Any Experience with these setups... ?

[PastorGary]

Hypothetical situation:  A company that provides maintenance services to two large shopping malls approximately 25 miles apart has a radio system that uses 4 watt portables and two suitcase repeaters - one in each mall so the portables can all be heard in the separate malls without simplex drop out. The portables and suitcase repeaters also have REVERSE programmed as a "channel 2"  so the two mall location supervisors can speak to each other directly by having the suitcase repeaters in reverse activate a conventional repeater centrally located between the two malls. 

 

Since this may not be allowed on GMRS under Section 95.29b,  I was wondering if anyone has used this setup personally in a non-GMRS venue and if so, was it effective to expand the two local systems into one communications network?

 

 

Any thoughts ? - Thank You.

[JohnE]

we commonly call that a link repeater and have a couple out there. not exactly legal in the part 90 world either.

it would be much easier to explain over the phone than in this venue

the LINK is a bi directional repeater and will need 2 antennas. each side is capable of TX & RX.

in a RICK each radio would be set up as a mobile (TX on hi  side and RX on lo side) when a lo side signal is receiver it goes out on the hi side of the other radio. the hang times have to be set to zero or you lock up all 3 machines. thats pretty much it.

[PastorGary]

Thanks, John... Info is much appreciated.

 

Next Question.....

 

Does anyone here know of any active regional multi-repeater TRUNKING on GMRS?   I did some brief internet research and only found info on a couple Part 93   440 MHz systems and of course, in Part 90, this is common.  Again, under Part 95, it seems as if this is disallowed as well...

 

Thanks...

[cwheeler]

I don't think trunking would be practical on GMRS considering you only have 8 channels available for the whole country, and you have operate in a manner that complies with the channel sharing requirements.  Real trunking requires a full time (or near full time) control channel, which would make it illegal, wouldn't it?

[JohnE]

it could be done through IP controllers, not really hard to do.

[cwheeler]

Linking by IP, yes.  But trunked GMRS?

 

We do trunked radio with ROIP on a network of over 100 repeater sites, but we still have a control channel on every repeater that is keyed up all the time.  Even if a control channel worked on-demand, I don't know it would legally work on GMRS.

[PastorGary]

Thanks everyone... That's the kind of discussuion that I was hoping for, because no one I have chatted with about these two topics in the past knew what the tech details were as it was applied to GMRS or if either tech scenario was proper to do at all.

[JohnE]

Linking by IP, yes.  But trunked GMRS?

 

We do trunked radio with ROIP on a network of over 100 repeater sites, but we still have a control channel on every repeater that is keyed up all the time.  Even if a control channel worked on-demand, I don't know it would legally work on GMRS.

key word being "legally".

and on a side note when I was having lets just say receive problems w/650 I had a trunking controller all ready to go as a last resort. keeping the rif-raf out is at the top of my list.

as a solo trunk I don't see it as not being legal as it is just a fancier coding system. whats the difference between DPL and trunking data really.

I believe this was discussed in another thread a while back or it might have been on the previous version of this board.

[cwheeler]

key word being "legally".

and on a side note when I was having lets just say receive problems w/650 I had a trunking controller all ready to go as a last resort. keeping the rif-raf out is at the top of my list.

as a solo trunk I don't see it as not being legal as it is just a fancier coding system. whats the difference between DPL and trunking data really.

I believe this was discussed in another thread a while back or it might have been on the previous version of this board.

 

OK...  I get it ... it did start with "hypothetical."

 

But as for the legalities of PL and DPL.  In GMRS we are only authorized voice communication.  DPL and PL are specifically allowed to be continually transmitted under your voice communication because it's "sub-audible."  Audible signalling is only allowed for call alert and paging, and is not allowed to go for more than 15 seconds.  I assume that includes DTMF repeater controls.

 

In trunking the control channel is doing just that, controlling.  It controls remotes radios on a repeater output.  Control stations in GMRS cannot transmit on repeater output freqs.

 

And how would a GMRS trunked system share the channels with non-trunked users?

 

I know it was all hypothetical.... but I think just calling it a fancier coding system wouldn't fly.     They have us screwed down pretty tight in GMRS.  Pretty much limited to simple voice communication.  Heck - even if you do one-way paging, it has to be voice paging.  

 

Ya know... we should always remind ourselves that all these cool hypothetical ideas are why the amateur service exists.  I think there have been some trunking experiments there - don't know if anyone is still doing it anywhere.

