Interesting aspect, can someone elaborate?

[NS9710]

How is it sometimes a user of a radio for whatever system can be transmitting clearly to where the scanner can get the transmission perfectly, but the dispatcher claims the signal to be too much distortion or too poor of a signal for them to hear it?

Like just now in Petersburg's P25 city system, I heard the O/D Sgt just mark on a location, yet the dispatcher said 3 times "You're unreadable", however I heard every time to be perfect volume, strength, and clarity, how is this?

 

[belvdr]

It's location. If you're close enough to the tower that is transmitting, it may be clear, but unreadable from another tower. If it's IP based, I can see congestion or link integrity causing an issue with the data being sent to another tower.

This from a non-RF guy, but technical in other aspects.

 

[jaspence]

Very similar to older scanners. I live in an area known for simulcast problems, but even my Pro-106 does a good job with little garbled audio due to my location.

 

[buddrousa]

Just to add to this in my Fire Station I have our pager for calls our 800 trunking radio my 2 scanners and all of them decode just enough different to produce a slight echo and this is a ANALOG System.

 

[RFI-EMI-GUY]

How is it sometimes a user of a radio for whatever system can be transmitting clearly to where the scanner can get the transmission perfectly, but the dispatcher claims the signal to be too much distortion or too poor of a signal for them to hear it?

Like just now in Petersburg's P25 city system, I heard the O/D Sgt just mark on a location, yet the dispatcher said 3 times "You're unreadable", however I heard every time to be perfect volume, strength, and clarity, how is this?

That normally should not be the case.

1) If the dispatcher has a defective headset the audio may be distorted. Just a bit of hair in the earpiece or a broken wire. I actually witnessed the commissioning of a new radio system where the dispatchers plugged their old headsets into the new consoles at midnight and started complaining the new system was no better than the old. Thankfully we had new headsets to hand out, funny to think that new headsets could have fixed the old system. It would have saved $6.8 million!

2) Usually dispatch is via consoles hard wired into the repeater system. As a back up, and often at sub stations, an RF control station is used. That is a radio like any other and poor placement of the antenna can introduce simulcast distortion.

3) the dispatcher may have a hearing deficiency that corresponds with the tone of the radio users voice. This is exacerbated by the digital vocoder in a project 25 radio system.

 

[buddrousa]

Or simple intermod from a new system could explain it.

 

[ScubaJungle]

Its funny you post this, because I get this ALL the time. Just happened two minutes ago, transmission was crystal clear and dispatcher asked for a repeat, citing low volume/distortion. It's been from different dispatchers too, so I dont think hearing issues is the problem. Old headsets, maybe, or location?

 

[ofd8001]

In addition to the above, it could be other human factors too. A lot of background noise at the dispatch center, failing to have the headset plugged in properly and so on.

It's unfortunately something that "just happens".

 

[RFI-EMI-GUY]

Its funny you post this, because I get this ALL the time. Just happened two minutes ago, transmission was crystal clear and dispatcher asked for a repeat, citing low volume/distortion. It's been from different dispatchers too, so I dont think hearing issues is the problem. Old headsets, maybe, or location?

I find the audio levels in P25 jump all over the place and there is no ideal volume setting. One would think that the AGC in the console would track this, but early Motorola P25 CAI systems had problems with volume and level setting,

 

[buddrousa]

I see on our state system that is multiple sites linked microwave and T1 that we get dropped packets here from the links but dispatch hears just fine.

 

[wtp]

it could be that they don't want to say "someone here is yelling over you" it sounds unprofessional.
there is a deputy here that when asked a question says "can you repeat that i had noise here".
i have joked for years that he is not paying attention to the radio, or has his FM up a bit.
once i hear his number called, i just say "what" and the wife now sees the pattern.(10-9)

 

[RFI-EMI-GUY]

I see on our state system that is multiple sites linked microwave and T1 that we get dropped packets here from the links but dispatch hears just fine.

That is a good point.

 

[ten13]

I heard the O/D Sgt just mark on a location, yet the dispatcher said 3 times "You're unreadable"

Maybe the Sgt is a hump, and the dispatcher doesn't like him (or her).....

 

[slicerwizard]

I've had the displeasure of dealing with Motorola gear with absolutely terrible embedded audio AGC logic. Could be as simple as that.