You are an asset to the community! Thanks.
Coverage Maps of Colorado DTRS sites (image heavy)
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You are an asset to the community! Thanks.
well now I know why I don't get zap from berthoud! cant wait to see Smokey hill .
BTW your doing great this is very enlightening for me (us) I wonder what the trunked sites like Lakewood or Denver PS look like as well I hear Lakewood just fine even at work in the hole of Windsor yet north of Longmont Denver don't exist
BTW your doing great this is very enlightening for me (us) I wonder what the trunked sites like Lakewood or Denver PS look like as well I hear Lakewood just fine even at work in the hole of Windsor yet north of Longmont Denver don't exist
soundchaser
Member
Did the map explain your reception problems? One thing that's interesting is the mix of 700 and 800 freqs on the voice channels for some of these sites.
soundchaser
Member
I've made the maps for Smokey, DTB, DRDC, and Admin, but haven't had a chance to get them posted yet. Check the wiki again tomorrow and I should have them added.
Yes - I learned that even a few miles from Chevron there are some pretty unexpectedly low signals... Again, I get Chevron fine driving around... but when I'm at home, according to my personal experience AND your map, signal isn't so great. Thanks again for the map!
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What best covers (if anything can) 93 from Golden on up to Boulder? Most of that drive is so close to the foothills that I'd expect it to be shadowed from any of the mountain-based sites. Seems it would have to be primarily served from something in town that could 'see' that stretch of road back to the west. It's always been a cell phone crap shoot.
Hmmm - that's the second issue with the new Thorodin propagation map that I've run across today. It projects little to no coverage up 93. It also projects that we should have Thorodin with a decent signal up here in NE Boulder County, but that ain't a happening event. I'll have to get with Soundchaser to see if we can sort out what's happening with that one. It's important enough in what it covers that getting it as right as we can would be a good idea.
The Lookout map indicates decent but not perfect (holes of no coverage in various places) coverage up 93.
Given my current in-vehicle limitations, I'm trying to stick with 800MHz systems. Fortunately, both of those are purely 800 (so far).
soundchaser
Member
I had no problem picking up Thorodin in NE Boulder County, Larimer and western Weld when I was through there a couple of weeks ago, 5 bars the whole time. The map indicates this.
As for the Thorodin map, as it says in the information link on the page, "If there is red coloring on nearby ridges then the signal often reflects well enough into non-colored areas."
Last fall, I tried to monitor Thorodin from the front of Flagstaff Mountain, west of Boulder and could not decode.
I'll have another look at Thorodin here, but at about this location -- N40.20343, W105.10262 -- no can do. Some funny little hole, perhaps?
soundchaser
Member
Odd. I zoomed in and it's solid red with no holes nearby. Maybe a cell tower or some other local interference? And this image shows a straight shot. What happens if you just try to monitor a voice channel (obviously with no decode), what kind of signal strength do you get?
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I'll have to pick the channels off one at a time to see what happens with each. In this location, there are no obstructions of any sort. I'm working from out 'on the flats' here. If there is an obstruction, it must be down range somewhere. As you noted on some sites, not all antennae are treated equally with regard to mounting, and I've surely seen some differences in control vs. audio channel strength here before.
I think I'll load the PRO197 into the car (it seems to have slightly better sensitivity than the PRO2096) and take a short drive around the area this weekend to see if I can figure out what the devil is happening up here.
I think I'll load the PRO197 into the car (it seems to have slightly better sensitivity than the PRO2096) and take a short drive around the area this weekend to see if I can figure out what the devil is happening up here.
Scrapped prior version of this post...
OK. I'm getting good digital decode of all of the audio on the voice channels I'm hearing. The problem seems to be the control channel. Listened to it for a while, and my impression (and it's very subjective) is that the audio isn't as crisp - lacking in higher frequency components - even though the signal strength is, or would be, adequate for a decode on any other site. Pro96Com doesn't see a thing there, and I never get a CC decode that leads to an audio channel. All quiet.
