An idiot in Ontario county

[TheStressMachine]

Title is my disclaimer. I'm not new to the hobby, but I've had good luck squeaking by with minimal knowledge until I moved. I'm new to the area and I'm having trouble wrapping my head around this problem.

I previously lived in the Boston area and purchased two "MVP" scanners (Minimum Viable P25), the BCD996P2 and the BCD325P2 because money. They both worked fine for the very local monitoring I was looking for.

Now I'm trying to monitor the Ontario North Simulcast. I'm a mile northwest from the tower in the center of Canandaigua and put a 700-900mhz ducky on the base scanner, but I get nothing. Occasionally I get a hit with no audio and the RSSI value is in the 3 or 4 hundreds (I don't know how to translate that to dbi). For comparison a weak FM station comes in above the 500's, so I assume weak signal, maybe that's my first bad assumption.

When I grab my portable with said ducky and ride my bike towards the tower with broadcastify in one ear (thanks whoever you are) and the scanner in the other, I start receiving reliably about a half mile away.

Now I've heard that minimum viable scanners such as mine can struggle with Simulcast, but the examples I find online seem to suffer from distorted audio, not weak-signal-no-audio.

I'm willing to start the campaign of convincing my wife to buy better equipment if I know it will work, but concluding on whether I have a signal problem or a simulcast problem is tough. I thought it was reasonable that an indoor antenna can catch the tower just down the street.

Do you have any pointers on confirming the type of problem I have and if antenna's or new equipment are the remedy?

 

[wtp]

it does sound like simulcast problems.
i have been around scanners since 1970 and had a good many radio shack and uniden radios.
the system here changed to 700 Mhz simulcast and the best i could get at home was ,
1/4 second of sound and then 1/4 second of silence.
when getting out of the neighborhood the 325 worked fine.
we saved up and bought a uniden SDS100, and it has worked great from day one, anywhere !
i am not here to try and sell you one or something like that, but it does work.
it is on now next to the wife.

 

[Joshuascanner2021]

Title is my disclaimer. I'm not new to the hobby, but I've had good luck squeaking by with minimal knowledge until I moved. I'm new to the area and I'm having trouble wrapping my head around this problem.

I previously lived in the Boston area and purchased two "MVP" scanners (Minimum Viable P25), the BCD996P2 and the BCD325P2 because money. They both worked fine for the very local monitoring I was looking for.

Now I'm trying to monitor the Ontario North Simulcast. I'm a mile northwest from the tower in the center of Canandaigua and put a 700-900mhz ducky on the base scanner, but I get nothing. Occasionally I get a hit with no audio and the RSSI value is in the 3 or 4 hundreds (I don't know how to translate that to dbi). For comparison a weak FM station comes in above the 500's, so I assume weak signal, maybe that's my first bad assumption.

When I grab my portable with said ducky and ride my bike towards the tower with broadcastify in one ear (thanks whoever you are) and the scanner in the other, I start receiving reliably about a half mile away.

Now I've heard that minimum viable scanners such as mine can struggle with Simulcast, but the examples I find online seem to suffer from distorted audio, not weak-signal-no-audio.

I'm willing to start the campaign of convincing my wife to buy better equipment if I know it will work, but concluding on whether I have a signal problem or a simulcast problem is tough. I thought it was reasonable that an indoor antenna can catch the tower just down the street.

Do you have any pointers on confirming the type of problem I have and if antenna's or new equipment are the remedy?

The ontario county north cells are going to be quite a challenge for you, all of the North sites are pretty close together. In Canandaigua area especially. I've never had much luck with even a yagi. Your only options are what has been suggested extensively here in the forms for Simulcast issues. An SDS 100 or 200, a unication G4 (which is all you need for ontario county since most everything for the county is on the Monroe/ontario TRS). Or a computer or similar and run SDR trunk with and SDR dongle.

I don't know who runs the two feeds for broadcastify for the police scanner side of things but both feeds are a good substitute.

I run the ontario fire and ems analog main channel which you can only hear the tones on that anyways. I even get the analog simulcast issues as well but I'm working on fixing that issue.

 

[k2hz]

The ontario county north cells are going to be quite a challenge for you, all of the North sites are pretty close together. In Canandaigua area especially. I've never had much luck with even a yagi. Your only options are what has been suggested extensively here in the forms for Simulcast issues. An SDS 100 or 200, a unication G4 (which is all you need for ontario county since most everything for the county is on the Monroe/ontario TRS). Or a computer or similar and run SDR trunk with and SDR dongle.

I don't know who runs the two feeds for broadcastify for the police scanner side of things but both feeds are a good substitute.

I run the ontario fire and ems analog main channel which you can only hear the tones on that anyways. I even get the analog simulcast issues as well but I'm working on fixing that issue.

