Question About Modes

Status
Not open for further replies.

jgorman21

Member
Premium Subscriber
Joined
Feb 21, 2008
Messages
585
Location
Glenmont N.Y.
Good Morning.
I’ve seen other posts in the past regarding the many possible modes that are being used today by Federal Agencies. Just wondering what (if any) updates could be shared and/or confirmed?

After picking up recent activity on UHF, I though that it would be a good time to “reset” some frequencies on both UHF and VHF. That is, to clear the mode and NAC that was stored to “start over.” My findings were this on a Phase 1 capable radio. While there are still some P25 Phase 1 transmissions (and an analog?), I noticed a few frequencies stopping and showing the various NAC’s but no sound - encrypted or otherwise! Is this Phase 2 or possibly another digital mode? I do have a Phase 2 capable radio that I can check this with too. I guess I’m behind the times on this and as always this is a “moving target.”

Always searching and listening...

Thanks.
 

ChrisP

Member
Premium Subscriber
Joined
May 20, 2002
Messages
1,330
Location
Portland, OR
As far as federal agencies go, it's going to be mostly analog or P-25 digital. Yes, some agencies, such as the US Postal Service, have been deploying DMR systems at their mail sorting faculties and small agencies or offices have been reported to be using NXDN or DMR radios.

As for the P-25, if it's a conventional channel, it will be Phase 1. Phase 2 is only used on trunking systems.

I doin't know what kind of radio you have, but some models are designed not to pass the encrypted audio, so you would hear nothing if encrypted. The Whistlers can block the encrypted sound and the Uniden radio skip encrypted transmissions.

- Chris
 

ecps92

Member
Joined
Jul 8, 2002
Messages
14,360
Location
Taxachusetts
As Chris pointed out, most is going to be Analog or P25 and yes there are NXDN and DMR

Key word is "Most" and that is generally LE type agencies, yet my local FRB just went DMR for both PD and Maint.

And of course there will always be an exception , or something found that has not been reported/shared yet. :)

And Yes - I would reset your monitoring and see what you get for the next month.
YYMV but don't assume if ENC in the AM, that it will be ENC tonight

Happy Hunting and do share, once you go thru your notes.
Do keep any active SURV Ops, off list for awhile, till that cools down :) fun to listen to tho.
As far as federal agencies go, it's going to be mostly analog or P-25 digital. Yes, some agencies, such as the US Postal Service, have been deploying DMR systems at their mail sorting faculties and small agencies or offices have been reported to be using NXDN or DMR radios.

As for the P-25, if it's a conventional channel, it will be Phase 1. Phase 2 is only used on trunking systems.

I doin't know what kind of radio you have, but some models are designed not to pass the encrypted audio, so you would hear nothing if encrypted. The Whistlers can block the encrypted sound and the Uniden radio skip encrypted transmissions.

- Chris
 

jgorman21

Member
Premium Subscriber
Joined
Feb 21, 2008
Messages
585
Location
Glenmont N.Y.
Thank you Chris and Bill. I will keep listening and always be discreet. It’s always been fun. I can recall doing these types of searches on the old tunable radios too!

One other thought on those “flashes” I’m seeing on a couple frequencies/agencies. The radio is a GRE PSR 500. It routinely picks up most if not all local traffic. Could that brief “pop” I’m getting be some sort of data? I usually hear both clear and encrypted transmissions. I also hear all the clear stuff on my G5 too.

Thank you again! 73’s!

Everybody be well and stay safe!
 
Last edited:

ChrisP

Member
Premium Subscriber
Joined
May 20, 2002
Messages
1,330
Location
Portland, OR
The brief key-ups that some folks see on the federal P-25 conventional systems is most likely a "vote-scan" beacon. The repeater signals its presence by transmitting briefly at a regular interval. The radios in the field have a pre-defined list of repeater frequencies that it looks for and once it finds one with a good receive signal, it stays there until it no longer sees the beacon then looks for another.

There are also brief transmissions of radios sending their locations, but they usually do that when the radio push-to-talk is keyed.

And some have suggested that the radio signals the dispatch console when it changes channels, but I don't think that happens on conventional systems.

- Chris
 

ecps92

Member
Joined
Jul 8, 2002
Messages
14,360
Location
Taxachusetts
a flash, blip, quick hit can be almost anything.

