Railfan Technology > NXDN - Good news and bad news.

The good news and the bad news about NXDN.

I went to the Dayton Ohio Hamvention this past weekend. I’m a ham and it’s the largest gathering of hams in the nation each year. Manufacturers show off their new stuff and there is a pretty good size flea market. Actually, the entire parking lot becomes either bus, commercial vendor, official (fire, police, etc…), accessible (wheelchair) parking or flea market. All attendees have to park off sight.

I talked to Kenwood, Yaesu, Icom, and GRE. Even though this show was aimed at the Amateur Radio community, some of the representatives are very knowledgeable of other products and business lines within the company. The Kenwood rep that I talked to was the most helpful. He had knowledge of DPU, Freds, telemetry, etc… He was heavily involved in doing custom modifications for UP and BNSF. The GRE rep was the least helpful. They didn’t know what I was talking about. Admittedly, “he no speak too good American” and there may have been a problem communicating with him. His associate was about the same but he took my e-mail address and said he would see what he could find out and send it to me in the following week.

Here’s the good news. Yes, the railroads are going to digital BUT it will probably be several years before they convert to the format system wide. The railroad police will probably be the first to convert since they don’t have to interface with the day to day running of the railroad as much as the actual operating crews and dispatchers. They can convert by changing a relatively few units. They also get the benefit of some extra security. He also said that some shortline railroads may convert to digital earlier than class 1 roads do. Again, a shortline can purchase and install 10 or 15 radios and put them in service a lot easier than a class 1 can put 10,000 or more radios in service. In the meantime, the railroads will convert to narrow band. Some radios will now receive this mode without any problems. Just enter the option for NBFM. Radios without this option will still work. You’ll just have to crank the volume up a bit.

Now for the bad news. No one that I talked to has anything on the drawing boards for scanning and using NXDN. Yaesu suggested I talk to AOR but they didn’t have a booth. I’ll have to e-mail them and see if I can get some info from them. If you are not familiar with them, the build really versatile scanners and receivers but they are quite expensive also. I looked at their web site and none of the radios currently in production support NXDN.

I know there are commercial radios available but in this thread I’m just addressing the scanner market for the railfans / foamers. Hope this answers a few questions for everyone.

John

The reality of making sure every wayside base radio, every talking HBD, all mobile maintenance of way vehicles and crew handhelds are all NXDN capable, plus the requirement to cut over all of these relatively simultaneously for a given territory means it will be several years yet before any large RR cuts over to NXDN. Add to that, the need for any run-through leader power to have an NXDN radio and it only adds to the complexity of any cutover effort.

NXDN is? Out of the loop on this one.

Haven't listened to aircraft in years. When I tried recently I notice I'm not picking up much. Has there been any change in the AM aircraft band in recent years?

sphogger

I think the only way the folks at Yaesu will make radios using the NXDN technology is if the FCC insists on this emerging technology for amateur radio just as much as will those companies involved with making scanners only such as those folks "who not speak American that goodly" at GRE and places like Uniden although I read recently where GRE beat out other radio companies vying for the lucrative CHP radio contract with their new all digital radio - a GRE PSU 600.

Now if only Jetstream could get their act together with their new radio entry............................

A place called CBT, Inc. from what I'm told is developing the software to program the JT220M radio much like the RT Systems do for the Yaesu radios. If it's successful, there might be another player on the open market !

I think that Yaesu should just make a scanner with the same sensitivity found in their amateur radios.



KI6WDX

wa4umr Wrote:
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> The good news and the bad news about NXDN.
>

>


The railroad police will probably be the
> first to convert since they don’t have to
> interface with the day to day running of the
> railroad as much as the actual operating crews and
> dispatchers. They can convert by changing a
> relatively few units. They also get the benefit
> of some extra security. He also said that some
> shortline railroads may convert to digital earlier
> than class 1 roads do.

The "real" benefits of going fully digital using the NXDN format is in mixed use voice/data traffic. In congested terminal areas where multiple users try to communicate with multiple yardmasters/dock managers/dispatchers and the like would see some benefits, especially with a limited number of channels (frequencies) available. Some yard crews, especially in port areas, carry various data capturing devices for reading car and container numbers which is relayed to the office for sorting and placement. The "narrow narrowband" 6.25kHz data channel would work well in this service.

