Railfan Technology > NXDN Scanner is coming

NO date or price yet.

http://aorusa.com/whatsnew/

Here is a photo;

http://www.universal-radio.com/catalog/widerxvr/6369.html

That's good news for people wanting to hear NXDN. I wonder what the price will be on it AOR's aren't cheap.



Edited 1 time(s). Last edit at 01/21/15 08:11 by rich6000.

I'm hoping for a handheld eventually

With all of the various digital modes and the required licensing on the various digital decoders, I am estimating somewhere in the $1500+ price range.

Having worked most of my working career for both a state agency and a consultant, the major cost of the radio is the licensing fee.

I would be greatly interested in both a base and handheld radio for NXDN but I am not going to shell out anything above $700, otherwise I will purchase and NXDN mobile and handheld.

Pat
WA5VRO
South Austin, TX

AOR makes probably the best radios in their field, and the price goes along with that. I don't know this from experience. I've never had one because of the price. I believe AOR has had a package that would decode NXDN for awhile but it was two units... the digital receiver and the decoder. I did a little searching around on the subject of prices. They haven't been released yet. AOR handheld scanners run in the range of $900 and up. Mobile radios or base units are slightly more expensive. And that is for the low priced units. Searching for prices (and no one know at this time), the speculation is that the radio mentioned will have an MSRP around $3000 with the units discounted to about $2500 in the consumer market. Don't be clobbered with sticker shock when this thing does hit the market. AOR has some radios with an MSRP of $15,000 that retail for just under $12,500.

The attachment below shows some of the specifications. It does list NXDN. Some of the others listed are vendor specific. It covers 100 KHz to 1.3GHz with 2000 memories, 40 banks of 50 memories, well beyond the needs of rail fans, but really nice to have if you have additional needs.

On the other hand, and this is just sort of a "pie in the sky dream," Yaesu is selling digital radios to hams in their "System Fusion" series that they introduce about a year ago. The MSRP is in the $600 range but retail closer to $400 for a handheld. These radios use the same C4FM modulation that is used for NXDN. I doubt that anyone could "hack" one of these radios unless you could reprogram the processor in it. However, they are using the same modulation and they could possible introduce a scanner capable of NXDN. Any manufacturer can use the C4FM protocol. The down side is that System Fusion is not NXDN and Yaesu doesn't have a lot of incentive to introduce a new radio that is not compatible with the current crop. They need a market available to purchase several thousand radios at $400 a copy.

I make an annual trip to a convention in Dayton every May and I talk to the manufacturer reps. One I talk to with Icom has intimate knowledge of NXDN and railroads. He has worked with BNSF directly to resolve problems with their implementation of NXDN. I'll be posting comments in May with whatever I find out.

Until then, lets just keep our fingers cross that someone will introduce a radio for maybe $200 that knows how to speak NXDN.

John

---

I looked on line and Yaesu has a FT-1DR-HD. Ham radio outlet has them on sale for $267.00.
It said in the write up that it was designed with the scanner people in mind. It has more bells
and whistles than any scanner I have used......Swedel...Albany,Or.

I'm aware of the FT1DR. Yaesu is coming out with the FT2DR, probably in the next month. Looks like a great radio. It's expected to be around $300 since the MSRP is about $50 above that of the FT1DR. The FT1DR is a great little radio and the digital voice mode sounds great. It has a short battery life, not something you want to deal with if you're out all day rail fanning. Hopefully the FT2DR will have a better battery life but I don't expect it to be too much better. I don't have one but I know people that do and they say 5 or 6 hours is about all you get from a charge. Either one of these would be overkill for a rail fan. About 2/3 of what you would be buying would not be usable without a ham license. Yaesu also make the FTM-400DR for mobile use. MSRP is $850 but retail is under $640. It has even more features that you can't use, such as sending/receiving pictures from the FT1DT or another FTM-400DR. Early reports are that it has an overheating problem but that's only on transmit. The Yaesu VX-170 that many foamer use was also overkill but it was available for $100 to $130, a price comparable to a decent scanner.