I've had folks report [via logging software] many one-hit wonders, which turn out to be
the Scanner software being overloaded and reporting the prior NAC etc

Sitting on a Freq and seeing a blip/ping of a NAC is generally a sign of a "Vote-Scan" network
similar to your cellphone where it registers to the network when turned on , or for two-way either
turned on or channel changes

Also keep in mind [coming back into the new Scanner era] Vote-Scan networks are Wide-Area.
Depending on the system design [example - the user could be in Northern VT, yet you are hearing
the ping on the networked Southern VT or Western MA repeaters]

Thank you Chris and Bill. I will keep listening and always be discreet. It’s always been fun. I can recall doing these types of searches on the old tunable radios too!

One other thought on those “flashes” I’m seeing on a couple frequencies/agencies. The radio is a GRE PSR 500. It routinely picks up most if not all local traffic. Could that brief “pop” I’m getting be some sort of data? I usually hear both clear and encrypted transmissions. I also hear all the clear stuff on my G5 too.

Thank you again! 73’s!

Everybody be well and stay safe!
 

es93546

A Member Twice
Premium Subscriber
Joined
Aug 18, 2020
Messages
1,044
Location
Right Side of CA on maps
As far as federal agencies go, it's going to be mostly analog or P-25 digital. Yes, some agencies, such as the US Postal Service, have been deploying DMR systems at their mail sorting faculties and small agencies or offices have been reported to be using NXDN or DMR radios.

As for the P-25, if it's a conventional channel, it will be Phase 1. Phase 2 is only used on trunking systems.

I doin't know what kind of radio you have, but some models are designed not to pass the encrypted audio, so you would hear nothing if encrypted. The Whistlers can block the encrypted sound and the Uniden radio skip encrypted transmissions.

- Chris

As far as I know "Phase 1" applies to trunking systems, not conventional frequency use. P-25 is an APCO project that established criteria for digital radio design. Phase 1 trunking allows one user per channel or talkgroup and one user on a frequency used by a trunked system repeater. Phase 2 is Time Division Multiple Access allowing two users simultaneously on a single frequency used by a trunking system repeater.
 

Floridarailfanning

Member
Premium Subscriber
Joined
Sep 22, 2015
Messages
419
Location
East Tennessee
As far as I know "Phase 1" applies to trunking systems, not conventional frequency use.
You're confusing the two. Phase I can be simplex, conventional, or trunked, Phase II is the version that is exclusively available in trunking operation.
 
Last edited:

ecps92

Member
Joined
Jul 8, 2002
Messages
14,360
Location
Taxachusetts
P25 for Conventional / Simplex is inherently Phase I, but commonly just called P25
P25 for Trunking can be either Phase I or Phase II

CP was pointing out, what folks commonly confuse - Unless it is trunking P25 is Phase I, if it is trunking it can be either

As far as I know "Phase 1" applies to trunking systems, not conventional frequency use. P-25 is an APCO project that established criteria for digital radio design. Phase 1 trunking allows one user per channel or talkgroup and one user on a frequency used by a trunked system repeater. Phase 2 is Time Division Multiple Access allowing two users simultaneously on a single frequency used by a trunking system repeater.
 

INDY72

Monitoring since 1982, using radios since 1991.
Joined
Dec 18, 2002
Messages
14,636
Location
Indianapolis, IN
And in the FED's... The oddball is the VA. VA uses P25, and still some analog, conventional in VHF, and UHF. Trunked LTR, DMR, NXDN, P25. And piggybacks on MANY Statewide TRS systems. VA is one you really need to have patience and search skillz! USFS is finally making the P25 shift on the conventional nets they have. NPS is mostly P25 now, ACE is also mostly P25 now.
 

ecps92

Member
Joined
Jul 8, 2002
Messages
14,360
Location
Taxachusetts
IMHO USFS is only moving to P25 for LE functions, most other operations will remain Analog
And in the FED's... The oddball is the VA. VA uses P25, and still some analog, conventional in VHF, and UHF. Trunked LTR, DMR, NXDN, P25. And piggybacks on MANY Statewide TRS systems. VA is one you really need to have patience and search skillz! USFS is finally making the P25 shift on the conventional nets they have. NPS is mostly P25 now, ACE is also mostly P25 now.
 

es93546

A Member Twice
Premium Subscriber
Joined
Aug 18, 2020
Messages
1,044
Location
Right Side of CA on maps
IMHO USFS is only moving to P25 for LE functions, most other operations will remain Analog

They will lose a lot of coverage as a result, that is why they are leaving most communications analog. They lost quite a bit of coverage with the narrowband mandate already.
 

zerg901

Member
Premium Subscriber
Joined
Apr 19, 2005
Messages
3,725
Location
yup
"They will lose a lot of coverage as a result, that is why they are leaving most communications analog. They lost quite a bit of coverage with the narrowband mandate already."


