Portland Public Safety 700 MHz P25

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jeb2942

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I use a Uniden 536HP with a yagi antenna pointed at Council Crest. Nothing special but you're probably right sparklehorse it's probably just the luck of location. We'll have to see how it progresses as the system builds out.
 

ScottPDX

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I don't hear the decode errors on jeb2942's feed. Does it matter that he is outside the ring of West Simulcast tower sites and using a yagi pointed in, (which would make sense why he might avoid multicast issues), vs. myself and SparkleHorse being inside the ring of West Simulcast towers?

But yes, I will be putting up a yagi. I may put up a discone and yagi on same mast on separate coax feeds, just to use each antenna for different listening scenarios.
 

sparklehorse

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I use a Uniden 536HP with a yagi antenna pointed at Council Crest. Nothing special but you're probably right sparklehorse it's probably just the luck of location. We'll have to see how it progresses as the system builds out.

The problem I have with my 536HP is it often misses P25 transmissions altogether. It sounds pretty good, but misses a lot. This is easy to prove by using one radio held on a channel on the old analog 800 system, and comparing to the 536 held on the same channel on the P25 system. The lag time for your Broadcastify feed is like 30 seconds, plus you're scanning so it's harder to tell, but I thought I caught a couple missed transmissions in your feed when I listened for a bit last night. It sounds very good though, for sure.
I suspect my 536 is having problems with the same 3 system frequencies my Whistler chokes on, but the difference is the Whistler passes the choppy audio where the Uniden doesn't. I'm thinking the Uniden just skips the transmission if it's below a certain error rate. All just theories until I can do more testing. Unfortunately the 536 doesn't display the current frequency when a talkgroup is active, so I will have to program all the system freqs as conventional channels to observe what's going on 'under the hood'. Also I need to upgrade the 536 to the latest firmware (1.11.20), which is supposed to help with P25. Perhaps you've done that already?


But yes, I will be putting up a yagi. I may put up a discone and yagi on same mast on separate coax feeds, just to use each antenna for different listening scenarios.

You might try feeding both the discone and the yagi to your radio simultaneously with a simple BNC T-connector. I'm doing that with my radio and was surprised to find it actually helped the P25 reception a little, while allowing me to scan VHF/UHF conventional at the same time. It shouldn't work, but it did.

.
 

jeb2942

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I believe that you're right that it occasionally misses a transmission. I've monitored the error rate on the 536 by holding the Function knob and pressing the volume control and it always shows 0 errors. I am on the beta firmware 1.11.20 and have set the digital threshold to Manual 8 and have noticed it has improved reception. I've also monitored the signal level using the "Siren" App which does show the current frequency and seen fluctuations in signal strength on a number of channels but never on the control channel.
 

ScottPDX

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Thanks, all.

Maybe I'll consider a 536 after the first of the year, and after the transition to P25 is complete. Thanks for the tip on binding the discone and the yagi together.

ScottPDX
 

sparklehorse

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Thanks for the tip on binding the discone and the yagi together.

I wasn't clear in my earlier post. I'm not actually feeding a discone + yagi to my scanner, I'm feeding a Comet GP-1 VHF/UHF ham antenna to my scanner, along with the yagi. But feeding a discone+yagi is a cheap enough experiment that it's certainly worth a try if you already have a discone. Heck, try the discone by itself, you never know until you try.

.
 

PaulNDaOC

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So I tried listening to East Simulcast because of my proximity of being direct east base of Mt. Tabor, but heard little. So I switched to West Simulcast and that is working. So here on RR it says that West Simulcast P25 700 is currently only being served from Council Crest. Is that correct? If so, Mt. Tabor us directly in my way. When might Mt. Scott be serving West Simulcast? That is direct line of site from my east base Mt. Tabor home reception site.

Thanks in advance.

ScottPDX

West simulcast is using at leat four sites, Mt Scott, Council Crest, Willalatin Water Tank (NW Skyline several miles south Of Corn Pass) and Prune Hill in Camas. You should get great reception from Mt Scott where you are.
 

sparklehorse

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West simulcast is using at leat four sites, Mt Scott, Council Crest, Willalatin Water Tank (NW Skyline several miles south Of Corn Pass) and Prune Hill in Camas. You should get great reception from Mt Scott where you are.

I drove out I-84 into the gorge today. My Unication G5 stayed locked on West Simulcast all the way to milepost 33. It sounded pretty good out there too, just a little garbling as I got out toward Multnomah Falls, then it finally switched over to East Simulcast. That tells me the Prune Hill site must be functioning as part of West Simulcast. Coming back the G5 remained on East Simulcast until I got to the Hollywood area, where it switched back to West Simulcast. Not a big data point, but I thought it was worth adding to the conversation.