Even though the FT1DR/FT2DT radios use C4FM, the same as NXDN, they don't use the protocol used for NXDN. The C4FM describes how the signal is modulated to convey a signal. The information used to modulate it is the data or voice information. The protocol used to encode and/or address the signal is different. For example, I speak English. If I use a radio to talk to you we both agree to use the English language with the rules for using nouns, verbs, pronunciation of word, syntax, etc... If we change to French we have a completely different set of rules. It doesn't matter which language we use, the radio part of it uses the same type of modulation, analog FM for example. The C4FM modulation is for digital protocols. Using the C4FM the radio uses different protocols for digital voice, digital data, or pictures.

Right now there are two digital modes being used for digital voice on amateur radio. In my area we have repeaters using both protocols. They are not compatible with each other. I'm sort of waiting to see which one becomes the most popular before I flop down my money but it's starting to look like the Yaesu System Fusion might be the winner. They were a bit late entering the field but their advertisement and promotions are more aggressive. The club I belong to is a Beta test site for Yaesu and as such received a free repeater to use for 2 years. After that we own it. We have to report problems and successes to them from time to time.

John

So how about the reception range and the CLIFF EFFECT --Brickwall effect???
In order to really hear the action I say you
need to hear easily a 100--yes 100 mile range easily.
By definition this digital radio nonsense fails that standard badly.
Only analog radio can give you that great reception range.
--- Daniel



Edited 1 time(s). Last edit at 01/21/15 23:35 by daniel3197.

There are other problems with using scanners nowadays
to monitor railroad movements.

One is that little info is now transmitted by voice. Some
Track and Time is now often given by mouse click over
the computer. Another problem for railfans trying
to use scanners to hear movement instructions for
trains is that RRs no longer use place names for block
occupancy. They now use alphanumeric CTC Control
Point IDs, i. e. -- CP XY 12 -- which have no intrinsic
meaning. And without an up-to-date RR Employee
Timetable, you will have no way of knowing what those
CTC IDs mean.

Sooooo --- Is it really worth it to shell out big bucks
for a scanner if you won't hear much useful info on it,
and if you won't understand most of what you hear?

Margaret_SP_fan Wrote:
-------------------------------------------------------
> There are other problems with using scanners
> nowadays
> to monitor railroad movements.
>
> One is that little info is now transmitted by
> voice. Some
> Track and Time is now often given by mouse click
> over
> the computer. Another problem for railfans
> trying
> to use scanners to hear movement instructions for
> trains is that RRs no longer use place names for
> block
> occupancy. They now use alphanumeric CTC Control
> Point IDs, i. e. -- CP XY 12 -- which have no
> intrinsic
> meaning. And without an up-to-date RR Employee
> Timetable, you will have no way of knowing what
> those
> CTC IDs mean.
>
> Sooooo --- Is it really worth it to shell out big
> bucks
> for a scanner if you won't hear much useful info
> on it,
> and if you won't understand most of what you
> hear?

I beg to differ from you. Oh sure some lines might be like that like the BNSF Peavine line going into Phoenix doesn't have that much talking, however the BNSF San Bernardino Sub and the Metrolink Orange sub both talk a lot if you have a scanner or listen to railroadradio.net I can make out most of what they are talking about on both lines. I am interested in this new radio. I do hope they make a handheld one though with a antenna for both magnetic to put on your car and the regular antenna that comes with the radio that receives the radio reception.

jkurt Wrote:

> I beg to differ from you. Oh sure some lines
> might be like that like the BNSF Peavine line
> going into Phoenix doesn't have that much talking,
> however the BNSF San Bernardino Sub and the
> Metrolink Orange sub both talk a lot if you have a
> scanner or listen to railroadradio.net I can make
> out most of what they are talking about on both
> lines. I am interested in this new radio. I do
> hope they make a handheld one though with a
> antenna for both magnetic to put on your car and
> the regular antenna that comes with the radio that
> receives the radio reception.

I have to agree. CSX in the Georgia/Florida area uses radios a lot. Crews are required to call in signals, and dispatchers regularly talk to trains to let them know what is going on ahead of them. Radios are still very much in use down here.

jkurt and RFandPFan --
Point well taken, gentlemen. I do not know
what is going on all over the country, but --
what about the "cliff effect" when RRs use
digital radios? Your reception will be much,
much poorer than when RRs used analog
exclusively.

