Scott @K4KDR, could you give some details about the antenna & LNA you are using to receive HERMES H1/H2 ?
Glad to!
I use a 2.5-turn (RHCP) helical omni. If the picture below looks like some #6 solid copper ground wire on a pizza pan, that’s because it is! The build dimensions for this style of antenna can be calculated at: Antenas - Helix - Javascript on-line calculator
Located about 1/2 meter below the antenna is a wideband LNA (https://v3.airspy.us/product/upu-fpwb/)
There is a 15-meter run of LMR-400 from the roof into my house where the antenna is connected to an Airspy-Mini. I use GQRX to observe the downlink in real time, record both audio & I/Q files, and feed the audio to GNU Radio for decoding and upload to SatNogs.
On a related note, please remember that your SDR software needs to be configured for both the observed RF bandwidth -and- the audio OUT bandwidth must be large enough to pass the expected baud rate. For instance, in GQRX, to decode the HERMES 25k downlink, my settings look like this:
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HYDRA-W and HADES-ICM are about to be or have been deployed from Alba Orbital deployer (in the ION deployer) and here are the TLE provided by the satellite teams, changed to have the SatNOGS DB temporary NORAD IDs:
HADES-ICM
1 98637U 25000XX 25090.36753651 .00004178 00000-0 -12631-4 0 9990
2 98637 97.4406 345.4012 0010279 257.8499 176.9529 15.18290345 59109
HYDRA-W
1 98634U 25000XX 25090.36753651 .00004178 00000-0 -12631-4 0 9997
2 98634 97.4406 345.4012 0010279 257.8499 176.9529 15.18290345 59106
Satellites will be available for scheduling in the Network in the next hour.
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HADES-ICM TLE Update after two passes:
HADES-ICM
1 98637U 25000XX 25090.42910023 .00000000 00000-0 -12631-4 0 08
2 98637 97.4406 345.5181 0010279 257.8499 153.0281 15.17867874 09
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HYDRA-W TLE Update after two passes:
HYDRA-W
1 98634U 25000XX 25090.42911604 .00000000 00000-0 -12631-4 0 01
2 98634 97.4406 345.6095 0010279 257.8499 153.3972 15.21130000 00
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All TEVEL2 satellites are updated to a coordinated state.
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Some improvements on the HADES-ICM and HYDRA-W TLE
HADES-ICM
1 98637U 25052X 25090.42913198 .00000000 00000-0 79995-3 0 05
2 98637 97.4434 345.4584 0004588 342.2991 68.7531 15.17816928 02
# 20250331.36-20250331.43, 26 measurements, 0.060 kHz rms
HYDRA-W
1 98634U 25052X 25090.42914761 .00000000 00000-0 12004-2 0 06
2 98634 97.4434 345.5108 0004588 342.2991 69.1149 15.21063799 07
# 20250331.36-20250331.43, 25 measurements, 0.148 kHz rms
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That’s interesting.
The application date is mentioned as March 23rd were as the launch date was already on March 15th.
The application was 8 days after the launch.
8 days seem ok, but if you are 21 days after launch, you’ll end up declined (HayaSat).
IARU is not in a position to coordinate frequencies for satellites that are already in orbit.
On the other side, if you are too early, it’s also not good.
3 days prior to launch ended up declined (SelfieSat)
No coordination was possible due to the short time between receiving the request and the actual launch.
3 days prior to launch could also end up declined (BEESAT-10/11/12/13) with this comment:
Coordination declined as request was received after launch had occurred.
IARU, are you serious?
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Hi everybody,
the HERMES team performed a detailed analysis of the available NORAD TLEs and our closest matches for the HERMES H1 and H2 are:
H1 → OBJECT AJ/63242
H2 → OBJECT AK/63243
Thanks again for all your support!
Yuri for the HERMES Team
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Updated in DB and Network future observations!
