800 MHZ vs. 1900 MHZ

[BigBroni]

Can anyone tell me what the difference is between the two? Advantages/disadvantages of each? Why are companies going to 1900 MHZ more?

[KevinJames]

BB:

Here is some links that may help you.

Kev

[MTS2000]

Originally posted by: BigBroni
Can anyone tell me what the difference is between the two? Advantages/disadvantages of each? Why are companies going to 1900 MHZ more?

800 MHz is a lower frequency band, US Wireless Companies use frequencies in the 850-864MHz range (iDEN), and 870-894 (Digital and analog cellular, both TDMA and CDMA). This was the original band for cellular radio systems, dating back to it's first use in 1979 for the USA's first cellular system, and is shared by other radio services, such as SMR, public safety and private radio systems. 800 has some advantages: better in-building penetration as lower frequency radio waves generally travel longer distances (higher you go, radio waves begin to become very directional, and are attenuated by enviornmental factors), and are not as attenuated by trees, foliage, etc as 1900MHz. Note that with 800MHz cellular portion, there are two blocks, the "A" block of channels, originally meant for use by companies that were not offering local (wireline) phone service in a given market and a "B" block of channels for use by system owners who provide or are associated with wireline phone service in a given area. iDEN (Nextel and Southern LINC) are really licensed as Digital SMR's, and have channels interleaved with other services in the 851-864MHz band.

1900MHz band, sometimes referred to as "PCS" for Personal Communications System, was a radio service created by the FCC in the early 1990's. The main reason it was opened up for use was to allow for more competition and spectrum for use by the wireless industry. PCS 1900 is EXCLUSIVELY commercial wireless- there are no analog wireless, SMR's or public safety, and much more spectrum available for use for wireless companies. 1900 MHz however, is much more of a challenge as far as coverage and in-building penetration than 800. More transmission sites are needed than an 800 system, even with similar technologies (i.e., TDMA, CDMA, etc). This is because the higher frequency radio waves don't travel as far as lower ones, are much more directional, and are attenuated more by trees, foliage, obstructions, etc than 800MHz.


Why are companies going to 1900 more? Simply it's all that is out there. 800MHz spectrum has been spoken for, most systems have been in operation for years, and incumbent licensees are unlikely to give up their spectrum. The 800MHz networks are more mature, so owners are less likely to want to leave, as a new network at 1900 would be a large outlay of capital, and more sites would be needed to cover the same geographic areas as their 800 systems do. In short, because there is more available "radio" real estate at 1900, it isn't neccesarily in the best part of "town" (radio spectrum) than 800MHz is, but in due time the PCS 1900 systems will have been built out and have coverage similar to 800MHz systems.

On the new horizon, the FCC is getting ready to open up the 2.1GHz (2100MHz) band for PCS, SMR and new technologies. Higher in frequency than 1900, 2.1 is likely to be the next wave for companies like Nextel and other digital SMR's who want contiguous spectrum to implement 3G technology like wCDMA.

More spectrum is due to become available in years to come as we move away from analog TV (NTSC) to digital television. Part of conversion to DTV means releasing much radio spectrum for use in other services. In public safety communications, the 700MHz band will be almost exclusively public safety, and will offer law enforcement and government much desired radio "real estate" to build out secure digital netowrks for dispatch, mobile data, video and audio and records management systems. But that is at least 2006 before those frequencies will become available, as they cannot be used until the exsisting analog TV stations using those frequencies vacate the band.

[BigBroni]

Thanks for the replies. I am deciding between Verizon and Sprint right now. I heard that Verizon uses more 800 MHZ, whereas Sprint uses 1900 MHZ, out here in southern California. Is that why Verizon has better coverage than Sprint? Is Verizon ever going to change to 1900 MHZ or will they stay at 800 MHZ? Thanks in advance for your replies.

[BigBroni]

Sorry forgot this question too. Will 2.1GHZ be less effective in coverage than 1900 MHZ (less penetration in buildings, etc.)? In other words the higher the frequency the less coverage?

[ComicalMoodyDan]

If the network is built out right it doesn't make a difference if you are on a 800 mhz or 1900 mhz system both provide good coverage.

