....

[MCCSolutions]

So I may get my hands on several of the EU hytera md782g mobile radios soon and im thinking of building a DMR Repeater(GMRS to begin with, yes I have applied for a licence)..

I built a Duplex Analog one before with 2 Motorola CDM1250 Radios in a go box, batteries, duplexer etc. and it worked great

My question is has anyone tried it before? I found the pinouts for the accessory connector on the front and the DB on the back and im thinking the fact that Hyteras CPS Software allows for programming of several of the pins and has sufficient I/O for audio.

View attachment 73864


I have a left over RJ45 repeater interface cable with gain that im thinking I can adapt for use here.

Vox as a trigger may be an option if necessary?

Any thoughts, suggestions, or experience is welcome...

 

[speedway_navigator]

PC49 - Back-to-Back Data Cable | Programming

Back-to-Back data cable for use with mobiles and repeaters.

www.hytera.us

This will do all the magic for you

 

[MCCSolutions]

PC49 - Back-to-Back Data Cable | Programming

Back-to-Back data cable for use with mobiles and repeaters.

www.hytera.us

This will do all the magic for you

Thats awesome! Your the man, I searched online for something like this but came up empty.

So the radio does have the same connector and looking at the pinouts they are identical to the radio. the connector is in short supply though I only found one for $40 so im going to snatch it up.

View attachment 73897
View attachment 73899

One other thing to note is I do plan to eventually purchase the UHF and VHF dedicated DMR repeaters from Hytera so this cable will be reused. I want to start a non-profit community Radio system in my area, we have surprisingly alot of repeaters already.

Using the mobile will be a good start for me cost wise. Im surprised more info and examples of them being used for this isnt on the internet...

Thanks again for all your help!

 

[speedway_navigator]

All the US mobiles have that 26 pin accy connector of the rear.
I have used them in a VHF rx to UHF link tx setup, works fine.

 

[cmjonesinc]

Is it not just a standard 26 pin dsub? That would be an easy cable to make for far less than 40 bucks.

 

[speedway_navigator]

I found a cable mfg online who had them cheaper than $40, it will take a while for me to search old credit card records to find the vendor.
I have a bag of cables I cut down to make 26 pin to RJ45 adapters, I'll look around for them, that project was in 2016.

 

[speedway_navigator]

26-Pin (HD26) Deluxe HD D-Sub Cable - Copper Shielded - Male / Male

26-pin (HD26) Copper Shielded High Density Male/Male D-Sub Cables by Amphenol provide exceptional performance in commercial, industrial or enterprise applications where longevity and repeated disconnects are

cablesondemand.com

 

[jeepsandradios]

So I may get my hands on several of the EU hytera md782g mobile radios soon and im thinking of building a DMR Repeater(GMRS to begin with, yes I have applied for a licence)..

FCC prohibits DMR on GMRS. Read the rules.

 

[MCCSolutions]

FCC prohibits DMR on GMRS. Read the rules.

You misunderstand, Im using them in Analog first under GMRS licence while I process the full licence for 2 frequencies. These radios and repeaters do simplex, wide and narrow analog....

 

[MCCSolutions]

Is it not just a standard 26 pin dsub? That would be an easy cable to make for far less than 40 bucks.

For sure thats why I ordered some D sub ends and breakouts so I can build one for the others. Its just a convenience for me to purchase one already done and you can mitigate the cable as an issue if you have problems getting it all set up.

I also ordered some to use Pin 26(ign sense) on the ones I install in my vehicles.

 

[N4GIX]

You misunderstand, Im using them in Analog first under GMRS licence while I process the full licence for 2 frequencies. These radios and repeaters do simplex, wide and narrow analog....

I'm afraid that you are misunderstanding how DMR works:

1. Only one frequency pair is required, just like an analog repeater.
2. The structure of a DMR repeater is radically different from the "client radios" (mobile and HT), which only use one time slot at a time.
3. DMR repeaters use both time slots simultaneously. This means you cannot simply cobble together two mobiles in a box and expect them to work.

