can't decode it doesn't make it any less legitamate, it is not to obscure the meaning of any traffic. 3)- Saying that MDC is illegal because the plain ear can't decode it would be akin to saying that packet radio or P25 is illegal because the plain ear can't decode it. Get real.

Exactly. Just to be annoying, I have system access tone, pre and post on all my channels, including ham.

I find that the trouble repeaters in the area open right up to me, and as a safety feature if the system doesn't get the ID the first time around, hopefully the second (common problem on my PD/FD repeaters that never gets fixed).

And number 2, I know that my radio is keying up so I don't sound like a doofus (more than usual) until the radio times out. Also makes a good dekey acknowgement instead of saying "over" (I hate that) when using simplex.

The most that I get on the ham repeaters is "that sounded like a commerical radio" and that's about it. Some inquire what it is and I will explain it to them.

The day someone complains about my MDC and how it "isn't right", is the day that I ask them to go back to the good old days and build a radio like ham are suppose to... Feed them a little of their own fiber.

In case anyone was wondering why I want to used 70cm for ham trunking, here is why:

-less band openings (then 2m)
-can use neat-o public safety mics
-UHF antennas give more gain / height over 2m
-70cm has more bandwidth then 2m band

I don't really want to see all of the 70cm convential repeaters get dropped (at least not immediatly). I'm sure we could find another piece of 70cm bandplan to use. A 20 channel system only uses 1/2 of a MHz in spectrum.

If you want to see some REAL intresting stuff... try crosslinking the talkgroup to the convential repeater! Talk about a lot of work!

This sort of project wouldn't be all that bad if /\/\otorola donated some of the gear. You know, a 501c3 non-profit ham club could accept a trunking system as a charitiable donation, and give /\/\otorola a BIG tax writeoff. Are you listening /\/\?

KC8RYW wrote:In case anyone was wondering why I want to used 70cm for ham trunking, here is why:

-less band openings (then 2m)
-can use neat-o public safety mics
-UHF antennas give more gain / height over 2m
-70cm has more bandwidth then 2m band

I don't really want to see all of the 70cm convential repeaters get dropped (at least not immediatly). I'm sure we could find another piece of 70cm bandplan to use. A 20 channel system only uses 1/2 of a MHz in spectrum.

If you want to see some REAL intresting stuff... try crosslinking the talkgroup to the convential repeater! Talk about a lot of work!

This sort of project wouldn't be all that bad if /\/\otorola donated some of the gear. You know, a 501c3 non-profit ham club could accept a trunking system as a charitiable donation, and give /\/\otorola a BIG tax writeoff. Are you listening /\/\?

Hey KC8RYW...on the public safety mike subject, I use an NMN6244C with a Visar VHF antenna for ham use at events and disaster training on the HT1000 VHF I got from Yosh. It works great, though the awkward legnth of the antenna makes it look kinda funny...but it works well.

Onto the trunking subject, I too would enjoy a SmartNet UHF amateur system- but I barely hear any use of the more than 20 metro Atlanta UHF ham repeaters other than a few small cliques here and there. It seems like the activity on the whole is going down. What really pisses me off to no end is how few hams actually do any REAL public service work, and I don't mean just standing around with a radio with your thumb up your but either- but volunteering at events as a regular volunteer. So many people always have excuses as to why they can't (but they have plenty of time to talk on the radio). anyway...another topic for another day.

1. With 400 lightly-used channels available on 25 kHz spacing on 440 mHz, why on earth would anyone need a trunked system?

2. With 800 lightly-used channels available on 12.5 kHz spacing on 440 mHz, again, why on earth would anyone need a trunked system?

3. Anyone who wants to make a serious improvement in VHF/UHF radio for the amateur service should, in my opinion, put the efforts into encouraging some type and standard of digital voice communications.

Tom, W2NJS
...in D.C.

I too like the trunking idea, but for me I'd rather have a controler and a couple of radios just to play with and learn about the system. Nothing more than that at this point.

