This document is a list of known signals as seen by Signal Hound 3 at DSL.
Each listing can be expanded to show a screenshot of an example of the signal.
Specific events that should always be reported are noted in bold, but this is not a comprehensive list!
Use your own judgement and report anything that seems out of the ordinary.
Extremely broadband but short signals are typical of snowmobiles and
other vehicles with sparkplugs. Don’t worry about it unless they’re
excessively bright.
Typical sparkplug signature around 17:00Z
450–452 MHz: LMR
Signal levels around −29 dBm are typical
When the attenuator (at the RF building) is off, the signal level
increases to the point where it overloads the signal chain. See 04/16/25
for an example. There will be harmonics present up to around 4 GHz!
Report any time you see the attenuator off
Example of turning off the LMR attenuator:
1.25 GHz: Satellite radar on ALOS-21.62 GHz: Iridium - Expect this to be the brightest signal by a large margin. Around −5 dBm is typical.2.07 GHz: mystery digital signal. I think it has something to do with
LMR, based on how it behaves when the attenuator changes state. May be an
artifact/alias. Not currently a concern.
2.4 GHz: WiFi & Bluetooth.
Constant signal at 2.40, 2.426, and 2.48 GHz are the BLE advertising channels.
Ideally this would be quiet but the current reality is that some signal is normal.
Report obvious changes from baseline with their exact start and end times so that we can try to track down the culprit.
In this example, the BLE advertising channels are visible, and there is a transmission incident around 02:00Z that continues until around 05:00Z.
3.24 GHz: Probably an Iridium harmonic4.2–4.4 GHz: Aircraft radio altimeter5.26 GHz: Satellite scatterometer on Metop-B or C5.40 GHz: Synthetic aperture radar on EOS-04
Per the satellite’s handbook: “Initially, SAR payload of EOS-04 was configured in C-Band at a frequency of 5.35 GHz, similar to that of RISAT-1. However, in order to avoid WLAN interference, the centre frequency of payload is shifted from 5.35 GHz to 5.4 GHz.”
5.8 GHz: High frequency WiFi/ISM band.
Currently quiet, note any disturbances from that background.
An example of 5.8 GHz WiFi being switched on.
7.74 GHz: Extremely mysterious squiggly signal
Frequency shifts can’t be doppler shifts: to shift as much as it
does, it would have to be moving at around 40x orbital velocity at
LEO
Appears to be some sort of CW signal, and smoothly shifts in both
amplitude and frequency
Signal is overall quite dim. This is a curiosity, not a concern.
If you can figure out what this is I’ll buy you your drink of choice
at the next collaboration meeting!
8.3G Hz: DSCS. Expect 2 passes/day, each ~6 hrs long, at around −50 to −45 dBm.
Note if there are more or fewer than 2 passes, or if the power level deviates significantly.13.52 GHz: Satellite scatterometer on OceanSat-314.0–14.5 GHz: Starlink uplink
15 GHz: TDRS. Expect 1 pass per day, with bandwidth ~300 MHz and power level around −65 dBm. Note if this pass is missing or at significantly different power.
