HELP! P25 Phase 2 Reception Problems

I am having choppy reception from my local P25 phase 2 system. I am currently monitoring a single
CC. The tower i am receiving is only 2 to 3 miles away and have line of sight to it. I have a signal strength
of 5 bars, with the "T" solid indicator. When voice begins, I get a "D2" indicator. The audio is choppy and the "T" indicator flashes in sequence to the choppy audio. Once the audio stops, the "T" returns to solid.
Here is what I've done to fix the problem.

1. DSP - Changed up and down to different levels.
2. AGC - Turned it on and off.
3. ATT - Turned it on and off.
4. Threshold - Moved both numbers up and down.
5. Moved around to different spots. Went outside. Could see the tower.
6. Changed frequency options from FM to NFM and back to FM.
7. No priorities are set.

Thank you for your suggestions!

I'm just curious what frequency you are using as the control channel? I noticed there are three simulcast systems (Calhoun County Simulcast, Huntsville Simulcast and UA Simulcast). A simulcast system will experience the type of problems you describe as a result of multiple signals on the same frequency arriving from different towers at your scanner.

Alabama First Responder Network

Shawn

Sounds exactly like Simulcast distortion I had to deal with in Chicago-land. Phase 2 did the same things, cut out and dropped. I happened to hit the (attn) button on the scanner and it came in better. I found a better way to attenuate than dampening ALL the frequencies. In this THREAD link --- http://forums.radioreference.com/ar...o-668-not-receiving-rwc-much.html#post2360940

It's discussed on how to (attn) in EZScan or I-SCAN programs by selecting attn-per site in your SYSTEM at top, then attn the individual SITE itself (Cookstar21) in my photo example in the thread) This is kind of like attenuating a control channel using a Pro96/2096 or other older scanners. There's TOO much signal so I tried the ATTN for the problem site. It fixed it pretty well even using ducky antennas at home but I still had location problems. I eventually bought a YAGI 700/800mhz antenna and have beaten Simulcast that way. It's just one room in my apartment that was the bad location but the directional YAGI solved all. Now the D2 signals are loud and clear and I hear both sides of the conversations. And even though it's a limited frequency range antenna, I still get the stronger local signals in 155.000-476.000, airband and NOAA weather too, even from a county away.

Try setting the DSP level adapt to 16. Leave AGC on and ATT off. You are definitely experience LSM distortion and it is always more prevalent with Phase II TDMA (you can read about why using the search function). My other suggestion is if another simulcast further away carries the same traffic, use that one instead of the one that is slamming in. This way you can eliminate hearing multiple simulcasts from different directions and may only get
one site off the further simulcast instead of multiple sites from the closer one. And last as others suggest, YAGI antenna !


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This is exactly the same problems experiences by users of PSR-800. The Metrolinx system in Ontario is mixed Phase 1 and 2. I hear Phase 1 loud and clear, Phase 2 transmissions are choppy and in a lot of cases unintelligible. I hope they have improved Phase 2 on the WS1095 .

Andy

Thanks for all your help. I have now changed DSP to 16, added "ATT" to the site and turned agc on and off. I even drove around with the same results, choppy audio, ie in and out audio. Please keep sending ideas. I will try them all.

I'm on 152.7800

In a stationary environment use a yagi antenna and aim it towards one site. Mobile, you are pretty much screwed except to use a less effective antenna (or even no antenna) that hopefully prevents you from receiving so much competing signals. Good luck.

Donradtke said:

I am having choppy reception from my local P25 phase 2 system. I am currently monitoring a single
CC. The tower i am receiving is only 2 to 3 miles away and have line of sight to it. I have a signal strength
of 5 bars, with the "T" solid indicator. When voice begins, I get a "D2" indicator. The audio is choppy and the "T" indicator flashes in sequence to the choppy audio. Once the audio stops, the "T" returns to solid.
Here is what I've done to fix the problem.

1. DSP - Changed up and down to different levels.
2. AGC - Turned it on and off.
3. ATT - Turned it on and off.
4. Threshold - Moved both numbers up and down.
5. Moved around to different spots. Went outside. Could see the tower.
6. Changed frequency options from FM to NFM and back to FM.
7. No priorities are set.

Thank you for your suggestions!

Click to expand...

Set DSP level adapt to 16-18, you also need to attenuate, or use Yagi antenna and aim it towards that site tower. The issue is the multiple towers

I am having the same prob on my phase 1 system as well

It will be more prevalent on Phase II, but can happen on Phase I systems as well because they both utilize LSM CPQSK.


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CQPSK.


