Guilford/Orange 453.75 Mhz

[thumbtrap]

453.75 Mhz is guilford county fire dispatch crosspatch, used for pagers. The 46.5 Mhz paging seems to be dead - I haven't heard anything on it in a few weeks, but I'm not monitoring it continuous - I have noticed that it is silent even when traffic is coming out on the TRS and 453.75.

Lately I've been trying to do some recording, trying to get tones in wav format. In our corner we get a lot of chitchat from what sounds like a water / works dept - I've heard it's chapel hill. I got frustrated enough to look it up, and that frequency doesn't show up in the database as anybody real close. (Durham police, but this is definately not police traffic and it's quite definately water works guys.) Neither does the input to the repeater. It's mostly annoying, but I have heard them interfering with emergency traffic before. I'm really curious now that they dont seem to show up in the database. My best guess is the Durham police freq got reshuffled, but I hear a lot of references that sound like it's Chapel Hill, and that would require it to change licensees, not just reused.

Does anyone know who this is? Any way of finding out if they're stepping on a repeater somewhere, or if this is direct interference? If they're even supposed to be on this frequency?

 

[KE4ZNR]

This is what I show from an old frequency list:
453.750=Chapel Hill or Orange County Water/Sewer (Used by Durham Public Works too)

Don't know if that is up-to-date (frequency list is from 2-15-2004) but from what you say it sounds like it could be one and the same...I would assume they are using a standard +5 Mhz repeater offset....

Hope this helps out a little!
Marshall Sherard, KE4ZNR
http://wake800.nctrafficman.net
Wake County Admin: RadioReference.com

 

[JJones27320]

453.750 is crossband repeat with 46.500, and also with 155.115 when ems and county fire are dispatched together. I'm not sure what this link is used for, but I don't think it is for paging purposes, due to the audio being so bad and distorted on 453.750. I don't think a pager would be able to decode the tones to alert.

 

[CCHLLM]

My sources tell me that the low band Guilford fire (46.50) transmitter is no longer in use, and that OWASA in Orange County is still using their 453.750/458.750 repeater with PL, though there's a rumor that the transmitter site has been moved. 453.750 in Guilford is a TX only channel and has no PL, so it probably doesn't bother the users in Orange. In addition, Guilford's 453.750 is also a simulcast frequency which means there are two or more transmitters broadcasting the same modulation on the same frequency simultaneously (Multicasting is two or more broadcasting the same modulation simultaneously on different freqs). The poor audio comes from the fact that even with the equipment that synchronizes the transmitters, that same equipment has no control over multipath, and Greensboro/Guilford seems to be "eat up" with mulitipath, not to mention that I don't think the synchronizing equipment has ever really worked correctly. The pagers seem to tolerate the multipath and lousy audio, but I share your pain trying to monitor it on ANY kind of radio.

 

[thumbtrap]

I have a BCT-8 in the car, it's dedicated the 800 mhz system (even went so far as to give it a cellular antenna). No problem there. We get Chapel Hill on the pagers though all the time, often so much of it that you just can't leave the pager open. (Which I like to do when possible - the way they dispatch I can usually scoop way more time leaving the pager open than I could driving like a madman.) . My BC350C in the house doesn't do trunking, and so it basically duplicates the pager. (I got it planning to do the discriminator output hack. Just haven't got it done yet.)

I finally got our tones, and my first working fire at that. Right there in the middle of it, not only are the water guys in it - but they're using unit numbers that coincide with ours. Real traffic is on the trunked system of course, but that part still bothers me.

 

[thumbtrap]

453.750 is crossband repeat with 46.500, and also with 155.115 when ems and county fire are dispatched together. I'm not sure what this link is used for, but I don't think it is for paging purposes, due to the audio being so bad and distorted on 453.750. I don't think a pager would be able to decode the tones to alert.

It is indeed the frequency that is used for paging. As wx4cbh pointed out, 46.5 is dead, Chapel Hill comes across the pagers too, and at times I've heard other people's tones so garbled that their pagers did not go off.

 

[CCHLLM]

453.750 from Orange is absolutely gangbusters in central and eastern Guilford, and it ain't no slouch at the western extremes either. Info I have says the Orange County transmitter is now on the state's tower on Occoneechi (Eno) Mtn. at the I-40/I-85 split, but the transmitter is in the other building there, not in the state's building. If it ain't there, that leaves only one other location for that kind of coverage, and that's at the Terrells' (Chatham) Mtn site where the state TV tower is located south of Carrboro.

 

[thumbtrap]

Chapel Hill PL tone is 94.8 Hz. I'm seeing a second strong peak at 120 hz with it - not sure if it's an power line artifact or indicative of some method other than CTCSS, but 94.8 on the scanner will kill it. Too bad my non trunking scanners don't do CTCSS.

 

[JJones27320]

I have a dedicated Plectron receiver on 46.500 mhz and I am still receiving transmission from Guilford County fire all the time.

 

[CCHLLM]

Well, go figure. All we keep hearing is that "it's not in use anymore." Those supposedly in the know obviously don't.

 

[thumbtrap]

I have a dedicated Plectron receiver on 46.500 mhz and I am still receiving transmission from Guilford County fire all the time.

It's dead Jim

Gibsonville is running a call right now. Pager's Squawking. 46.5 is silent. Has been every single time I have run the pager and scanner side by side in the past 2-3 weeks.

Sorry - I stand corrected. Another call came through, I killed the pager and opened the squelch wide open. It's life Jim, but not as we know it. (Sorry, it was hard enough to resist the first one. Apologies if your name actually is Jim.) The signal is there. Buried so far down in the noise that it's indistinguishible to squelch. (Meaning there is no value of squelch that will open for signal. You can barely hear it in the noise if you leave it open.)

 

[JJones27320]

I seem to have the exact opposite problem as you guys, in southern Rockingham County I can hear 46.500 much clearer than 453.750. However the best thing is to do away with both and just listen to 800mhz. lol