That does not sound right. Didnt the studies from 10 years ago show that P25 and analog had the same range, but analog faded out at the edges of the coverage area, but the P25 dropped like a rock.
 

es93546

A Member Twice
Premium Subscriber
Joined
Aug 18, 2020
Messages
1,044
Location
Right Side of CA on maps
"They will lose a lot of coverage as a result, that is why they are leaving most communications analog. They lost quite a bit of coverage with the narrowband mandate already."


That does not sound right. Didnt the studies from 10 years ago show that P25 and analog had the same range, but analog faded out at the edges of the coverage area, but the P25 dropped like a rock.

Coverage was lost when narrowbanding was put in place. I would be interested in studies that have looked at analog vs. digital and any differences in coverage.
 

zerg901

Member
Premium Subscriber
Joined
Apr 19, 2005
Messages
3,725
Location
yup
Digital vs. Analog | Tait Radio Academy

Tait claims that digital is better than analog. But I dont recall ever seeing any radio studies that said fewer digital sites would be required than analog sites. Let me check further.

----------

Range: Digital Vs Analogue | Wildtalk

This article, apparently from 1970, says that experienced radio users find that analog and digital have the same range.

----------

https://www.npstc.org/download.jsp?...id=3204&file=P25_Best_Practice_Specifying.pdf

per page 11 of 39 - Phase 2 sites may need to be closer than Phase 1 sites - maybe 2013 info

(never heard that before - just throwing this in to make things more confusing)

---------

C4FM (Fusion) vs Analog on VHF: real world experiences?

Dec 10 2017 comment by a ham - no real incentive to switch from analog to digital
 
Last edited:

es93546

A Member Twice
Premium Subscriber
Joined
Aug 18, 2020
Messages
1,044
Location
Right Side of CA on maps
Digital vs. Analog | Tait Radio Academy

Tait claims that digital is better than analog. But I dont recall ever seeing any radio studies that said fewer digital sites would be required than analog sites. Let me check further.

----------

I'm not sure what you are trying to convey here. I know that having fewer sites once a system switches to digital is likely not the case. I think the opposite is true. Digital tends to get distorted in marginal coverage areas, making it nearly impossible to copy. With analog other noises might cause difficulties in understanding the transmissions, but can often be copied. As I understand it, or so I've heard, digital is all or nothing, that in marginal areas you don't get any signal at all, whereas an analog signal might not provide copy for every single word, but will give you a few words, which might be enough to understand what the traffic is. I have a lot of experience with this one. Sometimes you get into a situation where you can recieve a base station or another unit, both using a repeater, while they cannot copy or barely copy. Sometimes other units or base stations will then ask you a number of questions, with the old "one click for negative and two clicks for affirmative" procedure. Is this possible with digital?

I remember switching from an analog cell phone to digital. The tinny sound, the distortion and dropped calls became more frequent after leaving analog. This in rural areas where redundancy with other nearby cells does not exist, because cell areas are huge and not numerous.

I have a suspicion that radio manufacturers try to sell digital and trunking, when the best option, on the ground, is to stay simple on lower frequency bands.
 

jake_Braker

C/O 2Ø21
Premium Subscriber
Joined
Sep 27, 2018
Messages
591
Location
Somewhere in NC
As far as federal agencies go, it's going to be mostly analog or P-25 digital. Yes, some agencies, such as the US Postal Service, have been deploying DMR systems at their mail sorting faculties and small agencies or offices have been reported to be using NXDN or DMR radios.

As for the P-25, if it's a conventional channel, it will be Phase 1. Phase 2 is only used on trunking systems.

I doin't know what kind of radio you have, but some models are designed not to pass the encrypted audio, so you would hear nothing if encrypted. The Whistlers can block the encrypted sound and the Uniden radio skip encrypted transmissions.

- Chris
Hey Chris, I know I'm a bit late to the party here, but I was wondering if there was a way I can disable the skipping of encrypted systems so that way I can at least make note of the frequency/TGID being used?
 

INDY72

Monitoring since 1982, using radios since 1991.
Joined
Dec 18, 2002
Messages
14,636
Location
Indianapolis, IN
Hey Chris, I know I'm a bit late to the party here, but I was wondering if there was a way I can disable the skipping of encrypted systems so that way I can at least make note of the frequency/TGID being used?
That depends on your scanner model.
 
Status
Not open for further replies.
Top