This post describes the situation very well. A proper scanner or SDR is the only solution.
As you have found, normal scanners can only receive the system very close to a tower, and probably with the attenuator on, to eliminate the simulcast distortion that the scanner can not handle. I strongly recommend a Unication G4 due to the spurious response and desense issues with the SDS scanners that can be a problem although they do well with Local P25 simulcast and may be OK in Ontario County but have problems with strong in-band signals in Rochester.

 

[TheStressMachine]

The ontario county north cells are going to be quite a challenge for you, all of the North sites are pretty close together. In Canandaigua area especially. I've never had much luck with even a yagi. Your only options are what has been suggested extensively here in the forms for Simulcast issues. An SDS 100 or 200, a unication G4 (which is all you need for ontario county since most everything for the county is on the Monroe/ontario TRS). Or a computer or similar and run SDR trunk with and SDR dongle.

I don't know who runs the two feeds for broadcastify for the police scanner side of things but both feeds are a good substitute.

I run the ontario fire and ems analog main channel which you can only hear the tones on that anyways. I even get the analog simulcast issues as well but I'm working on fixing that issue.

Thanks for confirming, I misunderstood simulcast symptoms.

I would love to use the broadcastify feed, but my two main uses are 1.) Go listen to an incident after the fact or 2.) queue up last Saturday to just know what happens on a busy weekend night. If there is a way to chop up the broadcastify feed into concise date stamped files I'd certainly do that.

The SDR software/dongle is right up my alley, so thanks for pointing me in that direction, surprised I haven't bumped into it yet.

 

[TheStressMachine]

This post describes the situation very well. A proper scanner or SDR is the only solution.
As you have found, normal scanners can only receive the system very close to a tower, and probably with the attenuator on, to eliminate the simulcast distortion that the scanner can not handle. I strongly recommend a Unication G4 due to the spurious response and desense issues with the SDS scanners that can be a problem although they do well with Local P25 simulcast and may be OK in Ontario County but have problems with strong in-band signals in Rochester.

Interesting, I tell myself now that I don't need Rochester stuff, but perhaps I should future proof my thinking, I never thought I'd move here so anything can happen.

 

[TheStressMachine]

it does sound like simulcast problems.
i have been around scanners since 1970 and had a good many radio shack and uniden radios.
the system here changed to 700 Mhz simulcast and the best i could get at home was ,
1/4 second of sound and then 1/4 second of silence.
when getting out of the neighborhood the 325 worked fine.
we saved up and bought a uniden SDS100, and it has worked great from day one, anywhere !
i am not here to try and sell you one or something like that, but it does work.
it is on now next to the wife.

Thanks.

I might be able to make a case to the wife to sell the old stuff so the $ stings less, may the math games begin.

 

[wtp]

you mentioned after the fast, so i guess you mean at the scene.
that is when the 325 comes in hand as i have the repeater inputs on there for stuff in the neighborhood or on the scene stuff.
for the 700 band, they are 30 mhz higher.

 

[Joshuascanner2021]

This post describes the situation very well. A proper scanner or SDR is the only solution.
As you have found, normal scanners can only receive the system very close to a tower, and probably with the attenuator on, to eliminate the simulcast distortion that the scanner can not handle. I strongly recommend a Unication G4 due to the spurious response and desense issues with the SDS scanners that can be a problem although they do well with Local P25 simulcast and may be OK in Ontario County but have problems with strong in-band signals in Rochester.

I have an SDS100 and it works pretty well here in Ontario county on the Monroe/ontario TRS and in general with other systems. At least this is my experience having one here. I have taken the SDS100 scanner up into Monroe county and I have noticed a little bit of the spurious and desense issues in the higher signals areas too. I also do have a Unication and love it but it still has its limitations. I personally find the SDS scanner to be pretty good especially since its a true scanner compared to Unication not having the true scanner functions.

 

[Joshuascanner2021]

Interesting, I tell myself now that I don't need Rochester stuff, but perhaps I should future proof my thinking, I never thought I'd move here so anything can happen.

If you do want to listen to the Rochester stuff make sure you are listening on the Monroe/ontario TRS system and make sure you are at the very minimum are listening to it on the actually Monroe side (Monroe south) or else you wont receive everything (even though, yes you WILL hear Rochester traffic on the Ontario side but its not everything). Even though the two systems are tied together, they still have it set up so most of the traffic stays with the county they are in unless a unit is roaming which does happen a lot.

The reason I said make sure if you want to hear any of the Rochester stuff on the Monroe/ontario TRS is because, yes the 460 UHF frequencies are tied to the system but Monroe county and Rochester have been in slowly migrating agencies from UHF to the 700 TRS and as kh2z and others are finding out very recently one of the UHF channels and I think there was a couple more that where turned off or no longer patched/tied to the TRS anymore since all the agencies moved over completely now and apparently the UHF was no longer needed (as a guess). Plus the UHF frequencies especially if the Rochester PD or the towns the UHF signals are not very easy to pick up down here.

