Finding digital on 436?

[WeldGuy]

I've asked for suggestions before, but none have woked. Let me give all the specifics and try again.
*Local Sheriff Office has begun using digital transmissions on ONE existing frequency.
*The digital signal is transmitted along with the analog signal on the same frequency at the same time.
*I've been told to think of this method as a type of "sideband" arrangement where the digital is transmitted on the "upper" side of the frequency and the analog on the "lower" side of the frequency.
My question is: is there a way to search with the 436 with ANALOG SHUT OFF so the information needed to program the digital can be obtained from the transmitted digital signal?
Only 453.8250 is set up this way.
Thanks for your suggestions... this digital stuff is frustrating to my 67 year old brain!

 

[RandyKuff]

What county are you talking about?

If your talking about Franklin county... What I see in the database here is they are on the MARCS IP system. That is a P25 phase 1 trunked system.

I see they also show up on an old analog trunked system too.

 

[JoeyC]

Never heard of such a simultaneous arrangement where a digital and an analog signal exists on same frequency and are transmitted at the same time. More likely some radios on the channel are digital and some are analog. In the 436 set the audio option on the channel to ALL will get both analog and digital, or if you wish, change the type to DIGITAL to exclude the analog transmissions and use the default NAC search.

 

[phask]

Need to tell us what system - if it's Fairfield SO - that is DMR/TRBO, no scanner will receive it.

You've asked this before, been told the same over & over fwiw.

Fairfield SO is the only system ID'd with that freq. in Central Ohio.

edit
Here http://forums.radioreference.com/ohio-radio-discussion-forum/321586-fairfield-county-sheriff.html


DSD - this guy is currently copying it.

 

[Jay911]

I absolutely guarantee they cannot be transmitting analog and digital at the same time on the same frequency. They might be operating in "mixed mode" which means some transmissions are analog and some are digital, but not simultaneously.

If we are sure that the transmissions are P25 digital, then JoeyC's last suggestion (change the signal type to digital and the tone to "NAC search") will work for you. If, however, there is any chance it might be something else, like MotoTRBO/DMR or NXDN/NEXEDGE/IDAS, a better method might be to identify what tone they are using for their analog comms and use the "tone lockout" feature, which will mute all comms that match that tone. I don't have access to the "Easier to Read Manual" right now, but I'm sure that'll be in there. Then, any digital comms will come through. They will probably sound like noise, but you'll at least know if they're present.

 

[WeldGuy]

Phask,
It is Fairfield County. The tech doing the conversion said it is NOT TRBO.
Sorry if my persistance offends you. If I were a super brain like you must be I would have figured it out myself.

 

[RakkFO]

I am a stones throw away from Fairfield Co. I will put my equipment on it and see what I can find. 453.8250 you said correct


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[ecps92]

They exist in both TRS and Conventional systems

TRS Example: MSP Analog TRS has P25 Capability on a.) Certain TG's and b.) These will only be allocated to a limited amount of Freq.'s in the TRS Assignments per Zone

Conventional Example: Civil Air Patrol - each Repeater is Dual Mode
ie: It can handle CTCSS and P25 depending on what the user Selects on his/her Portable, Mobile, Base

Also in New Hampsshire we have Disp selecting Analog but the Cruiser selecting P25

Never heard of such a simultaneous arrangement where a digital and an analog signal exists on same frequency and are transmitted at the same time. More likely some radios on the channel are digital and some are analog. In the 436 set the audio option on the channel to ALL will get both analog and digital, or if you wish, change the type to DIGITAL to exclude the analog transmissions and use the default NAC search.

 

[phask]

According to this:
http://forums.radioreference.com/oh...ld-county-switching-mototrbo.html#post2313328

It is Mototurbo.

Also links to FCC data - 453.825 is in there. I'm too lazy to chase down emission types but will presume that W8RMH is correct.