[Edit - about #4] I may take a shot with the WinRadio and throw the audio into the spectrum analyzer to see if this control channel looks significantly different from others that decode properly. That would tell me if it's just my ears or there's something actually different that I'm hearing.
OK. I'm getting good digital decode of all of the audio on the voice channels I'm hearing. The problem seems to be the control channel. Listened to it for a while, and my impression (and it's very subjective) is that the audio isn't as crisp - lacking in higher frequency components - even though the signal strength is, or would be, adequate for a decode on any other site. Pro96Com doesn't see a thing there, and I never get a CC decode that leads to an audio channel. All quiet.
[Edit - about #4] I may take a shot with the WinRadio and throw the audio into the spectrum analyzer to see if this control channel looks significantly different from others that decode properly. That would tell me if it's just my ears or there's something actually different that I'm hearing.
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Further on to the above (since it's been so long I can't edit now)...
CANNOT get a CC decode off the PRO197 sitting on my desk. Signal strength is entirely acceptable, and is on a par with the voice channel signals, all of which decode properly for audio.
Tossed the PRO197 into the vehicle, and in the garage, with mickey mouse antenna on roof of vehicle, I get a perfect CC decode and trunking begins. There's something REALLY strange happening at this location. Base antenna is good, and 25' higher than the vehicle sitting in the garage. I'm thinking of getting up and shifting the position of the discone up there to see if I can do anything. Have no idea what the malfunction is. Since the voice channels are all great, the signal strength is comparable, why the lack of CC decode up there?!?
CANNOT get a CC decode off the PRO197 sitting on my desk. Signal strength is entirely acceptable, and is on a par with the voice channel signals, all of which decode properly for audio.
Tossed the PRO197 into the vehicle, and in the garage, with mickey mouse antenna on roof of vehicle, I get a perfect CC decode and trunking begins. There's something REALLY strange happening at this location. Base antenna is good, and 25' higher than the vehicle sitting in the garage. I'm thinking of getting up and shifting the position of the discone up there to see if I can do anything. Have no idea what the malfunction is. Since the voice channels are all great, the signal strength is comparable, why the lack of CC decode up there?!?
OK - my own personal weirdness with Thorodin continues, and the mystery may be solved - but I don't much like the answer.
To reiterate: no CC decode from my office rig (PRO197) with a discone up high. Signal strength indicates MORE than enough signal for an acceptable CC decode under normal circumstances. So I dump the trunking and just program in the voice freqs... and ALL of the voice channels are decoding audio just fine, loud and clear. FWIW, the signal strength on voice channels identical to that of the CC (in fact, they're more uniform than what I see from most sites), so it's not one of 'those' antenna issues where there's a significant difference between CC and voice channel signal strength.
Figured I'd swap the PRO2096 in the vehicle out with the PRO197 from the office and take a ride to see if I can find the hot and cold spots around here. There I am, 75' from my office, and a full 25' below the height of the discone used in the office, in the garage, with a so-so mag mount on top of the vehicle, and perfect Thorodin CC decode. HUH? Scrap the drive-around test. Back to the drawing board.
So I am playing around with a cheesy whip antenna in the office vs. the discone up above, and still no decode of the CC for Thorodin. Signal strength on the whip is a bit below that of the discone above, of course.
I stand up at my desk, and accidentally start to shield the antenna to the north while I was standing in front of it. Bam. CC decode. NOW WT*???
I'm beginning to suspect adjacent channel interference (there's nothing else on 853.97500 anywhere near here) from something north of me, give or take. So I'm on the hunt for something adjacent. Crap. I forgot the site very close to me with terrific elevation; Mead ... CC = 853.98750. Uh oh. That's a delta of only 12.5KHz from the Thorodin CC = 853.97500. I suppose, given the proximity to Mead here, that the PRO197 just doesn't have the selectivity to deal with that. Apart from throwing up yet another and more directional antenna, and all of that expensive RG213U that is a TOTAL bugger to route the 40' to the office through a chimney chase, etc., I'm not going to solve this one.
