Why did various agencies switch over to P25 from analog. What was the advantage?
What is the advantage of P25 over analog?
- Thread starter streetbob
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Welcome to radio reference Bob. I see you have 2 posts, should be a very interesting thread.
P25 digital mode helps to eliminate noise and static and fading therefore providing a much cleaner clearer audio being easier to understand.
in our system parts for the analog system and radios were becoming hard to get.
It eliminates channel congestion and mainly for conservation. The idea behind all the trunking systems.
There is a lot of other things that come along for the ride like location and emergencies.
Talk groups can be discriminated or up to system wide calls.
Like say my local site handles ALL of the public safety groups and accounts for almost 2000 users.
This is all squeezed down to the same as 7 analog channels. analog can also use the system besides digital.
The digital can be encrypted with no impact on the system.
73s
There is a lot of other things that come along for the ride like location and emergencies.
Talk groups can be discriminated or up to system wide calls.
Like say my local site handles ALL of the public safety groups and accounts for almost 2000 users.
This is all squeezed down to the same as 7 analog channels. analog can also use the system besides digital.
The digital can be encrypted with no impact on the system.
73s
mmckenna
I ♥ Ø
P25 does not equal trunking. Trunking can be P25, but P25 can also be conventional (both simplex and repeated), and trunking can be analog.
Federal grants usually require P25 capable radios be purchased. "Capable" is different from actually running them in P25 mode. You can still use just plain old analog. None the less, federal grants require it.
It also allows hauling of low speed data along with the audio. Things like GPS location, radio ID's, text, paging, etc.
Federal grants usually require P25 capable radios be purchased. "Capable" is different from actually running them in P25 mode. You can still use just plain old analog. None the less, federal grants require it.
It also allows hauling of low speed data along with the audio. Things like GPS location, radio ID's, text, paging, etc.
Fleet management and positive access control for each and every radio on the system. Lost radio? System manager disables it remotely. Intruder on the system?… and yes it does happen on analog systems… but it’s a non-issue on a digital system. Need robust and highly effective encryption / voice privacy? Piece of cake compared to analog.
JamesWest
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many advantages as you have seen listed here. i will never forget monitoring my first LAPD P25 transmission right after they switched over from analog years ago. sounded like they were talking through some sort of underwater snorkel.
and many complaints about dead spots. but they worked it out.
lwvmobile
DSD-FME
Of course, the drawback is if you have bad digital signal, you don't get anything. Bad analog signal, you can still listen and make out words. Kind of like Analog TV vs Digital TV, even distant stations can be viewed, even with static, but distant digital signals get all blocky and choppy, and then just drop off entirely. Not to mention the need to decode the digital stream takes time, causes lag in tuning.
RFI-EMI-GUY
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P25 advantages:
1) Fixes huge coverage problems caused by /\/\andatory VHF and UHF narrowbanding.
2) Its a standard!
3) Its "state of the art".
P25 disadvantages:
1) Sounds like kraap.
2) Expensive subscriber costs that exceed any possible federal grant assistance.
3) Increased voice latency = poorer spectral efficiency when factoring in gross airtime wasted in call completion. (We should have stayed with wideband FM analog!)
4) Its a standard??
5) Sounds like R2D2, very spacey man..
1) Fixes huge coverage problems caused by /\/\andatory VHF and UHF narrowbanding.
2) Its a standard!
3) Its "state of the art".
P25 disadvantages:
1) Sounds like kraap.
2) Expensive subscriber costs that exceed any possible federal grant assistance.
3) Increased voice latency = poorer spectral efficiency when factoring in gross airtime wasted in call completion. (We should have stayed with wideband FM analog!)
4) Its a standard??
5) Sounds like R2D2, very spacey man..
RFI-EMI-GUY
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- 7,515
Those remote fleet management features were available on analog conventional and Project 16 trunking systems. It was done in band, yes, but it all worked.
RFI-EMI-GUY
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All those available in analog APCO Project 16 systems.
RFI-EMI-GUY
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Planned obsolescence at work.
Thank you for all the answers. I appreciate it.
But one of the bigger motivators was a mandate from the FCC mandating narrow banding. That meant some significant changes as it "narrowed the lanes" of radio traffic. Many of the features noted above were secondary to the narrow banding rule.
MTS2000des
5B2_BEE00 Czar
Migrating from an analog trunked environment to P25 digital trunked gave us:
1-Modern, supported FNE. Our original system was implemented when Reagan was still in office. No joke.
2-Better uniform round trip coverage within our county
3-No static, multipath distortion (we had one of the first analog simulcast systems our vendor implemented in the country)
4-INCREASED CAPACITY. TDMA essentially doubles the talk paths
5-INCREASED SECURITY Encryption is now standard on subscribers, and no degradation in voice quality unlike the legacy analog system which did support digital encryption (ancient CVSD modulation at 12Kbit/sec sounded like crap and had less usable range), not to mention the cost of hardware crypto and the hassle of it. Modern P25 subscribers include basic encryption at no/low cost and it's easy to use and seamless to end users.
6-VARIETY OF COMPATIBLE SUBSCRIBERS- the old system, while APCO 16 compliant, did not allow us to procure subscriber radios from multiple vendors. Our current P25 trunking system has subscribers from multiple vendors. So long as a subscriber product meets the DHS P25 CAP standards and we have verified performance to these standards and can provision/program them, they can be procured by our stakeholders and used on our system.
1-Modern, supported FNE. Our original system was implemented when Reagan was still in office. No joke.
2-Better uniform round trip coverage within our county
3-No static, multipath distortion (we had one of the first analog simulcast systems our vendor implemented in the country)
4-INCREASED CAPACITY. TDMA essentially doubles the talk paths
5-INCREASED SECURITY Encryption is now standard on subscribers, and no degradation in voice quality unlike the legacy analog system which did support digital encryption (ancient CVSD modulation at 12Kbit/sec sounded like crap and had less usable range), not to mention the cost of hardware crypto and the hassle of it. Modern P25 subscribers include basic encryption at no/low cost and it's easy to use and seamless to end users.
6-VARIETY OF COMPATIBLE SUBSCRIBERS- the old system, while APCO 16 compliant, did not allow us to procure subscriber radios from multiple vendors. Our current P25 trunking system has subscribers from multiple vendors. So long as a subscriber product meets the DHS P25 CAP standards and we have verified performance to these standards and can provision/program them, they can be procured by our stakeholders and used on our system.
One thing DIGITAL compared to ANALOG both radios at the same power and the same height on the same antenna DIGITAL has better RANGE
To eliminate a lot of money from our wallets.
KG7PBS
Member
That it is P-25 that’s the advantage. No it’s the better sounding audio and security of Encryption
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