Colorado Springs DTRS site ch/freq moves

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dw2872

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I've been monitoring the Colorado Springs sites of Cedar Heights (424) and Austin Bluffs (416) for a while now and noticed that two channels/frequencies that used to be on Austin Bluffs are now on Cedar Heights.

Is there any way anyone else in the area can confirm?
 

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dw2872

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Here is 416 Austin Bluffs updated tower file:

FileVersion:7
-TowerInfo
#This section is here for information only. With the exception
#of the Call Sign(s), This data is not Read back into the program at all.
System ID : D1C
System Name : State of Colorado DTRS
WACN : BEE07
Tower Number (Decimal): 4-16
Tower Number (Hex) : T0410
Tower Description : Austin Bluffs
Control Capabilities : Data,Voice,Registration
Call Sign(s) : WPMK711
Timestamp : Mon Jun 16 12:22:08 2014

-Tables
#Format: Table ID,Base Freq,Spacing,Input Offset,Assumed/Confirmed,BandWidth,Slots
00,851.00625,0.00625,-45.00000,"Confirmed",0.00625,1
01,762.00625,0.00625,30.00000,"Confirmed",0.00625,1

-Frequencies
#Format: Channel,Usage,Frequency(/Slot),Input Channel,Input Frequency(/Slot),Input Explicit(1/0),Hit Count
"00-0011","vi",851.07500,"00-0011",806.07500,0,195
"00-0203","vd",852.27500,"00-0203",807.27500,0,10748
"00-0213","vd",852.33750,"00-0213",807.33750,0,10767
"00-0281","vd",852.76250,"00-0281",807.76250,0,10797
"00-0287","vd",852.80000,"00-0287",807.80000,0,10707
"00-0331","vd",853.07500,"00-0331",808.07500,0,10701
"00-0377","vd",853.36250,"15-4095",0.00000,1,10688
"00-0409","avd",853.56250,"00-0409",808.56250,0,290
"00-0421","avd",853.63750,"00-0421",808.63750,0,96
"00-0441","av",853.76250,"00-0441",808.76250,0,1
"00-0461","c",853.88750,"00-0461",808.88750,0,0

-Neighbors
#Format: TowerID,TowerIDHex,System ID,Channel,Frequency,Tower Name
411,"T040B",d1c,"00-1437",859.98750,"Fountain Valley"
412,"T040C",d1c,"00-0433",853.71250,"Stanley Canyon"
413,"T040D",d1c,"00-1433",859.96250,"Ski Summit"
415,"T040F",d1c,"00-0267",852.67500,"Woodland Park"
417,"T0411",d1c,"00-1317",859.23750,"Peterson Air Force Base"
418,"T0412",d1c,"00-0437",853.73750,"Mount Pittsburg"
421,"T0415",d1c,"00-1349",859.43750,"Black Forest"
422,"T0416",d1c,"00-0837",856.23750,"Templeton Gap"
424,"T0418",d1c,"00-1569",860.81250,"Cedar Heights"
648,"T0630",d1c,"00-0327",853.05000,"Cheyenne Mountain"



-----------------



Here is 424 Cedar Heights updated tower file:

FileVersion:7
-TowerInfo
#This section is here for information only. With the exception
#of the Call Sign(s), This data is not Read back into the program at all.
System ID : D1C
System Name : State of Colorado DTRS
WACN : BEE07
Tower Number (Decimal): 4-24
Tower Number (Hex) : T0418
Tower Description : Cedar Heights
Control Capabilities : Data,Voice,Registration
Call Sign(s) : WPUF980
Timestamp : Mon Jun 16 15:08:48 2014

-Tables
#Format: Table ID,Base Freq,Spacing,Input Offset,Assumed/Confirmed,BandWidth,Slots
00,851.00625,0.00625,-45.00000,"Confirmed",0.00625,1
01,762.00625,0.00625,30.00000,"Confirmed",0.00625,1

