Why no P25 900mhz?

[SKYNET156]

Why is it that their are no radios capable of 900mhz P25 or IMBE?
I know that most of the major radio companies have VHF/UHF/800mhz Digital, but no Lowband 30-50 or 896-956mhz P25, Why is that?

[DaveNF2G]

Probably because there is no market for them. If nobody wants a particular kind of radio (or if not enough people will buy it to pay back the cost of development), then manufacturers won't make it.

[fineshot1]

Originally Posted by SKYNET156

Why is it that their are no radios capable of 900mhz P25 or IMBE?
I know that most of the major radio companies have VHF/UHF/800mhz Digital, but no Lowband 30-50 or 896-956mhz P25, Why is that?

I could be wrong but this is my take on this subject.

The 900mhz band was already setup as narrow band right from the start.
That is 12.5khz channel steps and 2.5khz deviation with the regular fm.
As far as I know P25 does not yet work well enough in a narrow band configuration.

As far as low band is concerned there is a lot of receiver noise in this spectrum
and this does not work well with the P25 receivers. Makes for too many bit errors
on the receive side.

[mm]

P25 works just fine in narrowband 12.5 KHz channels so I don' t know where you got your information, perhaps you were confused with 6.25 KHz phase II.

I don't know anyone who is using 25KHz channel spacing in P25, everyone is using 12.5 KHz channeling and even 6.25 KHz TDMA P25 is working now but there are still very little Phase II infrastructure that has been set up at this time.

P25 works just fine in VHF Low band also, and it is not a factor with Ambient noise in VHF-low that keeps mfg from making more radios that operate here.

Tyco MaCom has had some demo radios that work just fine around 29.79 Mhz using P25, I have heard them on E skip and they sound just fine.

It comes down to Public safety, there are very little public safety agencies using 900 MHz and even the market for public safety in the VHF Low band has and will continue to dwindled.

As a result The big Companies that make the infrastructure like Motorola, Ma/Com, Daniels, Tait aren't making any repeaters for these bands, why market something when the majority of the money from P25 sales is in 700/800 MHz infrastucture.

My Company has been testing and demoing VHF low P25 in our wide band avionics radios for some time but as of yet there is zero market for them since no one wants to put any money into a VHF low band handheld or mobile anymore.

[ILMRadioMan]

Ditto MM,

It has nothing to do with noise, etc....its money.

[fineshot1]

Originally Posted by mm

P25 works just fine in narrowband 12.5 KHz channels so I don' t know where you got your information, perhaps you were confused with 6.25 KHz phase II.

Yes, sorry - I should have written "new narrow band configuration" instead. Was in a hurry at the time.

Originally Posted by mm

I don't know anyone who is using 25KHz channel spacing in P25, everyone is using 12.5 KHz channeling and even 6.25 KHz TDMA P25 is working now but there are still very little Phase II infrastructure that has been set up at this time.

When was 6.25 Khz TDMA P25 fixed & working? Guess I am behind the times. Last I new moto
was still working on some fixes before it was considered reliable. Is this being marketed yet for just
conventional or also trunking? I could swear there was some kind of hold up with this as issues
were worked out.

Originally Posted by mm

P25 works just fine in VHF Low band also, and it is not a factor with Ambient noise in VHF-low that keeps mfg from making more radios that operate here.

Tyco MaCom has had some demo radios that work just fine around 29.79 Mhz using P25, I have heard them on E skip and they sound just fine.

It comes down to Public safety, there are very little public safety agencies using 900 MHz and even the market for public safety in the VHF Low band has and will continue to dwindled.

As a result The big Companies that make the infrastructure like Motorola, Ma/Com, Daniels, Tait aren't making any repeaters for these bands, why market something when the majority of the money from P25 sales is in 700/800 MHz infrastucture.

My Company has been testing and demoing VHF low P25 in our wide band avionics radios for some time but as of yet there is zero market for them since no one wants to put any money into a VHF low band handheld or mobile anymore.

Well - I didn't mean to say it does not work at all in a low band configuration. More of what I meant was that in this band with much more noise sources (ie: electric pole noise, spark plug noise, lightning noise, oscillator noise, etc.) the mobile receivers have a lot tougher time decoding the data. Some errors can be tolerated but LB definately has a lot more noise than vhf-hi & uhf. I have experienced on vhf-hi & uhf some local areas where a portable will not decode due to noise from an electric sub station. Once I moved away
decode recovered. That's just one example.

[N_Jay]

There is very little public safety, and therefor very little market.

[wayne_h]

I heard something about bandwidth similar to what fineshot mentions. Is the sales thing speculation or?

From what I recall the bandwidth for P25 Phase I is 3.6kHz which would be too wide for 900Mhz operation. So school me on this...

[N_Jay]

P25 flits easily in a 12.5 kHz channel, so I don't see how that is anything more then someone who does not know all the pieces guessing.