[Rasputin]

Originally posted by: BigBroni
Thanks for the replies. I am deciding between Verizon and Sprint right now. I heard that Verizon uses more 800 MHZ, whereas Sprint uses 1900 MHZ, out here in southern California. Is that why Verizon has better coverage than Sprint? Is Verizon ever going to change to 1900 MHZ or will they stay at 800 MHZ? Thanks in advance for your replies.

Verizon will probably go with more 1900 PCS, that is dependent on the outcome of the Nextwave case and the FCC. Verizon has 1900 PCS in the old PrimeCo markets, of Texas, Florida. They will stay with more of the capacity being in 800Mhz, in 5 years they will get rid of analog, you will see CDPD disappearing I believe only the old Bell Atlantic had built it out ? Verizon has better coverage, because of the freqs and because they are a mature system that has been around a lot longer. Eventually, we are talking a few years in the metro areas they will be caught up or close to it, the rural areas are years away from full coverage.

As to your other post regarding 2100Mhz, the coverage is very similar to 1900Mhz, but do not expect those freqs for at least 5 years, the DOD would need to move off of there for us to get those freqs for 3G.

[redheadzpms]

So can fewer calls be made on 800MHz than 1900MHz??? And will you get more busy signals with 800MHz vs 1900MHz???

[Rasputin]

No not at all, at 800Mhz the carriers have 30Mhz of Freqs, at 1900Pcs the carriers have anywhere from 10-30 Mhz of freqs. The type of technology is a variable also a CDMA system of SprintPCS/Verizon will hold more users because you can reuse the same freq at the adjacent cell sites, where with TDMA/GSM you put them into groups like A-F, and want like to other groups of freqs between cells of the same freq group. The TDMA/GSM will hold less users than a comparible CDMA system. People love to complain about SprintPCS, but they are using less than 1/2 of their freqs. that leaves them room to run 1X EV/DV or DO 3G technology without a problem, and the current 1XRTT will increase capacity for phones with 1X by 2. Sprint has its own share of Debt problems and filling holes but they are pretty well set with capacity and room to grow. Verizon is also in a good position with the 1X technology allowing twice the capacity once users start moving over to 1X phones.

Where Voicestream problems lie is their amount of bandwidth, which in a lot of markets is only 10MHz, not a lot for a GSM system. They either need to join with another GSM carrier ie Cingular or hope they can get their hands on some bandwidth from the Nextwave Vs. The FCC.

As far as busies goes, systems like ATT in the major metros like NYC and LA can have some busy problems, and Cingular in Cali has been known to have a few busy problems. People complain about dropped calls with SprintPCS, but I never really hear about busy problems. Verizon I have never had busy problems with.

That is my 2 cents.

[IdiOTeQnoLogY]

agreed. basically what is good is while sprint may have some capacity problems in some areas it is not because of spectrum which is a lot more costly to fix rather than just the equipment costs of adding more capacity handling........they dont have to worry about buying spectrum at least just worry about the hardware side of it and switch and landline capacity stuff.......whereas other carriers may have to worry about spectrum allocation on top of all that.

[BigBroni]

Thanks again for all your replies. So 800 MHZ is actually better as far as capacity and coverage? If this is the case, why don't all wireless providers go with 800 MHZ? Is it because the FCC doesn't allow companies to purchase 800 MHZ any more and only the 1900 MHZ is available?

[KevinJames]

BB:

No, not quite right. What it comes down to for each and every carrier is how well their network is built out. One tower does not a network make.

1900MHz carriers just put more towers up to address the need.

Bottom line: What is your main concern here? Is it having strong signal? If that is it, then forget the waveband and concentrate on finding which carrier has the most robust system as a whole. In general, that would be Verizon and ATT and only because they have been around a while. "Newer" companies, such as Sprint and Cingular (GSM) are still building out their network. In fact, that is one reason I personally am NOT gunhoe to switch from ATT's TDMA to ATT GSM's network--because their GSM network is pretty lean right now.

