Better coverage with Kenwood NXDN?

[phadobas]

My company gave me the task of researching, budgeting and implementing a radio system for our campus. After spending weeks diving into this project, I've got a decent budget for 200 radios and 2 repeaters with trunking - from Hytera. All good, and my budget proposal is on the lines for financial approval. Meanwhile, I told my (to-be) vendor that I performed some tests with 2 sample radios and a single test-repeater, and encountered 2-3 dead spots around the campus (actually a lot better result than I expected).
In reply to that, my vendor is telling me that the 6.25KHz bandwidth of the NXDN has better coverage and penetration into the basements of buildings where I have dead zones. At the same time, I also notice that the Kenwood repeater is "only" 40W as opposed to the 50W of Hytera. Also, when I did my tests, I was using a roof antenna with 3dB gain, while the quoted antenna has 7dB gain.
So now, is this correct that penetration should be better with the 6.25KHz bandwidth? Also, isn't the narrower bandwidth requires more voice compression, resulting in worse sound quality (much like voip over bad internet line requires more compression with more data-loss, resulting on worse sound quality?)
And if this penetration is really better, isn't that benefit cancelled out by the weaker repeater?
I don't have a quote from my vendor for a Kenwood system that matches the Hytera system he quoted, so I don't know yet, if going with Kenwood will be cheaper or more expensive compared to Hytera, but would be good to get a 2nd (or more) opinion on the above questions.
Finally, if the answers are all pointing in the Kenwood direction, the main feature I'm after is that I have 2 repeaters, with 4 talk-paths, and those 4 paths are dynamically assigned (as opposed to different groups being assigned a static talk-path), to best utilize available capacity. Will 2 Kenwood repeaters, networked, do that for me?

 

[kd4efm]

My company gave me the task of researching, budgeting and implementing a radio system for our campus. After spending weeks diving into this project, I've got a decent budget for 200 radios and 2 repeaters with trunking - from Hytera. All good, and my budget proposal is on the lines for financial approval. Meanwhile, I told my (to-be) vendor that I performed some tests with 2 sample radios and a single test-repeater, and encountered 2-3 dead spots around the campus (actually a lot better result than I expected).
In reply to that, my vendor is telling me that the 6.25KHz bandwidth of the NXDN has better coverage and penetration into the basements of buildings where I have dead zones. At the same time, I also notice that the Kenwood repeater is "only" 40W as opposed to the 50W of Hytera. Also, when I did my tests, I was using a roof antenna with 3dB gain, while the quoted antenna has 7dB gain.
So now, is this correct that penetration should be better with the 6.25KHz bandwidth? Also, isn't the narrower bandwidth requires more voice compression, resulting in worse sound quality (much like voip over bad internet line requires more compression with more data-loss, resulting on worse sound quality?)
And if this penetration is really better, isn't that benefit cancelled out by the weaker repeater?
I don't have a quote from my vendor for a Kenwood system that matches the Hytera system he quoted, so I don't know yet, if going with Kenwood will be cheaper or more expensive compared to Hytera, but would be good to get a 2nd (or more) opinion on the above questions.
Finally, if the answers are all pointing in the Kenwood direction, the main feature I'm after is that I have 2 repeaters, with 4 talk-paths, and those 4 paths are dynamically assigned (as opposed to different groups being assigned a static talk-path), to best utilize available capacity. Will 2 Kenwood repeaters, networked, do that for me?

Short answer yes.


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[phadobas]

Thank you for the short answer.
In my post, there were a few questions, so I'm not sure which one your "yes" replies to:
- is 6.25KHz providing better penetration?
- if yes, is this benefit nullified by the "weaker" repeater?
- is 6.25KHz giving worse sound quality?
- Can 2 Kenwood repeater networked together, provide dynamic talk-path assignment?

 

[mmckenna]

#1 thing I see with those new to two way radios, more power ≠ more range. You won't be able to tell the difference between a 40 watt repeater and a 50 watt repeater.

Antenna gain is a double edged sword. More gain does increase ERP, but it comes by compressing the radiation pattern down. Higher gain can decrease coverage close in around the repeater site. If you were getting decent coverage with a 3dB gain antenna, jumping to 7dB might give you more coverage farther away from the campus, but come at the expense of coverage down in basements.

