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The new Ham Radio P25 master site.

This forum has been created to foster the discussion on future and cutting edge technology. This discussion is not limited or restricted to Motorola. Examples of allowed discussion are open source hardware (GNU Radio for example) and software (Open source P25, Asterisk, ROIP, etc). Discussion is also permitted where older technology could be applied to areas where it had previously not been used (Example: Trunking on amateur radio).

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MOEtorola
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The new Ham Radio P25 master site.

Postby MOEtorola » Thu Sep 23, 2010 8:18 pm

A thought I had a long time ago, wouldnt it be cool if some rich amateur purchased a P25 master site (the brains of a trunking system) and let amateurs across the country connect sites to it. For a sort of a nation wide trunking system. Just food for thought. I have not really thought much about the technical details though. Any rich hams out there.

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Re: The new Ham Radio P25 master site.

Postby escomm » Fri Sep 24, 2010 8:32 am

Well it's already being done with TRBO.

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Re: The new Ham Radio P25 master site.

Postby Tom in D.C. » Fri Sep 24, 2010 12:17 pm

It's also being done on analog. From the DC area I have access via an internet connection to most of the SW United States via a linked repeater system in that area. It's not trunked and it has no fancy protocols, just voice, but it works very well.
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Re: The new Ham Radio P25 master site.

Postby AEC » Sat Sep 25, 2010 11:05 am

Tom, are you referring to the Cactus Intertie system?

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Re: The new Ham Radio P25 master site.

Postby MOEtorola » Mon Oct 11, 2010 12:12 pm

escomm wrote:Well it's already being done with TRBO.

No it is not, as far as Amateur Radio. And Trbo trunking as of this far cannot be networked.

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Re: The new Ham Radio P25 master site.

Postby MOEtorola » Mon Oct 11, 2010 12:32 pm

Tom in D.C. wrote:It's also being done on analog. From the DC area I have access via an internet connection to most of the SW United States via a linked repeater system in that area. It's not trunked and it has no fancy protocols, just voice, but it works very well.

Again not trunked.

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Re: The new Ham Radio P25 master site.

Postby MOEtorola » Mon Oct 11, 2010 1:38 pm

MOEtorola wrote:
escomm wrote:Well it's already being done with TRBO.

No it is not, as far as Amateur Radio. And Trbo trunking as of this far cannot be networked.

Oops forgot about ConnectPlus, but havent heard of this being used in amatuer.

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Re: The new Ham Radio P25 master site.

Postby escomm » Mon Oct 11, 2010 3:21 pm

MOEtorola wrote:
escomm wrote:Well it's already being done with TRBO.

No it is not, as far as Amateur Radio. And Trbo trunking as of this far cannot be networked.

OP talked about a master site linked across the country to other repeaters that hams can connect to. This has in fact been done. Not sure why you are latching on the trunking part but if you can offer insight as to what benefits trunking would have for ham users please do share. Trunking serves no useful purpose in amateur radio.

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Re: The new Ham Radio P25 master site.

Postby tvsjr » Mon Oct 11, 2010 4:57 pm

escomm wrote:
MOEtorola wrote:
escomm wrote:Well it's already being done with TRBO.

No it is not, as far as Amateur Radio. And Trbo trunking as of this far cannot be networked.

OP talked about a master site linked across the country to other repeaters that hams can connect to. This has in fact been done. Not sure why you are latching on the trunking part but if you can offer insight as to what benefits trunking would have for ham users please do share. Trunking serves no useful purpose in amateur radio.

Sorry, but I disagree.

What's the purpose of trunking? Better utilization of existing spectrum? Look at 2m or 440 in any major metro and you'll find a multi-year waiting list for a new frequency coordination.

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Re: The new Ham Radio P25 master site.

Postby resqguy911 » Mon Oct 11, 2010 5:56 pm

But, if you only have one frequency anyway due to tight allocations- how is trunking better for hams than DMR? With 2-slot TDMA you can use your current frequency with a $1000 repeater and get two conversations. With trunking, you are going to be waiting a while for comparable equipment to be advantageous. Even if you did voice on control channel, you still only get one voice path with FDMA.
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Re: The new Ham Radio P25 master site.

Postby tvsjr » Mon Oct 11, 2010 7:26 pm

resqguy911 wrote:But, if you only have one frequency anyway due to tight allocations- how is trunking better for hams than DMR? With 2-slot TDMA you can use your current frequency with a $1000 repeater and get two conversations. With trunking, you are going to be waiting a while for comparable equipment to be advantageous. Even if you did voice on control channel, you still only get one voice path with FDMA.


You're totally confusing two technologies. DMR and trunking are totally different things.

