Duluth Simulcast Problems

[Oriley]

BCD996XT

Brother lives just north of Cloquet and it is all garbled.
Scanner is fine, comes up here to Da Range and we listened
to Virginia Simulcast with no problems.

So...I mad a map of where he is and the simu towers. Seems
I've heard of directional antennas that he could point straight
west away from most towers, there is one only 3 miles away.
No idea if this will work.

I might be in La-La-Land, wouldn't be the first time.

Thanks

 

[dave3825]

Brother lives just north of Cloquet and it is all garbled.

What is brother trying to listen to? There is some encryption on the system.

Scanner is fine, comes up here to Da Range and we listened
to Virginia Simulcast with no problems.

Scanners not designed for simulcast can do that. Just moving it to a different room and make reception better or worse.

I've heard of directional antennas that he could point straight
west away from most towers, there is one only 3 miles away.
No idea if this will work.

Brother could try a zero gain antenna, a paper clip, or a Yagi facing the tower closest to him. Cheapest and fastest thing to try is a paper clip as the antenna.

Or for 25 bucks, and 800mhz yagi like this one may help. Free returns if it does not help.

 

[dwgelle]

What is brother trying to listen to? There is some encryption on the system.


Scanners not designed for simulcast can do that. Just moving it to a different room and make reception better or worse.



Brother could try a zero gain antenna, a paper clip, or a Yagi facing the tower closest to him. Cheapest and fastest thing to try is a paper clip as the antenna.

Or for 25 bucks, and 800mhz yagi like this one may help. Free returns if it does not help.



View attachment 196393

This is what I have done here as well. Very similar.

 

[ofd8001]

Best reception I ever got on a simulcast system is when I inadvertently messed up the antenna mount on my truck.

With Simulcast systems, there is too much signal bombarding the scanner and it has trouble decoding the audio. So you get either no audio or garbled audio.

The model scanner you have is not friendly to simulcast systems. I just about gave up trying to monitor ARMER while on trips to Minnesota years ago with the x96 model scanners.

 

[kayn1n32008]

With Simulcast systems, there is too much signal bombarding the scanner and it has trouble decoding the audio. So you get either no audio or garbled audio.

No, you are trying to use a FM receiver, to listen to a signal that has an AM components to it.

 

[dave3825]

What AM components are involved with P25?

 

[kayn1n32008]

What AM components are involved with P25?

Simulcast uses, depending on the manufacturer, a flavour of QPSK, not C4FM, for base station to subscriber link. FM receivers, using some flavour of a discriminator tap, struggle with QPSK. This is what has become called "simulcast distortion"

PSK is used in simulcast to increase delay spread tolerance.

 

[ofd8001]

I’m having trouble comprehending that line of thought.

 

[ofd8001]

And if it’s P25 simulcast, the manufacturer doesn’t matter because that’s supposed to be open architecture.

 

[kayn1n32008]

I’m having trouble comprehending that line of thought.

apologies, It uses phase shift, not AM. Regardless, Discriminator tap scanners(pre-SDS series) struggle with it because the decision points of the PSK wave form are wrecked by the FM receiver.

And if it’s P25 simulcast, the manufacturer doesn’t matter because that’s supposed to be open architecture.

Yes. But like everything else, the 'standard' is open to interpretation. take the differences between Harris and Motorola talkgroup patches.

 

[ofd8001]

From a scanner listener perspective who has listened to the ARMER system in many areas including the twin cities metro, my experience is that any scanner "older" than the SDS models can have challenges with simulcast. If you are receiving multiple towers, garble is likely. The SDS scanners were a significant improvement in decoding audio.

In my home area of Louisville KY, we have a 13 site simulcast system. Simulcast distortion is/was horrible to monitor with scanners from a garble standpoint. Back when the SDS scanners were on the drawing board, the Uniden Product Manager, Paul Opitz was here for the Mid-America truck show. He wanted to get with me and try out this newfangled scanner on a challenging simulcast system. It was a day and night difference listening with the "new" scanner and my old scanners (x36 and 396x versions).

And back to the original post, yes a directional/Yagi antenna is a potential solution to simulcast.