KMLC frequency change

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sooner77

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Was listening to the KHRO feed on liveatc.net when a new frequency came up. What used to be 135.45 at KMLC is now 128.125, FYI, which is in Fort Worth Center territory. Stuck mic? Hear the aircraft side on 128.125 presumably at KMLC on a separate scanner. Sorry about the controller-only at KHRO, but I cannot get to an outside antenna--metal building.

Anybody know where 134.475 is? It is not at MLC or TXK. Belongs to Fort Worth Center.
 

AirScan

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Sooner77,

Thanks for the heads up.

What used to be 135.45 at KMLC is now 128.125
128.125 is a published ultra high Forth Worth (ZFW) frequency, on the chart the sector extends from FL360 and above and sits overtop 135.450 and 134.475. I suspect it is only open as required, perhaps to accomodate weather diversions ?

The other possibility might be the ultra high sector was still closed and they have temporarily subbed 128.125 for 135.450 ? Listening now it appers that 134.475 is still in use, so this might be the case ? And just as I'm about to send this message they have gone back to using 135.450.

As far as where they are actually transmitted from I'm not sure ? The latest FAA AFF data shows 128.125 transmitting from Marshal, it's not listed in the Radio Reference database (needs to be updated).

Anybody know where 134.475 is? It is not at MLC or TXK. Belongs to Fort Worth Center.
The latest FAA AFF data shows 134.475 transmitting from Paris and Texarkana, while the Radio Reference database shows Texarkana and McAlester. You're saying these are wrong ?

Anyone familiar with Fort Worth Center, do they open their ultra high sectors very often ? In my limited time monitoring this area I've never heard them in use ?
 
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Sooner77,

The latest FAA AFF data shows 134.475 transmitting from Paris and Texarkana, while the Radio Reference database shows Texarkana and McAlester. You're saying these are wrong ?

Anyone familiar with Fort Worth Center, do they open their ultra high sectors very often ? In my limited time monitoring this area I've never heard them in use ?
Former Ft. Worth controller here. When I left a couple of years ago they were designing some Ultra-High sectors. I haven't followed up to see if they were implemented or not.

As for 134.47, it was still at MLC and TXK when I left. As that is a high altitude freq., it would make no sense to have a site at Paris, so close to TXK. Betting it's still MLC and TXK. There is a low altitude freq. at Paris.

The FAA database is, and seems to have always been a questionable source of info. I have my guesses as to why based on experience. Anything in it, or the RADAR site info, should be corroborated by actual eardrum and eyeball observation.
 

sooner77

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Changed back to 135.45

I stand corrected and spoke too soon. They have now gone back to 135.45 at MLC as heard on my feeds at KFYV and KHRO. 134.475 is not at MLC or TXK as documented on RR. I have been to both places. Neither is 126.575 at TXK, either. It used to be, but not now, or only occ. 123.925 is the only consistent frequency at TXK. I guess a pilot uses FSS after the tower closes to pickup an IFR clearance.

Beats me where they are. Gentleman who works with the radios at TXK states that 134.475 and 126.575 are at Cumby. Apparently the RCAG at TXK is in a place not conducive to good transmissions (west of the Texas
&M-Texarkana college) as I only heard 123.925 clearly. The other two are not there or not being used due to reception issues up high. Paris is only monitored for IFR pickup on 124.875 as I was there, too.


120.125 is indeed at Marshall. Don't know why Fort Worth used it instead of 135.45 unless a stuck mic was the issue. Gave the Memphis Center controllers a problem for a little bit as 135.45 has always been at MLC. I wish they would put 134.475 at MLC so I could put an online feed on using 132.2, 134.475, and 135.45 on with their associated UHF freqs. I hear aircraft checking in on 134.475 at FL400 so I guess it is at Cumby. I hear all the aircraft clearly on 134.475 in Roland, OK. Pretty busy as it is a handoff from KORK, KFYV and KHRO RCAGS.

Finally, the man at TXK states they are trying to build a new site or extend the antennas to bring back 126.575 and 134.475. MLC just won't do because of reception/interference problems (most likely).

Happy listening!
 
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Actually, there is a rack at MLC with 134.47 in it. Due to the limitations (as you stated above) of both MLC and TXK, the sector assigned 134.47 (DECOD-high) will transmit from MLC or TXK depending on need. 135.45 is also at MLC, and serves the MLC-high sector.

Cumby would be good site for 134.47, possibly making MLC and/or TXK un-needed.
 

AirScan

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When I left a couple of years ago they were designing some Ultra-High sectors. I haven't followed up to see if they were implemented or not.
Thanks for the info.

I have a sector chart from ZFW dated January 2012 that shows 7 ultra high sectors.