DMR describes 2 TDMA talk paths in a 12.5KHz channel

Trunking describes a system where logical talkgroups are separate from physical frequencies, allowing more efficient use of spectrum and infrastructure.

You could get 2 talk paths in 12.5KHz using conventional TRBO, conventional P25 Phase 2 (theoretically - I don't think Moto supports F2 on conventional), two NXDN/IDAS repeaters (6.25KHz FDMA), etc.

Any of these technologies could be combined with trunking to increase efficiency, allow multisite operation. There are trunking variants of TRBO, P25 F2, NXDN, etc.

Escomm's comment was that trunking served no useful purpose in amateur radio. I disagree. Considering the number of underutilized frequencies out there (backyard repeater for the wife to call home on, repeaters only used for certain events, etc.), my opinion is that trunking makes perfect sense for amateur use. Trunking was created for exactly this purpose. I don't care if you use old-school Smartzone, TRBO ConnectPlus, or go buy a P25 F2 master site and infrastructure.

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Re: The new Ham Radio P25 master site.

Postby escomm » Mon Oct 11, 2010 10:28 pm

Nonsense. The repeaters are on paper. Aside from the technical issues that make trunking generally incompatible with FCC rules for amateur radio, any trunking system deployed will necessarily be restricted to a vendor's trunking format, as no open source trunking format exists. Although TRBO is based on DMR I think it's safe to say that any trunking protocols over TRBO will not be public format -- scratch that, looking at the cost of the license it's clear that it's not open.

That said, I fail to see how a trunking system is an answer to the "problem" of crowding in the ham spectrum. There would need to be 3 or 4 simultaneous conversations occurring at any given moment before the system has reached critical mass and will begin "saving" spectrum, how many new systems are waiting to be deployed for lack of spectrum that would really have that many simultaneous conversations going on at once. And even then there are only a small handful of major metropolitan areas where this would be needed, Trunking in amateur bands to "save spectrum" is a silly idea. Much more effective would be monitoring, inspection and ultimately revocation of the paper coordinations for dummy repeaters.

Never mind that that the forced use of expensive and proprietary infrastructure & subscriber equipment is contrary to the spirit of amateur radio, interpretations of the vague rules notwithstanding.

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Re: The new Ham Radio P25 master site.

Postby alex » Mon Oct 11, 2010 11:45 pm

Having a master site for P25 trunking system to be used on Amateur radio would be very cool. That being said, I agree with escomm that you still have an issue in a large number of metropolitan areas where channel space is at a premium. For example it is my understanding that there are *NO* free 900mhz repeater pairs in NYC. I was actually kind of suprised to learn this.

So unless you are going to do voice on control using an intellipeter/master then it probably for the masses will not work. Keep in mind you also have QOS issues with P25 and moving data from site to site via IP has to be done using point to point links to minimize latency. I've been reading up on E/T lines over IP and it is very doable but your links and using things like channel banks to do this gets expensive very quickly.

With respect to DMR/Mototrbo - there is a published standard for trunking using this format. The format itself uses talkgroups and allows for private calls between devices via the repeater or across the network. Per usual, Motorola does not have any security or control on the network level of the system. You need other third party tools to analyze what is going on with your repeater and personally I think that is their largest flaw in the entire system.

Jeff, in response to your comment about Mototrbo being an "open" standard it is basted on ETSI TS 102-361, avaliable here: http://www.dmrassociation.org/what-is-dmr.htm. What is *not* open is DVSI's vocoder. But if you notice on the site, TS 102 361-4 is a DMR Trunking protocol which I would imagine will be implemented in most manufactures radios either coming soon or already here.

I have to say that I have been very impressed with Mototrbo. I did not know what to think or expect from it but the IP linking is excellent and can not be beat. I did hear through the rumor mill that Motorola is looking at using 4 TDMA slots via 1 25khz channel. This would probably be the start of bringing more trunking type solutions to light.

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Re: The new Ham Radio P25 master site.

Postby resqguy911 » Tue Oct 12, 2010 4:58 pm

Where did you get the idea I confused anything? I was merely saying that you get more capacity from an affordable TRBO repeater than any currently available single site trunking. And there is currently no such thing as P25 Phase2 conventional. (And for that matter, there is no such thing as P25 Phase2, merely Motorola "X2" until TIA completes its mission)
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Re: The new Ham Radio P25 master site.

Postby akardam » Tue Oct 12, 2010 5:09 pm

For the sake of the community, keep the discussion civil.

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Re: The new Ham Radio P25 master site.

