THP low band setup (Fall Branch)

[jfhtm350]

I didnt know this until I started using two scanners but I have found that the trooper will use 42.2600 173.8 PL (input freq) and the dispatcher will use 42.4200 (FB, FB2). Couldnt hear the trooper on 42.4200 and couldnt hear the dispatcher on 42.2600. Like they were using simplex on two frequencies. There are repeaters on Sevier Co, Cocke Co, Hawkins Co and Carter Co and Base to mobile at the post.

How does this setup work? Surely he couldnt reach the post from Jefferson Co by bypassing the repeaters could he?

 

[n4yek]

42.26 is the input to the Tower to base fixed relay that is on 72.02 MHz. You asked me once how I monitored the THP, i listen to dispatch on 42.42 and listen to the troopers on 72.02. That way I get both sides of the conversation.
I don't know the exact setup, but the 42.420 MHz repeater has multiple location in District 5. The Dispatcher chooses which area to transmit in and chooses the appropriate repeater that covers that area. While I can't hear Fall Branch on 72.02, I would guess it is also being used by the Dispatcher to transmit to the correct repeater and then it repeats on 42.42.
The trooper then transmits on 42.26 MHz, which is then received by the Tower and relayed back to dispatch on 72.02 MHz.

District 1 similar except different frequencies.

Other Districts have UHF freqs and relays.

It is one big mess trying to monitor then THP if you travel from Johnson City to Memphis, lots of freqs to have to choose from

 

[jfhtm350]

Yea I figured you were going to say that. 42.2600 is input for 42.4200 in the database so I wasnt sure. Got another input 42.2600 107.2 PL, Knoxville district input. Have to wait for a car to get close enough to me before I pickup 42.2600 which isnt real often.

 

[jimg]

42.26 is the input to the Tower to base fixed relay that is on 72.02 MHz. You asked me once how I monitored the THP, i listen to dispatch on 42.42 and listen to the troopers on 72.02. That way I get both sides of the conversation.
I don't know the exact setup, but the 42.420 MHz repeater has multiple location in District 5. The Dispatcher chooses which area to transmit in and chooses the appropriate repeater that covers that area. While I can't hear Fall Branch on 72.02, I would guess it is also being used by the Dispatcher to transmit to the correct repeater and then it repeats on 42.42.
The trooper then transmits on 42.26 MHz, which is then received by the Tower and relayed back to dispatch on 72.02 MHz.

District 1 similar except different frequencies.

Other Districts have UHF freqs and relays.

It is one big mess trying to monitor then THP if you travel from Johnson City to Memphis, lots of freqs to have to choose from

Yes, and I have found that over the years some of UHF and mid-band (70 mhz) relays have been replaced by microwave frequencies. For example, in District 2-Chattanooga, the relay on Monteagle was 72.86 mhz, and could be heard for several miles, but now I hear nothing. Someone said it was now on a Forestry Dept. microwave relay and perhaps the frequency was 955.800 mhz, but all I ever heard on that frequecy, when passing by the fire tower, was a continuous tone with no modulation. Also, in District 3-Nashville, you used to be able to hear the cars talk back to Nashville dispatch on 452.275 mhz, but that too is no more. And, earlier I read a post in the Tennessee forum that the new TROOPNET radio system may be encrypted!

 

[jfhtm350]

What about these two relays?
451.55000 131.8 PL THP Fixed Relay Elizabethton
451.60000 131.8 PL THP Fixed Relay Mooresburg
Do you know what frequencies come in/out or how they work? You are right, I didnt realize THP was so jumbled up.

I stated earlier that I recieved 42.2600 107.2PL that I figured was Knoxville district and I come to realize they dont use 42.4200 that I know of. I'll have to try to figure out what that one goes to.

 

[EZlistener]

I can't help much with the fixed relays, but here are the sites of the bases in Fall Branch District:
Site#1: Fall Branch post, Washington County-Channel 1 (42.42/42.26)
Site #2: Short Mtn, Hawkins County-Channel 1 Tone 1 (Dispatch); Channel 7 Tone 1 (45.66/42.28 c-c repeater)
Site #3: English Mtn, Cocke County-Channel 1 Tone 8 (Dispatch); Channel 5 Tone 2 (45.58/42.28 c-c repeater)
Site #4: Holston Mtn, Carter County-Channel 1 Tone 4 (Dispatch); Channel 6 Tone 4 (45.62/42.28 c-c repeater)
Site #5: Bays Mountain, Sullivan County-Channel 8 (45.70/42.74) Tone 6
Channel 4 (42.36/42.36) is the simplex car-car channel in this district.
The common decode tone in this district is 141.3.
Monitoring the mobiles with the appropriate type of scanner will give you the input tones.

 

[n4yek]

I can't help much with the fixed relays, but here are the sites of the bases in Fall Branch District:
Site#1: Fall Branch post, Washington County-Channel 1 (42.42/42.26)
Site #2: Short Mtn, Hawkins County-Channel 1 Tone 1 (Dispatch); Channel 7 Tone 1 (45.66/42.28 c-c repeater)
Site #3: English Mtn, Cocke County-Channel 1 Tone 8 (Dispatch); Channel 5 Tone 2 (45.58/42.28 c-c repeater)
Site #4: Holston Mtn, Carter County-Channel 1 Tone 4 (Dispatch); Channel 6 Tone 4 (45.62/42.28 c-c repeater)
Site #5: Bays Mountain, Sullivan County-Channel 8 (45.70/42.74) Tone 6
Channel 4 (42.36/42.36) is the simplex car-car channel in this district.
The common decode tone in this district is 141.3.
Monitoring the mobiles with the appropriate type of scanner will give you the input tones.

English Mtn uses 42.26 tone 173.8 for the input, not 42.28

 

[EZlistener]

Thanks, Danny, I did not clarify. English has both a base station and a car-car repeater. The input to the 42.42 base is 42.26. The input to the car-car repeater is 42.28. The latter is referred to as "5&2" or "Five-hotel."

 

[n4yek]

Thanks, Danny, I did not clarify. English has both a base station and a car-car repeater. The input to the 42.42 base is 42.26. The input to the car-car repeater is 42.28. The latter is referred to as "5&2" or "Five-hotel."

See where you are coming from now.