[JohnE]

correct me if I'm wrong but are you speaking of the Motorola type system. I have never worked on that , now LTR is a different story.

my go to plan at the time was an IDA LTR controller w/ability to switch from conventional repeater to  single channel trunk over the air/IP or wireline.

[captdan]

I have heard of something similar - but maybe not so legal at all.  On a remote property in easten Tenn. some people working out in the woods - in the field as they say - cell phone does not work so they - have legal MURS radios that transmit to their vehicle - truck or one of those  side by side UTV's equipped with a Wouxun Mobile.

 

The Wouxun serves as an " maybe not so legal" crossband repeater and repeats the signa on a GMRS frequency to their base repeater.  The 45 watt Wouxun apparently gets the job done.  In reverse - the Wouxun mobile receives the GMRS signal and repeats it on low power MURS to the hand held units working the the field.

 

Disclaimer for the FCC and Forum lawyers - I abosutley do NOT know who is alledgedly doing this or exactly where they are doing it ...If I remember correctly I read about it on a internet posting by a french model.

 

 

 

 

 

 

 

Edited to corret a typo 03/21/2014 @1224 hrs DST

[cwheeler]

correct me if I'm wrong but are you speaking of the Motorola type system. I have never worked on that , now LTR is a different story.

my go to plan at the time was an IDA LTR controller w/ability to switch from conventional repeater to single channel trunk over the air/IP or wireline.

I have never worked on an LTR system. I understand they don't use a full time control channel. I used to do some work on a Motorola system years back... a Type I system. The company I work for these days is getting away from a vhf conventional system, and we have rolled out a MPT system on 450/460. Like many trunked systems, MPT has a dedicated control channel at every repeater. That dedicated channel can carry voice if the system gets busy, but it slow the service down for users when that happens.

 

So yes indeed you are looking at a different flavor of trunking than me.

[JohnE]

I have heard of something similar - but maybe not so legal at all.  On a remote property in easten Tenn. some people working out in the woods - in the field as they say - cell phone does not work so they - have legal MURS radios that transmit to their vehicle - truck or one of those  side by side UTV's equipped with a Wouxun Mobile.

 

The Wouxun serves as an " maybe not so legal" crossband repeater and repeats the signa on a GMRS frequency to their base repeater.  The 45 watt Wouxun apparently gets the job done.  In reverse - the Wouxun mobile receives the GMRS signal and repeats it on low power MURS to the hand held units working the the field.

 

Disclaimer for the FCC and Forum lawyers - I abosutley do NOT know who is alledgedly doing this or exactly where they are doing it ...If I remember correctly I read about it on a internet posting by a french model.

 

 

 

 

 

 

 

Edited to corret a typo 03/21/2014 @1224 hrs DST

I would call that a x-band link repeater. legal, I think not.

to accomplish that would require 2 antennas and some filtering or the whit noise will beat the hell out of the RX on both sides.

 

I read about it on a internet posting by a french model.

AAAAAAAAAAAAHAHAHAHA ,thats great.

[quarterwave]

I have heard of something similar - but maybe not so legal at all.  On a remote property in easten Tenn. some people working out in the woods - in the field as they say - cell phone does not work so they - have legal MURS radios that transmit to their vehicle - truck or one of those  side by side UTV's equipped with a Wouxun Mobile.

 

The Wouxun serves as an " maybe not so legal" crossband repeater and repeats the signa on a GMRS frequency to their base repeater.  The 45 watt Wouxun apparently gets the job done.  In reverse - the Wouxun mobile receives the GMRS signal and repeats it on low power MURS to the hand held units working the the field.

 

Disclaimer for the FCC and Forum lawyers - I abosutley do NOT know who is alledgedly doing this or exactly where they are doing it ...If I remember correctly I read about it on a internet posting by a french model.

 

 

 

 

 

 

 

Edited to corret a typo 03/21/2014 @1224 hrs DST

Hmmm, now there's an idea...

 

I also "heard" of a mess like that, only maybe worse...guy has about 3-4 GMRS repeaters, has them linked with ITINERANT CHANNEL (part 90) LOW BAND vhf radios....and uses UHF mobile with cross band to VHF for mobile extender, and the VHF is, you guessed it, High Band Intinerant. Oh good golly...can't wait to see the fines levied on that one. 

[JohnE]

 

I also "heard" of a mess like that, only maybe worse...guy has about 3-4 GMRS repeaters, has them linked with ITINERANT CHANNEL (part 90) LOW BAND vhf radios....and uses UHF mobile with cross band to VHF for mobile extender, and the VHF is, you guessed it, High Band Intinerant. Oh good golly...can't wait to see the fines levied on that one.

the truth of the matter at least here is, unless some one really pisses and moans about it nothing will be done.