Postby escomm » Tue Oct 12, 2010 7:47 pm

alex wrote:Jeff, in response to your comment about Mototrbo being an "open" standard it is basted on ETSI TS 102-361, avaliable here: http://www.dmrassociation.org/what-is-dmr.htm. What is *not* open is DVSI's vocoder. But if you notice on the site, TS 102 361-4 is a DMR Trunking protocol which I would imagine will be implemented in most manufactures radios either coming soon or already here.

OK, I should have been clearer about the "open" trunking protocols being for multi-site trunking, not single site trunking, but anyway let's assume for a second that the "open" protocol does include multisite trunking (and it's not clear that it does, that spec makes no mention of interconnection of master sites that I could find) -- How does this solve anything? P25 trunking is "open" and I can count the number of manufacturers offering P25 trunking infrastructure on one hand. At $46k per XRC9000 site controller TRBO is going to be cost prohibitive for all but the richest of hams. Who else has DMR trunking on the market in the US? Who else has multi site DMR trunking on the market in the US? Does anyone in Europe or Asia have it?
I have to say that I have been very impressed with Mototrbo. I did not know what to think or expect from it but the IP linking is excellent and can not be beat. I did hear through the rumor mill that Motorola is looking at using 4 TDMA slots via 1 25khz channel. This would probably be the start of bringing more trunking type solutions to light.

It's walking and talking and acting like Tetra.... I don't think Motorola will ever let Tetra into the US, unless Warren Havens is somehow successful in convincing the Feds they can use eminent domain to take the intellectual property from Ma /\/\... :roll: :lol:

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Re: The new Ham Radio P25 master site.

Postby alex » Wed Oct 13, 2010 12:48 am

I see your point with the cost of the controller.

Currently it is my understanding that the Trbo IP Site Connect feature only supports 16 repeaters.

So if you say ok, there's 16 repeaters...

Let's take the 40K, divide it out by the 16 repeaters in the network. That's $2500 per repeater owner to join the trunk system. it *is* a lot of money, but if you say there are 40 subscribers per system - $62.50 one time fee per subscriber to add to the system. If you already have hams running out buying a $400 used portable, 2 batteries, 2 belt clips, 1-2 chargers, and programming cable.... what's $62? A drop in the bucket.

Some of the repeater owners have already spent another 2-3 grand on top of the cost of the repeater itself to build up the system to make it do what they want...

This of course is only if they need 1 master - and each site does not require a master? This I don't know. Right now it only supports a total of 6 sites so my numbers are a bit off... There is no reason why in the future it can not support more.....

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Re: The new Ham Radio P25 master site.

Postby escomm » Wed Oct 13, 2010 8:08 am

That controller is per site, not per system. $46k per site.

And although the specs may limit the number of repeaters linked at 16for IP Site Connect, the folks here in LA that are really blazing this path have something like 20 or 22 sites hooked up. I'm not sure how they get around the "limit" but they did. IP Site Connect is the real strength of TRBO for amateur radio, and there's no additional license or fee like there is with Capacity Plus or Connect Plus

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Re: The new Ham Radio P25 master site.

Postby alex » Wed Oct 13, 2010 8:47 am

Yeah, I guess that would make sense as if you loose a link you would still want the system to fall back to site trunking.

The ceiling to how many repeaters you can link together is based upon the bandwidth available at each repeater site as well as the total link capacity of the master site. For example you could be limited if the connection was only 10/100 on the network side. I think Motorola says 16 but to the extent that this has been tested over things like internet internet links vs local lan would be another good question.

If Motorola comes out with a MTR3000 which when using 25khz channel supports 4 time slots - I could see a few of those controllers flying off the shelf.... If you have two frequencies why not get 7 voice paths plus 1 data? Seems like a good idea. Even at 42k for the controller you are getting 7 channels where you used to have 2.... or even 3 where you had 1 frequency.

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Re: The new Ham Radio P25 master site.

Postby escomm » Wed Oct 13, 2010 10:03 am

What amateur needs 7 voice paths? Who is going to have 7 simultaneous conversations (plus data) in the same local area? How many ham clubs out there even have enough members, let alone the need to segregate transmissions by talk group

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Re: The new Ham Radio P25 master site.

Postby 123 » Wed Oct 13, 2010 10:59 pm

With all due respect Jeff. I live in a rural area and it is 2 am, and right now I am listening to 5 conversations on ham all within range of a crappy scanner on a crappy antenna. And yes, there are about 18 other repeaters on the air RIGHT now within range of my portable that are ghost repeaters. Meaning NOONE ever talks on them {And yes, I know they are there, I have keyed each one of them up} ! So yes, it is unfair that people can not get a pair because the pairs are taken to just to sit there. It would only make sense to condense the 30 or so repeaters in this area into only maybe 5 trunked repeaters for the area. Will it happen? Probably not. NOT because it cant be done, or not because noone has the money. But because noone wants to do something that actually makes sense. Which is condensing into something more plausible to conserve bandwidth. Which is what trunking was designed to do in the first.

