HFU HF Underground

Loggings => 10/11 meters => Topic started by: R4002 on October 20, 2021, 1211 UTC

Title: 27.255 MHz - RadioShack On-Site Paging System Waveform (Waterfall) Test Video
Post by: R4002 on October 20, 2021, 1211 UTC
https://www.youtube.com/watch?v=VrtAHDOtVII (https://www.youtube.com/watch?v=VrtAHDOtVII)

It seems that the data transmissions heard on 27.255 MHz (and the other RC channels) during band openings are not from these paging systems...at least not the Radio Shack PG-99 17-6020 or 17-6023 (which is a 4-watt transmitter, and may work on 26.995 MHz instead of 27.255 MHz...not 100% sure there).

Thanks to Chris S. for providing the SDR and the test transmissions from the RadioShack 7 watt paging transmitter pager system (with stock back of set CB radio antenna). 

Unlike the signals noted on 27.255 and 27.195 lately (27.195 only during band openings) - this system transmits a single FSK signal about 500 Hz from center frequency 27255.0 kHz.  Center of the FSK signal is 27.2545 or 27254.5...usually there are two FSK signals - usually about -2.5 kHz or -3 kHz from center frequency and + 2.5 kHz or +3 kHz from center frequency.