[Rasputin]

Originally posted by: BigBroni
Thanks again for all your replies. So 800 MHZ is actually better as far as capacity and coverage? If this is the case, why don't all wireless providers go with 800 MHZ? Is it because the FCC doesn't allow companies to purchase 800 MHZ any more and only the 1900 MHZ is available?

In 800Mhz there are only two real cellular bands A/B Wireline/NonWireline. Nextel operates in the Specialized Mobile radio bands of 800Mhz and 900Mhz. In PCS it goes A-F. PCS was introduced to allow for competition with the new digital technologies CDMA/GSM/TDMA. Companies like ATT purchased PCS to go into markets they did not occupy like Arizona, NM, Denver, Houston(?) and to give more capacity in the major metro markets. Sprint purchased the whole country to build a national network from the ground up. T-Mobile has piece mealed their system together with the purchase of Omnipoint and Powertel and agreements for sharing with Cingular. Capacity is dependent on the technology the Sprint/Verizon will hold more users than the GSM/TDMA networks, that is why there is UMTS for high speed data, and high capacity for voice. It will just take the PCS companies a few more years to catch up to the coverage of the 800Mhz., ie build more cell sites fill in dead spots. Sprint is the best built out by far of the PCS carriers, and the coverage will only get better. I like Verizon since it already built out, all they are doing now is adding capacity, filling new dead spots and trying to increase the in building coverage.

[bobolito]

And before Verizon can finish filling dead spots, 4G will come out and the whole game will start all over again. [img]i/expressions/face-icon-small-smile.gif[/img]

Kevin, Cingular as a company is new but the networks they are using are as old as AT&T or Verizon. Let's recall that they simply merged a bunch of existing systems so they are not exactly building a network from the ground up like Sprint and Voicestream. So basically they simply purchased already existing and running networks and renamed them. Now they are converting their TDMA systems to GSM, so again, nothing new from the ground up.

On a different note, if 1900Mhz waves are more affected by trees, buildings, etc. then that means the lower the frequency, the more transparent their path is to a receiver. Then, with that scenario established, I have a question for all of the technical savyy people here: Why is it that VHF TV channels and FM stations cannot penetrate certain buildings while UHF stations come in just fine and cellular phones signal penetrate without problems? I am sure I am not the only one who has noticed this.

[ZaphodB]

Bobolito,

My guess regarding the FM/VHF vs. UHF/Cell signals is that there will be many more repeaters for UHF TV stations and cell signals (towers, in that case), due to the known fact that higher frequency requires more points of presence to cover the same area to the same quality. VHF and FM stations tend to have many fewer towers broadcasting, but a higher power. (For example, nearly all the local television stations in Los Angeles have their transmission towers on top of Mt. Wilson, which is northeast of Pasadena and nowhere near, say, Torrance or Long Beach).

Just my guess.

[Rasputin]

All the VHF is at MT. Wilson, I have spent years of my life on those towers, there are a few UHF up there, but a lot of the local one's are closer to the areas they serve, there are a few in Signal hill, Santa Monica Mountains. I believe it is more of location than penetration. The power difference between VHF and UHF is massive also. The ABC/NBC/CBS towers could warm up my tools after a while when I was on those towers.

I was on Howards website and was on a thread of 800 vs 1900 and people tried to say that the penetration of PCS is better than cellular, I find that hard to believe. I know with MV equipment the higher you go in freq the more that clouds, fog, heavy rain, trees affect the RSSI values. It just takes a lot of time for PCS operators to get the same coverage as Cellular operators.

[bobolito]

Rasputin, when you go home, go to the bathroom, turn off the light and look at the mirror and see if you glow...[img]i/expressions/face-icon-small-smile.gif[/img] Gosh, isn't dangerous to expose yourself to radiation so intense that will warm up your tools?

By the way, most of the FM and TV stations broadcast from NYC which is about 15 - 20 linear miles from where I am so the signal is fairly strong. However, UHF stations transmitting from the same location make it into the building just fine, but the VHF signals, even though they come in stronger than UHF, cannot penetrate the building. This is why I am puzzled about it.

[Rasputin]

Originally posted by: bobolito
Rasputin, when you go home, go to the bathroom, turn off the light and look at the mirror and see if you glow...[img]i/expressions/face-icon-small-smile.gif[/img] Gosh, isn't dangerous to expose yourself to radiation so intense that will warm up your tools?

