How feasible is it to pick up Baltimore City in Southern Howard County?

[SpectrumKing]

I'm in Columbia in a 2-story house. Very much want to pickup Baltimore City because I don't think there's a feed with all the talkgroups, so I want to provide that. My budget is $700 and I am not permitted to put a massive antenna outside but anything inside is fine.

 

[maus92]

The nearest Baltimore City transmit sites to Howard County are on the roof of St Agnes Hospital, and a 270' freestanding tower off of Edmonston Ave in West Baltimore. The city uses 75W transmitters at these sites, whereas a county site might use a 100W transmitter. Each of those sites is roughly 12 air miles from Howard General Hospital, and probably farther to where you live. So, you probably won't have much luck receiving the city system from where you are, but you *might* be in a good position to receive Montgomery County (before they migrate to a Phase 2 system.) As far as radios go, if you want to buy a scanner and you live in Maryland, buy a SDS 100 or SDS200 - you will require it in the near future as the systems surrounding your home migrate to P25 Phase 1/2 systems.

 

[maus92]

deleted.

 

[SpectrumKing]

I found this feed which is for Baltimore police:
http://bmorescanner.dyndns.org:8000/index.html?sid=1

Questions. It looks like currently the feed is broken up into geographical districts. How does that translate into the trunked system? Am I missing anything by listening to this main feed?

I’m still trying to understand everything with radio, so correct me if I’m wrong, but aren't trunked talkgroups like filters on the feed?

 

[SpectrumKing]

The nearest Baltimore City transmit sites to Howard County are on the roof of St Agnes Hospital, and a 270' freestanding tower off of Edmonston Ave in West Baltimore. The city uses 75W transmitters at these sites, whereas a county site might use a 100W transmitter. Each of those sites is roughly 12 air miles from Howard General Hospital, and probably farther to where you live. So, you probably won't have much luck receiving the city system from where you are, but you *might* be in a good position to receive Montgomery County (before they migrate to a Phase 2 system.) As far as radios go, if you want to buy a scanner and you live in Maryland, buy a SDS 100 or SDS200 - you will require it in the near future as the systems surrounding your home migrate to P25 Phase 1/2 systems.

Just measured from the two locations. My house is 13 miles and 14 miles, respectively.

Is P25 compatible with SDR’s?

 

[doctordialtone]

aren't trunked talkgroups like filters on the feed?

Trunking Basics

Trunked Radio

 

[maus92]

Just measured from the two locations. My house is 13 miles and 14 miles, respectively.

Is P25 compatible with SDR’s?

If you use the proper software, yes. OP25 for P25 Phase 2 systems, DSD+ for Phase 1 (it might also do Phase 2, not sure.) It does take a bit of tweaking to get it configured properly. OP25 is a linux based program; I have an install running on a Raspberry Pi 3+.

 

[maus92]

I found this feed which is for Baltimore police:
http://bmorescanner.dyndns.org:8000/index.html?sid=1

Questions. It looks like currently the feed is broken up into geographical districts. How does that translate into the trunked system? Am I missing anything by listening to this main feed?

I’m still trying to understand everything with radio, so correct me if I’m wrong, but aren't trunked talkgroups like filters on the feed?

Those are police districts and they are unrelated to the functioning of the radio system other than each being assigned a discrete TGID. I notice that the feed provider is using a RTL-SDR as the source radio,

 

[ka3jjz]

Talkgroups ae not like filters - they are users (usually groups of users). The Trunking Basics link in message 6 of this thread given earlier has much more to say about this....Mike

 

[riveter]

You are very, very unlikely to effectively receive decodable signal on the City system from southern Howard. Geography doesn't work on your side for that.

 

[SpectrumKing]

Even with an SDS100 or SDS200?

 

[maus92]

Even with an SDS100 or SDS200?

No - still unlikely. The tech of the transmitter and waveform, and the height of the transmit tower still limits reception range to about 8-12 miles to a receiver indoors at ground level

 

[u2brent]

If you use the proper software, yes. OP25 for P25 Phase 2 systems, DSD+ for Phase 1 (it might also do Phase 2, not sure.) It does take a bit of tweaking to get it configured properly. OP25 is a linux based program; I have an install running on a Raspberry Pi 3+.

Yes DSD+ Fastlane does track P25 PH2 now..

Even with an SDS100 or SDS200?

I'd try the SDR dongles before investing in the SDS100/200 to see first..

 

[SpectrumKing]

I'd try the SDR dongles before investing in the SDS100/200 to see first..

I was having so much trouble with them. I didn't realize how there really is no 1 good program. Different functionalities are fractured over half a dozen different programs. Tried DSD+, OP25, SDRtrunk, Unitrunker. Each seemed to have a dependency that I couldn't resolve or a config file I didn't know what to put in.

I eventually got some transmissions but it was just static and garbled.

If anyone has a Howard County, MD DSD+ file or other config file, please share it. It would save me a lot of aggravation. Then I can move onto phase 2 of the project, which is to automate recording and have it publicly available on a website using the OpenMHZ.com code.

 

[maus92]

I was having so much trouble with them. I didn't realize how there really is no 1 good program. Different functionalities are fractured over half a dozen different programs. Tried DSD+, OP25, SDRtrunk, Unitrunker. Each seemed to have a dependency that I couldn't resolve or a config file I didn't know what to put in.

I eventually got some transmissions but it was just static and garbled.

If anyone has a Howard County, MD DSD+ file or other config file, please share it. It would save me a lot of aggravation. Then I can move onto phase 2 of the project, which is to automate recording and have it publicly available on a website using the OpenMHZ.com code.

I was incorrect about OP25 - it does do P25 Phase 1 as well - just no analog. But you are correct: there really is no one good all-around software / program - yet.

 

[SpectrumKing]

I was incorrect about OP25 - it does do P25 Phase 1 as well - just no analog. But you are correct: there really is no one good all-around software / program - yet.

I’m on a MacBook Pro. An issue I was having was that Parallels (which runs my VMs) would let me attach one of the two SDR’s but when i went to attach the second one, it would disconnect the first SDR.

I ordered a Uniden 436HP from Amazon. If I like it I’ll keep it and if not, then I just paid whatever return shipping is (around $10) to rent a scanner for a month.

 

[maus92]

I’m on a MacBook Pro. An issue I was having was that Parallels (which runs my VMs) would let me attach one of the two SDR’s but when i went to attach the second one, it would disconnect the first SDR.

I ordered a Uniden 436HP from Amazon. If I like it I’ll keep it and if not, then I just paid whatever return shipping is (around $10) to rent a scanner for a month.

You *could* buy a refirb Windows notebook for $300 to run the software - that's what I did. Or to run OP25, a RPi 3+. The OP25 soulution only requires one SDR dongle.

 

[dcr_inc]

Or spend the extra and get a Unications G4 and listen to it all

 

[maus92]

Or spend the extra and get a Unications G4 and listen to it all

Good radio, but hard to stream with it - which is a goal for him. And the county he lives in currently has a SmartZone system thus G4/5 are incompatible (although probably will transition to a P25 P1 system shortly.) Seems like a working DSD+ installation is his best bet for now.

 

[maus92]

Good radio, but hard to stream with it - which is a goal for him. And the county he lives in currently has a SmartZone system thus G4/5 won't work currently (although probably will transition to a P25 P1 system shortly.) Seems like a working DSD+ installation is his best bet for now.