UHF Skip Tonight 460.150

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OutPost

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I'm receiving here in Benton County on 460.150 a strong skip (last night) and should be evident tonight on our S.O. freq (after 10 pm). Besides overlapping comm from Union City, etc; I DO believe we're picking-up Louisville, KY.

They are on the same freq and have 4 antennas pushing a total of 860 watts or so......

Their callsign is "Central" with units using 2000 callsigns. The 400's should be Union City though.

Please let us know if you are receiving this skip tonight and tomorrow night 7/25/05. Also confirm the originating station as Louisville, or elswhere..

Thanks...
 

RandyB

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First of all, let me tell you that I’m a huge fanatic of VHF/UHF skip (band openings). Unfortunately I missed last night’s event due to other obligations. I’m located near Dickson although I lived in Clarksville for years. Some of the best skip/ducting events that I have witnessed where when I lived in Clarksville. I have monitored Louisville police before from Clarksville! In fact, I’ve monitored Cincinnati Police before, who are also on UHF (or were). So don’t let anyone tell you that skip doesn’t happen on UHF. This seems to be a common misunderstanding –UHF skip does occur and often coincides with skip in the VHF band. Actually, I’ve monitored 800 MHz signals from nearly 200 miles away during the best of band openings.

As far as whether the signal on 460.15 that you heard last night was indeed Louisville Police or not is hard to say. One of the best methods I have found for identifying distant police/fire repeaters during a band opening is the use of my scanner’s PL/CTCSS decode feature. I set my BC780XLT to search for the CTCSS tone and match that with the information in the database. If your scanner has CTCSS capability, you might try it. LPD uses a CTCSS tone of 192.8 on all of their repeaters. I have monitored them several times and can attempt to give you a description as to what they sound like. However, if you were able to listen to them you would likely be able to compare and determine whether what you heard last night was indeed them or whether it was someone else. To listen to LPD live online, go to < http://www.rcfop.com > and click on “scanner.” If I remember right, the call signs used by LPD are not around 2000 –rather they are in the hundreds with an alpha character at the end (i.e. 235 Charlie). Also, the dispatcher in Louisville is referred to as “radio” rather than “central.”

Let me know what you hear tonight! Time permitting I will be scanning the bands as well in an attempt to catch what seems to be shaping up as one of the biggest stretch of nightly band openings of the year and possibly as big as the band opening of June ’04.

I talked to a fellow ham radio operators who said that he made contacts in the 2 meter band (VHF) from his location in Western Kentucky to Wisconsin and Alabama on simplex! That’s very impressive and certainly a rare event!
 

OutPost

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10:04 pm SDunday

I advised our dispatcher to expect a good skip tonight from possibly Louisville (KRL406) one of four antenna's putting-out 350 watts. Our units are concerned the freq will be as busy as it was last night with Louisville and Union City traffic.

Last night I was trying to get street names and hopefully a callsign will be transmitted, but 10-50 at the momemt, except for a couple hits within the last 30 minutes. I think this heat bubble we're in may have us under a temperature inversion.

Central mentioned a hwy 61 and another time mentioned a Timber Ridge Ct. and a 10-28 records check for license out of Bowling Green. The dispatcher talks rapidly and she's hard to follow.

Over here in our little neck of the woods, we're putting-out 40 watts and they are putting out 860 watts with 4 towers.

Tonight might be one of the off anomaly nights. I'll wait another our and then hit the sack. I've discussed this problem with our TEMA Director and he's waiting for comfirmation as to where the busy and strong station is located. I've got a Realistic 2002 working, a Pro-2020 and the best receiver tuned to 460.150 is an MX-7000.

Maybe you will here her where you are. It sounded as though she was switching her computer to "Records," but same freq.

Good luck, let me know.....
 

bg_nashville

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I have montiored skip from Louisville before on UHF. To help confirm that it is Louisville, listen to how the patrol units call dispatch. If they are saying "Radio" then it is may well be Louisville. Not many cities use the "Radio" term in referring to dispatch. The only one that I know of off hand is Atlanta (at least they used to).
 