By the way, most of the FM and TV stations broadcast from NYC which is about 15 - 20 linear miles from where I am so the signal is fairly strong. However, UHF stations transmitting from the same location make it into the building just fine, but the VHF signals, even though they come in stronger than UHF, cannot penetrate the building. This is why I am puzzled about it.

Luckily I carried around a handy dandy RF monitor, as soon as it started beeping or the tools get hot down you go and have the TV station turn down the power. I have not had to climb in a couple of years( they higher up you on the Corporate Ladder the lower to the ground you get), probably helped me to conceive my child. I will look into the UHF to VHF scenerio, I do not remember anything that would make it be so, but who knows. I never dealt with RF in that way I did coverage modeling but you really can not test in building coverage with those type of modeling programs, they do a good job, of taking into effect building, to some degree. I am a little rusty on my RF equations I will look at the mound of RF books I have, it will help me go to sleep tonight. Most of it should have to with more of materials like Concrete, steel, window tinting, wood, plaster vs. drywall etc.

Have you had any busies with Cingular in your neck of the woods, I have heard some other people complaining of busies at night or in the evening, but you never know with most people it could be their phone, cell site work ( normally down after midnight).

[bobolito]

I rarely have busies in this area and if I do it is normally between 5:30PM and 8:30PM. I don't remember the last time it happened. I use AT&T towers with Cingular here because I use a TDMA phone.

[Rasputin]

I always wondered whose system you were using there. I did not think Cingular has a TDMA system on PCS in that neck of the woods.

[bobolito]

Cingular has TDMA PCS in many places such as FL, PA, CT, NY, TX and others. Note that this doesn't mean the entire state is covered by PCS. Also, NY means upstate, not NYC.

[Rasputin]

Originally posted by: bobolito
Cingular has TDMA PCS in many places such as FL, PA, CT, NY, TX and others. Note that this doesn't mean the entire state is covered by PCS. Also, NY means upstate, not NYC.

I do know they have quite a TDMA coverage, BellSouth and SWBell and now the Ameritch conversion from CDMA to TDMA, you would have even a greater network if BellSouth paid the extra money to outbid Craig McCaw, back when he picked up the Lin Broadcasting portfolio for 3.4 billion in 1987 back in the time of analog. Not a bad bid in today's money for Los Angeles, New York, Philadelphia, Houston and Dallas among others.

[MTS2000]

VHF (50-200MHz) doesn't work well inside buildings because of the inefficient design of most portable antennas.Use a good portable antenna and you will have outstanding performance. A quarter-wave whip at 850MHz is around 4 inches, at 150MHz it is 17.5 inches long. I get into this debate with Motorola salespeople who want to shove 800MHz digital trunking radio down every public safety agencies' throat. A properly engineered VHF repeater with remote recievers can provide not only superior in-building coverage, but wide area mobile coverage. For example, our 800MHz trunking radio system operates with 3 sites simulcasting on the same frequencies, with 300 watt ERP to penetrate most buildings and it is barely enough, get near a damn Nextel tower and your portable goes deaf.

A nearby agency is still using thier single site VHF repeater, on a much smaller in elevation site, with only 75 watts ERP, yet they cover their entire city. I can hear them 30 miles away with a portable on the lower floor of my house with no noise. 30 miles away from our 800 system yeilds a noisy, unstable signal.

The only issue with lowering your frequency is antenna size. You need longer antennas to be effective the lower you go. Also, the lower in frequency you go, the more susceptible to nautral and manmade interference, such as noise from electrical power lines, computer/TV's, even flourescent lights. Remember the old 43/49MHz cordless phones? What made them so bad was the poor antennas, and the noise on the band. 900 and 2.4 GHz phones only perform better because they use better antenna and higher power, and the higher frequency makes them immune to atmospheric and electrical interference. Plus, there more bandwidth available which means less interference from other devices, and allows for digital transmission and spread spectrum operation.

