Spur from WKYI 1600 on 1736 FM 2236 UTC 8 Feb 2021

[ChrisSmolinski]

Well.. this is a weird SDR recording catch:

2236 Tom Petty "Learning To Fly"
2237 Pseudo ID by the DJ, mentions of 94.1, southern rock legends, which suggests it is WKYI Louisville KY, which matches what I logged back in December here:  UNID 1740 (variable) FM 2224 UTC 8 Dec 2020 https://www.hfunderground.com/board/index.php/topic,75321.0.html  Then gone
2241 Back again with OM talk, mention of 94.1 again.
2245 Back on, then on and off a bunch of times
2312 Johnny Cash "I Walk The Line"
2315 "Love Hurts"
2330 DJ talk, mention of southern rock, country legends. "My 94.1"
2335 Steve Miller "The Joker"
2345 The frequency shifted to 1733 or so. Same pattern, short transmissions of a few minutes, then gaps
0115 Gone?

So... is this a pirate relay, or some sort of weird spur? The FM was narrow, not wide FM like an FM broadcast station uses.

Here is a waterfall showing part of the reception period, you can see the transmissions appear to be deliberate short busts, vs fading in and out:

[ChrisSmolinski]

Back again circa 2320 UTC 12 Feb 2021. More and more convinced this is a spur.

[redhat]

There is a possibility that the PWM switching frequency of the transmitter is leaking though the RF stage.  The station is daytime only, so if this is what your hearing, it should disappear after local sunset.  Still, If they are running to parameters, 500 miles is a long haul for a signal that is supposed to be less than 70dB down from carrier, never mind the additional attenuation caused by the transmitters output network and ATU.  See if you can see a similar low side spur as well at 1464 KHz when the upper component is visible.

+-RH

[ku4a]

My YL lives just a few miles from that transmitter site, which is off Kentucky state route 55 south of Eminence. The next time I'm there, will check to see if I hear 1736, plus see if the 1600 is on past bedtime.

[ChrisSmolinski]

I checked my morning SDR recordings, and sure enough found them at 1100 UTC sharp, with IDs for both the AM and FM outlets. Another bit of evidence for this originating at the 1600 kHz transmitter site.

[ChrisSmolinski]

I checked last night, while I could pick up the NFM signal circa 1736 kHz, signals inside the MW were simply too strong to see any evidence of another signal circa 1464 kHz.

Sign off was 0115 UTC, same as the other night.

And look at this... I ran the SDR recordings through Carrier Sleuth, and there is a 1600 station that went QRT at 0115 UTC:

[ChrisSmolinski]

Another update, I connected to KU4A's KiwiSDR which picks up their 1600 kHz AM outlet in the daytime. I tuned to 1599 USB, and the carrier from the station ended up at 1005 Hz, implying a 1600.005 kHz carrier, very close to the 1600.006 I saw on the waterfall for the station going QRT at 0115 UTC, which then re-appeared at 1100 UTC at 1600.005 kHz in fact.

The glove fits, your honor.

[ChrisSmolinski]

Noted again circa 0000 UTC 16 Feb 2021, but closer to 1732 kHz this time.