I think the most annoying part is when you have a club that wants to put up a repeater, but can't get a pair because ONE person in your area happens to run a system and tie up 3/4 of them for no real reason. It's a somewhat decent linked system, but we have 1 repeater on the 13th story of a building on UHF, which has about a 30-60 mile footprint (and is also the highest point on campus), which from almost anywhere on a portable you can get into it with better coverage than the other persons system. This person also tries to deny you a pair because they don't believe that we have the ability to run one. Which is complete BS, since we do have the best UHF repeater in the county now. We just need a good Master II so we can up the power.

I am all for having repeaters for "rag chewing." When I commuted 30-45 minutes each day to work I would use a repeater up in Boston that had great coverage - and the topics were usually very interesting. Even if you couldn't chime in, it was still worth listening to. Except during lunch time "medical nets" where this person would complain about that problem, and this new medication they were on. Now, I'm more concerned about using the repeater we have on campus to get intouch with my roommates, and a few other people. Occasionally we get some people yacking on there which is fine, but I like the fact that most of us listen to it because we know the people on it are people were actually interested in talking to.

Using trunking on a UHF system to accomplish this task would be pretty cool, as you could simply have different talkgroups to talk to different subsets of people, or if you like your peace and quiet - sit on your own talkgroup and wait for someone to call you. I think a lot of the frequency pairs for repeaters could be much better utilized for a system like this, than having 5 repeaters sit idle, while one with better coverage remains active.

Now who wants to figure out how to add a Morse ID to a control channel?

-Alex

MDC on amateur radio is a good idea. So is the trunking/smartzone stuff you all are talking about. If a club wants to get a repeater or two or three than let them connect them together adn become one big system. We're not talking abotu the cheap-o links that you have to use the DTMF controller for, I'm talking a real system. If you really think about it, maybe motorola would possibly CONSIDER donating some equipment that came back to them and it's al fixed, for a nice write off. It might open up Vertex and Icom into making some better products that aren't all junk sometiems.

Pj wrote:. . . Exactly. Just to be annoying, I have system access tone, pre and post on all my channels, including ham. . . .

Whether MDC/MODAT, etc is useful or not is not a debate I'll get into. I just wish our repeater would use DPL and eliminate some of the idiots we can't get rid of. On the other hand, there is so little use now anyway, I can go days hearing only CW IDs.

My beef with the MDC use on the ham bands is that most folks aren't using it for anything. The sentiment I've quoted above, while the right of every ham to act upon, is not in the amateur spirit. I've never operated "just to be annoying." If that's what you got your ham ticket for, that's sad. There are already too many annoying folks on the bands who are annoying by nature, and not trying to be. If y ou have use for the MDC, go for it, but just to annoy? Very sad.

Trunking is a neat idea. I like the concept, but here in Central NJ, there is just no activity on the repeaters. My MT1000 scans eight UHF ham repeaters in the convertacom, and it stops on CW IDs only. Except for one linked system that gets used every few days. Two meters isn't much better. Very sad.

Good luck,

Sorry, didn't make myself too clear.. The annoying part was just ment to be an expression. There are a few repeaters that in the ham band too that take a bit to open up, and I find that the prestuff gets me right in, otherwise you get front clipped. No one complains about it though, and as I said before, they find it interesting.

We don't have really any jammers, but widespread use of PL/DPL would be great. Around here, all the good repeaters are on high mountain tops, however no one has a PL on them, hence lots of skip gets in on the inbound. I have suggested putting on Full PL or at least partial PL on the repeaters, but is seems like the other guys don't have a true understanding of how it works. They believe that if you have PL on any part of the repeater (in or out) that other people can't hear the transmissions. Trying to explain to them that if YOUR radio RX's in CSQ, you will hear everything. They don't seem to get that part.

A trunking system would be neat, but here in the home of ARRL, we can't get a decent APRS network in place. Even the ARRL digi doen't get more than 10 miles out from their massive antenna array (however they are in a valley I'll give them that).