OutPost

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Sunday night (Nothing)

I think the only skip (last night) was Union City and maybe a distant (other) that I am suspecting as Louisville. Maybe tonight the skip will re-appear. If it continues to be a problem in this county, I believe the frequency will be changed, but my question would be....

Since Louisville has 4 antennas with a total output of 860 watts on that frequency, are all 4 antennas transmitting at the same time?? Heck...one antenna (KRL406) puts-out 350 watts ! That would do the job alone :idea:
 

RandyB

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Louisville’s system is a multi-site system. The three towers are strategically places across the city in an effort to provide the best possible coverage. One site does the transmitting while all three sites receive. A voter determines which of the three sites is receiving the signal best. All sites are linked via microwave or T1 lines. To answer your question, if all sites were to transmit at once the audio would be unintelligible.

There’s really no need in switching frequencies. Nearly everyone has to deal with skip at one point or another. There are simply not enough frequencies available for everyone to have their own, realistically. So the only way to get everyone on the air is to assign the same frequency to multiple agencies. These frequencies are coordinated so that they are just far enough away as to not interfere with each other under normal conditions. However, temperature inversions are just a normal part of the atmosphere’s process and there’s no way around this phenomena. When these do occur we all have to put up with skip. Luckily they don’t occur that often. Just remember that your county isn’t the only county suffering from the skip.

Are you familiar with CTCSS tones? You may be familiar with them but I will mention them just in case someone else reading this isn’t familiar with how they work. They were designed to reduce the interference such as skip. Each agency will sent a different CTCSS tone. The radios will only let the audio through if the tones match. Here in Dickson County, law enforcement uses the frequency of 460.05 MHz. It just so happens that La Vergne Police (60 miles to our east) uses the same frequency. However, the law enforcement radios in Dickson County are set to decode a tone of 107.2 Hz. So unless the signal on 460.05 MHz is sending a tone of 107.2 Hz, nothing is heard on the Dickson County radios. Since La Vergne Police use a tone of 131.8 Hz, their signals do not come through on the Dickson County radios. I can set my scanner do decode the tone of 107.2 which allows me to hear only Dickson County. If I do not decode any tone at all with my scanner then I will hear both Dickson County and La Vergne as well as any other agency out there that happened to be on that frequency.

Can you find out what CTCSS tone is being used in your county? I'm guessing it is 114.8 since that is the tone used on the 460.175 repeater in your county. Maybe the interference problems are as simple as tones from the other agency coincidentally matching. This seems unlikely but possible. Switching a CTCSS tone is much easier than switching an entire frequency. Do all of the county's radios actually hear the skip?

The following is a list of other nearby agencies that use the frequency of 460.15 MHz:

Hardeman County / Bolivar, TN
Maury County, TN
Obion County, TN (Union City) –as you mentioned.
Trousdale County / Hartsville, TN
Blytheville, AR
Florence, AL
 

OutPost

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CTCSS Tones

RandyB.......

Excellent info about CTCSS Tones. I would bet that our 460.150 is operating wide-open, if that is the proper term. I will look further into this though with our TEMA director.

Tonight, Union City is coming across loud and clear, but the other station in question has not been heard. Our dispatcher and units in the south part of Benton County are receiving what I receive on my MX-7000 that does not have CTCSS capability selection.

Either conditions have changed and we're not receiving (possibly) Louisville, and/or our TEMA director is on it.

Is it possible that Louisville changed their CTCSS tone that fast because of our complaint and maybe from others??

The reason why I suspected Louisville is because of the constant traffic Saturday night, typical of a very large city, the northern accent and very fast. I checked all possible users of 460.150 and no other city/town could possibly have that much traffic.

While receiving that station, Union City was coming through also, therefore you can imagine what our dispatcher was experiencing with her antenna, as opposed to my 30 footer. The mobile units had problems with all the traffic that night too!

