Montgomery County PSSM Program update

[Mr_Boh]

It's mixed but for the most part the only stuff left that was analog was MOSCAD since that can't be digital modulated over P25 voice. There are also new towers near the river as part of the switch, so I would expect someone in Tysons to actually have better reception.

So my thoughts would depend on what you @viggendriver is using to listen. If you are using anything other than an SDS, Unication G4/5, or SDR with something like OP25, likely simulcast distortion is causing problems since it impacts full P25 systems much worse than a SmartZone system with digital voice talkgroups.

 

[maus92]

853.9375 is the current control channel for the P25 system, and is currently the highest frequency in the system. That seems to be a trend in new P25 deployments.

851.275 (mentioned earlier) and 853.4375 are new traffic channels in service.

Both of the above channels are not reporting to be active on the P16 system as of ~1130.

 

[viggendriver]

I'm using both an SDS100 and OP25 tied to an Airspy and Rpi4. The SDS locks on to 853.9375 but getting very few hits. OP25 doesn't see anything.

 

[maus92]

This is not correct, once the transition is complete all 20 frequencies will be active on the new system. That is several weeks away.

Lol, I thought in one of the presentations they mentioned a 13 channel system - now I need to find it! Otherwise, I was dreaming.

 

[dwlipp]

Thanks! Expect March 24th for the MCFRS cutover to the P25 system.

Unfortunately the Chief was incorrect when he said that MCFRS moves on March 24th, we are moving on March 4th (next Thursday) as long as the weather doesn't interfere with the needed tower climbs. Right now it looks like the weather is likely to cooperate, so March 4th is more likely than not.

 

[villlythekid]

Thanks! Expect March 24th for the MCFRS cutover to the P25 system.

I've heard March 4th as the date. But I could very well be mistaken. EDIT: Capt Lipp clarified above. Thanks!

 

[FQ1100]

What control channel are you guys hitting? I'm trying 853.9375 and 853.6875 and getting nothing however I'm down in Tysons and might be too far South

I live in Warrenton Va and on my G5 i get 1-2 bars signal strength and with a external antenna I get full strength signal I've been in Sterling Va and get full signal so u should have great signal in Tysons

 

[KR3E]

I've heard all of the police MCPD dispatch TGs except A2 with a BCD436HP using a rubber duckey in an apartment in Gaithersburg. Reception isn't nearly as good as MCFRS on the old system. I'm certain I'm missing a lot of adjustments. Can someone with a 436 tell me if there's an adjustment that I need to make for the new P25 system?

Ed

 

[maus92]

I've heard all of the police MCPD dispatch TGs except A2 with a BCD436HP using a rubber duckey in an apartment in Gaithersburg. Reception isn't nearly as good as MCFRS on the old system. I'm certain I'm missing a lot of adjustments. Can someone with a 436 tell me if there's an adjustment that I need to make for the new P25 system?

Ed

The only adjustment that seems to work with P25 simulcast systems is to your wallet: unless you can find a sweet spot in your apartment (sometimes there are,) you will need to replace the 436 with a SDS100 or Unication pager to receive reliable reception.

 

[KR3E]

The only adjustment that seems to work with P25 simulcast systems is to your wallet: unless you can find a sweet spot in your apartment (sometimes there are,) you will need to replace the 436 with a SDS100 or Unication pager to receive reliable reception.

Wondering if it's also a case of the Sentinal software not having added some frequencies to its most recent update. It lists only six. One appears to be the control channel, 853.9375, but 851.275 and 853.4375 (and I assume others) are missing.

 

[Mr_Boh]

Yeah, likely the changes haven't hit the Uniden sentinel database. That's on Saturdays if I remember correctly

 

[KR3E]

Yeah, likely the changes haven't hit the Uniden sentinel database. That's on Saturdays if I remember correctly

Checking the RR database I see that Sentinal only has one frequency that isn't a CC or an alternate CC and only one comms freq. I'm going to have to try to add the others, manually, to my Sentinal file.

 

[maus92]

Checking the RR database I see that Sentinal only has one frequency that isn't a CC or an alternate CC and only one comms freq. I'm going to have to try to add the others, manually, to my Sentinal file.

New control channels were not added, the active cch just switched to an alternate. You only need to program the 4 control channels in Sentinel (and update the radio,) and those frequencies did not change. Some (ahem, lazy) people only program the active control channel as shown in the rrdb, but that is bad practice as the cch can roll to an alternate at any time. However, there is no need to program traffic channels as the active traffic channels are read from the control channel stream.

 

[KR3E]

Copy, maus92. Thanks.

 

[radiojoedc]

I'm using both an SDS100 and OP25 tied to an Airspy and Rpi4. The SDS locks on to 853.9375 but getting very few hits. OP25 doesn't see anything.

I'm near Tysons, I'm using rtl-sdr v3 with a broadcast FM band reject filter (and an old radioshack TV amplifier, and my antenna is just some coax with the shield stripped back and twisted into radials both of which may or may not be helping). Very clean decode in DSD+, very few errors.

 

[jeffkraussws]

I'm hearing the six MCPD dispatch TGs and Park Police pretty well on my BCD436 programmed with the Sentinel app.
I'm in the Rockville/Potomac area.

 

[maus92]

I'm hearing the six MCPD dispatch TGs and Park Police pretty well on my BCD436 programmed with the Sentinel app.
I'm in the Rockville/Potomac area.

Try this experiment: pull up the OpenMHz stream for the new P25 system and compare it to the reception you are able to achieve with the 436. Radios not optimized for P25 simulcast typically miss entire transmissions that you may not even notice unless you have a reference source like the SDR setup used by the OpenMHz stream provider, or a tool like Unitrunker that allows you to watch the radio system channel assignments as they occur.

 

[jeffkraussws]

Try this experiment: pull up the OpenMHz stream for the new P25 system and compare it to the reception you are able to achieve with the 436. Radios not optimized for P25 simulcast typically miss entire transmissions that you may not even notice unless you have a reference source like the SDR setup used by the OpenMHz stream provider, or a tool like Unitrunker that allows you to watch the radio system channel assignments as they occur.

That's hard to do because the OpenMHz feed is substantially delayed compared to the off-air reception.

 

[maus92]

That's hard to do because the OpenMHz feed is substantially delayed compared to the off-air reception.

Yea, it is difficult because of the processing delay, the latency of the steaming software, and general internet conditions. I ran my old 436 against a Unication, and it was shocking what was missed. I subsequently sold the 436. You may be lucky that in your exact location the 436 will work acceptably. Comparing to the OpenMHz stream would allow you to compare audio quality.

 

[danesgs]

I am hearing from scan-dc folks that the switch over did not totally go as planned and that MCFD are still using the simulcast sites on 153.950 and 154.160. Can anyone confirm that these will still be used analog as backup for a while?

Greg-KJ4DGE