Base/Step/Offset Calculation?

mbstone99 · #1 (**permalink**) 10-15-2012, 12:43 AM

Does anyone know what the general area where base/step/offset starts for the 420Mhz band? I was out in Mississauga today scanning the Petro Canada Refinery. They have a Motorola Type 2 System with licensed frequencies 420.1000, 2000, 3000, 4000 (409.1000, 2000, 3000, 4000 are licensed which I believe are the inputs). I heard voice traffic on 3000 and the CC on 4000 but wasn't able to figure out the base/step/offset as I didn't have a laptop with me. I did see tg 16 and 48 active when I was monitoring the CC. Any help would be appreciated.

Matt

MikeOxlong · #2 (**permalink**) 10-15-2012, 6:01 AM

You'll need to get the channel numbers sent over the control channel first.

You could always guess with the lowest frequency being the base with an offset of 380 and then play with the spacing to see if it will track the other frequencies.

mbstone99 · #3 (**permalink**) 10-15-2012, 10:22 AM

Quote:

Originally Posted by MikeOxlong

You'll need to get the channel numbers sent over the control channel first.

You could always guess with the lowest frequency being the base with an offset of 380 and then play with the spacing to see if it will track the other frequencies.

I thought that would be the case. Damn. I was trying a 12.5khz step but looking at similar Motorola trunks in the 421/422mhz band I wonder if that band is a 25khz step not 12.5khz?

Matt

MikeOxlong · #4 (**permalink**) 10-15-2012, 10:52 AM

It can be any step that the system programmer wants as long as its set the same in the subscriber radios.

Forts · #5 (**permalink**) 10-15-2012, 1:48 PM

I find with most UHF systems I have to search to find the bulk of the voice channels for the system, then (using another radio) compare them to the activity I'm seeing on Trunk88/UT. Once you can fill in the blanks of what frequency fits which LCN, then you can usually figure out the base/step/offset. It's a pain, but it's doable.

slicerwizard · #6 (**permalink**) 10-16-2012, 7:41 AM

723D, "Petro-Canada - 385 Southdown Rd; BSI=VCV834"

Bandplan Range #1 = 420.1000 12.5 380

Bandplan Range #2 = 451.0000 12.5 480

Input Bandplan Range #1 = 409.1000 12.5 0

Input Bandplan Range #2 = 456.0000 12.5 100

;;[Channels]

; channels: bandplan channel number, physical channel number, frequency, (input bandplan channel number, input frequency,) time limit, BSI, control channel, comms count

380, 0, 420.1000, 0, 409.1000, 0, 1, 0, 41
388, 0, 420.2000, 8, 409.2000, 0, 0, 2, 0 ; CC (current)
396, 0, 420.3000, 16, 409.3000, 0, 0, 0, 56
404, 0, 420.4000, 24, 409.4000, 0, 0, 0, 42
607, 0, 452.5875, 227, 457.5875, 0, 0, 0, 40
724, 0, 454.0500, 344, 459.0500, 0, 0, 0, 29

mbstone99 · #7 (**permalink**) 10-17-2012, 12:22 AM

Quote:

Originally Posted by slicerwizard

723D, "Petro-Canada - 385 Southdown Rd; BSI=VCV834"

Bandplan Range #1 = 420.1000 12.5 380

Bandplan Range #2 = 451.0000 12.5 480

Input Bandplan Range #1 = 409.1000 12.5 0

Input Bandplan Range #2 = 456.0000 12.5 100

;;[Channels]

; channels: bandplan channel number, physical channel number, frequency, (input bandplan channel number, input frequency,) time limit, BSI, control channel, comms count

380, 0, 420.1000, 0, 409.1000, 0, 1, 0, 41
388, 0, 420.2000, 8, 409.2000, 0, 0, 2, 0 ; CC (current)
396, 0, 420.3000, 16, 409.3000, 0, 0, 0, 56
404, 0, 420.4000, 24, 409.4000, 0, 0, 0, 42
607, 0, 452.5875, 227, 457.5875, 0, 0, 0, 40
724, 0, 454.0500, 344, 459.0500, 0, 0, 0, 29

Great work slicer! Thanks! I never would of known about the extra two channels either.

Matt

mbstone99 · #8 (**permalink**) 10-17-2012, 1:26 AM

There are two others frequencies that use 409.1/2/3/4 and 420.1/2/3/4 in the Toronto area. I believe they are both trunked if I remember correctly but not sure what flavour. I was going to check them out sometime or another when I get into the city. One is the Woodbine Racetrack Slots and the other the Royal York Hotel. At least now I know if they are Motorola systems I have a hint on how to set up the band plan.

Matt

slicerwizard · #9 (**permalink**) 10-18-2012, 4:49 AM

Quote:

Originally Posted by mbstone99

Great work slicer! Thanks! I never would of known about the extra two channels either.

Yep, they're sneaky bastards...

Quote:

Originally Posted by mbstone99

There are two others frequencies that use 409.1/2/3/4 and 420.1/2/3/4 in the Toronto area. I believe they are both trunked if I remember correctly but not sure what flavour. I was going to check them out sometime or another when I get into the city. One is the Woodbine Racetrack Slots

LTR Standard

Area 0

420.1 LCN1
420.2 LCN2
420.3 LCN3
420.4 LCN4

Quote:

and the other the Royal York Hotel.

