170.7625/171.3875 mhz.

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W4UVV

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Can anyone id these two frequencies as to the user(s)? They appear to be data control channels that sound like an EDACS system. Since I am hearing the Md. 162.5000 NOAA wx transmission relatively strong at this time I suspect the data transmissions are in NOVA or the Md. area. Previously in periods of ducting activity I have heard these same two data data channels but no other related digital activity indicating a TRS. They are relatively strong today with signal level averaging S5.
 

ChrisP

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W4UVV said:
Can anyone id these two frequencies as to the user(s)? They appear to be data control channels that sound like an EDACS system. Since I am hearing the Md. 162.5000 NOAA wx transmission relatively strong at this time I suspect the data transmissions are in NOVA or the Md. area. Previously in periods of ducting activity I have heard these same two data data channels but no other related digital activity indicating a TRS. They are relatively strong today with signal level averaging S5.
The 170.7625 MHz channel has been identified as an EDACS control channel for an analog VHF trunked system at Wallops Island, VA:

http://mt-fedfiles.blogspot.com/2007/08/vhf-edacs-mystery-solved.html

- Chris
 
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W4UVV

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Wallops Island TRS

Ok...tnx...makes sense. I now am hearing three trs analog voice channels definitely related. One is 172.6875 mhz., 172.9875 mhz. and 173.4250 mhz. Using multiple receivers to monitor, sometimes voice repeaters both key up simultaneously with dead carriers or voice on one and a dead carrier on the others. Comms presently are radio maintenance types attempting to get a good PTP video link for something. Another trs comm was a weather watch warning for 28 knot winds. I suspect there are a few more trs frequencies not active due to current low volume use. I'll check out the MT site for more info. The second EDACS control channel implies another trs unless EDACS has two standalone data control channels one for primary and one for alternate for each trs...just a guess. I am not familiar in detail how EDACS systems work.
 

W4UVV

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another one...

W4UVV said:
Ok...tnx...makes sense. I now am hearing three trs analog voice channels definitely related. One is 172.6875 mhz., 172.9875 mhz. and 173.4250 mhz. Using multiple receivers to monitor, sometimes voice repeaters both key up simultaneously with dead carriers or voice on one and a dead carrier on the others. Comms presently are radio maintenance types attempting to get a good PTP video link for something. Another trs comm was a weather watch warning for 28 knot winds. I suspect there are a few more trs frequencies not active due to current low volume use. I'll check out the MT site for more info. The second EDACS control channel implies another trs unless EDACS has two standalone data control channels one for primary and one for alternate for each trs...just a guess. I am not familiar in detail how EDACS systems work.
add 172.9625 mhz. to the trs.....asking for permission to cross the airport runway.
 
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