 

[MCCSolutions]

I'm afraid that you are misunderstanding how DMR works:

1. Only one frequency pair is required, just like an analog repeater.
2. The structure of a DMR repeater is radically different from the "client radios" (mobile and HT), which only use one time slot at a time.
3. DMR repeaters use both time slots simultaneously. This means you cannot simply cobble together two mobiles in a box and expect them to work.

Im afraid reading and comprehension is not your strong suite. And the Mobiles are not functioning as a DMR repeater as I already stated, im using them as an analog repeater at first. AND YES THEY WILL WORK AS A DMR REPEATER if I choose to use them as such, if you refer the the pinout they have been designed to do as such and have the same interface as the Hytera DMR Repeaters as they have a Time slot A and B interface.

1. Duhh
2. The mobile and handhelds also use two time slots, just one at a time, hence why you need two of them to make a duplex repeater, the main difference as I understand it is you loos the ability to individually identify radios on the TX side, the user receiving will only get the RID/TG from the transmitting Mobile Radio.
3. Refer to #2

Im signal too, I just happen to install several LMR Sites with Motorola when they rolled out on DOD Pacific so I understand the technology enough lol

Stop hijacking my thread with this garbage...

At least read before you "cobble" up a comment...

 

[N4GIX]

I just happen to install several LMR Sites with Motorola when they rolled out on DOD Pacific so I understand the technology enough lol

Stop hijacking my thread with this garbage...

At least read before you "cobble" up a comment...

I did read carefully. Regarding #1, you are the one who wrote: "while I process the full licence (sic) for 2 frequencies." Why do you think you need more than one frequency pair?

Furthermore, a proper DMR repeater provides the timing signal for the time slots, which mobiles and HTs do not.

Since you insist on being rude, arrogant, obnoxious and nasty, I'll refrain from any further comments. Having owned and operated multiple /\/\ DMR repeaters and having been in the LMR business for nearly fifty years means nothing.

<plonk!>

 

[MCCSolutions]

I did read carefully. Regarding #1, you are the one who wrote: "while I process the full licence (sic) for 2 frequencies." Why do you think you need more than one frequency pair?

Furthermore, a proper DMR repeater provides the timing signal for the time slots, which mobiles and HTs do not.

Since you insist on being rude, arrogant, obnoxious and nasty, I'll refrain from any further comments. Having owned and operated multiple /\/\ DMR repeaters and having been in the LMR business for nearly fifty years means nothing.

<plonk!>

Apparently you didn't read carefully enough, and just because im paying for more than one freq doesn't mean im using both for this purpose, ALTHOUGH YOU CAN, every DMR Radio I have is capable of separate TX and RX frequencies so im not sure how you could not know that being in the LMR business for 50 Years.... Also split frequency is the preferd method in a congested RF area, I personally use a 5mhz step on UHF because of the cheaper more compact duplexers I use.

Dont confuse my bluntness for rudeness, im only stating the truth and i didn't find your comment helpful at all or even related to the thread really...

Its aggravating how matter of fact people are online in these threads when they seemingly know nothing of the subject, its a complete waste of time for both people..

One other thing to note is I do plan to eventually purchase the UHF and VHF dedicated DMR repeaters from Hytera so this cable will be reused. I want to start a non-profit community Radio system in my area, we have surprisingly alot of repeaters already.

Thanks again for all your help!

All the US mobiles have that 26 pin accy connector of the rear.
I have used them in a VHF rx to UHF link tx setup, works fine.

 

[fwradio]

I'll try to help you with understanding why you can't use two mobile radios back to back for an in-band repeater. Yes you can use them for links between UHF-UHF and VHF-VHF channels, but you can't simply put two in-band radios back to back and expect it to work like an analog repeater would. In simplex mode you could key into the receive radio and hear it, it would repeat it on the transmit radio. But if your radio was in repeater mode, it wouldn't even key up. It is expecting some timing instruction from the repeater and a mobile radio does not have the software in it to send the proper signalling and timing to another radio that is trying to key up as a repeater.