Thanks for the good info and we'll play it by ear :shock:
 

RandyB

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You mentioned that Union City was coming through also. To me, that does sound like a CTCSS issue. But there are two things to consider here. First, according to the database on this site, Union City and Maury County both use the same tone. So if Benton County happens to also use that tone, this would explain why you’re hearing both signals –it would all be just one huge coincidence that all three happen to be on the same tone. The second thing to consider is that it would seem more likely that Benton County simply isn’t using a tone. But, I’m 99% sure that all repeaters in the public safety band are required to use a CTCSS tone. Someone on here may be able to confirm that. If this is the case then the simple solution is to add a tone.

You mentioned that the signal that you are thinking may be Louisville has a lot of traffic and that they speak very quickly. Maury County has grown considerably over the past several years. The city of Columbia has grown, especially. I guess it would be possible that it would be Maury County that you are hearing, though it does seem unlikely given your description.

The next time that you hear the signal which you are assuming is Louisville, try switching to 460.025 MHz. This is Louisville’s other dispatch frequency. It should transmit at just as much power as 460.15 MHz. My thinking is that if you’re able to hear them on 460.15 that you should also be able to hear them on 460.025 MHz. If the two sound similar in the way they dispatch calls and handle radio traffic then more than likely the signal on 460.15 MHz is in fact Louisville.

How often do these other signals come in? Slight temperature inversions are fairly frequent, especially in the summer. These smaller temperature inversions usually wouldn’t quite be significant enough to bring in a signal as far away as Louisville but could certainly bring in a signal from as far away as Union City or Columbia. The temperature inversion that we experienced Saturday night was not a typical one. It covered a very large area and resulted in some major skip problems for many radio users. So I’m wondering if you hear these distant signals only in the most significant of temperature inversions which usually only happen once or twice a year, or if you hear these signals as often as one or two nights a week.
 

OutPost

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114.8 Tone

I see that Benton County does not indicate a tone for 'South' freq, but they do for 'Main' freq as 114.8PL.

Is it possible that South has no tone discrimination? I would agree that we should be receiving Maury as well, but in this rare case, which you pointed out the anomaly Saturday night, then anything could have happened and may not happen for a while. It would be interesting to hear from someone in Maury County in-order to determine if they use callsigns in the 2000 (2200) etc.

The suspect station was communicating over Union City that night. Very strong signal. The other characteristics I noticed were similar to the type of dispatching in Dade County (Miami, FL.). It appeared that at midnight they went from general dispatching to records only checks. It was extremely active until about 1:30am CDT. I have not heard them since.

Anyway, maybe our dispatchers got a real dose of hectic dispatching and would put a couple of them in the dust.

Thanks for your insight and if I hear that station again, I will post it here.
 

MemphisFire

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I had Chicago FD (Englewood) coming in pretty good for a while on Collierville FDs 154.4150 for a while the other night.

I also been catching some burb fire dept from around St Louis coming in on SCFD F1 as well
 

CAPTLPOL1

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I picked up Metro Nashville on my PRO-96 with the 800 MHz Radio Shack antenna all the way up to Metropolis, IL about 3 weeks ago.
 

emcom

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RandyB said:
...Here in Dickson County, law enforcement uses the frequency of 460.05 MHz. It just so happens that La Vergne Police (60 miles to our east) uses the same frequency. However, the law enforcement radios in Dickson County are set to decode a tone of 107.2 Hz. So unless the signal on 460.05 MHz is sending a tone of 107.2 Hz, nothing is heard on the Dickson County radios. Since La Vergne Police use a tone of 131.8 Hz, their signals do not come through on the Dickson County radios...


Gibson County, TN dispatch randomly comes across Athens, Alabama's Police repeater on 460.050. I can remember a few years back being on patrol on midnight shift listening to an older female dispatcher shreek into the mic "Gibson County to Bradford 5!!!!" We never heard the mobiles, tho. The database shows Gibson Co. with a 127.3 PL while we used a 123.0 PL. Gibson Co/Humbolt has gotten into the Athens, AL repeater on and off for years.