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I'm having a very similar issue with a simulcast system. My Uniden BCD436HP is lighting up every couple of seconds, but I'm lucky to get ONE transmission from the 800. I'm updated on firmware. I've been using Uniden for a while, and haven't used a GRE scanner since my 197, so it's possible I'm missing something, but not likely.

DSP Level Adapt = 16, I've tried using a paperclip. I know I'm getting bombarded with IF, because I'm downtown Atlanta.

This radio works like a champ with another Phase II system that is not simulcast, a Phase I system that is not simulcast, and an analog system, but Im lucky to get above 5% of transmission out of the GRE.

Is there something I'm missing? I'm not entirely sure what ADC ad DAC gain levels do, but my guess is to amplify or decrease signal pre- and post-decoder.

I'm not new to digital scanning. I have a 396T and the 436HP. I've heard so many great things about this radio and decided I might be able to do better with it than what I had, but after 5 days, I'm pretty frustrated with everything that I've tried. Help????

<EDIT> I should add that I've tried every possible combination of DSP, ATT, ADC, DAC and antennas that I can think of, outside of a directional antenna </EDIT>

icarus1963 said:

This is exactly the same problems experiences by users of PSR-800. The Metrolinx system in Ontario is mixed Phase 1 and 2. I hear Phase 1 loud and clear, Phase 2 transmissions are choppy and in a lot of cases unintelligible. I hope they have improved Phase 2 on the WS1095 .

Andy

Click to expand...

This has been bugging me for a while. Just for fun, I went to a known metrolinx site in Kitchener, and stood right under the antennas.

I tried all combinations of antenna, no antenna, attenuation, and no attenuation. Along with various DSP settings commonly tossed around here. Nothing made any difference on my 668.

Is this as expected for simulcast distortion behavior?

At a tower site is likely one of the worst places for reception for at least two reasons:

1. You are in a null for the antennas you want to 'monitor'.

2. There are likely many other transmitters on the site that will interfere with the scanner.

Best to try the test a mile or two away from the site, but in visual range of the antenna.

Voyager said:

At a tower site is likely one of the worst places for reception for at least two reasons:

1. You are in a null for the antennas you want to 'monitor'.

2. There are likely many other transmitters on the site that will interfere with the scanner.

Best to try the test a mile or two away from the site, but in visual range of the antenna.

Click to expand...

Still learning -- Thank you for the education.

I am having choppy reception from my local P25 phase 2 system. I am currently monitoring a single
CC. The tower i am receiving is only 2 to 3 miles away and have line of sight to it. I have a signal strength
of 5 bars, with the "T" solid indicator. When voice begins, I get a "D2" indicator. The audio is choppy and the "T" indicator flashes in sequence to the choppy audio. Once the audio stops, the "T" returns to solid.

Click to expand...

I'm having exactly the same problem with my WS1080 monitoring a very close non-simulcast site on the Oregon State Radio Project with P-25 Phase II. The two Phase I systems I monitor in the Portland Metro area are great. Not a simulcast issue for me.

Today the techs were testing the Oregon State Radio Project in Phase I and Phase II modes on the same TG. When the transmissions were in Phase I, the audio was clear as day. When the audio switched to Phase II the scanner showed D2, the "T" flashed until the transmissions stopped, and I got no audio. This is not on a simulcast site. I have a full signal too. There is something else going on. It is not simulcast distortion.

Interesting...

I can vouch for observation that this is not a simulcast issue. I have been having similar problems with the UHF (470 MHz) side of LA-RICS (tdma on the 700 MHz side sounds beautiful) - definitely not a simulcast system.

I have yet to hear a tdma transmission on UHF that wasn't hammered by a stong 3-5 Hz beat-like distortion. This is consistent across all the UHF sites, under weak signal, strong signal, moving and stationary reception... I'm beginning to suspect it's an issue in the firmware...

Just out of curiosity, has anyone managed to figure out what is happening? What bands are the other problematic sites on?

Thanks!

bcorbin said:

Interesting...

I can vouch for observation that this is not a simulcast issue. I have been having similar problems with the UHF (470 MHz) side of LA-RICS (tdma on the 700 MHz side sounds beautiful) - definitely not a simulcast system.

I have yet to hear a tdma transmission on UHF that wasn't hammered by a stong 3-5 Hz beat-like distortion. This is consistent across all the UHF sites, under weak signal, strong signal, moving and stationary reception... I'm beginning to suspect it's an issue in the firmware...

Just out of curiosity, has anyone managed to figure out what is happening? What bands are the other problematic sites on?

Thanks!

Click to expand...

Same here. Everytime I receive a TG from the Oat Mtn site I get the choppy audio. When I later received the TG on the Verdugo Peak site, the audio was clear as day.