.
 

PaulNDaOC

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I drove out I-84 into the gorge today. My Unication G5 stayed locked on West Simulcast all the way to milepost 33. It sounded pretty good out there too, just a little garbling as I got out toward Multnomah Falls, then it finally switched over to East Simulcast. That tells me the Prune Hill site must be functioning as part of West Simulcast. Coming back the G5 remained on East Simulcast until I got to the Hollywood area, where it switched back to West Simulcast. Not a big data point, but I thought it was worth adding to the conversation.

.

Biddle Butte on east simulcast should provide great coverage out in the Gorge and along I-84. Did you notice if OSP is simulcast on east?
 

sparklehorse

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Biddle Butte on east simulcast should provide great coverage out in the Gorge and along I-84. Did you notice if OSP is simulcast on east?

I didn't get too deep into the gorge - I turned around at milepost 35, but East Simulcast did sound good out there. It was even still pretty good in Hollywood. A little garbling there but not much. I think the Unication pager doesn't go looking for a better control channel until the error rate of the current one reaches some pre-determined level, but it still seems to work quite well as it nears that point. The site switching would be transparent to most users. I had both OSP talkgroups programmed into the radio but didn't hear anything on those. Maybe those are patches that are only active when a system user switches to them for interops, or just to monitor OSP.

.
 

ScottPDX

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West simulcast is using at leat four sites, Mt Scott, Council Crest, Willalatin Water Tank (NW Skyline several miles south Of Corn Pass) and Prune Hill in Camas. You should get great reception from Mt Scott where you are.

Yes, I am getting really good signal and reception. So much in fact that I've enabled Global Attenuation on the scanner with a telescoping set indoor antenna. Just need an outdoor Yagi now to reduce the occassional Multipath Simulcast garbled audio.

Someone should update the East and West Simulcast notes in the database here for the Portland Public Safety P25 where each indicate only one site tower is currently active.

ScottPDX
 

sparklehorse

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The problem I have with my 536HP is it often misses P25 transmissions altogether. It sounds pretty good, but misses a lot. <snip>

If it helps anyone, here's what I've learned about my BCD536HP monitoring the Portland P25 system:

As posted earlier, I had been having trouble with the radio clipping or missing transmissions altogether. Yesterday I put each of the system frequencies into the radio as conventional P25 channels, and then monitored each channel for at least five or six transmissions. I had my Unication G5 parked on the same conventional frequency at the same time as a control. During this testing I only observed the 536 clip or miss a tx three times out of about a hundred transmissions. Then I set the 536 to ID Scan the system, while simultaneously scanning the system with my Whistler WS1065. These two radios have similar scan lists and delay times, and shared the same 800mhz yagi+Comet GP-1 combo by way of a BNC T-connector and an SP-1300 Combiner/Splitter. Then I had my Unication G5 scanning a similar list as a control.

While scanning the system the Whistler passed the audio on nearly every tx, while the 536 clipped or missed a lot. I estimate the 536 missed about 10% of tx's. The whistler maybe 1%. But the Whistler audio was sometimes choppy and broken. The Uniden audio was usually quite good, very rarely choppy.

What I gleaned from this testing is the 536 actually does quite well on each frequency when monitored conventional, but it misses a lot when scanning. For some reason it's not receiving or executing the control channel commands consistently.

After doing some googling on this issue, I tried a changing a few different things that had worked for others, and I did notice some improvement.

These changes seemed to have a cumulative positive effect, I can't say any one by itself made much difference:

Upgraded the firmware to latest version (1.11.20)
AGC I changed to OFF (system setting)
I locked out East Simulcast and Goat Mtn sites
For W. Simulcast I set the Digital Threshold Mode to Manual, and set Digital Threshold Level to 5
Attenuator is left OFF (site setting)
I deleted ALL the site frequencies except the control: 772.60625 (Sentinel downloads all RR site frequencies)
Squelch set at 2
Lastly, I set the System Hold time to 3 sec.

See post #15 in this thread regarding the System Hold Time:

http://forums.radioreference.com/florida-radio-discussion-forum/232146-new-p25-system-help.html

Also post #5 here showing it relates to the x36 models as well:

http://forums.radioreference.com/uniden-tavern/291925-some-intresting-notes-scanner.html

After these changes the 536 is still clipping or missing a tx occasionally, but it's more like 3-4% of tx's now. So it's back in the error range of its conventional P25 performance. Still not acceptable, but I can at least live with it.