There is no (production) P25 at lowband also. (and that market was almost dead in analog.)

[wayne_h]

I just find it hard to believe that because Public Safety doesn't use 900MHz that manufacturers won't build the equipment for it.

[N_Jay]

Originally Posted by wayne_h

I just find it hard to believe that because Public Safety doesn't use 900MHz that manufacturers won't build the equipment for it.

Why?

Why is it hard to believe that manufacturers have not produced a radio for a market that does not exist? (or is extremely small)

There are no Public Safety allocations in 900 MHz (some is use in frequency impacted areas).

There are no public safety interoperability assignments in 900 MHz.

To my knowledge there are no regional Public Safety systems on 900 MHz

And other than iDEN, there is no 900/800 MHz dual band equipment.

I would be surprised if some one did make P25 equipment for 900 MHz as it stands today.

You know, there are no purpose built P25 amateur stations today.

I would hazard a guess that there are more P25 ham users than 900 MHz public safety users.

[SKYNET156]

As i know that you have explained no P25 on 900mh, what about lowband 30-50mhz?
I know alot of states have Low band inter-op and still use lowband...so why no lowband P25?

[wayne_h]

Originally Posted by N_Jay

There are no Public Safety allocations in 900 MHz (some is use in frequency impacted areas).

So if I follow your logic only PS can use Project 25 equipment. Got it.

[N_Jay]

Originally Posted by wayne_h

So if I follow your logic only PS can use Project 25 equipment. Got it.

"Can use" vs. "Driving the market" Get it?

As for Low band:
Take a look at the total market, look at how small it is, look at how many companies that used to serve it no longer do, or do so only weakly.

[MTS2000des]

Motorola sells the XTL/XTS series for 900MHz, but only offers it in "Astro ready" configuration. Wonder if anyone tried to order it with an Astro 25 flash if they'd sell it? Seems like all the hardware is there to support IMBE, I've held one (XTL1500), programmed one and used one, so it is not as if the possibility isn't there for them to easily flash them to IMBE/Astro 25 if the demand was there. In fact the XTL1500 and XTS1500/2500 are the replacement products offered for the MCS2000, GTX and MTS2000 product lines.

Most of the 900 systems are private wireless and the migration path is toward SMR networks such as iDEN/Harmony and MotoTRBO versus P25. There are still several 900 analog trunked systems in use, Aeronautical Radio, Inc. (AIRINC) operates a 900MHz iDEN network at most major US Airports and still has some analog Smartnet 900 systems at their facilities. P25 just doesn't offer what the typical 900 user wants (full duplex interconnect, fleet management, etc) as P25 is designed for public safety not business radio users.

I don't know of any law enforcement agency of substantial size using 900MHz. As far as ham operation, from a personal experience, it is a crap band. Noise floor is through the roof, propagation sucks, and because it is shared with ISM and part 15 devices, the QRM on the band makes it unfriendly towards repeater use in many areas. Lots of people are playing with it, thanks to Nextel putting iDEN up there and shutting off their legacy analog systems, cheap and plentiful infrastructure and radios make it affordable for most of us to play. Been there, done that- 440 is a much better band IMO and most every ham has it.

[davidbond21]

Originally Posted by N_Jay

To my knowledge there are no regional Public Safety systems on 900 MHz

Originally Posted by MTS2000des

I don't know of any law enforcement agency of substantial size using 900MHz

Scanner Frequencies: Lower Colorado River Authority (LCRA) Trunking System, 32 Counties, Texas

Whether or not this satisfies your definitions for "regional" or "substantial size," this is a pretty large 900 MHz system that carries a good amount of Public Safety traffic(as well as utilities and city services).

[N_Jay]

Originally Posted by davidbond21

Scanner Frequencies: Lower Colorado River Authority (LCRA) Trunking System, 32 Counties, Texas

Whether or not this satisfies your definitions for "regional" or "substantial size," this is a pretty large 900 MHz system that carries a good amount of Public Safety traffic(as well as utilities and city services).

I now know of one. Thanks. (That is called learning)

Still not much of a market.

[pachanga22]

Originally Posted by SKYNET156

Why is it that their are no radios capable of 900mhz P25 or IMBE?
I know that most of the major radio companies have VHF/UHF/800mhz Digital, but no Lowband 30-50 or 896-956mhz P25, Why is that?

Because the new, magical 700 band is going to solve everything, including interoperability, especially when used with Astro25.

At least that's what the motorola salesman will have you believe.

[N_Jay]

Originally Posted by pachanga22

Because the new, magical 700 band is going to solve everything, including interoperability, especially when used with Astro25.

At least that's what the motorola salesman will have you believe.

Really?

Either you have different sales people or you misunderstand what was said.

[wayne_h]

Alright N_Jay, lets bump the arrogance level down a bit.