Which was all previously covered in

http://forums.radioreference.com/ge...n/304977-irritating-noise-has-us-stumped.html

Not to sound like a $%$# - but it really seems to be beating the same old dead horse that has been beat to death in the Ohio Forum.

 

[RandyKuff]

According to this:
http://forums.radioreference.com/oh...ld-county-switching-mototrbo.html#post2313328

It is Mototurbo.

Also links to FCC data - 453.825 is in there. I'm too lazy to chase down emission types but will presume that W8RMH is correct.

Which was all previously covered in

http://forums.radioreference.com/ge...n/304977-irritating-noise-has-us-stumped.html

Not to sound like a $%$# - but it really seems to be beating the same old dead horse that has been beat to death in the Ohio Forum.

There is a link to a youtube video in the link you posted... Columbia Gas must be using Mototurbo too...
That's what I hear when they key up...

 

[WeldGuy]

Thank you to those who are helping.
The reason I'm possessed by this is it's preventing several of us who are volunteers with Fairfield County Sheriff Community Watch program who monitor scanners in our day-to-day activities. Some who live close to repeater sites have found it impossible to monitor Ch1 because the digital signal tears up the analog so badly. Since I have the latest digital scanner, they are hoping I can figure this out before they invest in digital equipment. The problem is even present with older radios in our cruisers that are not digital.

 

[JoeyC]

They exist in both TRS and Conventional systems

TRS Example: MSP Analog TRS has P25 Capability on a.) Certain TG's and b.) These will only be allocated to a limited amount of Freq.'s in the TRS Assignments per Zone

Conventional Example: Civil Air Patrol - each Repeater is Dual Mode
ie: It can handle CTCSS and P25 depending on what the user Selects on his/her Portable, Mobile, Base

Also in New Hampsshire we have Disp selecting Analog but the Cruiser selecting P25

Apples and oranges. The OP stated that a digital and analog signal was being broadcast on the same frequency simultaneously presumably from the same entity. I am quite aware of the ability to transmit many different modes over a single frequency or TRS but thats not what the OP described.

 

[ecps92]

You say Tomatoe and I Say Tomato

And since we BOTH are not the OP, we are reading between the lines and attempting to filter his comments/information. So we both are making A$$-u-m(e)ptions :roll:

Apples and oranges. The OP stated that a digital and analog signal was being broadcast on the same frequency simultaneously presumably from the same entity. I am quite aware of the ability to transmit many different modes over a single frequency or TRS but thats not what the OP described.

 

[JoeyC]

So we both are making A$$-u-m(e)ptions :roll:

I've made my comments based on what he said in lines 2 and 3 of his original post. I'm not sure what you were assuming.

 

[jhal94]

Kek, Are you scanning in wide-band? If the are "transmitting analog and digital at the same time" it could mean they recently narrow-banded and simulcast on two adjacent frequencies for 12.5khz each. If you scan with 25khz you will land on them both.

One may be on 453.825 and the other on 453.818750 or 453.8125 which would be fine if they are running narrow but if you're running wide-band then you'll end up listening to both.

If it is also a TRBO system it will be running TDMA which has two 12.5khz (or four 6.25khz) channels running back to back on one 25khz frequency (all digital though). You will not be able to scan this.

Of course it may just be heterodyne imaging, or their radios are off frequency, or your scanner is downconverting (somehow).

 

[W8RMH]

Have you tried 453.57500 I believe they multicast .825 on that frequency although I don't know if they multicast the digital as well. I do receive .575 clearly in Grove City (3 bars) on the HP-2 and haven't noticed any digital sounds or interference on that frequency.

 

[WeldGuy]

W8RMH,
My patrol partner lives really close to the repeater site near I70 and 204. He tried the .575 and it didn't help.
I'll take all these suggestions and see what I can come up with as time permits.
I wish I could get past the tech's wife who "guards" the front desk and spend 5 minutes with him. One way or another it would put and end to this.
Thanks again.