Let me see if I can address a few of the previous comments. First, the easy one. Different railroad have different operating procedures. In the east, CSX and NS call signals on the radios. As far as I know, BNSF and UP do not. Not sure what KCS, CN, CP, and others do. All of that is subject to change.

The CLIFF EFFECT or BRICK WALL. It’s real but what is it and what difference does it make. First, digital voice generally has better quality than analog voice. There is no argument about that. Digital offers a truer reproduction of what goes into the radio at the origin. The cliff effect comes into play when the signal gets weak or the receiver is in an electrically noise environment and there are errors in the transmission. Error detection is easy to do in digital transmissions provided the protocol is designed to detect it. Most any modern digital communications today has some way to handle errors. With digital transmission, when the error rate exceeds a threshold, the signal just drops out completely. It’s going to sound very good until it reaches that point. That’s the point where the error rate falls off the cliff, so to speak, or where it hits a brick wall and can’t go any further. In the same signal situations with an analog system, the signal becomes noisy. It’s not a “no noise and then all of a sudden there is too much distortion to receive the signal.” It’s more of a gradual degrading as the signal becomes weaker. The analog radio could probably get through in worse condition than digital. The question becomes “How much can that signal degrade before it becomes unusable. It’s like comparing black and white (digital) with shades of gray (analog.)

1oo miles? That depends on what part of the country you live in. I live in Louisville, Ky. In Eastern Kentucky we have some pretty good hills. That works for you in some ways and against you in other ways. Antennas in high places have better range than antennas in a valley. The hill work against you if you happen to be behind one of those hills. As you go west through Kentucky, the terrain starts to become rather level, just some gentle rolling hills. There are fewer tall hills and antennas are not all that high unless you have a bunch of tower to hold it up there. The height of the two antenna, the transmit antenna and the receive antenna, the terrain, the geography, transmit power, receiver sensitivity, all play a part in determining communications range. Walking around a downtown area of a city, the signals are usable but often are not completely quiet. Get on an elevator and about the time you get to the 3rd of 4th floor, the noise starts to decrease. An antenna mounted at 1000 feet above average terrain has a mathematical range of 38.7 miles to the horizon. A person with a handheld radio, about 5.5 feet above ground has a 2.9 mile range to the horizon. Together, they would have 38.7 + 2.9 =41.6 miles. This is assuming a perfectly flat terrain (allowing for the curvature of the earth), no hills in between, no forest along the route, etc…, this would be the maximum range. In the practical world, there are other factors that can come into play and at 161 MHz, assuming the power levels and receive sensitivity were adequate, you could probably get 45 or maybe 50 miles range. Those are the mathematical facts. In practice as a ham, I have used a repeater that was about 1200 feet above average terrain and I was able to talk through it from about 50 miles away in my car. Not 60, but 50. Mathematically you would have to be 6655 feet above average terrain to obtain a 100 mile range to the horizon. Even if you put an antenna on the top of a 10,000 foot hilltop, it’s not 10,000 feet above average terrain, it’s only 10,000 feet above sea level. If average terrain was about 6,000 feet your antenna would only be 4000 feet above average terrain. 100 miles between two station is possible if they are both in range of a repeater system but in the railroad industry, usually the communications is between the dispatcher and the train or between the front and the rear of the train.
There is a decent explanation at http://www.hamuniverse.com/lineofsightcalculator.html

Everything above is theory in a perfect world. In an imperfect world with zillions of variables and other factors to consider. Your mileage may vary. In some situations, personal traits (voice and ear characteristics,) experience, ambient noise, microphone and speaker quality, and judgments can determine if a communications system is usable or not. I hope this answers some of the question the readers might have. No matter what, we have to deal with the location of transmitters, the mode used (digital vs voice,) and their operating procedures.

John

John ---
Thank you very very much for your kind and very
detailed and interesting explanation. I really
appreciate that! I like learning new things, and
you taught me a lot by your very kind reply.
Thank you.