The original Motorola XPR repeaters were two mobiles in a box, but even they had special software in them to handle the timing and protocol data required by the subscriber radios when operating in repeater mode.

Hope it helps.

 

[MCCSolutions]

I'll try to help you with understanding why you can't use two mobile radios back to back for an in-band repeater. Yes you can use them for links between UHF-UHF and VHF-VHF channels, but you can't simply put two in-band radios back to back and expect it to work like an analog repeater would. In simplex mode you could key into the receive radio and hear it, it would repeat it on the transmit radio. But if your radio was in repeater mode, it wouldn't even key up. It is expecting some timing instruction from the repeater and a mobile radio does not have the software in it to send the proper signalling and timing to another radio that is trying to key up as a repeater.

The original Motorola XPR repeaters were two mobiles in a box, but even they had special software in them to handle the timing and protocol data required by the subscriber radios when operating in repeater mode.

Hope it helps.

I actually understand it perfectly, no one refers to building a full flegged repeater when they are talking about using two mobiles to make a repeater. Just the same as Analog you forfeit advanced features. In band and out of band are essentially the same when talking about building a mobile repeater because they are both receiving and transmitting on separate frequencies NOT THE SAME fq. For DMR radios its essentially the same as talkaround, you are just triggering PTT and providing voice through interconnect oppose to holding the handset yourself.

Without isolation and with UHF frequencies +5 it does require a duplexer which is no big deal. Im not talking about building a DMR network here. Its essentially two talkgroups on separate freq., time slot management is unnecessary. Its still Digital, its still DMR.

This thread isn't about how DMR works or if DMR repeaters are possible(Because we know they are, (simplex and duplex) its about building a repeater using two Hytera MD782 Mobiles.

ANY HT that is capable of transmitting to another HT is capable of providing function as a repeater, including the Proprietary FHSS Motorola i355 handhelds that people swore couldn't serve as a repeater in Duplex but I had them functioning as in one weekend.

This is just a fun project stepping up eventually to full featured duplex DMR Repeaters... I dont see why thats hard to grasp.

 

[MCCSolutions]

And being its interface does have a Slot A and Slot B there is no reason true in group repeating wouldn't be possible. With some work im sure maybe worth exploring but at some point with mobile DMRs being available @ $1-2k its probably not worth the trouble.

I would expect to find more people like Speedway_Navigator that actually have experience with this that would provide input. Either way I look forward to posting more info from my experiences with this project...

 

[jeepsandradios]

I think your not getting what everyone is saying here or we are not understanding what you plan. In the analog world you are correct that this is a common repeater setup. I am not sure where your 5 mhz comment came from also as all UHF repeaters use a 5mhz split.

Anyway in a UHF conventional repeater analog setup you would program your repeater like this (using GMRS Frequencies for reference)-

RX Mobile - RX Freq - 467.700 / CTCSS 67.0
TX Mobile - TX Freq - 462.700 / CTCSS 67.0

Your portable would be programmed

RX - 462.700 / CTCSS 67.0
TX - 467.700 / CTCSS 67.0

When you switch to the DMR world you will change from CTCSS to Talkgroup and Color Code and Repeater Slot. Using the same frequencies above and changing your radio to DMR from Analog would work in simplex only mode. If you change your TX frequency to 5mhz + you will not be able to key up and most likely get the beep beep. There is no way for the radio to get an "acknowledgement" to know it can transmit. The true repeater sends the acknowledgement. I guess if you can advise how you are programming the portable to talk to the repeater it may help some but I just tried 3 different DMR radios and they all get bonked if i set the TX for 5mhz +.

As reference this did work in the P25 for tacticle repeaters. It was not ideal for the same reasons and also it meant we were double encoding and decoding which caused the audio to sound bad, but it did work for some large incidents until a proper repeater could be deployed on site. I dont have a Hytera to try this on so maybe they allow things the Motorola or TYT do not.