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TLE update for HADES-ICM
HADES-ICM
1 98637U 25052X 25091.35145342 .00000000 00000-0 76908-3 0 07
2 98637 97.4434 346.6322 0004588 342.2991 66.6780 15.18408989 03
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TLE update for HYDRA-W:
HYDRA-W
1 98634U 25000XX 25091.47951150 .00000000 00000-0 30238-3 0 08
2 98634 97.4406 346.3687 0010279 257.8499 131.6834 15.18539045 09
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Hi all,
today the HERMES satellites H1 and H2 could have switched, automatically, also the beacon transmission in the S-band.
Details are as follows:
Freq: 2222 MHz
Datarate: 500 kbps
Symbol rate: 250 kBaud
Bandwidth: 312500 Hz
TX always on (PRN modulated on carrier)
The beacon should alternate between S and UHF bands every 3 minutes; in each interval the beacon is active every ~20 s.
The antenna beamwidth is 68 degrees.
Modulation: OQPSK
Encoding:
CCSDS 131.0-B-2: TM sync and channel coding
CCSDS 131.0-B-2: TM Space Data Link Protocol
Reed-Solomon 223
Convolution code 1/2
Pulse shaping RRC filter (0.5 roll-off factor)
Observations also in S-band are encouraged!
Thanks in advance for your help.
Riccardo on behalf of the HERMES team
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We have successfully communicated with OTP-2 using the NORAD ID and associated TLE twice now.
Will continue to track and confirm against our next GNSS pull.
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Hi friends,
I already received mails about HYDRA-W and I want to share with you this information.
HYDRA-W, as HYDRA-T, was already delivered some months ago, so it wasn’t possible to make any fix to its transmitting frequency.
As part of the team that designed and built the satellite I want to apologize to the amateur community for having this satellite in this band.
As with HYDRA-T, we were adviced that it was legal although, as HAMs, we weren’t happy to have it here. The last decission wasn’t ours and it finally ended in the 70 cm band.
We will try to turn it off, at least all the transmissions we can. It is also running an experiment for a University so we need to take at least that telemetry.
We tried to turn HYDRA-T off but it is not responding to command, as you can see the ones who decode status packets.
In any case I apologize again and be sure this is not going to happen again.
We hope that HADES-R and HADES-ICM compensate a bit these two errors. We are always trying to put satellites in space for the amateur community but sometimes when working with the private sector we are part of its errors.
Thanks all for your understanding
Félix EA4QGS
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Good morning Felix,
Thank you very much for sharing this information.
Now with both satellites launched I am trying to get some good, working TLE.
All the best,
Jan | PE0SAT
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HYDRA-W TLE Update
This one is a challenge
HYDRA-W
1 98634U 25052X 25092.40649045 .00000000 00000-0 12001-2 0 03
2 98634 97.4434 347.3087 0004588 342.2991 70.4775 15.18279010 04
These have quite an error but better then we had before.
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HADES-ICM TLE Update
HADES-ICM
1 98637U 25052X 25092.34373891 .00000000 00000-0 42496-2 0 03
2 98637 97.4434 347.3229 0004588 342.2991 86.6061 15.18376415 09
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Hi all,
the deployment of the next HERMES satellite from ION - HERMES H6 - is foreseen for tomorrow, April 3, at 09:05 UTC.
We kindly ask your support with H6 observations, details of the UHF beacon are the same as for H1 and H2 (401.5 MHz, GFSK 25000 baud)
As a preliminary TLE, those of ION SCV-017 can be used:
ION SCV-017
1 10224U 25999XX 25092.46224877 .00004178 00000-0 31313-3 0 9995
2 10224 97.4400 347.4567 0004008 248.3898 96.3245 15.16765846 59108
(this TLE is essentially coincident with NORAD Object W, 63230U)
Updated TLEs will be communicated as soon as we have confirmation of the state vectors after deployment.
Thanks in advance!
Yuri for the HERMES Team
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