We dont need more conventional repeaters on ham. We have plenty of those already.

Jeff I quote from you:

"forced use of expensive and proprietary infrastructure & subscriber equipment is contrary to the spirit of amateur radio"

No one is forcing anyone to use trunking. First off even if you are a licensed ham, talking on a repeater is a Privilege. NOT a right or requirement. No one is forcing all repeater owners to throw away their repeaters and buy trunking ones. We are merely asking or suggesting the idea and hope others catch on to save spectrum. And all infrastructure if done correctly is expensive... Subscriber trunking radios on the other hand are NOT expensive. You can buy any MTS 2000 for $85 to do analog trunking and you can buy any astro saber for $150 for digital. TRBO radios cost more then that ! But again, talking on a repeater is NOT a requirement of ham radio. If someone doesn't want to buy a trunking radio to talk on the system then they can talk simplex or go elsewhere. Just like if I want to talk on a D Star 1.2Ghz repeater, what do I have to do? Buy a ID-1 radio for around $800 used or $1,200 new ! I dont see the difference or your point. Far as the "spirit of amateur radio" Well...The spirit of amateur radio is to experiment with different technology, share ideas and help each other out. NOT to tell people "you cant do that" or "I think thats a silly idea"

And to everyone in the group that is complaining about "how expensive" things are to put up. Seriously,... I cant believe you guys are even talking about money. How many you of own a few XTS 5000s? a few astro spectras, XTL 5000s, a few repeaters, a few APX 7000s? keyloaders, programming cables, the list goes on and on. Add up all your gear and I am sure you will be in the several thousands fairly quickly... If someone wants to do something, they will find the way. And in the used market anything is possible. Sure a controller is $46K but NOT in the used market its not! And seriously, I know SEVERAL repeater owners, A good friend of mine owns the TOWER,the building, the land, transmission lines, antennas, generators, etc, etc. He has about 8 ham repeaters on his tower. Trust me, he has well OVER $46K of equipment just dedicated to ham radio. So no, money isnt the problem to those of us that are serious about the hobby. Just like any other hobby, someone that likes model trains, model airplanes, antique cars, hot rods, serious collectors on any kind. They have thousands of dollars invested in their hobby. Radios are no different.

The OP just stated his dream and what he wishes for. What the heck is wrong with that? How about positive postings instead of so many negative ones !


my 2 cents.
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Re: The new Ham Radio P25 master site.

Postby akardam » Thu Oct 14, 2010 5:14 am

123 wrote:Trust me, he has well OVER $46K of equipment just dedicated to ham radio.

Well, as they say, give me numbers. Or, as Joe Friday says, just the facts, ma'am.

Assuming a Motorola based solution, Astro25 7.x IP based Master Site, using Ethernet based site links, with two VHF 3 channel standalone (e.g. non-simulcast) sites, and absolutely no redundancy what-so-ever, you're looking at about $500,000. That's half a million bucks... and it doesn't include any backhaul (that's up to the customer) or site infrastructure (shelter, tower, power plant, feedline, antennas, combining, etc).

Show me a ham group that wants to spend over half a million bucks (realistically approaching $700,000) for just two simultaneous talk paths over a not-large geographical area...

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Re: The new Ham Radio P25 master site.

Postby 123 » Thu Oct 14, 2010 7:00 am

akardam wrote:
123 wrote:Trust me, he has well OVER $46K of equipment just dedicated to ham radio.

Well, as they say, give me numbers. Or, as Joe Friday says, just the facts, ma'am.

Assuming a Motorola based solution, Astro25 7.x IP based Master Site, using Ethernet based site links, with two VHF 3 channel standalone (e.g. non-simulcast) sites, and absolutely no redundancy what-so-ever, you're looking at about $500,000. That's half a million bucks... and it doesn't include any backhaul (that's up to the customer) or site infrastructure (shelter, tower, power plant, feedline, antennas, combining, etc).

Show me a ham group that wants to spend over half a million bucks (realistically approaching $700,000) for just two simultaneous talk paths over a not-large geographical area...



You are talking brand new prices. I am speaking of buying surplus which is a fraction of the cost. And as stated already, there are plenty of repeater owners that own the "(shelter, tower, feedline, antennas, combining, etc)" So I still do not see your point. Again, if someone wants to do it, they can. But I think no ham wants to be the "first" to put up a trunking system on ham. That is the real problem. Not the money.
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Re: The new Ham Radio P25 master site.

