UNK 455.9825mhz Digital

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SCPD

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I searched FCC database advanced search by using Oklahoma City, Oklahoma and exact frequency 455.9825mhz. Nothing turned up in the results. here is a screenshot and recording. Recorded audio only in HDSDR

I get that it that Part 15 unlicensed transmissions are permitted 455-470mhz. What I don't get is what is this digital mode?

https://vocaroo.com/i/s0mMLJ6VLumJ
 

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kd4efm

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455.9825 more than likely, it is an Harris STL from a studio to tower. (Part 74) and no, part 15 is not allowed in part 90 or Part 74 450-455.
 

nd5y

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It's probably 450.98. There are 4 licenses on that frequency in OK.
The 450-451/455-456 MHz band is under Part 74 and doesn't have all 12.5 kHz spacing like the rest of the 450-470 band.
It's not a STL. Any time you hear low speed FSK or AFSK digital SCADA type signals on a Part 74 Remote Pickup frequency It's usually transmitter-to-studio telemetry.
That's how some broadcast stations monitor their transmitter output power, temperature, antenna SWR, etc.
STLs transmit audio/video programming (which might be analog or digital) to the tower not low speed data.
 
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SCPD

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455.9825 more than likely, it is an Harris STL from a studio to tower. (Part 74) and no, part 15 is not allowed in part 90 or Part 74 450-455.
It's outside of 450-455. The frequency is greater than 455mhz. 455.9825 falls in 455-470mhz. Non license is permitted 455-470mhz which I originally stated, I did not say 450-455mhz. The frequency is not listed on the FCC database. I'm thinking since it is not listed on the FCC database for Oklahoma City it is low power Part 15

My source:
https://fccid.io/frequency-explorer.php?lower=455&upper=470

ND5Y It very well could be drifting in frequency because this morning i checked it again and it was on 455.981mhz. My rtl-sdr has a 0.5 ppm tcxo and usually pretty accurate.
 
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nd5y

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It's outside of 450-455. The frequency is greater than 455mhz. 455.9875 falls in 455-470mhz. Non license is permitted 455-470mhz which I originally stated, I did not say 450-455mhz. The frequency is not listed on the FCC database. I'm thinking since it is not listed on the FCC database for Oklahoma City it is low power Part 15

My source:
https://fccid.io/frequency-explorer.php?lower=455&upper=470
There is so much FAIL in that post I don't have time to adress it all right now.
 

W3DMV

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Just in case, a few locals if your freq is a little off.

455.9900 Clear Channel broadcasting. KPG978

455.9800 Oklahoma State U. Stillwater. WPY665

455.9800 Chickasaw Nation. Ada, Ok.
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kd4efm

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455.9825

There is so much FAIL in that post I don't have time to address it all right now.
What he is saying, Part 74 = 450.0000 to 450.99875 and 455.00000 to 455.99875

what you saw is 455.0000 and went tunnel vision. Not failing you, just helping you understand.

Part 74 has the 450 to 451 / 455 to 456 segment of the UHF band for RP and telemetry.
There are other frequencies they can use also (like the remote monitor or ear pieces / wireless mics)

see this link to understand more.
https://www.law.cornell.edu/cfr/text/47/74.402

it has also come to light, that some stations are now able to use DMR in part 74 (I just installed one in Florida
on 2 - 450 pairs)


Now, as for non-licensed operation 451 to 455 (TX) and 456 to 459 (RX) and 460 to 465 (TX) and 466 to 470 (RX) that's a negative EXCEPT FOR FRS. ANY WHERE IN THE US you have to have a license. The only exemption is part 15 and only where part 15 is allowed.

See this link for more information
https://www.law.cornell.edu/cfr/text/47/part-15
 
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nd5y

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That's the exact same rule I linked to in post #4.

Non license is permitted 455-470mhz which I originally stated, I did not say 450-455mhz.
I don't know where you came up with that but it's wrong.

The frequency is not listed on the FCC database.
Yes it is.

I'm thinking since it is not listed on the FCC database for Oklahoma City it is low power Part 15.
Probably not. If you can't find a license for a frequency in a radio service that requires site-based licensing then it's more likely to be somebody operating illegally without a license. There is a TV station in my town that runs IFB on 450.98. It IDs every 15 minutes with a CW ID callsign that doesn't exist.

fccid.io is great for looking up equipment authorizations (FCC ID). They pull that data from the FCC OET database and present it in a user freindly format but their frequency search function appears to have a lot of errors.


Just because a cheap Chinese hobby/consumer grade piece of junk says it as .5 ppm stability doesn't mean it's true. How do you know that the signal you found is really on or near 455.98? How exactly are you calibrating this SDR?
 

SCPD

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Just because a cheap Chinese hobby/consumer grade piece of junk says it as .5 ppm stability doesn't mean it's true. How do you know that the signal you found is really on or near 455.98? How exactly are you calibrating this SDR?
yes it is accurate to .5ppm. I am not disputing it with you. I see it with my own eyes everyday always on frequency. Your opinion is just your opinion has no weight to me about the rtl-sdr whatsoever. It is widely used. Move on.Have a nice day sir.
 

ecps92

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I keep forgetting about 450.9800, so used to the 12.5 Khz or 6.25 Spacing.

It's probably 450.98. There are 4 licenses on that frequency in OK.
The 450-451/455-456 MHz band is under Part 74 and doesn't have all 12.5 kHz spacing like the rest of the 450-470 band.
It's not a STL. Any time you hear low speed FSK or AFSK digital SCADA type signals on a Part 74 Remote Pickup frequency It's usually transmitter-to-studio telemetry.
That's how some broadcast stations monitor their transmitter output power, temperature, antenna SWR, etc.
STLs transmit audio/video programming (which might be analog or digital) to the tower not low speed data.
 

SCPD

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Let me tell you where the confusion is with Part15. fcc io specifically states here

https://fccid.io/frequency-explorer.php?lower=455&upper=470

"Operation of unlicensed Part 15 Devices is permitted between....." everywhere in that page. I have no idea as to why fcc io would tell the public this. It certainly does confuse. they should remove that sentence if Part 15 is not allowed. FCC band plan does not list this particular as PART 15. There may be exceptions you and I are not aware of. There has to be a legitimate reason FCC IO listed it as such
 

xerb1962

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Let me tell you where the confusion is with Part15. fcc io specifically states here

https://fccid.io/frequency-explorer.php?lower=455&upper=470

"Operation of unlicensed Part 15 Devices is permitted between....." everywhere in that page. I have no idea as to why fcc io would tell the public this. It certainly does confuse. they should remove that sentence if Part 15 is not allowed. FCC band plan does not list this particular as PART 15. There may be exceptions you and I are not aware of. There has to be a legitimate reason FCC IO listed it as such
HA! Dude that is a clickbait site with Google Ads hidden on every page. In no way is that site legitimate.
 

nd5y

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HA! Dude that is a clickbait site with Google Ads hidden on every page. In no way is that site legitimate.
Basically that site is only good for looking up FCC IDs and viewing the documentation submitted with them. They download the FCC OET authorization database and present the data in a more user friendly format than the FCC web site, similar to what RadioReference does with parts of the FCC ULS database.
 
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