BCD325P2/BCD996P2: BCD996P2, Seminole Co P25 no go

[RFI-EMI-GUY]

Ok, I did notice the signal bar was good (2 to 4 bars) on the Sem Co system depending on the channel but the screen shot is of the local Orlando CC not the troublesome Sem Co system.

I do find it a bit strange the BCD996P2 works fine on the Orlando system and I have towers all around me.

It is currently hooked up to the Discone as I also use the scanner for other stuff like Air and ham bands. I was also able to get 100% copy on the scanner using the yagi but I had it mounted low (about 6 feet above ground) to attenuate the towers to the right, left and behind and pointed it at the closes tower.

In any case the little mini computer with the SDR and DSDplusFL is working great and it has Bluetooth so I have it paired to my Echo dot for the audio output. It's a really neat system that really did not cost all the much.

The problem with simulcast is the delay spread between towers . You can be surrounded by towers and be fine . But if you are receiving outside Seminole county and one of the more distant towers is received, the discriminator in the 536 cannot parse out the digital stream . receivers with I/Q detection like SDR and Motorola radios, can detect subtle phase information and synchronizing information in the simulcast linear modulation.

 

[dkcorlfla]

The problem with simulcast is the delay spread between towers . You can be surrounded by towers and be fine . But if you are receiving outside Seminole county and one of the more distant towers is received, the discriminator in the 536 cannot parse out the digital stream . receivers with I/Q detection like SDR and Motorola radios, can detect subtle phase information and synchronizing information in the simulcast linear modulation.

Perhaps the SDR software is just that much better at sorting out the phase information. I did notice that DSDplusFL worked much better then Unitrunker on the Seminole system. I do like Unitrunker and it works great on the Orlando system but did not do near as good as DSDplusFL on the Seminole system.

 

[Abarbaro]

I’m currently using two SDR radios to feed calls for Orange County Gov Simulcast. It took a bit of learning to finally tune out the distortion. What helped was adding all the control frequencies onto one SDR radio and let the other SDR radio handle the traffic. You can set this up in SDRTrunk. What also helped was manually tuning the gain and making sure your PPM is set properly. As for a scanner they may be using a mode that the scanner can’t decode event though you have signal. Large simulcast systems require a lot of processing power and it might be skipping over calls if it’s not tuning to the right frequencies based on the control. I would just use SDRs to monitor as they are more reliable than scanners. Unless you go with and SDS100 or 200.