6.25KHz NXDN will likely give you some additional coverage gains.

Audio quality is fine. Analog audio compressed into a 6.25KHz digital signal is good enough for 2 way radio use. 6.25KHz will give you about 4800kb/s, which is fine for what you are doing.

Don't let people talk you into DMR for the "2 time slot per channel" thing. Design your system correctly based on your needs, not what people on the internet tell you to do. 2 time slots per channel works great, but if you lose one repeater, you've lost 2 traffic channels. On a small trunking system, that can be an issue.
Also, shop the vendor, not the brand or technology. You will need support, so making sure you have a good relationship with the vendor is very important. Don't decide on the technology first then look for a vendor that will support it. Look for the vendor that will give you what you need, then decide.

DMR is a good system, not bashing it, but look closely at NXDN.

I replaced an old 5 channel SmartNet trunked system at my campus about 7 years ago. I trialed DMR and NXDN. NXDN sounded better. I had some additional challenges with DMR that made it a no-go for us. Been happy with our NXDN trunked system, 5 channels, about 450 radios. No issues with the system, and Kenwood provides great support.

 

[mmckenna]

Thank you for the short answer.
In my post, there were a few questions, so I'm not sure which one your "yes" replies to:
- is 6.25KHz providing better penetration?
- if yes, is this benefit nullified by the "weaker" repeater?
- is 6.25KHz giving worse sound quality?
- Can 2 Kenwood repeater networked together, provide dynamic talk-path assignment?

I answered the first 3 above.

As for 2 repeaters networked together, that's what Kenwood refers to as NexEdge trunking, and is what I'm running with 5 repeaters.

 

[phadobas]

Nice! Thank you for the input.

 

[kd4efm]

I answered the first 3 above.

As for 2 repeaters networked together, that's what Kenwood refers to as NexEdge trunking, and is what I'm running with 5 repeaters.

Dont forget, you can have nxdn site roaming also with the nxr-x10 series, and still offer campus wide without the trunking cost factor. 2 repeater sites, with whole campus
Coverage.
Or trunk system if it involves more than 100 unit plus and various talk groups.

Didnt want to over load him on that simple reply, but yes, Mmckenna is correct.

I work on a Florida wide nxdn system and we have colleges and schools that use it. They also have on campus nxdn repeaters for local use.

Yes, your dealer should have thier ducks lined up and be there from the start till .....

Welcome aboard!


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[mmckenna]

Nice! Thank you for the input.

On the antenna gain subject, I had some coverage issues with my system when I first put it up. Had 9dB gain antennas. I swapped them out with 6dB gain antennas with 3º of electrical downtilt and that solved most of the coverage issues down in the basements. I still have good coverage 60+ miles south of my location, where I don't really need it...

 

[phadobas]

On my tests with the 3dB antenna, I had perfect coverage of the basement of the building where the antenna was on the 10th floor roof. However, 4 miles away, indoors, I had some issues, and also, half a mile away, in the basement of another commercial building I had issues. I guess, when we get to that point, I'll work with the vendor to resolve these the best possible way.

 

[kd4efm]

On my tests with the 3dB antenna, I had perfect coverage of the basement of the building where the antenna was on the 10th floor roof. However, 4 miles away, indoors, I had some issues, and also, half a mile away, in the basement of another commercial building I had issues. I guess, when we get to that point, I'll work with the vendor to resolve these the best possible way.

Your vendor will help you out with a good degree of confidence. Probably hasn't lead you wrong yet. Listen to what the vendor has to offer.

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[RRR]

Should be noted, VHF/UHF/800.... The higher the frequency, the better the penetration, the lower the frequency, the better the long range. You should at least be on UHF (400+ MHZ range)

 

[kd4efm]

Should be noted, VHF/UHF/800.... The higher the frequency, the better the penetration, the lower the frequency, the better the long range. You should at least be on UHF (400+ MHZ range)

They are already 450-460

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[RRR]

They are already 450-460

Good deal... I didn't see where he stated that

 

[danielxgame]

just and input, dont know how big your campus and how many freq. you need, if you are are using UHF i think your good for the building 1 repeater is good already for the whole campus if you are using trunk more money input. used good duplexer, good ant. and your good

 

[hitechRadio]

Finally, if the answers are all pointing in the Kenwood direction, the main feature I'm after is that I have 2 repeaters, with 4 talk-paths, and those 4 paths are dynamically assigned (as opposed to different groups being assigned a static talk-path), to best utilize available capacity. Will 2 Kenwood repeaters, networked, do that for me?