There would be little gained by going fully digital along vast stretches of, say, BNSF former Santa Fe Transcon line, much of the original UP/SP and former BN lines in thinly populated areas.

The railroads have already invested heavily in wayside RFID equipment for scanning passing trains and reading transponders. Digital radio wouldn't provide any incentive in this service.

As for shortlines, imagine Modesto and Empire Traction for instance. They interchange daily with UP and BNSF. Imagine having to train all the crew members in using existing analog channels to communicate with BNSF/UP and digital for communicating with their base. Seemingly easy, but with many non-radio literate employees (no offense intended) it would be interesting how many times a frustrated crew member calls their dispatcher/operator on their cell phone!

And ultimately, no matter how many channels are available, there is only 1 dispatcher in a given district listening to 1 conversation at a time. How many times has anyone listening in on railroad communications heard a frustrated dispatcher trying to referee 4 different people trying to get their attention all at once. Unlike police and fire dispatching where there are multiple dispatcher desks covering fairly limited geographic areas, the railroad dispatching operation doesn't lend itself well to this kind of service.



Again, a shortline can
> purchase and install 10 or 15 radios and put them
> in service a lot easier than a class 1 can put
> 10,000 or more radios in service.

Many shortlines barely have resources (read-$$) to buy diesel fuel and keep their motive power running much less convert to digital radio operation where most will see little if any benefit.

And since the FCC and AAR have not issued any mandate to migrate to all digital operation, it seems likely that date remains very, very far in the future.

Thoughts?

Daniel

sphogger Wrote:
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> NXDN is? Out of the loop on this one.
>
>
> sphogger

Hey SPHogger. Don't feel bad about not knowing about NXDN. That's why we're all here, to ask questions and share information. As I recall, you've answered some questions for folks that wanted some info that you are expert in.

Anyway, NXDN is what they are calling the next generation digital radio format. It's just one of the many digital communications formats. NEXEDGE is Kenwood's trade name for the product. There seems to be advances in digital communications every day. It seems that before one technology can be fully implemented something else comes along with something that is even better. In the case of the railroads, they seem to have standardized on NXDN for voice communications since they have to choose something that everyone is going to use. Even if something else comes along, it looks like NXDN is what is going to be used by the railroads.

At this time, all you really need to know is that the railroads are converting to narrow bandwidth so that more people can talk at the same time. It's like taking a 4 lane highway, then making cars and trucks half the width. When the cars and trucks have all been converted to half width, paint new lines on the pavement so you have 8 lanes and more vehicles can travel down that pavement (ignoring the fact that the narrow cars and trucks can't carry as much.) NXDN is just a better way of using the bandwidth that is available. They will convert to narrowband FM first and then convert those same radios to digital.

John



Edited 1 time(s). Last edit at 05/17/10 14:57 by wa4umr.

I've mentioned this in previous threads but not specifically about NXDN.

This is a link to the NXDN forum. Read the PDF documents mentioned at the bottom of the page. They will give a good overview about the fundamentals of the NXDN format developed jointly by Kenwood and Icom.

http://www.nxdn-forum.com/aboutnxdn/index.html

Daniel

We have a client that recently converted their radio system to NXDN. They love it, and it sounds a lot better than P25 and costs less also.

Pat
South Austin, TX

mopac1978 Wrote:
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> Add to that, the need for any run-through leader power to
> have an NXDN radio and it only adds to the
> complexity of any cut-over effort.

It's my understanding that locomotives that are available for 'interchange' must be narrow band (but not necessarily digital) compliant by July 1, 2010.

I don't remember how much warning we had for the DTV changeover. But, somehow I feel there will be some extensions in the effective dates partly due to the economy. I think the railroads will be in pretty good shape. It's the rest of the business world that is strapped for cash if not just plain ignoring the problem.

I'm glad to hear one poster remark that the NXDN audio is better than P-25.

However if you're comparing it to cellphones, please reconsider your opinion. I believe we've all been 'dumbed down' by persistent poor cellphone audio quality. If you don't believe it, check out "Consumer Reports" most recent cellphone survey. No product rated above 'good' in audio quality. The best sounding cellphone I could get is only moderately intelligible when standing still, facing mecca and in a strong signal location.

RailNet802, (stepping off soapbox)