I should mention the most important single thing anyone can do if they are having P25 trouble is to try a different antenna configuration first, or even parking your radio in a different spot might help if you're not using an external antenna. My 800 MHz yagi made a big difference for me. Also googling "simulcast distortion" will bring up a wealth of information on the topic.

Let us know if you try these settings and what changes, if any, you observe.

Hope that helps.

.
 
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PaulNDaOC

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Great info sparklehorse, it sounds like the way to go til the scanner makers upgrade their product,as I'm sure will be done out of necessity, the G5 is a good option with what I've read is commercial quality performance.

Is it correct the going price is about $900 or so?
 

sparklehorse

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Great info sparklehorse, it sounds like the way to go til the scanner makers upgrade their product,as I'm sure will be done out of necessity, the G5 is a good option with what I've read is commercial quality performance.

Is it correct the going price is about $900 or so?

I paid $945 for mine at Scannermaster. I see now there is a promotion going on until mid-January where you can get $200 off at one of the authorized dealers, like Ray's Pagers. I'm guessing Scannermaster is not an authorized dealer or you'd think they'd be running the same discount. See this thread for more:

http://forums.radioreference.com/unication-forum/342399-unication-usa-q4-2016-promotions.html

It's a very good radio, I'm liking it a lot. For 20 years the BOEC analog 800 system always sounded like crap on my scanners while mobile, but now it's a pleasure to drive around town and have the new p25 system actually sound good. The G5 just works on P25 simulcast, no tweaking of settings or any of that. It is a bit annoying that there's no delay at the end of transmissions, or that you can't hold on a talkgroup, but you can work around those limitations to some degree with programming. My Uniden 436 never leaves the house anymore!

.
 

ScottPDX

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Sparklehorse,
I applied a good number of your changes to my RS PRO-668 for the P25 Portland Public Safety, along with a change from a one indoor top of radio antenna to another, and have seen some improvements.

Following your guide, I changed the following:
AGC Global to off
AGC System (Portland Public Safety P25) to off
AGC Site (West Simulcast) to off
Removed East Simulcast, or any other sites
Set just Primary CC: 772.60625, and removed alternate
Changed top of radio telescoping metal antenna to rubber duck
Turned off Global Attenuation
No other Channel or other type attenuation
Digital Site Decode: 15 to 95 range

I am putting up the 700/800/900 Yagi and discone in the next month or so. We'll see how that works.

I have noticed prior to these settings that morning and early afternoon has good audio with little audio decode digital garble, due to (I'm assuming) multicast multipath errors, but later afternoon and evenings have more decode digital garble. I'll see if these new settings have the differing audio garble issues based on time of day. Have you noticed the morning vs afternoon/evening differences in amount of multicast multipath decode digital audio garble also?

Thanks for the configuration suggestions.
ScottPDX
 

sparklehorse

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Sparklehorse,
I applied a good number of your changes to my RS PRO-668 for the P25 Portland Public Safety, along with a change from a one indoor top of radio antenna to another, and have seen some improvements.

Hi ScottPDX,
The adjustments I listed were for my Uniden 536. They may or may not produce any benefit on your Radio Shack model. They could even make your reception worse. They may not benefit another 536 user either, a lot of this depends on your location relative to the towers. But there's no harm in trying. If they do help, perhaps your settings would benefit other RS or Whistler owners. A yagi is still the safest bet for improvement.

I have also noticed the decode seems a bit better in the morning than it is in the evening. It could just be atmospheric conditions, but I also have to wonder if when the system is very busy, and say there's transmissions on eight or ten frequencies at once, if the power on each isn't diminished a little. It's just a theory, I'm not a radio tech. But it seems odd that the decode is better when the system is relatively quiet. I'll have to pay more attention to system traffic to see if there could be a relationship.

.
 

bailly2

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shouldn't have problems with a tweaked uniden 436 or 536. best thing for simulcast distortion is stick the antenna through a hole in the side of an empty paintcan near the bottom. i built a yagi, still had some garbled transmissions. this is the best
 

ScottPDX

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Hello all,
Well, I factory defaulted all settings on the Radio Shack PRO-668 and then loaded all Portland P25 talkgroups by configuring a "wildcard" TG:, as this scanner's manual calls it, with West Multicast and just the one single West Simulcast Primary CC, and my reception and audio is much improved. Maybe also relocating the scanner away from other electronics could have helped too.

Now, I just need to find out how to hold on a TG......

ScottPDX
 

gmitch

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On the West simulcast RR list for the P25 system, 857.6875 is listed. Can someone verify this? Portland is not licensed for that frequency but WCCCA is.
 
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