Postby akardam » Thu Oct 14, 2010 7:08 am

123 wrote:You are talking brand new prices. I am speaking of buying surplus which is a fraction of the cost.

Well, yeah, I am. Unless you'd be prepared to reveal your source of reliable, surplus Astro25 7.x IP (or for that matter, any other manufacturer's P25 trunking system components) equipment? 'cause, according to the OP, that's what we're talking about here.

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Re: The new Ham Radio P25 master site.

Postby alex » Thu Oct 14, 2010 7:21 am

123 wrote: But I think no ham wants to be the "first" to put up a trunking system on ham. That is the real problem. Not the money.


Buy me the equipment and I'll be the first to inhibit your radio from the console.

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Re: The new Ham Radio P25 master site.

Postby escomm » Thu Oct 14, 2010 8:07 am

Well Roberto since clearly you've got your mind set on this, how about you build it and we'll see who'll come?

Nothing has been presented in this thread that supports the position that trunking has any place in ham radio beyond as an experimental thing. I am still failing to see trunking will resolve these crowding issues any better than an audit of the spectrum and removal of paper repeaters from coordination lists. Perhaps there is some non-obvious reasoning.

As for D-Star, well yeah, is anyone surprised at how it hasn't taken off like Icom would have liked? That it's not the second coming for amateur radio? Do you think that maybe it's got something to do with proprietary technology and high cost? Yet somehow if we go the "Motorola" route people will cast that all aside? Uh, sure . . .

Multi-site TRBO has taken off and frankly I think that's all the hams are really looking forward, a simple, extremely wide range network with pretty decent performance and reliability.

It's nice to wish for things in the radio world. One thing that should be clear is that a party can have basically whatever they want when it comes to two way radio... the sky is the limit... as long as you can write the check to pay for it.

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Re: The new Ham Radio P25 master site.

Postby com501 » Thu Oct 14, 2010 8:49 am

I have already installed a Trbo UHF and VHF mobile in my truck. Besides, its got over 1000 channels per radio!!

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Re: The new Ham Radio P25 master site.

Postby MikeOxlong » Thu Oct 14, 2010 11:28 am

If I didn't have a lot of money tied up in P25 gear, I would have definitely gone TRBO.

The ease of linking is the biggest selling point for me.

Heck, we just linked two cosited P25 machines a couple of weeks ago and hopefully within the next week, we'll have another P25 machine linked in over RF.

It only took about 5 years and a bunch of equipment.

Probably could have accomplished the same using TRBO gear a lot faster and cheaper.

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Re: The new Ham Radio P25 master site.

Postby 123 » Thu Oct 14, 2010 2:05 pm

No Jeff I never said I have my mind set on this, although it would be cool if the idea kicked off. But I was merely defending the OPs point of view because it seems some of you are ganging up on him just because you guys dont like the idea. And the reasons you guys are giving in here are not valid as I previously pointed out which is the only reason I posted my comments.

No one here has the right to tell someone else it doesn't belong on ham radio. Ham radio is a experimental band. Thats all the reason you need regardless if you agree with it or not. If someone wants to spend the money to do it no matter the cost then that is up to them to do it or not. Heck, you guys are sounding like the old timers over 12 years ago when people were putting up P25 conv. repeaters on ham. That is exactly the same argument they were saying back then. Its too expensive, thats silly, it doesnt belong on ham radio, etc etc. But it was done back then when quantars were much more expensive. Many of us bought several quantars when others were whining that just one quantar was too expensive didnt we?

I dont think any of us should assume what someone is or is not willing to spend towards the hobby. Will I spend that much on this idea? No, but that was never my point if you re-read my comments. Everyone's hobby spending money threshold is different.

We have had plenty of negative comments towards the subject, how about some positive comments for a change?
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Re: The new Ham Radio P25 master site.

Postby 123 » Thu Oct 14, 2010 3:22 pm

[quote="MikeOxlong"The ease of linking is the biggest selling point for me.

Heck, we just linked two cosited P25 machines a couple of weeks ago and hopefully within the next week, we'll have another P25 machine linked in over RF.

It only took about 5 years and a bunch of equipment.

Probably could have accomplished the same using TRBO gear a lot faster and cheaper.[/quote]


The expense and difficultly of linking is a matter of interpretation, which method you decide on, and if latency is an issue for you or not. TRBO is not the only cheap way to link. Motorola has not reinvented the wheel with linking... Hams have been linking repeaters cheap for how many decades now? But regardless of that. Its off topic so I will leave it at that. If you want to continue this conversation PM me.
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Re: The new Ham Radio P25 master site.