The answer to this is NO, not sure why it was not answered for you. NXDN is FDMA vs. DMR is TDMA

If I was in your shoes I would go with the DMR, You can also have the roaming ability.
And Hytera offers great radio's for a good price.

As far as coverage into buildings 6.25 vs. 12.5 is a crap shoot, in real world no notable difference. In fact when narrow banding occurred from 25khz to 12.5khz years ago a lot of users reported slight range loss. Many posts on here from years ago about this issue and other forums. So going from 12.5 to 6.25 one could surmise that range would be slightly lost also (everything being equal). But that is just my opinion.

Your unlikely to be able to tell any difference between a 40watt and 50watt repeater. The antenna/s engineering/placement at that point becomes a deciding factor on the coverage you get on campus, not the power.

As far as audio quality DMR vs. NXDN also a crap shoot, depends on the users ear, I think DMR sounds better. On DMR I think a Motorola sounds better than a Hytera (see my point). But this is just my opinion.

There are many more DMR vendors than NXDN so you can leverage that to your advantage when shopping for radio's in the future if you so choose. Kenwood makes DMR radio's too.

DMR radio's will typically offer longer battery run time during a shift vs. NXDN. This due to FDMA vs. TDMA technologies.

There are many vendors that make dispatching type software and various management tools software for DMR. Pick your poison type deal, there are many out there due to DMR in and of itself an ETSI Open Standard vs. NXDN is an Open Proprietary standard.

In the end though I don't think either would be a bad choice overall. I just think you get more bang for buck with DMR.

Just we a clear I am not a radio vendor or a shop.. whatever decision you make "I can't see it from my house" as the saying goes applies, so in the end I don't care what you choose. I can only help you make an informed decision.

Good luck!!
Here is some good information on one vs. the other.
https://blog.taitradio.com/2015/06/04/advantages-of-dmr-versus-dpmr-nxdn-nexedge/

 

[TampaTyron]

We seem to have quite a few of these threads lately. I am a big proponent of DMR. However, I strongly recommend you buy the service and support of the local dealer. If the local NXDN dealer is great and the DMR dealer is bad, then the pendulum would swing one way. If the roles were reversed, then it swings the other way. The reality is that they are so similar (my opinion), that it comes down to system design, installation, and support after the sale. TT

 

[kd4efm]

The dealer for this gent is very reputable and is working very close with them.

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[hitechRadio]

The dealer for this gent is very reputable and is working very close with them.

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That's your opinion! Whats your releation too the dealer? How do you have inside knowledge that are privy too, that we here are are not? Who directed the OP to this site? Did he come here on his own?
Hows that saying go, walks like a duck, quacks like a duck......
Seems fishy

Anyway....back to the OP phadobas

If your lucky enough to live in area that you have a couple radio shops. It does not hurt to shop around.

I agree with tampatyron your dealer can be the difference. And i will echo what tampatyron also eluded too. The system engineering, programming etc.. of the system design, especially antenna system is by far more important than DMR vs. NXDN. If you don't have good engineering it won't matter in the end. Hopefully Kd4efm is right about the dealer.. he knows so well!

 

[kd4efm]

I know the owner of the shop who is working with him. I also know about thier system, worked on it. some time ago, and yes, its hytera.

All I can talk about.

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[hitechRadio]

I know the owner of the shop who is working with him. I also know about thier system, worked on it. some time ago, and yes, its hytera.

All I can talk about.

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Interesting!

So it seems you probably do some wheeling and dealing with sunstate. You get discounts for commercial radios for ham radio use? I am assuming the dealer for the OP is sunstate?

Link
Evans F. Mitchell; KD4EFM / WQOD582

Link
Sunstate Communications, Inc. | Authorized Kenwood LMR Systems Dealer (863)425-3290

I do like hame frendly dealers..dont get me wrong!