JOhn I must thank you for you very detailed run down of this
new digial or NXDN railroad radio technology.
I did not know that modern NXDN radios have error correction built in.
The reception distance factor is an important one for folks like me.
I live a fair distance from the major railroad yard terminal in my area.
I do hope these new NXDN radios work well for the railroad crews in the field.
Thank you again for your educational reply.
Now I have someplace here on TO to learn about this new era in radios.

---- Daniel

I can only speak from my experience, but I work for an agency that went from analog to digital a few years ago. When it went digital we lost reception in a lot of areas that previously worked fine. I agree that the sound quality is better with digital, but I would rather have farther coverage than none at all. Most of us were very disappointed with the switch, but encryption mandates required the move to digital.

Thanks for explaining the effects of NXDN and the new radios. I have to point out if that's what happens to reception with Digital, then that's what we have to deal with. As they like to say "it is what it is". The counter-point would be using a network of radios in a manner similar to RR Scanner feed, listening to a series of monitoring radios via www, perhaps on a smartphone in the field.

Agree there's still plenty to hear, there are still active lineside detectors. The Denver area still has plenty of track warrants. Perhaps the more automated areas more be accessed with an ATCS set up. In Dunsmuir the sun rises by the Detector at 330.3, even if it is 8 degrees too warm.



Edited 1 time(s). Last edit at 01/23/15 14:07 by TCnR.

On signal calling the KCS calls everything and UP has started calling all signals as well other than clear/green/highball. I host the railradio feed for my area Texarkana AR/TX. http://www.railroadradio.net/content/view/226/268/

There is still lots of radio traffic be it Train crew, Yard Job, Yard Master,Dispatcher, M of W or local out working. Plus throw in the inter-locker for three RR makes it just about none stop radio traffic.



Edited 1 time(s). Last edit at 01/23/15 11:18 by CPR-489.

RFandPFan said, “I can only speak from my experience, but I work for an agency that went from analog to digital a few years ago. When it went digital we lost reception in a lot of areas that previously worked fine. I agree that the sound quality is better with digital, but I would rather have farther coverage than none at all. Most of us were very disappointed with the switch, but encryption mandates required the move to digital.”

I concur with what he says and let me see if I can explain it a bit. With the older analog radios you there were drop outs in the same area but it wasn’t as noticeable. If you walk around with you scanner or drive along while listening to fairly strong signal you may notice little drop outs, or burst of noise during a transmission. You may miss a syllable here and there, kind of like if I if you were reading this and saw “lo..motive” you would probably have no problem figuring out that I meant “locomotive.” In the digital world, the drop out would be more like “lo…….” A lot of missing information there. So much is missing that you have no idea what I was trying to say. Was I trying to say “locus” or “lost” or maybe “location?” Digital radios dropout when the BER, (bit error rate) exceeds a threshold and they basically have to recover synchronization and start producing voice output again. Different protocols do this in different ways. Some can recover quicker than others. In RFandPFan’s situation, the loss of signal was more noticeable. Radio signals don’t care how they are modulated. They go the same places whether it’s AM, NBFM, WBFM, SSB, pulsewidth modulated, or just a steady unmodulated carrier.

Error Correction. I mentioned previously that the digital radios made use of error correction. A slight expansion of that is warranted. In data communications circuits it’s common for some form of error detection and correction to be incorporated. Typically some form of a checksum is included in the data packet and the receiving end uses that and determines if the packet is correctly received. If not, it will request a retransmission from the other end. It works best in a full duplex operation, a system were signals can go both ways at the same time. Two way radios use half duplex, there is two way communications but the signal goes only one direction at a time. Because of the half duplex configuration, they often use FEC, or Forward Error Correction. There are several schemes to accomplish this, such as sending a duplicate or triplicate signal and mathematically (or logically) trying to figure out what the original signal was. It’s not a perfect system but it does increase reliability. The ultimate error correction protocol used on two way radios is the guy that didn’t get the information he needed saying, “What was that” or “Say that again.”

