Chicago Midway Airport -- Department of Aviation - UHF-T question

NWI_Scanner_Guy · Jul 23, 2009

Was heading up towards Midway this afternoon, so I decided to enter this system into my 346XT. Unfortunately I didn't hear anything except some hissing and static every now and then.

When I got home and checked my scanner settings against the database, everything looked to be in perfect order. But then I dug a little deeper.

From the look of things, a custom band plan is needed for this system, which was imported along with the freqs and tgid's. However, when I manually go into the scanner settings, band plan 1 is looking for upper and lower base frequencies. The system ( Scanner Frequencies: Chicago Midway Airport -- Department of Aviation - UHF-T Trunking System, Chicago, Illinois ) only shows 1 base freq... 474.0000. Should this be entered as the lower or higher base freq? And if the radio does need two freqs, how can I determine what the other freq is?

If anyone has a 346XT and has this system successfully programmed into their radio, I would greatly appreciate a tip or two as to how to get it working in mine.

Thanks in advance for any help you can provide.

SSSG

KB9WUV · Jul 25, 2009

the upper freq is 478.7375

Tony
KB9WUV
CARMA CHICAGO

NWI_Scanner_Guy · Jul 26, 2009

KB9WUV said:
the upper freq is 478.7375

Tony
KB9WUV
CARMA CHICAGO

Thanks.

I'll be back up that way Tuesday, so hopefully that will bring better results.

SSSG

werinshades · Aug 11, 2009

SouthSideScannerGuy said:
Thanks.

I'll be back up that way Tuesday, so hopefully that will bring better results.

SSSG

How did it work out for you?

Statevillian · Aug 11, 2009

To the original poster.........

346XT?.... or are you using a 396XT?.........
Midway UHF is a mixed analog/digital trunked system but I have never heard anything analog on it. The 346XT does not track any digital transmissions. So if you have a 3 FORTY 6 and not a 3 NINETTY 6, you'd be wasting your time using the frequency from the gracious expert who replied to request.

By the way, I am having serious trouble with that formula. I still can't hear anything of that MDW UHF system on my 3 NINETY 6XT using the Uniden site and formula. I'll keep trying but........

werinshades · Aug 11, 2009

I was reading the owners manual on the Nine Ninety Six XT, and was curious why Uniden did this to program UHF Digital Trunking Systems? Adding the Base, Step, Offset was a pain to begin with, but now you have to add an upper and lower base frequency, which seems to me as overkill. Anyone have an explanation why this is the new trend from Uniden?

Statevillian · Aug 11, 2009

That is a very good question. I have tried the formula on both the ORD and MDW system with no luck. The GRE tracks apparently flawlessly but the Uniden stays silent. Not even a flicker of a TG ID. Just "Search" riding across the display. Something about that upper base freq is not working. I have tried the (+) and (-) polarity too. nada!

werinshades · Aug 11, 2009

Thank gawd my old Seven Ninety Six-D, still works flawlessly on this system. Nice and easy to program...took me awhile to understand it, but trunks great.

chgomonitor · Aug 11, 2009

On the O'Hare system 477.1875 works as an upper frequency on the 996XT

NWI_Scanner_Guy · Aug 12, 2009

werinshades said:
How did it work out for you?

Not too well.

Statevillian said:
To the original poster.........

346XT?.... or are you using a 396XT?.........
Midway UHF is a mixed analog/digital trunked system but I have never heard anything analog on it. The 346XT does not track any digital transmissions. So if you have a 3 FORTY 6 and not a 3 NINETTY 6, you'd be wasting your time using the frequency from the gracious expert who replied to request.

By the way, I am having serious trouble with that formula. I still can't hear anything of that MDW UHF system on my 3 NINETY 6XT using the Uniden site and formula. I'll keep trying but........

The 346XT, just like I said in the OP.

It's no big loss that I wasn't able to hear anything. I don't get up that way all that much so I'm not going to lose any sleep over it LOL.

Thanks to all who replied and tried to help. I appreciate it.

SSSG

soncorn · Aug 12, 2009

How does one find the upper base frequency?

I have a system near me that might require it.

http://www.radioreference.com/apps/db/?sid=430

werinshades · Aug 12, 2009

SouthSideScannerGuy said:
Not too well.

The 346XT, just like I said in the OP.

It's no big loss that I wasn't able to hear anything. I don't get up that way all that much so I'm not going to lose any sleep over it LOL.

Thanks to all who replied and tried to help. I appreciate it.

SSSG

Yes, the villian was right, I missed that part. 346XT is not digital capable, which you'd need to monitor the Midway system.