-Frequencies
#Format: Channel,Usage,Frequency(/Slot),Input Channel,Input Frequency(/Slot),Input Explicit(1/0),Hit Count
"00-0097","v",851.61250,"00-0097",806.61250,0,9
"00-0143","v",851.90000,"00-0143",806.90000,0,8
"00-0481","vi",854.01250,"00-0481",809.01250,0,238
"00-0505","vd",854.16250,"00-0505",809.16250,0,3147
"00-0533","vd",854.33750,"15-4095",0.00000,1,3160
"00-0557","vd",854.48750,"00-0557",809.48750,0,3120
"00-0653","vd",855.08750,"00-0653",810.08750,0,3238
"00-0929","vd",856.81250,"15-4095",0.00000,1,3148
"00-1105","avd",857.91250,"00-1105",812.91250,0,1025
"00-1249","avd",858.81250,"00-1249",813.81250,0,506
"00-1409","avd",859.81250,"00-1409",814.81250,0,62
"00-1569","c",860.81250,"00-1569",815.81250,0,0

-Neighbors
#Format: TowerID,TowerIDHex,System ID,Channel,Frequency,Tower Name
411,"T040B",d1c,"00-1437",859.98750,"Fountain Valley"
412,"T040C",d1c,"00-0433",853.71250,"Stanley Canyon"
413,"T040D",d1c,"00-1433",859.96250,"Ski Summit"
414,"T040E",d1c,"00-0451",853.82500,"Calhan"
415,"T040F",d1c,"00-0267",852.67500,"Woodland Park"
416,"T0410",d1c,"00-0461",853.88750,"Austin Bluffs"
417,"T0411",d1c,"00-1317",859.23750,"Peterson Air Force Base"
418,"T0412",d1c,"00-0437",853.73750,"Mount Pittsburg"
419,"T0413",d1c,"00-1357",859.48750,"Truckton"
421,"T0415",d1c,"00-1349",859.43750,"Black Forest"
422,"T0416",d1c,"00-0837",856.23750,"Templeton Gap"
 

n0nhj

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The Co Sprs/El Paso Co zone has a system where frequencies can be moved between sites. - Motorola calls it Dynamic Frequency Blocking (DFB).

From a Motorola Document on the web:
Dynamic Frequency Blocking (Optional): When frequencies are sparse, Dynamic
Frequency Blocking allows you to reuse frequencies within cells in close proximity within the
system. This feature automatically allows the system to dynamically block the frequency at
site A while transmitting the same frequency at Site B.

It basically means they have a frequency / base station installed at several sites, and the site controller will activate it only at the site the has the highest loading. So even though you might log it on one site this week, some incident or special event could drive up the loading on another site where gets the use of the frequency next week.

At some point I think I identified 411 Fountain Valley as being one of the sites with DFB, but I don't have any others identified.

Chuck
 

dw2872

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I was afraid that might be the case and it totally makes sense. I was just hoping they had not made that technological advance yet. Thanks so much for that info. At least we now know that Cedar Heights and Austin Bluffs can do that and share channels/frequencies as needed.

It would be great to find documentation that shows how that all works.

Also, which sites was Fountain Valley doing that with?

Another thing I noticed is that neighbor connections between sites sometimes seem to change. I wonder if that is something automatic/dynamic as well.
 

dw2872

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It doesn't appear that Ski Summit (413) has this enabled.

I waited for a busy part of the day to ID all of the available channel/freqs on this site and when the last available freq was finally used, then another user tried for a channel grant and got queued (busied?).

I saw this several times on Ski Summit. It already has so many freqs assigned on that site anyway.
 

dw2872

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As far as the 2 freqs that seemed to move from the Austin Bluffs site to the Cedar Heights site, I will monitor Austin Bluffs for a few days and see if it uses those again anytime soon. Thanks for the Info Chuck!
 

dw2872

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OK, now I see those two chans/freqs back on Austin Bluffs as well (just 7 channel grants today) but yes that is pretty much solid confirmation of what Chuck was talking about with the DBF-Dynamic
Frequency Blocking.

It looks like at least Austin Bluffs and Cedar Heights share these two freqs.