LTR Standard

Area 0

420.1 LCN1
420.2 LCN5
420.3 LCN9
420.4 LCN13

Quote:

At least now I know if they are Motorola systems I have a hint on how to set up the band plan.

Which is why they went with LTR... (never mind saving a small fortune on hardware...)

mbstone99 · #10 (**permalink**) 10-21-2012, 2:00 AM

Quote:

Originally Posted by slicerwizard

Yep, they're sneaky bastards...

LTR Standard

Area 0

420.1 LCN1
420.2 LCN2
420.3 LCN3
420.4 LCN4

LTR Standard

Area 0

420.1 LCN1
420.2 LCN5
420.3 LCN9
420.4 LCN13

Which is why they went with LTR... (never mind saving a small fortune on hardware...)

Wow.. great work!

Not sure if you can answer this one or anyone else but I recall a very long time ago (probably more than 5 years ago) there was a post on ScanOnt about the trunk at the Toronto Star printer ops building in Vaughan. I believe if I was not mistaken was a low power 900mhz Motorola trunk. Are they still using that system? The frequenices listed in the TAFL are 935.0125, 0250 and 0375, are those correct?

Matt

slicerwizard · #11 (**permalink**) 10-21-2012, 5:20 AM

Quote:

Originally Posted by mbstone99

Wow.. great work!

Bah - LTR is too easy..

Quote:

Not sure if you can answer this one or anyone else but I recall a very long time ago (probably more than 5 years ago) there was a post on ScanOnt about the trunk at the Toronto Star printer ops building in Vaughan.

That was on 21-Dec-1998.

Quote:

I believe if I was not mistaken was a low power 900mhz Motorola trunk. Are they still using that system? The frequenices listed in the TAFL are 935.0125, 0250 and 0375, are those correct?

The system is still on the air, still in-house low power, but not too healthy:

935.0375 control
935.0125 voice
935.0250 PCN3 - TIB Malfunction

DaveH · #12 (**permalink**) 10-21-2012, 9:34 AM

A bit of side issue, but isn't there at least one system in the GTA in the 409/420
sub-band, which is inverted i.e. outputs 409 and inputs 420...just trying to recall.

Dave

MikeOxlong · #13 (**permalink**) 10-21-2012, 9:37 AM

I think it was reported that the Rogers Centre was inverted but IIRC, the outputs were on the high side.

Forts · #14 (**permalink**) 10-21-2012, 11:13 AM

That's what I recall from my searching while I was there... TRBO inputs were in the 409's while the outputs were 420's. I still wonder why they changed it from a Capacity Plus system to a Connect Plus system... big price difference in the setup there. But I guess Rogers isn't exactly hurting for $$ either haha

MikeOxlong · #15 (**permalink**) 10-21-2012, 11:17 AM

I asked the same thing about Casino Rama which runs a Connect Plus single site system.

The cost of the controller alone is something like $20,000.

I was told that the main reason was they could inhibit lost radios. I'm guessing there's some other features that make the cost worthwhile.

EJB · #16 (**permalink**) 10-21-2012, 2:43 PM

Quote:

Originally Posted by mbstone99

Wow.. great work!

Not sure if you can answer this one or anyone else but I recall a very long time ago (probably more than 5 years ago) there was a post on ScanOnt about the trunk at the Toronto Star printer ops building in Vaughan. I believe if I was not mistaken was a low power 900mhz Motorola trunk. Are they still using that system? The frequenices listed in the TAFL are 935.0125, 0250 and 0375, are those correct?

Matt

Matt: You were one of the Hamilton guys, are you back from Texas for good or just visiting?

mbstone99 · #17 (**permalink**) 10-21-2012, 4:39 PM

Quote:

Originally Posted by EJB

Matt: You were one of the Hamilton guys, are you back from Texas for good or just visiting?

I am actually back for good..

Matt

EJB · #18 (**permalink**) 10-21-2012, 4:44 PM

Quote:

Originally Posted by mbstone99

I am actually back for good..

Matt

Welcome back, I hope your reason for coming back was good, I dunno anything about Texas, not sure I'd like it there.

There isnt all that much to scan here anymore, not like it once was, Halton and Hamilton PS are doing their thing w/o us bums listening :-)

mbstone99 · #19 (**permalink**) 10-22-2012, 7:21 PM

Quote:

Originally Posted by EJB

Welcome back, I hope your reason for coming back was good, I dunno anything about Texas, not sure I'd like it there.

There isnt all that much to scan here anymore, not like it once was, Halton and Hamilton PS are doing their thing w/o us bums listening :-)

Thanks. Well I am glad to be back home but I do miss things in Texas. Unfortunately my wife told me sh e wanted a divorce back in June and I also lost my job back in May. So originally I was going to stay until the spring but my dad has Alzheimer's and has been getting progressively worse over past couple years and it was time that I came home sooner then late to help my mom.

I really can't believe of all of the encryption that is being used around Southern Ontario area, especially Hamilton encrypting their whole system! I guess it is just a sign of the times.

Matt

mbstone99 · #20 (**permalink**) 10-22-2012, 7:23 PM

Actually I have a question for slicer as he make know just to get this semi back on topic. I take it that both the Brampton and Hamilton sites for Fleetcom/Lakeshore are gone and only the Toronto system is left? I haven't heard a peep out of either system since I have come back.

Matt