SHP Catawba Backfeed

[BigLebowski]

There is a UHF backfeed of SHP Troop F in use in Iredell County on 456.300, and we have reason to beleive that there is a separate backfeed for Catawba County. Does anyone know the frequency of the Catawba backfeed if it exists and also any others that are not listed in the Database?

 

[Grog]

I know Jeff has an extensive list of the older SHP freqs. I have a copy that he posted (I forget where he posted it) and I'll see if I can find it in case Jeff does not see this soon.

 

[jeffmulter]

( I'm going to cautiously provide the information below, since I cannot confirm the remote links are still in use. )

>> There is a UHF backfeed of SHP Troop F in use in Iredell County on 456.300

456.300 (PL is 131.8 Hz) is the link back from the Watauga remote. The link from Newton to Watauga is on 72.30 / 131.8 . The Watauga remote would not be the primary remote for cars in Iredell County.

Iredell County cars would be heard off the Pores Knob (Wilkes Co) remote ... or off the tower at the Newton comm center on a good day. The multiplexed links to / from the remote are 953.550 MHz and 957.500 MHz., respectively. Additional 900 Mhz links branch off the Pores Knob site to extend coverage to a remote site in Ashe County.

>> Does anyone know the frequency of the Catawba backfeed if it exists ...

Dispatch can work Catawba County off the comm center tower, or off the remote on Bakers Mountain. At one time, there was a 2 GHz link between the center and Bakers Mountain, which also provided a connection into the 6 GHz backbone system carrying state communications and UNC-TV across North Carolina. I believe the 2 GHz link was replaced with a 6 GHz link, but I cannot confirm.

As the state has upgraded and extended the statewide microwave system, some of the radio links between NCHP comm centers and remote sites have been eliminated, or relegated to secondary status. The information above was current as of 10-15 years ago, but I'm not in a position to verify the current status of the links mentioned above.


Jeff Multer

 

[CCHLLM]

The Rich Mtn (Boone) 456.300 link is still current, but as for the Poore's Knob link, I won't swear it's still in use.

 

[al_wilkes]

957.500 MHz

The 957.500 MHz link is up and running. Comes in with varying (mostly good) signal strength here in Wilkes. Of course it continuously transmits (as all 900 MHz links?) with no PL detected. I'm wondering if a PL tone kicks in when actual audio is present, like some of my local drive-thru restaurants, on 457.5125 (71.9 PL). Anybody know?

Also bummed to find out that my BC780XLT will not accept any frequency above 956 MHz (until 1240 MHz), so I have to use my Pro-2006 and iCOM handhelds to monitor the 957 link.

Albert

 

[CCHLLM]

Good surmising on yer part. Most older 900 links are just basic crossband repeater systems, but some of the newer technoligies TX continuously and use PL/DPL or a function tone to tell the receiver on the other end when to open the audio path for the console/transmitter connections. Continuous TX makes for shorter reaction time by the receiver since there's no "carrier detect" time factor involved in its receiving process.

 

[jeffmulter]

>> The 957.500 MHz link is up and running. Comes in with varying (mostly good) signal strength here in Wilkes. Of course it continuously transmits (as all 900 MHz links?) with no PL detected. I'm wondering if a PL tone kicks in when actual audio is present ...

Al - the signal should be multiplexed coming back to Newton, with the possibility of carrying up to 10 ? audio carriers at any time. I have to think there is no PL tone involved.

The 10 carriers would include emergency management traffic, and the two feeds from the NCHP remotes at Pores Knob and Ashe County. Monitor the signal in wideband FM.

For those on the Newton end, I used to be able to catch the 953.550 feed off the Newton HP tower from the Food Lion parking lot at Hwy 10 and 16, near Dale Earnhardt Chevrolet.


Jeff

 

[Grog]

For those on the Newton end, I used to be able to catch the 953.550 feed off the Newton HP tower from the Food Lion parking lot at Hwy 10 and 16, near Dale Earnhardt Chevrolet.

What traffic would that carry?

Where is that coming from/going?

 

[jeffmulter]

A) 953.550 wide band FM - directional antenna pointed toward Pores Knob / Moravian Falls antenna farm ...

- One channel of NCHP communications on low band channel 5 (dispatch) from Newton to Pores Knob remote.

- One channel of NCHP communications on low band channel 5 (dispatch) from Newton to Ashe Co remote (via link between Pores Knob and Ashe Co)

- One channel of Emer Mgmt via Newton receiver on 47.50, from Newton to Pores Knob (signal linked from there to Raleigh)


B) 957.150 wide band FM - directional antenna pointed toward Newton comm center ...

- One channel of NCHP communications on low band channel 5 (mobile remote) from Pores Knob to Newton.

- One channel of NCHP communications on low band channel 5 (mobile remote) from Ashe Co, via Pores Knob, to Newton.

- One channel of Emer Mgmt from hqtrs in Raleigh on 47.50, via Pores Knob, to transmitter in Newton.

I believe another channel of EM that the multiplex handled was either 45.92 or 45.96, as one of these channels carried phone interconnect at one time.

Besides the Newton links to Pores Knob, I believe both Troop D and Troop E also have (or had) equipment on the site, which is near where Hwy 16 (out of Taylorsville) and Hwy 18 (out of Lenoir) intersect. I think NC Forestry also had a link running through the site.

Keep in mind that someone isn't likely to hear any voice discernable voice traffic on the Newton - Pores Knob links unless the Pores Knob or Ashe Co NCHP remote is handling traffic. And, make sure the receiver is set to WFM.


Jeff

 

[CCHLLM]

Thanx for the updates. I didn't even think about the link being a 900 MUX despite the fact that as a former state comm employee, I knew that the site IS a MUX site. Durn Alzheimers. Yes, there are multiple state agencies using the MUX systems, including NCDOT, so if you go to WFM some conversations should be discernable. As for separating them into useful intelligence when there's a bunch of traffic on multiple inputs, well, that's another matter altogether, but it can be done sometimes by warping the RX frequency and bandwidth a bit if yer receiver is capable of doing so. All these MUX sites will eventually be replaced by the digital microwave stuff.