Pj wrote: There are a few repeaters that in the ham band too that take a bit to open up, and I find that the prestuff gets me right in, otherwise you get front clipped. . .

I can't imagine being unable to push the PTT and waiting half a second. Not that tough, but. . . whatever.

Around here, all the good repeaters are on high mountain tops, however no one has a PL on them, hence lots of skip gets in on the inbound. . .

I can't think of one single repeater here in central NJ that isn't PL access anymore. Too many of them don't transmit PL, but all are PL access. That at least is a good thing.

I have suggested putting on Full PL or at least partial PL on the repeaters, but is seems like the other guys don't have a true understanding of how it works. They believe that if you have PL on any part of the repeater (in or out) that other people can't hear the transmissions.

I know some hams aren't clear on this. Oh well. And as for others not being able to hear the repeater, if only that could be done. Talk about getting rid of the idiots. Just block 'em so they don't even know you're there. I like it.

LOL... Private Line means my tx will be private, right?

I never did understand why a repeater would require PL on the input, and then send out the output without PL. Obviously, they don't want their users to avoid the problems that they are trying to avoid on the input by requiring a PL. I mean, how hard is it? Just attach the tone output to the modulation pot. Real hard work.

I think there is absolutely no reason why any repeater still doesn't use PL. PL has been out for at least 50 years. It's not very hard to understand the theory behind it.

If frequency coordinators were smart, they would realize that they could space repeaters closer together, if PL or DPL access was required on EVERY repeater.

What about DPL... lol . I'm sure someone has said before "You can't use digital in the ham bands." Plus the fact that only a few good ham rigs have DPL built in. Most 2-way rigs have been able to do DPL through programming for at least the last 15 years.

The DPL turn-off burst at the end of tx is a great way to prevent tail crashes. Sometimes rigs that do PL use 120", some use 180". This causes squelch tails. Every DPL rig should send out a turn-off code. Even my ham Yaesu Vx-5r sends out the turn-off code with DPL. This should cut down on squelch tails.

Jonathan: If you took a survey you might amazed at how many licensed hams have absolutely no idea what PL and DPL are and how they are used. Most hams, in my experience, even though they use UHF and VHF radios, have a very narrow view of the state of the art.

I probably toldl you how I was showing off a Saber III one day at a ham luncheon and several of the old timers (old timers to me, which makes them REALLY old!) remarked in loud voices how they didn't understand that Motorola stuff and further, didn't WANT to know about it. True story. ...and sad, too.

Tom, W2NJS
...in D.C.

Tom,

It always amazes me how so many people get set in their ways so early in life (old timers before their time) and yet others (with grey hair and all) stay receptive to new ideas. Oh, well!

The big problem with PL on repeaters has been the perception that so many hams have that it means the system is 'closed'. Granted, early in FM history PL was mostly used for closed repeaters. Now it is needed to deal with interference and minimize the confusion when the band opens.

The other problem is that most hams can't even remember how to turn tone on in their rigs.

There is some hope here, in some areas of the Country the coordinators REQUIRE PL on repeaters. Here is one example:

"These are the official standards of the Texas VHF-FM Society, Inc. regarding frequency coordination. These standards must be followed if you wish your system to be or remain coordinated......
...
.....The repeater input access control circuitry shall require a method of access protection to the repeater (a radio frequency carrier alone, shall be an insufficient condition) for the purpose of keying up the repeater by a user. The method of access may include, but not be limited to CTCSS, CDCSS, tone burst or any other commonly accepted means of input control, other than a simple carrier squelch method. Suggested CTCSS tones for open repeaters in each zone are at <http://www.txvhffm.org/ctcss.htm> ."


Back to the original topic of this thread, MDC would certainly meet the Texas rules and Motorola even has a repeater access word defined in the MDC standards.

But not having a PL on the output means nothing about being a "closed" repeater. You can still hear it WITHOUT the PL. The only thing the PL usually blocks you from hearing is the ID, the beep, and the squelch tail. I find that not having the radio recieve all that is a very helpful thing, especially if I am using a cross-band repeater to get into it.