Entering P25 Trunked Tower Sites

[rbritton1201]

I couldn't seem to catch any voice traffic off the Shirley Tower tonight, but the control channel is coming through full deflection on the signal bar. A lack of voice traffic off of the Shirley tower isn't typical for me, but signals were either so scarce that I missed them, or they were not using the Shirley tower tonight, other than the control channel being present. Do they sometimes consolidate transmissions onto other towers, and avoid using some towers at times? Update: Shirley (Rural) did come up and displayed around 11:30pm, and the signal bar fluctuated between 2 and 3 bars, but the control channel showed a full deflection consistently, just like the image below.



The METRO and RURAL channels were received via the St. Clair Tower, Weldon Spring Tower, and the Imperial Tower tonight, and these images reveal the statistical readings via each respective tower at the times indicated.







The images above are taken from my Proscan remote access server via my notebook computer. Sometimes you will notice that my camera doesn't capture the Site ID in the photos (Imperial tower image above, for example), but eventually it usually comes up on the display, but my camera doesn't capture it at the right time. There seems to be a latency delay before the readings display sometimes, but other times, no problem, it displays immediately. I attribute this to possibly being a latency delay caused by Proscan (?), but not sure.

 

[kruser]

I couldn't seem to catch any voice traffic off the Shirley Tower tonight, but the control channel is coming through full deflection on the signal bar. A lack of voice traffic off of the Shirley tower isn't typical for me, but signals were either so scarce that I missed them, or they were not using the Shirley tower tonight, other than the control channel being present. Do they sometimes consolidate transmissions onto other towers, and avoid using some towers at times? Update: Shirley (Rural) did come up and displayed around 11:30pm, and the signal bar fluctuated between 2 and 3 bars, but the control channel showed a full deflection consistently, just like the image below.

If there are no users radios associated with a site, you will not hear a peep out of that site. That's very common with the state patrol at night when manpower is reduced. Many areas or entire counties may not have a trooper in the coverage area of a site.
Once a trooper moves into range of the site and his/her radio associates with the site, then you will start hearing normal traffic again until that user associates with a new site, then only the new site will carry the traffic unless another user on the same talkgroup is still associated with the old site. This is how statewide trunked systems work and also how they free up sites so they are used for local area traffic only and not overloaded with radio traffic not used by anyone in the sites area.
This has been explained to you before in some of your past threads and posts. See the statement in post 2 in the thread below by @nd5y
MOSWIN TOWER ACCESS... | RadioReference.com Forums


I really don't have any more ideas for your issue(s). You are either in a poor area for RF or have antenna and/or coax issues.
Did you remove that splitter you mentioned recently in another thread? That will have a negative influence on your signals.

Perhaps the SDS series scanners are not a good choice for you. The SDS series were developed and marketed to combat LSM or simulcast distortion from simulcast trunked sites. Neither of which you have in your area. Uniden's late Product Manager, Paul Opitz, even acknowledged publicly in the forums here that the SDS models are not the best for VHF signals. I can fully agree with his statement when I compare the SDS models with almost any of the more than 50 radios I own.

 

[rbritton1201]

No metal roof on the house...I did remove the splitter, and connected the SDS200 and the BCD536HP to dedicated coax runs to two separate dedicated Diamond Discone antennas that are situated about 6 feet apart in the attic. Both use the same type of coax, which is the RG8/U mini foam coax. The most recent performance characteristics I've been experiencing are off of each scanner's dedicated Discone antennas.

But, frankly, after removing the splitter, and using dedicated antennas, I notice no difference in actual reception or in the statistical readouts shown on the scanners. I don't disagree that removing the splitter should technically improve reception by reducing losses, but based on my experience, being directly in front of those radios, I don't notice any difference in reception with respect to the quality of reception I expect and am actually quite satisfied with.

I don't really have any issues with VHF whatsoever, and as a matter of fact, I don't really have any "issues" with respect to the quality of reception of MSHP either. I just find some of the statistical performance displays on the SDS200, a $700 radio, to be inconsistent with the quality of reception I'm actually experiencing. You've expressed that these statistical readouts are often bogus, and I agree with you completely.

With regard to the Shirley tower, and it being so quiet last night, I understand that units have to be subscribed to the tower. But, I still find it difficult to accept that there is no audio traffic on that tower on a Saturday night at 9 PM to 11:30PM. I guess I could have missed some transmissions, which is always a possibility. But, I was trying to pay particular attention to that tower, and heard no audio traffic. Even with the inconsistency with respect to the readouts sometimes being bogus, clearly I was receiving fully deflected control channel transmissions from the Shirley tower, so the tower was working.

That's why I'm curious about whether these towers might be sometimes virtually shut down to voice communications for some reason, and unless someone is intimately involved with the MSHPs Communications Division, nobody in our position, as listeners, may really know what they're up to. Having come from a law enforcement background, and having significant experience with what to expect with respect to reception quality based on a number of years in the past in a supervisory position within the Communications Division of the St. Louis County Police, I have a certain level of expectation as to what to expect regarding reception. I'm also a licensed Advanced Class Amateur Radio Operator for almost 30 years as well. So, I do understand the technical challenges that some have mentioned. But, based on my experience, I also know that the technicalities in the books aren't always valid because there are too many variables that corrupt those technical assumptions.

I'm familiar with the technical considerations that should go into an antenna system, etc...But, we are all constrained by our individual circumstances with respect to what is logistically feasible and/or economically reasonable with respect to how our antenna systems are setup, and how geography affects reception. While my scanner antenna setup isn't perfect, it should be working fine due to my relative close proximity to the tower sites mentioned. My antennas have been doing a good job of reception, both with respect to VHF, as well as MSHPs P25 Trunked System. But, I must admit, I can't explain why I am not hearing the Washington tower, yet I am hearing the Shirley tower, the Weldon Spring tower, the Imperial tower, and the St. Clair tower, all providing good reception, even when a towers as far away from me as Weldon Spring and Shirley should be terrible according to MOSWIN, but they're not.

I'm just confused by how MSHPs system is represented to work versus how it is actually working. Others contributors on the forum have experienced some of these same odd performance characteristics I've mentioned. I don't know, maybe I'm looking for explanations as to performance of the MSHP system that don't have an explanation due to...who knows.

But, my comments in the forum are more of an intellectual curiosity, rather than my experiencing poor performance. The performance I'm experiencing is actually excellent using the hardware setup I have with respect to my antenna system, and while not perfect, I know what kind of reception it's capable of, even with it's minor detractors.

Did you remove that splitter you mentioned recently in another thread? That will have a negative influence on your signals.

Perhaps the SDS series scanners are not a good choice for you.