Postby escomm » Thu Oct 14, 2010 7:02 pm

123 wrote:No Jeff I never said I have my mind set on this, although it would be cool if the idea kicked off. But I was merely defending the OPs point of view because it seems some of you are ganging up on him just because you guys dont like the idea. And the reasons you guys are giving in here are not valid as I previously pointed out which is the only reason I posted my comments.

No, he was given reasons for why it will be difficult to work or why it's cost prohibitive. If someone wants to go out and spend their money, they've got every right. But spending a lot of money still doesn't resolve the technical rules issues nor does it do anything to actually resolve spectrum crowding, neither of which have been addressed by proponents in this thread.
No one here has the right to tell someone else it doesn't belong on ham radio. Ham radio is a experimental band. Thats all the reason you need regardless if you agree with it or not. If someone wants to spend the money to do it no matter the cost then that is up to them to do it or not. Heck, you guys are sounding like the old timers over 12 years ago when people were putting up P25 conv. repeaters on ham. That is exactly the same argument they were saying back then. Its too expensive, thats silly, it doesnt belong on ham radio, etc etc. But it was done back then when quantars were much more expensive. Many of us bought several quantars when others were whining that just one quantar was too expensive didnt we?

You will want to review the FCC rules for one-way transmissions and proper identification and proper emissions designators, there's a small handful of technical hurdles that actually are roadblocks to what can or can't be done with trunking in the ham bands.

Example: I can tell you all day long that you can't broadcast music on ham radio and you know what? I'll be correct.

Remember there are rules to be followed and you won't be having many control channels in the ham bands without a waiver from the FCC, especially on a multi-channel trunking system (I don't want to hear about single channel trunking systems as these are about as useful for 'saving' spectrum as community repeaters).

How will you get around the one-way transmission prohibition? A trunking system doesn't fall under the exceptions provided for one-way broadcasts. So you will need to find yourself a trunking format that does not have a full duty-cycle control channel. Reference 97.113

Also there's some problems with IDing, and not with the stations themselves. Let's say you key up to call your buddy, you ID, and the repeater assigns you channel 1 in the system. Then your buddy calls you back on channel 2 with his call. Everyone's ID properly, right? But then your reply is on the 3rd channel, and your buddy's is on the 4th, if you didn't ID when you were on the 3rd and 4th channel then you're not following the rules for proper IDing. Have fun IDing yourself on every transmission. Reference 97.119.

The vendor whose trunking format is used also needs to have documented the technical characteristics of the datastream publicly or else the datastream is not a permissible transmission. Reference 97.309

I'm sure if you got all your ducks lined up and submitted a superbly written exemption request, the FCC would be inclined to grant the STA. Of course, you'll still need to find the open frequency pairs if in a fully coordinated region, which means getting other repeater owners on board or... finding the paper repeaters and getting them canceled.

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Re: The new Ham Radio P25 master site.

Postby 123 » Thu Oct 14, 2010 8:53 pm

{Now I am no expert in this matter nor will I claim to be}

But my view is:

Reference 97.113 A control channel is not a one-way transmission. There is constant handshaking between the user radios and the controller on the control channel. Therefore it is not a one-way transmission.

Reference 97.119 If a station IDs after each end of transmission this solves that issue. It may be annoying to do, but covers your basis.

Reference 97.309
http://www.aeroflex.com/ats/products/pr ... ctions.pdf
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Re: The new Ham Radio P25 master site.

Postby alex » Thu Oct 14, 2010 11:41 pm

Jeff I agree with you to some extent that it would take a bit of research depending on where you are to find the spectrum to do it in, let alone the fact that it is cost prohibitive regardless. You also find that there are some people who complain that Trbo is not allowed in the ham band... "well, per regulation blah blah blah..." or because this is not met or that is not met. You are always going to find someone who will tell you no, you simply can not because I believe this, this and that. Welcome to the internet where everyone disagrees on a daily basis.

Trbo has taken off to the point where there are rumors that Motorola is actually considering MARKETING Trbo to hams. Yes you heard me right - considering marketing a commercial product to amateur radio. Apparently they have heard from so many people that groups are buying the stuff faster than the dealers can keep it in stock.

So before anyone says hey, that wouldn't work, hey hams wouldn't go for it.... This might be one product that makes Motorola make a radio marketed towards hams.

It might not be the step to get trunking on Ham Radio - but people are taking notice of the technology and are talking about it.

-Alex

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Re: The new Ham Radio P25 master site.

Postby escomm » Fri Oct 15, 2010 8:02 am

123 wrote:Reference 97.113 A control channel is not a one-way transmission. There is constant handshaking between the user radios and the controller on the control channel. Therefore it is not a one-way transmission.