To reiterate: no CC decode from my office rig (PRO197) with a discone up high. Signal strength indicates MORE than enough signal for an acceptable CC decode under normal circumstances. So I dump the trunking and just program in the voice freqs... and ALL of the voice channels are decoding audio just fine, loud and clear. FWIW, the signal strength on voice channels identical to that of the CC (in fact, they're more uniform than what I see from most sites), so it's not one of 'those' antenna issues where there's a significant difference between CC and voice channel signal strength.
Figured I'd swap the PRO2096 in the vehicle out with the PRO197 from the office and take a ride to see if I can find the hot and cold spots around here. There I am, 75' from my office, and a full 25' below the height of the discone used in the office, in the garage, with a so-so mag mount on top of the vehicle, and perfect Thorodin CC decode. HUH? Scrap the drive-around test. Back to the drawing board.
So I am playing around with a cheesy whip antenna in the office vs. the discone up above, and still no decode of the CC for Thorodin. Signal strength on the whip is a bit below that of the discone above, of course.
I stand up at my desk, and accidentally start to shield the antenna to the north while I was standing in front of it. Bam. CC decode. NOW WT*???
I'm beginning to suspect adjacent channel interference (there's nothing else on 853.97500 anywhere near here) from something north of me, give or take. So I'm on the hunt for something adjacent. Crap. I forgot the site very close to me with terrific elevation; Mead ... CC = 853.98750. Uh oh. That's a delta of only 12.5KHz from the Thorodin CC = 853.97500. I suppose, given the proximity to Mead here, that the PRO197 just doesn't have the selectivity to deal with that. Apart from throwing up yet another and more directional antenna, and all of that expensive RG213U that is a TOTAL bugger to route the 40' to the office through a chimney chase, etc., I'm not going to solve this one.
soundchaser
Member
Very interesting! I would not of thought of the 12.5KHz CC spacing between Mead and Thorodin. Good detective work!
But yeah, solutions to that problem are kind of limited. Maybe borrow a newer scanner which might have better selectivity to see how it works. I'll have to go park at the Mead tower again and see if I can decode both sites with my 996XT. That's a scanner acid test.
But yeah, solutions to that problem are kind of limited. Maybe borrow a newer scanner which might have better selectivity to see how it works. I'll have to go park at the Mead tower again and see if I can decode both sites with my 996XT. That's a scanner acid test.
Whenever you get the itch to perform that test, drop me a line and I'll show up with the PRO197 in tow and we can compare notes.
Another oddity. I've been prepping up a V-Scanner for travel back and forth into Denver. Adams does very nicely up here in Longmont, and I used that to cover the stretch that includes Thorton, Northglenn and from there on down to the edge of Denver. I was surprised to find that in the general area SE of Quebec and 36th or so (well up out of that hole just S of I-270 and back onto the flats, so that's not it), the decode rate was sometimes very poor. At times, it would drop down to 60% or so (unusable). I would have thought that at least the Civic Center site would have been positively BOOMING in at that location, with the Hilltop site coming in a close 2nd.
Whenever you get the itch to perform that test, drop me a line and I'll show up with the PRO197 in tow and we can compare notes.
Drop me a note as well Im on the other side of the hill
What kind of Thorodin reception do you have up there?!?Drop me a note as well Im on the other side of the hill
soundchaser
Member
I can't see what the problem is. The side profile shows a clear shot to both Hilltop and Civic, and Civic is booming at over 50 uV. Hilltop is not far behind. There is a small dead spot less than 2 miles east, just SE of Havana and Smith. I suppose that's why the DRDC site is there. As I recall, it's an 800 Mhz and the Adams family are 700 Mhz, so interference is unlikely. But you might double check to make sure.
I haven't studied the specific modulation scheme for P25 simulcast, but intuitively it seems like the more signals of the same freq you have bouncing around, the better the chances are for multipath interference.
I'll let you guys know when I head back out to Mead. I want to get a picture of that 8 element 800 Mhz phased array they've got on top of that tower. I can't seem to find one to buy online, so I might have to make one. 18 dB of gain would be really fun to play with up here.
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