CanesFan95
Analog already is interoperable.
How the what came through ?
Hillsborough County (EDACS and P25 32D.1E306)
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mmaguire180
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I have a question on Hillsborough p25. If anyone monitors them, Which site is HCFR mainly operate on i don't here the talk groups just dispatch and cad dispatch
zlandmedia
not that florida man
mmaguire180
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Using NAS on an apx im hearing everything else but HCFR channels except disp and cad
It may just be a location issue. For example I’m in Temple Terrace and get pretty good coverage of P25 West, but barely anything on P25 East. (Oddly, I get great EDACS coverage all around, but go figure!) A couple of thoughts:
• Separate the East and West sites into different numbered groups and then try one at a time.
• Make sure you are using “ID Search” instead of “ID Scan,” that way you get even those talk groups that you don’t have programmed. I see a lot of activity this way that I wouldn’t see otherwise.
• Kill your existing band plans and let the control channel(s) freshly propagate them.
• Try starting off with only the control channel(s) in your frequency list for each site.
• Finally, I found the P25 threshold to be extremely picky, so make sure you’re using manual mode, and on Uniden you’ll find the best luck probably somewhere between 6 and 10 (my best settings are on the lower end rather than the higher).
I also noticed that you will get the most activity on dispatch/CAD and EMS, e.g. ALS to ER. So, that might just be what you are hearing. I’d check those few things though unless you already have. Anyone else is welcome to chime in as they may have better ideas than mine own. Good luck!
zlandmedia
not that florida man
As I told you previously, if you're still using that BCD scanner then it's simulcast distortion. One of the West Site towers is also right there at TTFD #1 as well, which is why you hear them fairly well.
Right, but why do I have very poor reception when completely locking out the west side and only tuning into the east? Wouldn’t simulcast distortion only affect me if I have both sites unlocked and scanning simultaneously? I would think that would be the case as the scanner would have a difficult time tuning in on those broadcasts that go out via both sites. The way I now have it setup is with numeric groups, one or the other, and west comes in pretty well compared to before I made those changes I mentioned. It‘s actually night and day since I divided up the sites into numeric groups that are easily locked out.
Now, I will also get east, however I don’t get it clear from inside my house, but outside and especially as you move away, it starts to come in far better. That’s provided I have the west locked out the same as above. I could be wrong, but I just don’t see how simulcast distortion will cause such an issue if the other site is completely unknown to the scanner. That goes even more so now that I’m actually getting good reception using this technique. I think I actually replied asking this same question a while back, but it went unanswered (along with why the Unication pager(s) would be advantageous, albeit with a limited feature set over Uniden’s most premium offerings).
I wouldn’t mind upgrading, but don’t see a reason to do so if it’s working well for me at the current juncture. If I’m still missing something, explain how the upgrade will be worth it now that I’m getting good reception (relatively close to my home, but will eventually setup a better antenna system).
zlandmedia
not that florida man
No. Simulcast distortion occurs because each site has multiple towers that transmit the same thing simultaneously on the same frequencies, but because the transmissions are digital, they aren't exactly in sync with one another. Our scanners are in range of multiple towers, which cause the distortion.
Read up on the Wiki article, it describes in detail what it is and why it happens. Simulcast Distortion - The RadioReference Wiki
Okay. I gave it a read and it totally makes sense. I found a couple of other reliable articles prior, but the confusion was that those didn’t bother to differentiate between the (a) actual physical antenna “sites” (read: the towers), and the (b) virtual or logical “sites” that logically make up those antenna site groups (East & West for example). You make a good point and it makes sense that the problem is more granular.
Now, I get that there’s a big difference between these two scenarios, and that it will be phase shift as QPSK uses phase as its own form of modulation making it different than standard AM or FM modulation by design. Additionally, it makes a lot of sense that the FM capture effect will be negated due to this unique design. Being digital will always cause error and flow control to be necessary, Claude Shannon himself stated that this alongside with entropy are some of the most basic tenets of information theory. So, I understand how this could spiral out of control when using systems that work with a variables such as phase shifting to segue into error and flow control solutions.
You would think (maybe? hopefully?) that Uniden, et al., would have better planned for this, but P25 systems are finally becoming far more common after many years of trying, and not just here, but across the country. Simulcast has evolved and become more common since as well, so maybe they just didn’t think that this was going to be a very widespread issue at the time. I’d have to see what decoders are internally used within the BCD, but they probably preclude QPSK from working at the hardware level thereby negating a firmware solution from ever being developed. Many of the IC decoders that I have personally used have AM, FM, and SSB capabilities; I’m uncertain if phase could even be coded as a multidimensional sort of solution on top of the FM capabilities that will be controlled. I don’t think it would be very difficult to control phase, but separating the signals, then adjusting the timing could prove to be a huge pain! As you probably figured out, although I have many years working with opamps and other analog IC solutions, my undergrad is in Comp Sci, so radio developed into a hobby from it. I also have an electrical engineering background, but strangely that was in [large] power distribution systems. So, I know that I still have much to learn in this particular discipline.
