Trunking in the Amateur Bands?

[n9upc]

Greetings to all,

I have search Title 47 CFR Part 97 looking to see if it says anything about trunking being illegal in the ham bands or not. Needless to say I can not find anything and I thought that I might come over here and ask the board if anyone knows FOR SURE and can refer me to any sources for reference.

Looking at a 2 to 3 channel LTR system in VHF which would (at least I think) work good near the twin cities metro area where I am near.

Anyone?

[N4DES]

I know that this has been discussed at great lengths on a number of message boards, inlcuding here, and while there are no limitations as far as Part 97 to exclude trunking there are operational issues specific to the end user, such as the 10 minute identification requirement. As you know with multi-channel trunking there is no way for a user to know exactly what frequency they are on at any one time, with that being the case once an end user begins to be dynamicially assigned from one to the only way for them to be legal is to ID at the end of every single transmission.

In the past a lot of conversation was based on using a Motorola format that has a constant data channel that also doesn't ID and not LTR.

What you could do instead is to build an APCO25 conventional system and create conventional talk-groups for the different users and or functions. This would probably be cheaper and give you a large amout of portables and mobiles from different manufacturers to choose from.

[MTS2000des]

The biggest show stopper is the justification if legality were ever called into question. The entire purpose of trunking is to allow a large number of users to share a relatively small number of resources. That is a problem that does not exist on the VHF/UHF ham bands for the most part. Of the 30 or so conventional 2m and 440 repeaters in the Atlanta/North Georgia area, hardly 10 percent of those are in use during PEAK times (weekday morning/afternoons) and otherwise, the repeaters are sadly devoid of use. Your trunked system would never trunk, as the resources (channels) would never get tapped the least bit. Maybe this is different in other parts of the country, but over the last decade, use of ham repeaters has dropped dramatically around here, directly correlates to the popularity of other more advanced communications technology now available to the general populous (cellphones, iDEN, FRS, Internet/VoiP, etc). There used to be repeaters just used for "phone patches" back in the 80's and 90's- and I recall in the summer of 1991, every single channel in my 12 channel MX350-S were hopping with activity during daylight hours.

That seems so recent yet so far away.

[Tom in D.C.]

You might also encounter serious objections from your local repeater
coordinators regarding several matters, such as justification, as well
as the possibility of stepping on current QSOs, etc. Remember that
we're supposed to listen on any frequency before transmitting on it
and a trunked system removes that capability from your control.

Repeaters in my area (DC/MD/VA) are used just like KS4VT's, which is
to say not much activity at all these days.

[n9upc]

There are some repeaters here that are really hopping still and some people some days (still hard to imagine) need to find a repeater to talk on.

As for ID'ing yes that would be one of the hurdles that would need to be tackled. A thought to over come that would be using SmarTrunk instead of LTR as SmartTrunk is a non-centralized trunking format.

With a SmartTrunk format it would take care of a couple of issues: 1.) It holds the repeater open for X amt of time so the odds of being on the same repeater ARE greatly increased. 2.) SmartTrunk format would have the radio monitor so it would know if we have co-channel interference and not use that repeater.

It was just an ideal that sparked from having a GREAT location and wanting to use the site for a GREAT many things like: 1.) Large coverage repeater, 2.) Echolink-IRLP site, 3.) Able to monitor a system for traffic from certain people and only hear traffic from them (private or select talkgroups). [A lot fo repeaters will now no longer pass signaling or modulation is not set-up correctly.] 4.) One of the biggest things is for weather spotters/weather emergencies.

But just an ideal that some have toyed with.

[Grog]

One issue would be actually finding enough frequency pairs that are not taken. In NC that's almost impossible because of the large amount of "paper" repeaters.

[wazzzzzzzzup]

i too have thought it would be really cool to have an LTR system for hams, one really nice site with 2 or 3 repeaters would allow alot of hams to have thier own private wide coverage talk group. but i think the best way for LTR to be used by hams is to buy portables that cover UHF ham and LTR biz band and rent service from a local SMR provider. besides, if you use a biz system, you can choose how you want your channel to be used, you dont necessarily have to use ham calls, you could go by names, spotter id's, or made up unit numbers. you can talk BS,business or official topics, you could allow non ham family members or friends to use too. on business LTR no one really cares what you say on your own talkgroup. and the service rates per unit around the country are between 10.00 to 20.00 a unit. If you find an SMR that is run by a ham or otherwise supports the hobby and/or emergency communications, you might get a discount, or multiple talkgroups. most LTR SMR's dont have a time limit on useage either, so you can ragchew 24/7 if you wish. SMR owners carry the license for the system, you dont need one.

wazz

[George]

No reason why you can't do it. Nothing illegal about it as long as ID requirements are met.

I asked Reilly about it when I saw him last and he said this:

"Radio Amateurs are there to explore technology and technological applications and to push the limits of where the state of the art currently stands. Part 97 is not there to tell you what you CAN do, it is there to tell you what you explicitly CANNOT do."

That's paraphrased a little, but you get the idea.

Do it! Put it on the air and have at it.

[motorola_otaku]

Also keep in mind that coordination is voluntary. The owner of a coordinated repeater can claim interference from you and you will be required by law to remedy it, but that's the extent of it - you are not required by law to coordinate.

Here's what I'd do. Use 12.5 kHz-spaced frequencies on 440 or 7.5 kHz-spaced frequencies on 2m and program everything for narrowband operation. When selecting frequencies, try to go to either side of a normally-spaced frequency that you've verified to be quiet. That will lessen your chances of causing interference to a coordinated repeater or attracting the attention of a "squatter."

I have to recommend that you stay away from SmarTrunk. Late call break-in doesn't exist; someone turns their radio on or flips over to a particular group and a call is already in progress, you won't hear it until it's dropped and restarted.

[smokeybehr]

Also keep in mind that coordination is voluntary. The owner of a coordinated repeater can claim interference from you and you will be required by law to remedy it, but that's the extent of it - you are not required by law to coordinate.

Here's what I'd do. Use 12.5 kHz-spaced frequencies on 440 or 7.5 kHz-spaced frequencies on 2m and program everything for narrowband operation. When selecting frequencies, try to go to either side of a normally-spaced frequency that you've verified to be quiet. That will lessen your chances of causing interference to a coordinated repeater or attracting the attention of a "squatter."

And reverse the split, if the coordinator won't complain too much. The front end of the radio/repeater will take care of weeding out the out-of-bandpass adjacent channels.

[chpalmer]

The front end of the radio/repeater will take care of weeding out the out-of-bandpass adjacent channels.

Just remember... Depending on the radio this can be 30kc or so...