Except there may not be radios in the range of the controller, and the transmissions are not brief, so you'll have a really hard time with this one.
Reference 97.119 If a station IDs after each end of transmission this solves that issue. It may be annoying to do, but covers your basis.

Of course, this does not resolve trunking radios that only handshake to the controller.


Nice sales document for test sets but a technical standard it is not.

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Re: The new Ham Radio P25 master site.

Postby escomm » Fri Oct 15, 2010 8:31 am

alex wrote:Jeff I agree with you to some extent that it would take a bit of research depending on where you are to find the spectrum to do it in, let alone the fact that it is cost prohibitive regardless. You also find that there are some people who complain that Trbo is not allowed in the ham band... "well, per regulation blah blah blah..." or because this is not met or that is not met. You are always going to find someone who will tell you no, you simply can not because I believe this, this and that. Welcome to the internet where everyone disagrees on a daily basis.

Trbo has taken off to the point where there are rumors that Motorola is actually considering MARKETING Trbo to hams. Yes you heard me right - considering marketing a commercial product to amateur radio. Apparently they have heard from so many people that groups are buying the stuff faster than the dealers can keep it in stock.

So before anyone says hey, that wouldn't work, hey hams wouldn't go for it.... This might be one product that makes Motorola make a radio marketed towards hams.

It might not be the step to get trunking on Ham Radio - but people are taking notice of the technology and are talking about it.

-Alex

(p.s. my Inhibit comment to 123 above was a joke along the lines of if you pay for it and it gets built... I'll be the first one to goof around on the console)

I'm not aware of anything that would preclude TDMA modulation on the ham bands, other than maybe OFs that still think P25 is a big no-no and frankly they're holding back the hobby anyway. TRBO has really been going on the ham bands for awhile now and it was hams that got IP site connect up and working over thousands of miles and proved it was a viable solution. Hell many of them are using public internet connections with VPNs so anyone with a DSL connection can theoretically get in the mix.

I would be really happy to see TRBO advertised towards hams, especially since it's already so popular and working so well. If customers have the money then what skin is it off Motorola's teeth? A sale is a sale. It would also be pretty cool if some 3rd party wrote a data application to utilize the internal GPS for APRS

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Re: The new Ham Radio P25 master site.

Postby MikeOxlong » Fri Oct 15, 2010 10:14 am

123 wrote:Hams have been linking analog repeaters cheap for how many decades now?


There, I fixed that for you.

I'm talking about linking digital machines together.

TRBO is much easier and cheaper to link then P25.

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Re: The new Ham Radio P25 master site.

Postby 123 » Fri Oct 15, 2010 10:34 am

MikeOxlong wrote:
123 wrote:Hams have been linking analog repeaters cheap for how many decades now?


There, I fixed that for you.

I'm talking about linking digital machines together.

TRBO is much easier and cheaper to link then P25.



We linked 2 repeaters on P25 in about 1 hour and spent about $600 doing it. Again, PM me if you want to continue the discussion since its off topic.
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Re: The new Ham Radio P25 master site.

Postby escomm » Fri Oct 15, 2010 11:13 am

Conventional repeaters, yes? How much do you think it would take to link 2 P25 trunking repeaters with each other?

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Re: The new Ham Radio P25 master site.

Postby 123 » Fri Oct 15, 2010 11:51 am

escomm wrote:Conventional repeaters, yes? How much do you think it would take to link 2 P25 trunking repeaters with each other?



Thats the same thing people were saying with P25 conv. years ago. That it would take several thousands of dollars to link P25 conv. Even the above posted said it. If enough minds are put together, anything can be accomplished. Ive seen the impossible happen many times over. Heck, how many people said DES could not be cracked until the day that DES was indeed cracked? Come on...

Seriously, I am really tired of the negative energy you bring to this thread.

I got more productive things to do then to argue with people that do not think outside the box.

I think I have said all I had to say so I will stop here as this is getting nowhere now.
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Re: The new Ham Radio P25 master site.

Postby escomm » Fri Oct 15, 2010 2:36 pm

I asked a simple question. That you inferred negativity from it is pretty indicative of how you feel about what you're saying here.

So I'll ask again: How much do you think it will cost to link two P25 trunking systems? It's really not a difficult question, is it?

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Re: The new Ham Radio P25 master site.

Postby MikeOxlong » Fri Oct 15, 2010 3:09 pm

I and a lot of others would be interested in how he linked two P25 machines together for $600.

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Re: The new Ham Radio P25 master site.

Postby com501 » Mon Oct 18, 2010 9:20 am

+1 on that. Me too, since I need to do it for a customer, and the APB says its the price of a new car....