128.125 - FL360 and above, overtop 134.475 and 135.450
135.175 - FL360 and above, overtop 132.975
135.275 - FL360 and above, overtop 132.450 and 124.525
125.225 - FL350 and above, overtop 120.775
128.525 - FL350 and above, overtop 132.075 and 120.275
133.500 - FL350 and above, overtop 126.575 and 120.475
133.375 - FL350 and above, overtop 133.875

Anyone in that area ever hear anything on these designated ultra high frequencies ?
 

nd5y

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I just programmed in the ones on the right side.
I can hear ZFW on 133.500 and 135.275. They are located at the Wichita Falls site (or at Sheppard) and have a lot of traffic.

I don't think 133.500 is ultra high, they are handing off aircraft to Sheppard Approach and OKC Approach.
 
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I just programmed in the ones on the right side.
I can hear ZFW on 133.500 and 135.275. They are located at the Wichita Falls site (or at Sheppard) and have a lot of traffic.

I don't think 133.500 is ultra high, they are handing off aircraft to Sheppard Approach and OKC Approach.
The sites are acutally West of Wichita Falls in Iowa Park. Higher spot than SPS.
 

AirScan

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nd5y,

Thanks for the reply.

I don't think 133.500 is ultra high, they are handing off aircraft to Sheppard Approach and OKC Approach.
I notice now on the ZFW low chart that they also show 133.500 as being a low sector as well. So it would appear that the ultra high chart is in error.

I can hear ZFW on 133.500 and 135.275. They are located at the Wichita Falls site (or at Sheppard) and have a lot of traffic.
Can you tell if 135.275 is a dedicated ultra high sector or are they working traffic at all altitudes above FL240 ? Can you tell what area it is ? Maybe like 128.125 the other day they are subbing it with one of the high frequencies ?
 

nd5y

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Can you tell if 135.275 is a dedicated ultra high sector or are they working traffic at all altitudes above FL240 ? Can you tell what area it is ? Maybe like 128.125 the other day they are subbing it with one of the high frequencies ?
I don't know how to tell what kind of sector it is. Earlier all I heard was the controller handing off aircraft to other Fort Worth Center controllers, Albuquerque Center and Kansas City Center. I didn't hear any aircraft which is strange.

The Wichita Falls RCAG sites have a bunch of frequencies. They usually have several VHF and UHF simulcasting instead of just one VHF and one UHF. Sheppard AFB is the same way. If I remember right there are a few frequencies that I have heard Fort Worth Center, Sheppard Area Monitor and Sheppard Approach on at different times. Every time I try to figure it out it's different the next time.
 

AirScan

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I don't know how to tell what kind of sector it is. Earlier all I heard was the controller handing off aircraft to other Fort Worth Center controllers, Albuquerque Center and Kansas City Center. I didn't hear any aircraft which is strange.
This was on 135.275 right ? You are hearing the controller but no aircraft. I suspect the controller you are hearing would then also be transmitting on 124.525 and/or 132.450 and you would be able to hear the aircraft that the controller on 135.275 is talking to on those frequencies. Is this correct ?

You can tell if it's a dedicated ultra-high sector if you hear the controller working aircraft that are all at or above FL360 (in this case). I suspect that the normal sector configuration would be to combine the high and ultra-high sectors in which case you would normally hear the controller working all aircraft that are at or above FL240. Then when it gets busy they split off the ultra-high airspace as required.

The easiest way to confirm the area is by what adjacent frequencies aircraft are being handed off to. A sector map of the Center is helpfull here.

I've attached a ZFW sector chart below that shows high altitude sectors (above FL240) around the Wichita Falls area. It's based on official sector charts and my own personal monitoring. Any updates or corrections from anyone appreciated.
 
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sooner77

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Anybody with a scanner around the Sulphur Springs airport would probably hear 134.475 if it is at Cumby.

As far as I can ascertain, KMLC has 132.2/338.35 low and 135.45/257.92 ultra-high. Looking at the sector map shows 134.475 as the med-high.

At Wheaton, OK, FYI, is an interesting situation on the ZFW RCAG. I was there over the weekend around Will Rogers World and I can hear ZFW on 363.1 with aircraft answering on 132.45. ZKC is associated with it there 128.3/291.7, about four west of KOKC. I could hear the ZFW controllers on 363.1 talking to aircraft above FL340, but no aircraft response unless I dialed in 132.45. Weird setup. RR database has 132.45 at Clinton-Sherman airfield. Is 132.45 ultra-high? I have never heard 133.9 ZFW in the OKC area, btw.
 

sooner77

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There are two RCAG sites west of Wichita Falls. Same in San Antonio for ZHU, located to the north of the city. Probably quite a few Center freqs to listen to.
 

sooner77

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Never heard the ZME controllers at RCAGS KORK, KHRO or KFYV ever use 120.125....except last Sunday night and that lasted about 35 minutes at most. I have never tried 120.125 at MLC but it would probably be at Marshall or maybe TXK, who knows? In the Tulsa area ZKC has 128.8 low and 133.92 mid-high while the ultrahigh is 118.125 at Edna, KS. About 60 miles away usually is how it works for the ultra-high. I presume those aircraft at FL400 going north over OKC use the Anthony, KS site for ZKC.