It will be interesting to see what other sites share freqs as needed. Nightmare for the DB folks though.
 

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Mick

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Yesterday Pro96Com logged ten hits each on 851.6125 and 851.900 at Site 424. Some of the other freqs got up to 3,400 hits.
 

dw2872

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Yep Mick, that shows both sites were using the same two freqs on the same day. Can you post some times and channel grant data like I did above?

You can see from the above snapshot from Excel, filtered to only show those two channels, the busy time of day for Austin Bluffs was around 3:30 pm and a really short time at 4:21 pm. I am wondering what the busy time was on Cedar Heights.

Also, I am collecting on Fountain Valley for a while so I can see if there are any channel/freqs it shares with any other site (like Chuck said above).
I am thinking it may share with Ski Summit, or even Mount Pittsburg because that is a very busy site that can only be seen on the south side of the county (Cheyenne Mountain and other nearby peaks block it from most of the city).
 
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Spitfire8520

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The Co Sprs/El Paso Co zone has a system where frequencies can be moved between sites. - Motorola calls it Dynamic Frequency Blocking (DFB).
Does this apply to any other zone in Colorado or just Zone 4? I wasn't aware of such a feature, but it explains a lot of what I've seen over the past months of logging sites where neighboring sites that have overlapping coverage areas end up using some common frequencies. Some of the Zone 1 examples would be 104 and 107 sharing 851.27500, 107 and 108 sharing 851.11250, 107 and 102 sharing 853.17500, and 103 and 110 sharing 852.13750. If this applies system wide, then it would seem that a good indication for identifying DFB frequencies is to look at the tower files for sites you have logged for an extended period of time and then looking for something with extremely low hit counts when compared to the other frequencies.
 

dw2872

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I would definitely check to see if any two sites are using the same freq at least on the same day.

Things can be moved around manually and we might not notice for a while, but dynamically sharing the same freqs is a different story. One way to make sure and confirm what you were talking about with tower files is to check the channel grant files for two sites.
 

dw2872

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I would definitely check to see if any two sites are using the same freq at least on the same day.

Things can be moved around manually and we might not notice for a while, but dynamically sharing the same freqs is a different story. One way to make sure and confirm what you were talking about with tower files is to check the channel grant files for two sites.
Spirfire, that is a great idea you have.

I realized what I suggested earlier might be hard to do unless you have two Pro96Coms or 2 people with it at the same time.

I was able to confirm one of the ones you listed, the site 107/108 sharing (channel 00-0017/freq 851.1125). It does look like they do in fact both use it from time to time.

108 used it on 5/30/2014 at 12:29
107 used it on 6/01/2014 at 15:13
107 used it on 6/03/2014 at 14:01
108 used it on 6/10/2014 at 15:32 and 15:40

...and probably more but at least this shows they both use it alternately.

Cool stuff!
 
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dw2872

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Thanks to Spitfire and his list of possible shares, Chuck's idea about DFB, and Steve's TrunkingLogs.com, I can also now confirm that site 104 and 107 both share:

(channel 00-0043/freq 851.2750).

104 used it on 4/16/2014 at 08:39
107 used it on 5/20/2014 at 17:59
104 used it on 5/30/2014 at 13:14

These times/occurrences are hard to find since these apparently only come on when it is super busy so the channels are rarely used.
 
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Mick

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Hi Dan, Is this the time and grant data needed?

FileVersion:7
-TowerInfo
#This section is here for information only. With the exception
#of the Call Sign(s), This data is not Read back into the program at all.
System ID : D1C
System Name :
WACN : BEE07
Tower Number (Decimal): 424
Tower Number (Hex) : T0418
Tower Description : (null)
Control Capabilities : Data,Voice,Registration
Call Sign(s) : WPUF980
Timestamp : Wed Jun 18 22:41:11 2014

-Tables
#Format: Table ID,Base Freq,Spacing,Input Offset,Assumed/Confirmed,BandWidth,Slots
00,851.00625,0.00625,-45.00000,"Confirmed",0.00625,1
01,762.00625,0.00625,30.00000,"Confirmed",0.00625,1