Athens uses about a 150 FT guyed tower at the station, which is on flat ground. Not too high of a transmitter or receiver, really.


Years ago, I was a dispatcher for the neighboring Sheriff's Office. 155.010 is used statewide in Alabama as our mutual aid channel. We could hear Nashville PD downtown like they were next to us. We also heard "Sparta Central" dispatch in White County, TN. clearly. Our transmitter was near the top of a 200+FT tower on the north side of a 1600FT mountain. We are on the Tennessee line too. The dispatchers there now are glad that Nashville went to 800. Although, they did get into some good chases every now and then, which provided me something to listen to at 3AM when all was quiet at home.
 
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RandyB

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I remember the days of Nashville being on VHF! Well, I guess it wasn't too terribly long ago actually. If I remember right, they completed the switch to 800 MHz during the summer of 2001. That's when they turned off the simulcast links to the old VHF repeaters.

I guess given the fact that 155.01 in Alabama is used as a statewide mutual aid channel, a PL is not used. This makes sense but can sure cause aggravation for the users during skip. So I can understand why the dispatchers are glad that Nashville did move to 800 MHz. My guess is that they still do have problems with Sparta interfering since Sparta is still using 155.01 MHz.

As far as Gibson County's signals into the Athens repeater, that is odd considering a different tone is used. The only explanation that I can come up with is that there is more than one 460.05 repeater in Gibson County. Several counties in Tennessee have more than one repeater. For example, Dickson County is one of them. The primary repeater both transmits AND requires a PL of 107.2 Hz. But there is a second repeater in the northern part of our county which is on the same frequency that is less frequently used. It provides better coverage for the northern portion of the county. The way that it is set up is that it also transmits a PL of 107.2, just like the primary repeater. But, a different PL is used to access the repeater. So it's a split-tone setup. The PL needed to talk on it is 192.8 Hz. I wonder if Gibson County has a similar setup. Perhaps their primary repeater is the one that the mobiles use most frequently and requires a PL of 127.3 for access and maybe the other repeater is frequently used by the dispatcher and requires a PL of 123.0 Hz --thus the reason you hear the dispatcher only during skip. That's my best guess.

It is things like this that make our hobby so interesting in my opinion. I enjoy the challenge of trying to figure out some of the odd occurrences, such as skip and its affects, that we often see in radio communications.
 

firemedic2150

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Speaking of Nashville PD when I worked in Murray, KY we used 154.860 as primary that was also the NPD southwest repeater I think. I could hit the monitor pedal and get blasted by the picker boards anytime. If the weather was right our mobiles would get waxed by them before we went to a repeater.

Mark Mc.
 

RandyB

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firemedic2150,

I'm curious, when did Murray PD go to a repeater? I monitor them quite a bit when I'm up that way. They've been on a repeater since I've monitored them so I'm guessing it was at least 4 or 5 years ago, and likely a while before that.

Randy
 

firemedic2150

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Randy,

We installed the repeater on the tower at the PD in 1999 I think, it was not long after that when the Murray Fire Department installed their repeater also. It was due to move out on the new 340' tower the Murray Electric system put up on the north side of town a few years ago, but I think it got held up in politics.

Mark Mc.
 
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kytnradio

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MPD Repeater

The MPD repeater has been on the MES tower for several years. MPW also has a repeater on the MES tower. The MFD repeater is still downtown.
 

OutPost

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Hello Folks!

460.150 is still coming in loud and clear near the river here in Benton County, with strong comm from Union City. Last night, two of our S.O. units were looking for a car and an address and the conflict was apparent and maybe annoying for our guys. I'm not sure if Union can here us.....

I'm also grabbing some agency's "Record's" channel on our local 154.100 we use for rescue.

Anyway....we're expecting Katrina by Tuesday morning and this is going to be bad....

Dave

"Forget About Yesterday, Don't Worry About Tomorrow, But Enjoy Today!!"
 
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