HFU HF Underground

Loggings => VHF/UHF Logs, including satellites and radiosondes => Topic started by: Teotwaki on December 06, 2022, 1921 UTC

Title: Frequency Hopping ( UHF SatCom?)
Post by: Teotwaki on December 06, 2022, 1921 UTC

I started performing a spectrum survey to get an idea of what UHF SatCom transponders are in view to the SE here and ran across 243.785 to 243.8450 with what looks like frequency hopping.

Rough heading of SE from my location in Orange County, Calif

Anyone have info or ideas?

1917z 6Dec2022

Title: Re: Frequency Hopping ( UHF SatCom?)
Post by: sat_dxer on December 07, 2022, 1446 UTC

1917z 6 Dec /22
USA 227
Inclination: 4.6°
Mean Motion 1.00226/day (keplerian elements not updated since 21 Nov /20)

1917z 6 Dec /22
MUOS 1
Inclination: 3.1°
Mean Motion 1.00269/day

1917z 6 Dec /22
MUOS 5
Inclination: 5.2°
Mean Motion 1.00268/day
------------------------------------------------------------------
1917z 6 Dec /22
SKYNET 4F
Inclination: 10.8°
Mean Motion 0.99144/day

Title: Re: Frequency Hopping ( UHF SatCom?)
Post by: Teotwaki on December 07, 2022, 1730 UTC

I may have to go back to the garage and pull out the AV-2011

Title: Re: Frequency Hopping ( UHF SatCom?)
Post by: Teotwaki on December 07, 2022, 1824 UTC

Az-El is for my current location

USA 227    aka Quasar 13   Comsat / Relay, early warning
AZIMUTH:   152.7 SSE
ELEVATION    43.5

MUOS 1  - MUOS was originated as part of a WCDMA system. Was it repurposed to a frequency hopping system?
AZIMUTH:   151.2 SSE
ELEVATION:  44.8

MUOS 5   - MUOS was originated as part of a WCDMA system. Was it repurposed to a frequency hopping system?
AZIMUTH:   156.3 SSE
ELEVATION:  43.2

SKYNET 4F    4 SHF transponders (all), 2 UHF transponders (all), 2 C-band transponders (#D-F)
AZIMUTH:   125.5 SE
ELEVATION:  18.7

Title: Re: Frequency Hopping ( UHF SatCom?)
Post by: Teotwaki on December 07, 2022, 2032 UTC

Based on  the document at this link
https://www.jhuapl.edu/Content/techdigest/pdf/V30-N02/30-02-Oetting.pdf

The page 107 illustration shows that MUOS cannot downlink at 243 MHz
(https://i.ibb.co/1dy6cwC/MUOS-Band-Plan.jpg)

So that leaves the possibility of USA 227 since Skynet 4F is further east and lower on the horizon.

Title: Re: Frequency Hopping ( UHF SatCom?)
Post by: sat_dxer on December 08, 2022, 0136 UTC

1917z 6 Dec /22
USA 99
Inclination: 15.6°
Mean Motion 1.00271/day

1917z 6 Dec /22
USA 115
Inclination: 13.6°
Mean Motion 1.00270/day

Title: Re: Frequency Hopping ( UHF SatCom?)
Post by: Teotwaki on December 08, 2022, 0421 UTC

Both seem to have UHF band plans

USA 99
AZIMUTH:   134.8 SE
ELEVATION:   42.6

USA 115  aka Milstar
AZIMUTH:   184.1 S
ELEVATION:  52.5   

The Milstar system provides uplink communications at extremely high frequency (EHF), 44 GHz, and ultrahigh frequency (UHF), 300 MHz, and downlink communications at super-high frequency (SHF), 20 GHz, and UHF, 250 MHz. The crosslinks operate in the 60 GHz region. Survivability and endurability requirements are satisfied by anti-jam, hardening and system autonomy features.

Title: Re: Frequency Hopping ( UHF SatCom?)
Post by: sat_dxer on December 09, 2022, 1653 UTC

UHF FHSS Downlink 243.822 MHz (50 kHz wide) 1643z  9 Dec /22

USA 99
Inclination: 15.6°
Mean Motion 1.00271/day

USA 115
Inclination: 13.6°
Mean Motion 1.00270/day

USA 157
Inclination: 10.2°
Mean Motion 1.00273/day

USA 169
Inclination: 10.3°
Mean Motion 1.00271/day