That said, I am hoping to make the best of my experience with radio. As mentioned earlier, I did get some very good P25 signal, but I think it’s because of separating out any other logical interference plus what you said about being fairly close to one antenna site. I may have mentioned that I have been playing with [small] unidirectional antennas to create a solution by simply not needing one! Just focus the wide beam directly in the line of sight and go from there. I also tried one additional thing yesterday, that did seem to get about 80% to 90% clear audio on the East site. It was very simply, just force FM instead of NFM as the modulation. If I could find the “right” amount of attenuation, a simple antenna could even work, but it beats me why Uniden decided to throw 20dB as the lone option on their BCD radios! That’s entirely too much, even for me to hear Temple Terrace! So, I will likely order some smaller hardware attenuators and try them inline with my antenna, probably in 3dB increments.
So, what are your thoughts on those “simple” solutions that will allow you to focus on the nearest and strongest transmitter, they were:
1) Unidirectional antennas?
2) Small hardware attenuators inline with the “whip” antenna?
3) Only using the closest control channel to your area? (If so, why don’t we have locations for East? I only see them on the West site.)
I always try to believe that there are simple solutions available. The easiest ones tend to be the best, and the least expensive!
zlandmedia
not that florida man
My honest answer for a solution? Upgrade to an SDS100/SDS200. Or get a Unication G4 or G5.
Simulcast systems are a pain for scanner enthusiasts and unless you have an SDS scanner or a Unication G4/G5 pager, there is no way to truly defeat simulcast distortion.
Simulcast systems are a pain for scanner enthusiasts and unless you have an SDS scanner or a Unication G4/G5 pager, there is no way to truly defeat simulcast distortion.
in some early days of P25 trunking (Phase 1 anyway) simulcast systems (cough, Jacksonville) the answer - at least with a portable scanner - was to take the antenna completely off the radio. Turning the radio 90-180-270 degrees had a distinct effect on the received signal, and eventually you would find a particular spot that worked fairly well - this assumes that you were fairly close to one of the tower sites of the system. Just an observation - Seems that Phase 2 P25 systems using TDMA modulation (H-DQPSK) are MUCH harder for a non-SDS scanner to decode properly in simulcast environments. The SDS series are designed for this evolutionary step, so they perform much better. At the end of the day, if you are dealing with one of these systems that you really want to monitor consistently, you are going to have to purchase a Uniden SDS-series scanner. (edit - or as @zlandmedia stated, a Unication pager)
zlandmedia
not that florida man
Another cheaper alternative is to get ahold of four RTL-SDR dongles (v3/v4), which run for about $30-40 apiece for a kit including dongle and antennae, and set aside a computer with enough processing power and use SDRTrunk. SDRTrunk can fully decode P25 Phase II simulcast without issue, but it's probably not worth the hassle nor the space that a plain ol' scanner has.
I have SDR dongles and usually get great results, but you hit the nail on the head, it’s just not worth setting up a dedicated PC-based solution this way. I may try seeing if I could make a dedicated mini solution using a Raspberry Pi or similar as I could throw the whole thing inside of its own enclosure. I could also include a small 5 or 7 inch screen. I will just need to see if SDRTrunk had a compatible app that’ll run under PiOS. I found some other apps that will run, but they only did Phase 1. There could very well be more, I just haven’t spent a lot of time on this one point.
I am hearing you, I’ll keep an eye out especially on here to see if anyone is parting ways with their SDS scanner as that would save me a few bucks. Otherwise, I really like the BCD, so it’s a shame that this is such a major hurdle for it. Depending on what SDS I find, I’ll likely keep it as a backup even though I still have my old Whistler analog scanner for listening specifically to aircraft and the like.
Just for kicks, I may try a 3dB or 6dB in-line attenuator just to see if I could get it working. I just don’t get out much, so it’ll be used almost exclusively at home.
Finally, the Unication pagers seemed limited to me when comparing them to the SDS for example. For the price, will I actually be happy with one? Any articles showing the pros and cons of each?
I believe that is what County Wide Channel is for
I got a few unknown tg's not listed in the DB W is West site
W 11089
W 15023
W 15030
W 15063
W 11089
W 15023
W 15030
W 15063
CanesFan95
Analog already is interoperable.
11089 = Schools Security West
15023 = Tampa PD Wants
15030 = Tampa PD A Special
15063 = Tampa PD Events 3
15023 = Tampa PD Wants
15030 = Tampa PD A Special
15063 = Tampa PD Events 3
zlandmedia
not that florida man
11089 would be HCPS Security talk. Carryover from the EDACS system (1089).
Those 150xx TGs are TPD.
Those 150xx TGs are TPD.
As soon as I posted that I went to the edac side found that one sec channel. I didn't see the TPD what the other ones would be.
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