In all of my experience, 800MHz based systems for cellular work better not just because of the lower frequency, but they are more mature and built out than the PCS carriers. I just spent the last night at a semi-rural camp in East Georgia. My Verizon phone worked flawlessly, had a good signal even in the woods in the cabin, even though the nearest cell was 3.5 miles away. Sprint was dead, even though they were located on the same exact tower as Verizon, but the heavy trees, foliage and land layout made Sprint unusable.

[Rasputin]

Originally posted by: MTS2000
VHF (50-200MHz) doesn't work well inside buildings because of the inefficient design of most portable antennas.Use a good portable antenna and you will have outstanding performance. A quarter-wave whip at 850MHz is around 4 inches, at 150MHz it is 17.5 inches long. I get into this debate with Motorola salespeople who want to shove 800MHz digital trunking radio down every public safety agencies' throat. A properly engineered VHF repeater with remote recievers can provide not only superior in-building coverage, but wide area mobile coverage. For example, our 800MHz trunking radio system operates with 3 sites simulcasting on the same frequencies, with 300 watt ERP to penetrate most buildings and it is barely enough, get near a damn Nextel tower and your portable goes deaf.

A nearby agency is still using thier single site VHF repeater, on a much smaller in elevation site, with only 75 watts ERP, yet they cover their entire city. I can hear them 30 miles away with a portable on the lower floor of my house with no noise. 30 miles away from our 800 system yeilds a noisy, unstable signal.

The only issue with lowering your frequency is antenna size. You need longer antennas to be effective the lower you go. Also, the lower in frequency you go, the more susceptible to nautral and manmade interference, such as noise from electrical power lines, computer/TV's, even flourescent lights. Remember the old 43/49MHz cordless phones? What made them so bad was the poor antennas, and the noise on the band. 900 and 2.4 GHz phones only perform better because they use better antenna and higher power, and the higher frequency makes them immune to atmospheric and electrical interference. Plus, there more bandwidth available which means less interference from other devices, and allows for digital transmission and spread spectrum operation.

In all of my experience, 800MHz based systems for cellular work better not just because of the lower frequency, but they are more mature and built out than the PCS carriers. I just spent the last night at a semi-rural camp in East Georgia. My Verizon phone worked flawlessly, had a good signal even in the woods in the cabin, even though the nearest cell was 3.5 miles away. Sprint was dead, even though they were located on the same exact tower as Verizon, but the heavy trees, foliage and land layout made Sprint unusable.

Good Point. I designed a ton of systems at 220Mhz,400-510, and 800-900Mhz. It was amazing the coverage I could get with a properly designed 220Mhz system running a 5 watts on the hilltop compared with a 800Mhz running at 50 watts, with higher gain antennas. With properly designed antennas at 1/4 wave length or 5/8 wave length make a big difference. Once you try to start using loaded coils your RSSI drops considerably and you do not get the TX on the mobile or portable unit to repeater. For public safety the 150 band is great, Motorola just wants to sell everyone new equipment every few years, then make a new system to sell you. For Public Safety the range difference between analog and digital systems can be substantial also. I know quite a few Muni RF engineers who have lost coverage going with Motorola dig compared with the analog system they replaced. For public safety you can not loose coverage, Motorola would solve that by just selling the Munis more equipment.

Nextel has done a great job of destroying the private 2 way industry and screwing with Public Safety.

[bobolito]

From reading the last two posts, it would seem that regular old fashion retractable antennas for mobile phones are better fit for RX and TX than loaded coil stub antennas or internal ones. So, can I say that the reason why Verizon Wireless has a higher reputation than other carriers when it comes to signal availability (from a general national perspective) is because their phones use retractable antennas making their network look superior in the eyes of the customers? Can I then assume that Verizon and AT&T have equal coverage (generally speaking) and that it is their phones that make one network (Verizon) more reliable than the others? Obviously, I am not expecting answers, just opinions.

[ehcruzan]

Good question! I am curious also since I always thought Verizon and AT&T had similarly sized networks but there seems to be complaints about AT&T's coverage whereas I almost never hear any about Verizon.