Wichita Falls ZFW has to be interesting listening as the two RCAG sites are northwest of town. Don't know why they have have two RCAG sites, but ZHU does it also at San Antonio.
 

AirScan

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Sooner77,

Never heard the ZME controllers at RCAGS KORK, KHRO or KFYV ever use 120.125....except last Sunday night and that lasted about 35 minutes at most. I have never tried 120.125 at MLC but it would probably be at Marshall or maybe TXK, who knows?
I'm confused. Do you mean the ZFW controllers on 128.125 ? Where did 120.125 come from, you heard controllers on this frequency ?

Given the location of the 128.125 sector MLC and/or TXK seem like logical locations for the transmitter. Marshall seems like an odd choice considering it's further south than TXK. Although that's what the FAA is saying (but we know how accurate that info is).
 

nd5y

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I don't know why they have two sites here. Luckily they are up on a hill and I can hear them good. I can hear everything at Sheppard too.

There are a couple other RCAGs I know of (Amarillo and Midland) that had two sites next to each other but in the past one site was dismantled and the property appears to be privately used now. Another in north Fort Worth is no longer there. I don't know if they were relocated or just removed completely.

Many airports also have antenna farms with several short towers around a small building that look exactly like a typical RCAG site. DFW has 6 sites like that.

Wichita Falls is in a great place for civil and military aviation listening. Within about 130 miles there are 6 military bases with airports, several MOAs and three major civilian airports. There is a lot of stuff to listen to.
 
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Don't know why they have have two RCAG sites, but ZHU does it also at San Antonio.
The Wichita Falls site has two buildings to serve more equipment than the usual RCAG site. There are several UHF frequencies there dedicated to serving the Sheppard MOAs/ATCAAs. The San Antonio site probably was the same situation for back when Randolph AFB was open.
 

sooner77

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128.125

Former Ft. Worth controller here. When I left a couple of years ago they were designing some Ultra-High sectors. I haven't followed up to see if they were implemented or not.

As for 134.47, it was still at MLC and TXK when I left. As that is a high altitude freq., it would make no sense to have a site at Paris, so close to TXK. Betting it's still MLC and TXK. There is a low altitude freq. at Paris.

The FAA database is, and seems to have always been a questionable source of info. I have my guesses as to why based on experience. Anything in it, or the RADAR site info, should be corroborated by actual eardrum and eyeball observation.
To Profile Descent and Air Scan I discovered today in MLC that indeed 128.125 is transmitting from there concerning ultra-high aircraft. Still no joy on 134.475 at MLC. So, for the moment, MLC has three freqs: 132.2, 135.45. and ultra-high 128.125. Could change. Who knows? Do either one of you know the associated uniform frequency with 128.125?

In addition, as Profile Descent has commented on before, 132.45/363.1 is being switched from Clinton Sherman to KOKC (DECODE). I finally detected transmissions last evening at KOKC on 132.45, which I was never able to do before. A new sector for OKC shows also a 127.35 as an ultra-high freq, but I did not hear anything on it for hours last night near Will Rogers Airport. My hunch was that it would be placed alongside 132.45, but not so as in MLC.
 

AirScan

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sooner77,

Thanks for the update.

Do either one of you know the associated uniform frequency with 128.125?
The chart I have shows 306.92 to be the associated UHF fequency with 128.125.

A new sector for OKC shows also a 127.35 as an ultra-high freq, but I did not hear anything on it for hours last night near Will Rogers Airport.
What's your source for this ? 127.35 is listed as a Kansas City low sector transmitting from Manhattan Kansas. Sector 66. The current FAA approach charts for the area also confirm it (these are usually correct).
 

nr2d

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I don't know why they have two sites here. Luckily they are up on a hill and I can hear them good. I can hear everything at Sheppard too.

There are a couple other RCAGs I know of (Amarillo and Midland) that had two sites next to each other but in the past one site was dismantled and the property appears to be privately used now. Another in north Fort Worth is no longer there. I don't know if they were relocated or just removed completely.

Many airports also have antenna farms with several short towers around a small building that look exactly like a typical RCAG site. DFW has 6 sites like that.

Wichita Falls is in a great place for civil and military aviation listening. Within about 130 miles there are 6 military bases with airports, several MOAs and three major civilian airports. There is a lot of stuff to listen to.
The reason for 2 sites can be many. The most common is that there were several requirements from air traffic people. When the spectrum engineering folks started their frequency engineering they found that 1
or more of the requested frequencies would not play well with the established frequencies. This could be due to intermod, co-site frequency separation. When you locate a new assignment at an established site, co-site, there is a required frequency separation and they could not satisfy the requirement.

Frequency change may have been able to satisfy the requirement BUT the last thing the engineers want to do is to change an established frequency to add a new assignment. 9 times out of 10 this has a "snow ball" effect.

There could also been with adjacent channel interference that was predicted.

There are a lot of things to look at when an engineer starts to assign and new frequency assignment.
 
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