RADIOGUY2002 · Aug 12, 2009

wait

wait a minute, no digital. So, you mean to tell me it can't trace uhf digital systems like o'hare and Midway. Whats the point then? Geez, more bad notes on the xt series. I'm sticking with my decision to go with the gre more and more.

werinshades · Aug 12, 2009

RADIOGUY2002 said:
wait a minute, no digital. So, you mean to tell me it can't trace uhf digital systems like o'hare and Midway. Whats the point then? Geez, more bad notes on the xt series. I'm sticking with my decision to go with the gre more and more.

We were speaking of the 346XT...the 396XT is digital capable.

RADIOGUY2002 · Aug 13, 2009

Missed That

Missed that, I'm staying far away from conventional scanners these days. It just does not make a lot of economical sense at this point.

KB9WUV · Aug 16, 2009

I have 478.7375 as the upper base freq in my 396XT and track Midway P25 system just fine

KB9WUV
CARMA CHiCAGO

werinshades · Aug 29, 2009

KB9WUV said:
the upper freq is 478.7375

Tony
KB9WUV
CARMA CHICAGO

This is not correct. I have 2 scanners running this system, the 796D tracks it, while the 996XT does not. If I hold the control channel, the talkgroups show but no audio. We need a simpler math to figure this out...

werinshades · Aug 31, 2009

Band Plan Mystery Resolved

werinshades said:
This is not correct. I have 2 scanners running this system, the 796D tracks it, while the 996XT does not. If I hold the control channel, the talkgroups show but no audio. We need a simpler math to figure this out...

I had the 996XT a few days now, so I decided to dive into this mystery. This is not clear in any manual I found, so I decided to hook up the laptop and use the ARC software to keep tweaking this this afternoon. Here's my settings for Midway Trunking System on the XT models:

Band Plan 1: Lower Base: 474.000 Upper: 478.7375 Step: 12.5 Offset: 380

Band Plan 2: Lower Base: 474.000 Upper: 478.7375 Step: 12.5 ***(Offset: 0 )

***This was the major programming problem I discovered while trying to program UHF Trunking systems. Everything is the same in Band Plan 2, EXCEPT the Offset Channel is 0. I also programmed the Metro Correctional Center using the Upper Frequency of 416.4875. I calculated this using the ARC Software, using the Lower Base frequency in both Band Plans, changing the Offset on Band Plan 2 to 0, then it gave me the Upper Frequency. I'm not sure if all of you knew this and didn't put it in your posts, or just assumed everyone knew this. One other setting I kept changing was in the System Type. Changed them all to Motorola, and was trunking. Hope it helps someone else out there...

Statevillian · Aug 31, 2009

I concur with Werinshades on the fact that 'something' was missing.....He and I had spoken over the last several days trying to unravel this mystery. I programmed it according to what others had previously reported and had nothing as usual. I tried using all three abndplans from the Excel spreadsheet, and nothing. I was resolved to just not even try any more. it was frustrating. That '0' offset in the second bandplan appears to be critical for the system to accurately track and have audio. That is nowhere in the manual that I saw....and not referenced anywhere else...until here today. It makes me wonder what else may be missing a step in a process here and there and I am either not receiving ot getting optimal performance out of this scanner. Thanks again Werinshades for all the effort you put into resolving the issue.

werinshades · Aug 31, 2009

Statevillian said:
I concur with Werinshades on the fact that 'something' was missing.....He and I had spoken over the last several days trying to unravel this mystery. I programmed it according to what others had previously reported and had nothing as usual. I tried using all three abndplans from the Excel spreadsheet, and nothing. I was resolved to just not even try any more. it was frustrating. That '0' offset in the second bandplan appears to be critical for the system to accurately track and have audio. That is nowhere in the manual that I saw....and not referenced anywhere else...until here today. It makes me wonder what else may be missing a step in a process here and there and I am either not receiving ot getting optimal performance out of this scanner. Thanks again Werinshades for all the effort you put into resolving the issue.

Your welcome villian, and thanks to all the input you gave me.We're by no means "new" to these type of scanners, and I truly feel for those that may not be new to scanners, but new to this type of format. We know of three UHF trunking systems in this area, and I hope that when someone else get's frustrated in programming these systems, this will help. I don't know if a sticky would be in order in the Illinois forums, or maybe even the Uniden site, but somewhere there has to be a "programming UHF/VHF Trunking system" information. Another thing I must comment on, the format to determine your upper base channel didn't work for the Metropolitan Correctional Center UHF Trunking system. That one I was able to peg by using the ARC software. But, once again, had to use the Offset Channel as 0 to get the correct upper frequency. Whew...ok been here all day...time to go enjoy the nice day. I will post this later on the Uniden Forum...but just need to step away from the scanners...LOL!

Chicago Midway Airport -- Department of Aviation - UHF-T question

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