-Frequencies
#Format: Channel,Usage,Frequency(/Slot),Input Channel,Input Frequency(/Slot),Input Explicit(1/0),Hit Count
"00-0097","v",851.61250,"00-0097",806.61250,0,10
"00-0143","v",851.90000,"00-0143",806.90000,0,10
"00-0481","vi",854.01250,"00-0481",809.01250,0,244
"00-0505","vd",854.16250,"00-0505",809.16250,0,4050
"00-0533","vd",854.33750,"00-0533",809.33750,0,4015
"00-0557","vd",854.48750,"00-0557",809.48750,0,3964
"00-0653","vd",855.08750,"00-0000",851.00625,1,3948
"00-0929","vd",856.81250,"00-0000",851.00625,1,3944
"00-1105","avd",857.91250,"00-1105",812.91250,0,1114
"00-1249","av",858.81250,"00-1249",813.81250,0,571
"00-1409","av",859.81250,"00-1409",814.81250,0,51
"00-1569","c",860.81250,"00-1569",815.81250,0,0

-Neighbors
#Format: TowerID,TowerIDHex,System ID,Channel,Frequency,Tower Name
411,"T040B",d1c,"00-1437",859.98750,""
412,"T040C",d1c,"00-0433",853.71250,""
413,"T040D",d1c,"00-1433",859.96250,""
414,"T040E",d1c,"00-0451",853.82500,""
415,"T040F",d1c,"00-0267",852.67500,""
416,"T0410",d1c,"00-0461",853.88750,""
417,"T0411",d1c,"00-1317",859.23750,""
418,"T0412",d1c,"00-0437",853.73750,""
419,"T0413",d1c,"00-1357",859.48750,""
421,"T0415",d1c,"00-1349",859.43750,""
422,"T0416",d1c,"00-0837",856.23750,""



Yep Mick, that shows both sites were using the same two freqs on the same day. Can you post some times and channel grant data like I did above?

You can see from the above snapshot from Excel, filtered to only show those two channels, the busy time of day for Austin Bluffs was around 3:30 pm and a really short time at 4:21 pm. I am wondering what the busy time was on Cedar Heights.

Also, I am collecting on Fountain Valley for a while so I can see if there are any channel/freqs it shares with any other site (like Chuck said above).
I am thinking it may share with Ski Summit, or even Mount Pittsburg because that is a very busy site that can only be seen on the south side of the county (Cheyenne Mountain and other nearby peaks block it from most of the city).
 

dw2872

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No Mick, it would actually need to be the "grant log" file that shows each transmission and which chan/freq is used each time. But you would probably need to email that because it can be large, unless you filter it using Excel and take a snapshot like I did above in this post ( http://forums.radioreference.com/co...ings-dtrs-site-ch-freq-moves.html#post2204526 )

The "grant log" is among the files in the same directory as the "tower" file you posted the text from. Here is an example of what the file names look like:
 

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dw2872

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I am curious how this is going to be handled, database-wise.

Are the shared frequencies going to be listed on multiple site entries, possibly with some notation they are shared with adjacent sites but blocked (using Motorola's DFB feature) from use by the other when needed?

Dynamic Frequency Blocking (DFB) definition below is an excerpt from a related patent # US 20080108360 A1, "System and method for reassigning an active call to a new communication channel"... which may or may not be the same DFB used by P25 but it is definitely similar.

"DFB is a feature used by communication systems to eliminate interference between two communication channels at different base sites. Thus, if communication channel A at a first base site is interfering with communication channel B at a second base site, the zone controller blocks or prevents a call from occurring on communication channel B if there is a call on communication channel A. Typically, in order to preserve resources, a call is only assigned to a communication channel that causes such interference once all other available non-interfering channels at the base site are used. It may therefore be desirable to reassign the active call currently assigned to an interfering communication channel to a non-interfering communication channel once a non-interfering communication channel becomes available."
 
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