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Re: The new Ham Radio P25 master site.

Postby escomm » Fri Oct 22, 2010 4:46 pm

123 wrote:We linked 2 repeaters on P25 in about 1 hour and spent about $600 doing it.

How did you do this?

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Re: The new Ham Radio P25 master site.

Postby FatBoy » Wed Oct 27, 2010 11:35 am

probably used CriticalRF or some other ham type voip solution and mobiles or control stations. FatBoy
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Re: The new Ham Radio P25 master site.

Postby xmo » Thu Oct 28, 2010 7:43 am

123: "...We linked 2 repeaters on P25 in about 1 hour and spent about $600 doing it...."
escomm: "How did you do this?"
____________________________________________________________________________

Actually linking two P25 Quantars is very simple.
You just connect the V.24 ports with a cross-over cable.
This can be done over a distance with either the Motorola Astro modems or with external modems such as the Paradyne 326x series.
You could use a dedicated circuit or even dial-up! Motorola has an example of Wildcard programming instructions that will configure the station so that it will auto-dial upon powerup or loss of modem connect.

Another possibility for creating a group of linked P25 repeaters would be to use an Astro-Tac 3000 comparator as a sort of "hub". Assuming people can take turns talking [no doubles], the comparator would rebroadcast whichever input is active out to all the transmitters.

Individual stations could be connected or disconnected from the hub by users or control operators using DTMF or MDC signaling into a SAM card which would be programmed to interact with the Wildcard programming.

This simple concept would use all off-the-shelf Motorola hardware and enable the creation of a regional or wide-area linked P25 amateur repeater system. A DIU could also be connected to the comparator to provide an analog 'gateway' so that the P25 digital network could interface to other systems through a local connection, control station, asterisk, echolink etc.

One big issue in creating such a network is the connectivity. Dedicated phone lines would be too expensive. Internet connectivity is probably the most widely available resource. There are serial to IP converters available from companies such as Perle and Lantronix. Unfortunately the Astro V.24 links are serial and most of the available converters are asynchronous. I have experimented with the Perle and Lantonix converters. These devices operate in pairs to create a serial data link over IP. Because the converter is not "content aware" it must forward each serial character individually. This requires a complete IP packet for each data character. There are about 64 bytes of overhead for every character of actual "payload" transmitted.

There is probably a solution out there - I just have not found it - an affordable device that can efficiently pass synchronous serial data over IP.

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Re: The new Ham Radio P25 master site.

Postby escomm » Sat Nov 06, 2010 9:56 am

OK, I don't think we were talking about how easy or difficult it was, but instead the actual cost of the project. It's unfortunate 123 has not answered any inquiries as to how he put his system together. The dial up modem is an interesting idea but I can see the recurring cost of the long distance charges being pretty significant without some kind of unlimited calling plan

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Re: The new Ham Radio P25 master site.

Postby 123 » Sat Nov 13, 2010 1:18 am

escomm wrote:OK, I don't think we were talking about how easy or difficult it was, but instead the actual cost of the project. It's unfortunate 123 has not answered any inquiries as to how he put his system together.


Oh Come on Jeff, I quote from your website
"father-and-son team has more than 40 years experience in all aspects of two-way radio communications solutions."

Are you telling me that with over 40 years of experience in ALL aspects of two-way radio that you don't know or have a clue how I did it?

And I find it funny that you keep injecting yourself back into the thread poking me to give you a step by step answer to the question makes me wonder where that 40 years of experience went !

My goodness...Get over it !

The fact is, Jeff. You said it yourself, you just do no like trunking on ham radio and will find any excuse to be negative about it. I merely entered this thread because the OP was getting beat up by some of you and I felt it was unfair the comments you were bringing to the table. And like I said before, I am not contributing any further to your negative mood on the subject matter because the conversations are fruitless in nature and has ran off into left field. This moreless has turned into a pissing match and the educating portion of the conversation has dissipated. That is why I stopped the communication, to let others carry on the thread in a meaningful way. But you seem not want to let go...

PS. I may remind you, the OP stated "rich ham" therefore how much the system cost or any parts there-of has NO bearing on the conversation. So move on !

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Re: The new Ham Radio P25 master site.

Postby com501 » Sat Nov 13, 2010 7:19 am

I'm still waiting for an answer too, and I don't care who's d*** is bigger. Are you going to answer the question or not?

How DID you do it?

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Re: The new Ham Radio P25 master site.

Postby akardam » Sat Nov 13, 2010 8:00 am

Congratulations, gentlemen. Since you guys can't keep it on topic, here comes the lock.


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