[Airb330]

Bobolito, I think you could be right. I still think Verizon has better coverage though, well at least for my state. While many people can be happy with their 3360's and the like, retractable antenna's really help. I think Nokia is doing a great thing with the 3585 soon to be realeased (hopefully for Verizon), it has a dual antenna. I'm not sure how that works, but I suppose it has an internal and pull out. That'd be great for me, no fooling around with a dumb antenna (its hidden really well) in town, but out in the countryside, I could easily pull it out and have a clear conversation. Excellant idea Nokia!

[MTS2000]

Originally posted by: Rasputin

Good Point. I designed a ton of systems at 220Mhz,400-510, and 800-900Mhz. It was amazing the coverage I could get with a properly designed 220Mhz system running a 5 watts on the hilltop compared with a 800Mhz running at 50 watts, with higher gain antennas. With properly designed antennas at 1/4 wave length or 5/8 wave length make a big difference. Once you try to start using loaded coils your RSSI drops considerably and you do not get the TX on the mobile or portable unit to repeater. For public safety the 150 band is great, Motorola just wants to sell everyone new equipment every few years, then make a new system to sell you. For Public Safety the range difference between analog and digital systems can be substantial also. I know quite a few Muni RF engineers who have lost coverage going with Motorola dig compared with the analog system they replaced. For public safety you can not loose coverage, Motorola would solve that by just selling the Munis more equipment.

Nextel has done a great job of destroying the private 2 way industry and screwing with Public Safety.

No doubt that digital is not ready for public safety and public safety is not ready for digital. Especially at 800MHz with the Nextel interference, at analog, you get a lower SINAD (desense) but at least as long as your subscriber unit can hear the CC or VC you can get through, with digital (P25/IMBE or VSELP) you get garble or nothing at all. That is not acceptable when you are in a life threatening situation. I have always throught that VHF is more suited to suburban areas and UHF is better for urban ones. The largest munis in america agree, LA fought with Motorola when they bought their Astro Sabers in 1995. Motorola was wanting to trunk the whole city, but LAPD insisted on UHF for the coverage and interop. issues. and they were right on. An LAPD officer can talk to anyone he needs to from his portable (or ROVER as they call it- Remote Out of Vehicle Emergency Radio). We can only dream of that in Georgia. Now our BRILLIANT minded state public safety director thinks a statewide 800MHz trunking system is the answer for Georgia State Patrol. yeah, right, counties that can't afford a used VHF portable for their two fulltime deputies can afford a 5600 dollar Motorola XTS5000. and let's not even discuss the infrastructure. all this to line the pockets of equipment vendors and give it to the taxpayers. sad thing is, it won't work and GSP's communication problems aren't going to be solved. May cost someone their life, because all the hype gives them a false sense of security.

On Nextel, I have found that many people around here are going back to one of the many SMR's on UHF because they are sick of the poor audio quality and high prices that Nextel charges for dispatch. Nextel did put many SMR's out of business. But the market is demanding lower cost, higher quality services, and we have several UHF LTR system on the air in atlanta that are quite profitable and offer better bang for the buck for dispatch service than Nextel or Southern LINC. Nextel has a unique corner on the market but as soon as one of the CDMA providers offers PTT, that will soon change.

As a victim of public safety interference from Nextel, I can tell you there is only going to be so much before the FCC is forced to shut them down. Had they designed their network as an SMR and not try to pass themselves off as a cellular provider, this would not be happening right now. Southern LINC did it right, and they cause us no interference and use the same band, same base stations, etc. But they are an SMR, not a wanna-be celphone co like Nextel tries to be. Nextel has created several holes in coverage for various public safety systems around the country, and they have been slow to deal with it. Shame on them.

[bobolito]

Isn't FCC primary mission to avoid these kind of interference problems? If they take it so seriously, why is this happening? Even if Nextel was just a radio company not interested in the cell business, wouldn't this be happening anyway?

[emag0rad]

Originally posted by: bobolito
Isn't FCC primary mission to avoid these kind of interference problems? If they take it so seriously, why is this happening? Even if Nextel was just a radio company not interested in the cell business, wouldn't this be happening anyway?

Here you go, pick any one to get a background:

http://www.google.com/search?q=FCC+N...&output=search