I've see some really crazy stuff done in all the yrs I'm doin' this, I could tell you stories.

[quarterwave]

Yep, you are right about that. I know of businesses using Itinerant channels for years with no license. They didn't "mean" to, but it happened. One of them I knew of had radios that they inherited after they worked a large contract job with another outfit, and basically kept about 6 handhelds. That was 15 years ago, and they kept on using them on 151.625 without a clue. Seen some squirrely stuff on Part 90 systems too...mostly done by fly-by-night dealers. 

 

The fact is, there are so many "itinerant" random users on Itinerant channels in Part 90, there's no real good way to sort out who is and is not licensed. Can you imagine? The company I do some radio admin stuff for, I got them off 151.625 and, yes I know....154.570 which is MURS now (they were using it on 50 watt mobiles) and put them on 2 newer VHF intinerant narrow band freqs. This is in addition to their wide area VHF repeater system. 

 

So, for as much as some Part 90's are hard to "patrol" they are still usuable, and I think the same really goes for GMRS. If you use a channel and someone who isn't licensed turns up on it, odds are they will go away sooner or later. 

[JohnE]

found this to supplement the trunking question

http://www.signalharbor.com/ttt/00may/index.html

and for the record LTR data fits into the 95.181 (g) rule.

[zap]

Interesting…I've thought about setting up a couple of TK-880's and throwing the existing GMRS repeaters in a trunk group. Some of this reminds me of shotgunning repeaters…

 

If I read what PastorGary originally stated correctly. The basic idea was (what I'm assuming) using two GR300's (or similar), sending a command to have the channel steering on one repeater (both begin on the same splits with the same PL's) to swap RX/TX frequencies (called reverse on Yaesu gear) so that the other repeater can be directly keyed. Did I miss something or am I in the ballpark here?

[PastorGary]

That's correct... not allowed on Part 95 GMRS or in Part 90, but I have seen this in operation on a ham repeater network MANY years ago in Maryland. Repeater # 1 was conventional. Repeater 2, some 45 miles away, was reverse in some way. Repeater 3 another 40 miles further out was conventional again.  A mobile hitting repeater 1 would also trigger # 2 and # 2 would trigger # 3.  Each had a 1 second difference in hold timeout. I don't know what offsets they were using because I'm not a ham and only had a passing interest after the system was mentioned by a friend.

 

It worked, but I was told that sometimes the FM capture effect between #1 and # 3 during band openings would render the system useless.

[zap]

That's correct... not allowed on Part 95 GMRS or in Part 90, but I have seen this in operation on a ham repeater network MANY years ago in Maryland. Repeater # 1 was conventional. Repeater 2, some 45 miles away, was reverse in some way. Repeater 3 another 40 miles further out was conventional again.  A mobile hitting repeater 1 would also trigger # 2 and # 2 would trigger # 3.  Each had a 1 second difference in hold timeout. I don't know what offsets they were using because I'm not a ham and only had a passing interest after the system was mentioned by a friend.

 

It worked, but I was told that sometimes the FM capture effect between #1 and # 3 during band openings would render the system useless.

 

Yea…not what I would've done. I would've shotgunned, especially on amateur. Shotgunning and full-time link repeaters are how I'd link systems together over RF.

[quarterwave]

The shop I worked for put in 2 UHF repeaters in high profile locations on opposite ends of a large county for a water utility some years ago. They wanted coverage everywhere...the mobiles were 100 watt Maratracs. They used no portables, with the exception of a supervisor or two that had a PacRT with a 1 watt VHF portable so he had coverage out of the truck. 

 

The base did not want to switch frequencies. Ever. But they wanted to hear both repeaters, and have mobiles on one repeater hear the other, and vice versa. 

 

They got some waiver on the license to make this happen, there was a letter from the FCC at the time, I had seen it. The frequencies were exclusive for 150 miles and one pair was 450's the other 460's.

 

So to accomplish it, they put a link radio at 4-5 watts with a yagi on each repeater site, pointing at the other. When one was being used, it keyed it's link radio with same audio on the input of the other repeater (not a link frequency). Trucks could be on either repeater and talk, no channel changes needed. They just ran on what ever channel worked in their area. Base stayed on one channel...but we did put the other in it just in case of failure. They did not have talkaround at all at first, but I think later on, the shop added it for one frequency.