Portland P25 phase I or II demodulation?

[rpurinton]

We’re having problems with simulcast distortion on the Whistler 1040 and 1065 that we used to run Broadcastify and Zello for Portland and South Portland fire department.
apparently these models of scanner although they support basic P 25 phase 1 they lack proper demodulators for use on simulcast systems such as Portland’s.

I’m planning to invest in a box of SDR dongle‘s and I want to make sure that I’m going to be able to decode everything reliably.

So I was looking at the database information for the Portland PD 25 system and I found what looks to be some conflicting information regarding demodulation.

See attached screenshots for the main page and the page that I get when I click simulcast link.

One page says Phase 1 the other Phase 2? This might just be a database discrepancy.

is the demodulator correct?

I was checking out a tutorial for SDRtrunk software and it only showed C4FM and Simulcast LSM support in it’s P25 decoder. I’ll probably have most of my discussion in the SDR forum but I wanted to check in here to make sure I’m going to be able to find a compatible decoder.

Thanks for any feedback

 

[a417]

It's phase 1.

I have a DSD+ running RTL-SDR v3 hardware for decoding & op25 running on ARM hardware for streaming and can verify that it's p25 phase 1. I recall seeing that discrepancy in the pages some time ago.

 

[rpurinton]

It's phase 1.

I have a DSD+ running RTL-SDR v3 hardware for decoding & op25 running on ARM hardware for streaming and can verify that it's p25 phase 1. I recall seeing that discrepancy in the pages some time ago.

awesome thanks for the fast reply. I thought so. do you know what your demodulator is set to? C4FM, lsm, CQPSK, or something’s else?

you don’t have any issues with audio cutout from simulcast distortion?

 

[a417]

no cutout at all. the op25 gives better sounding audio & responsiveness, and op25 is set up for "CPQSK".

The closest tower to me is the site by Riverside.

 

[ScanMaine]

on that image on your post with the red circle, what is that supposed to be. im seeing it more and more but im not understanding it.

 

[a417]

it's a computer generated circle for 'theoretical coverage'.

 

[ScanMaine]

it's a computer generated circle for 'theoretical coverage'.

That is what i thought but wasn't sure! So most likely its not correct cause bigger and good antennas can pick it up and thats based off GPS

 

[a417]

and the theoretical coverage as depicted is not as definitive as an RF Propagation study, which is a computer generated model that takes things like radiated power, geography, distance, height above terrain of transmitter that would then give you a heat-map style projection of where the radios should work, and where they most likely wont.

that red thing you reference is just a cool red circle. I'll bet an RF Propagation model would be very different.

 

[ScanMaine]

and the theoretical coverage as depicted is not as definitive as an RF Propagation study, which is a computer generated model that takes things like radiated power, geography, distance, height above terrain of transmitter that would then give you a heat-map style projection of where the radios should work, and where they most likely wont.

that red thing you reference is just a cool red circle. I'll bet an RF Propagation model would be very different.

10-4 I appreciate it bud!

 

[ME343]

It could have been entered wrong in the database. I fixed it show the P25 Phase I simulcast modulation.

 

[a417]

It could have been entered wrong in the database. I fixed it show the P25 Phase I simulcast modulation.

You're a good man, Charlie Brown.

 

[a417]

on that image on your post with the red circle, what is that supposed to be. im seeing it more and more but im not understanding it.

I found it, couldn't remember where I saved the link.

Portland's System Migration Report , look at pages 21 - 27. That's what serious modeling looks like.

 

[ScanMaine]

I found it, couldn't remember where I saved the link.

Portland's System Migration Report , look at pages 21 - 27. That's what serious modeling looks like.

ty bud

 

[rpurinton]

The wiki page has been updated to show the right info, for anyone else interested it is Phase 1 Simulcast LSM/CQPSK. Portland is back on Broadcastify and Zello