 

[speedway_navigator]

The Hytera RD982Si will not repeat if a radio TXs on the input freq in simplex but will if another radio brings up the rptr and it's still TXing during its hang time. Since 2 separate mobiles are only passing audio and COR I don't know if they would act like the repeater and refuse to TX since there is no handshaking going on.
I think an analogy would be holding the mic from the TX mobile up to the spkr of the RX mobile and hitting PTT.

 

[MCCSolutions]

I think your not getting what everyone is saying here or we are not understanding what you plan. In the analog world you are correct that this is a common repeater setup. I am not sure where your 5 mhz comment came from also as all UHF repeaters use a 5mhz split.

Anyway in a UHF conventional repeater analog setup you would program your repeater like this (using GMRS Frequencies for reference)-

RX Mobile - RX Freq - 467.700 / CTCSS 67.0
TX Mobile - TX Freq - 462.700 / CTCSS 67.0

Your portable would be programmed

RX - 462.700 / CTCSS 67.0
TX - 467.700 / CTCSS 67.0

When you switch to the DMR world you will change from CTCSS to Talkgroup and Color Code and Repeater Slot. Using the same frequencies above and changing your radio to DMR from Analog would work in simplex only mode. If you change your TX frequency to 5mhz + you will not be able to key up and most likely get the beep beep. There is no way for the radio to get an "acknowledgement" to know it can transmit. The true repeater sends the acknowledgement. I guess if you can advise how you are programming the portable to talk to the repeater it may help some but I just tried 3 different DMR radios and they all get bonked if i set the TX for 5mhz +.

As reference this did work in the P25 for tacticle repeaters. It was not ideal for the same reasons and also it meant we were double encoding and decoding which caused the audio to sound bad, but it did work for some large incidents until a proper repeater could be deployed on site. I dont have a Hytera to try this on so maybe they allow things the Motorola or TYT do not.

We shall see, I dont see any reason it wouldn't work, having two frequencies, two talkgroups and what I consider a better interface to interconnect two radios than most mobiles have. I see no technical problems, I think everyone forgets DMR radios can talk to each other independently and every makeshift mobile repeater setup works off the principle of Direct Talk mode, the timing is received by the initiating radio on the first header packet as I understand it.

The 5mhz comment came from someone ranting about me getting more than one frequency... Last time i check you register both frequencies with the fcc.... I would never go through all the licencing and only get one freq anyway i may even get two spits.

As far as "bonked" when you try to key 5+ mhz im assuming your using a Motorola or something? I dont have this issue at all on my DMR Mobiles and I can even monitor two talkgroups, one on UHF and one on VHF and designate the TX freq in programming. If Baofeng has this capability and the others dont that would be pretty sad. I really dont recall having this issue on any mobiles.

The Hytera RD982Si will not repeat if a radio TXs on the input freq in simplex but will if another radio brings up the rptr and it's still TXing during its hang time. Since 2 separate mobiles are only passing audio and COR I don't know if they would act like the repeater and refuse to TX since there is no handshaking going on.
I think an analogy would be holding the mic from the TX mobile up to the spkr of the RX mobile and hitting PTT.

"I think an analogy would be holding the mic from the TX mobile up to the spkr of the RX mobile and hitting PTT."

Thats the exact principle I've built all SHFT/Mobile repeaters on, like with making a repeater out of mobile you only need to isolate the PTT trigger. For these Hytera Mobiles its +3v>, and they have far more outputs and 3 programmable pins something im not used to. Worse case scenario VOX has always been an option when building makeshift repeaters its just undesirable due to the latency.

I would also like to look more into the SFR mode on these, as I understand it their downfall is the Initiating and the End Radio cannot be in range of each other or there is overlap which makes sense, but in my case I would be using a mobile in the metal RF shield of a building I work in, to my Mobile in my vehicle with SFR, to my repeater or my home mobile. Several miles so the isolation is sufficient.

Would this be a project not worth exploring? Or will the negativity keep on?