There is a good overview article that answers some general questions about digital radio. It’s hosted by the Amateur Radio Association of Central California. It addresses several myths concerning digital communications in a mobile world. It’s published by Yaesu, and since they have chosen C4FM, it’s slightly tilted towards C4FM. If you look at the table I posted several days ago you’ll see that AOR (remember AOR, the original subject of this thread) also shows that many (most) digital protocols use C4FM. Go to: http://www.aracc.org/digitalcommunicationsguide.pdf The myths are addressed starting on page 10. It’s aimed at the ham radio market but addresses several concerns for LMR (Land Mobile Radio) users. Besides, radio doesn’t care what it being used for… railroad, ham, police, utility, etc…


A few additional comment about distance. Hams often talk to other hams at distances of several hundred miles while using the 144-148 MHz band (2 meter band,) a band that is very similar to railroad communications around 161 MHz. They don’t do it with FM very often. I have used a 2 watt radio and talked to a station about 300 miles away but that is rare. Other modulation methods are better suited for long distance, weak signal communications. SSB, Single Sideband works great in weak signal situation. CW, or “Morse Code” is the ultimate for getting through when all else fails. That being said, SSB is a form of AM radio and is subject to static from weather (lightning), ignition noise in cars, electric motors, or hundreds of other things we encounter every day. Generally speaking, the voice quality is not as true as FM. Also, a train going through Seattle doesn’t want to hear the dispatcher in Portland. Squelch systems don’t work very well with this mode either. Morse code works great, IF the operators on both ends have the skill set to use it. I have used Morse code to talk to people all over the world but I don’t use it enough to be very efficient. My code speed has been around 18 or 20 words per minute. Old railroad telegraphers could often copy 40, 50 or 60 words per minute. BTW, Morse was the original digital form of electronic communications.

A question I received in a PM asking about range and the lack of repeaters. In most cases the railroads don’t use repeaters. There are some situations but most communications is between “dispatcher and train” or “train crew member and another member of that same crew or a nearby crew (2 or 3 miles at the most.”) The dispatcher’s radio is remote to the dispatcher and is usually on a hill, tall building, or tower. The dispatcher’s radio has maybe 20 or 30 or even 50 mile range to the horizon. He can talk to a train 20 miles to the east and another that is 40 miles to the west but there is very little need for those two trains to talk the 60 mile distance between them. If they do need to talk to each other the dispatcher can handle the relay. There will undoubtedly be some gaps somewhere but I suspect there are some today, maybe only 50 feet along the back side of a building under a steel roof. It may not have been discovered because no one ever tried talking to the dispatcher from that location, but I’m sure there are a few dead spots. Digital radio will have the same problem and due to the error detection mentioned above, maybe more noticeable. Some of these problems will have to be addressed on a case by case situation. My local police department covers the entire county and for years they have had spotty communications in one small area behind a lone hill. You'll probably notice the same thing with your cell service, especially in rural areas. BTW, cellphones use a digital technology. You may have experienced the "cliff edge" effect. You're talking to someone and all of a sudden, they're gone. With older cellphones it got noisy before you lost your call.

Digital communications is just one step in the evolving world of radio. Hertz and Marconi used spark transmitters in the 1880s and 1890s. Voice communications was only a dream at that time. In 1899, Reginald Fesseden developed a crude system for voice over radio. It was so crude that the microphone was water cooled. The first clear voice was demonstrated around 1917 or 1919. Receivers were crystal radios. Radios that we might recognize today were developed in the first 15 years of the last century. Practical radios became available in the early 1920s. The concepts of TV came about in the 1920s. In the 1930s, Major Armstrong of the U.S. Army Signal Corps invented FM radio. Most developments after that and into the 1960’s was in the electronics area, better tubes and circuit design. WWII brought about many improvements and the development of RADAR. The transistor was developed in Bell Labs in 1948. The first integrated circuit only a few years later. These developments have brought us to where we are today. Things are still developing, often so quickly that before a new technology can be deployed, it’s already obsolete. NXDN is just one step in this march into the future. By the time affordable scanners are produced that copy NXDN, there’s going to be something newer and better. The railroads will probably stick with NXDN for 15 or 20 years but who knows what will be next.

Please excuse my rambling in the last paragraph or two but I just thought maybe it might put a better perspective on the subject.

John