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Peter Miles
Northam, Western Australia
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FLTSATCOM-7
(USA-20)
FLTSATCOM-7
(USA-20)
Background and technical
overview.
HOME >
OPERATIONAL
> MODES
& FREQUENCIES > SATELLITES
- RADIO TARGETS >
The old FLTSATCOM spacecraft had relatively simple repeater architecture. Some of its UHF transponders did not provide the sort of modern authentication and access control we associate with contemporary military satellite systems.
Consequently, unauthorized users discovered that they could transmit on the satellite uplink and hear their signals come back down over a huge area.
Details
| Satellite: |
FLTSATCOM-7
(USA-20) |
| Norad ID: |
17181 |
| Operator: |
US Navy |
| Status: |
Operational,
however superseded by MUOS. |
| Frequency Range: |
240.0 -
270.0 MHz VHF Down Link
|
| Mode: |
FM |
| Altitude [km]: |
36000 +/-
Near-geosynchronous, near-equatorial (Junkyard orbit) drifting
westward. |
| Tracking: |
https://www.n2yo.com/?s=17181&live=1 |
FLTSATCOM 7 (F7 / USA-20), the applicable historical frequency plan is Bravo. The FLTSATCOM architecture had 23 RF channels: ten 25-kHz channels, twelve 5-kHz narrowband channels, and one 500-kHz wideband channel.
Channel
confirmation was achieved by monitoring the channel frequency for
consistency with the band plan, verifying the bandwidth and antenna
targeting to assess the SNR (signal-to-noise ratio).
|
|
Bandwidth |
Status |
| 250.075 |
25
kHz |
Fleet
Broadcast - No channel noise floor heared |
| 251.95 |
25
kHz |
Appears
to FLTSATCOM 7. Not listed |
| 252.05 |
25
kHz |
Navy
relay - Confirmed 2026 |
| 253.75 |
25
kHz |
Navy
relay - Confirmed 2026 |
| 255.45 |
25
kHz |
Navy
relay - Confirmed 2026 |
| 257.05 |
25
kHz |
Navy
relay - Confirmed 2026 |
| 258.55 |
25
kHz |
Navy
relay - Confirmed 2026 |
| 265.45 |
25
kHz |
Navy
relay - No channel noise floor heared |
| 266.95 |
25
kHz |
Navy
relay - No channel noise floor heared |
| 268.35 |
25
kHz |
Navy
relay - No channel noise floor heared |
| 269.85 |
25
kHz |
Navy
relay - No channel noise floor heared |
| 244.045 |
5
kHz |
AFSATCOM
narrowband - Confirmed 2026 |
| 244.055 |
5
kHz |
AFSATCOM
narrowband - Confirmed 2026 |
| 244.06 |
5
kHz |
AFSATCOM
narrowband - No channel noise floor heared |
| 244.065 |
5
kHz |
AFSATCOM
narrowband - Confirmed 2026 |
| 244.07 |
5
kHz |
AFSATCOM
narrowband - No channel noise floor heared |
| 244.075 |
5
kHz |
AFSATCOM
narrowband - Confirmed 2026 |
| 244.08 |
5
kHz |
AFSATCOM
narrowband - No channel noise floor heared |
| 244.085 |
5
kHz |
AFSATCOM
narrowband - Confirmed 2026 |
| 244.09 |
5
kHz |
AFSATCOM
narrowband - No channel noise floor heared |
| 244.095 |
5
kHz |
AFSATCOM
narrowband - Confirmed 2026 |
| 244.1 |
5
kHz |
AFSATCOM
narrowband - No channel noise floor heared |
| 244.11 |
5
kHz |
AFSATCOM
narrowband - No channel noise floor heared |
| 261.950–262.450 |
500
kHz |
Wideband
- No channel noise floor heard. |
Reception Reports
| Date |
Time |
Frequency |
Details |
| 24
Sept. 2026 |
00:58Z |
252.050 MHz |
Strong transponder noise floor. No signals. Another strong transponder at 251.950 MHz that is consistent in strength with FLTSATCOM-7, however not consistent with known band plan.
|
|
Antenna: |
5 Element Yagi for 250MHz.
https://vk6ysf.com/yagi_250mhz_5el_20220925.html |
| Software: |
SDR Software: SDR++Brown |
| |
|
|
| Screenshot 1 Strong transponder noise floors |
References
TOP
OF PAGE
Page initiated 19 September, 2026
Page
last revised 24 September, 2026
|
|
|
Space Weather
https://www.swpc.noaa.gov/
|
Michael Faraday
born 22 Sep 1791
Shaping the modern electrical age, Michael Faraday (1791–1867) was a pioneering British scientist who transformed our understanding of electricity and magnetism. His discoveries included electromagnetic induction, which laid the foundation for electric generators and transformers, as well as the principles behind the electric motor.
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Notice Board
|
VK6YSF JS8Call and
Olivia 8/250 operations.
Current activity is generally
focused - though not restricted to - JS8Call operations on the 20,
30m, and 40m bands.
Olivia 8/250 is used occasionally on the 20m band.
Proposed
band and mode activity
is often communicated on HamSpots: https://hamspots.net/js8/
or my profile on
X: https://x.com/vk6ysf97230
.
Post
date: 27 August 2026
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Local
Repeaters
Repeaters Page Updated
- Expanded and refreshed information on VHF and UHF repeaters across Western Australia's Central Coast, Perth, the Avon Valley, and the Peel region. New AllStar Link information has also been added, including linked repeater details and
gateway information across the State.
Repeaters
details:
https://vk6ysf.com/local_repeaters.htm
AllStar Link notes:
https://vk6ysf.com/allstar_notes-20260703.htm
Post
date: 27 August 2026
|
|
Western Australian SSTV net
Popular
Western Australian SSTV net for both digital and anolog SSTV.
Generally
found at 7214.0kHz LSB every afternoon from 08:00 UTC (4:00pm WST)
For more
details: https://www.wasstv.net/wasstv.net/index.html
Post
date: 8 December 2025
|
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VK6MJM LF (136kHz) and MF (474kHz) Beacon
VK6MJM is a LF/MF station
located in Manjimup, Western Australia.
Common Mode: FST4W 300 (Similar to
WSPR)
Note:
other modes and sub-modes may be used.
Station details were presented by
Peter Hall (VK6HP) at PerthTech 2024.Presentation PDF: Peter
Hall VK6HP at PerthTech
QRZ Page: VK6MJM
on QRZ.com
Post
date: 10 March 2025
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