 

[DaveNF2G]

SDR dongles also suffer from simulcast issues. One advantage they give is the ability to reduce the gain (sensitivity) so that they don't get overloaded with multiple competing signals. As other have mentioned, this might have limited effectiveness where you are because the sites are close together and still likely to be pretty strong even after attenuation.

 

[TheStressMachine]

SDR dongles also suffer from simulcast issues. One advantage they give is the ability to reduce the gain (sensitivity) so that they don't get overloaded with multiple competing signals. As other have mentioned, this might have limited effectiveness where you are because the sites are close together and still likely to be pretty strong even after attenuation.

Thanks for that, a $35 experiment is worth it, worse case I'll find something else to monitor with it.

Question though. To me, the difference between an SDS scanner and lesser one when it comes to simulcast is that the software is much better at dealing with competing digital signals that all have the same data but offset by the distance travelled from each tower.

With an SDR, wouldn't one of the various software packages be updated by now to figure that out? Or is the software in the SDS (and OEM equipment) just THAT good that nobody else figured out how to deal with simulcast?

 

[wtp]

as i understand it, the SDS radios are an SDR in a scanner form.

 

[k2hz]

Thanks for that, a $35 experiment is worth it, worse case I'll find something else to monitor with it.

Question though. To me, the difference between an SDS scanner and lesser one when it comes to simulcast is that the software is much better at dealing with competing digital signals that all have the same data but offset by the distance travelled from each tower.

With an SDR, wouldn't one of the various software packages be updated by now to figure that out? Or is the software in the SDS (and OEM equipment) just THAT good that nobody else figured out how to deal with simulcast?

Most SDR software can deal with the simulcast issues and the SDS scanners are SDR based so they have the I/Q demodulating capability to at least receive the signal properly vs a regular scanner which is basically an analog device that has issues with demodulating a complex digital signal. The problem with the cheap SDR chips either on their own or in the SDS scanners is poor dynamic range so subject to overload. So manual gain adjustment and attenuation is necessary to compensate for the strength of the received signals.

The Icom IC-R8600 is a SDR based design with excellent dynamic range so not subject to overload or spurious responses. It does this with extensive switched bandpass filtering, AGC and other sophisticated digital signal processing features. But the features result in a cost of $2500 and it has no internal trunk tracking capability and the received P25 audio quality actually isn't that great.

The Motorola P25 simulcast modulation is called LSM (Linear Simulcast Modulation) which depends on the processing of the complex digital signal in both the transmitter and receiver be linear or the signal information is distorted. Conventional scanners, designed primarily for analog FM have limiter/discriminator circuits that are intentionally non-linear. The SDR chips I/Q output recovers the demodulated signal properly if the signal strength does not drive it into distortion. Assuming the receive device delivers a properly demodulated signal, it is up to the DSP circuits to recover the audio. There may be some issues with the particular DSP software with how well this is done.

The Unication scanners are a true P25 radio and offer performance comparable to professional radios. First responders tell me their Unication receives as well as their Motorola or Harris portable.

The bottom line is Motorola LSM, Harris WCQPSK and H-DQPSK are all complex digital transmission methods to overcome simulcast distortion issues designed for specialized receiver hardware and software for proper performance. Any attempt to emulate this in a general purpose hobby receiver is problematic, especially at a reasonable price. The Unication makes a good effort by focusing on P25 reception at the cost of not having all the features of a general purpose scanner. The SDS scanners try to do both with compromises that can be frustrating depending on how you use it.

 

[DaveNF2G]

As I understand it, the SDS scanners contain a hardware solution to simulcast, which is why other models cannot add the capability via firmware updates.

 

[k2hz]

As I understand it, the SDS scanners contain a hardware solution to simulcast, which is why other models cannot add the capability via firmware updates.

That is correct, once the signal in a regular scanner goes through the non-linear analog detector circuits it is distorted and no way the CODEC firmware can really properly recover it. That is where the I/Q detector circuits in an SDR or similar hardware are need to properly receive the signal so the CODEC firmware can do its thing to demodulate the audio. And here is where a professional radio may have more sophisticated firmware and a more processor power to do better under worst case multipath reception conditions. So, potentially, a SDR dongle on a PC can run more sophisticated decoding software than the processor and firmware in a scanner. Some SDR software has impressive capability to handle various type of digital signals well, not just P25 LSM. So, if you are up to dealing with the technology, a good quality SDR dongle and the right software can be a good solution for monitoring at home. I am in a very high RF environment that is daunting for even a good SDR and external filters so I still find limitations other than to monitor nearby systems.

One positive thing about the SDS scanners is they have done some significant firmware upgrades since the original release that mitigate, but don't totally resolve, the overload problem in strong signal areas.

 

[TheStressMachine]

Thanks for all the replies, you helped this idiot out.

SDR is working well except the 3mhz range doesn't cover the system, so hopefully the second tuner I just ordered will take care of that.