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<blockquote style="position: relative; padding-left: 55px;"><section><a href="https://fosstodon.org/users/AkaSci/statuses/112110598062386825">AkaSci 🛰️ (akasci@fosstodon.org)'s status on Thursday, 21-Mar-2024 21:26:55 JST</a><a href="https://fosstodon.org/@AkaSci" title="akasci@fosstodon.org"><img src="https://gnusocial.jp/avatar/20805-48-20221219024513.webp" width="48" height="48" alt="AkaSci 🛰️" style="position: absolute; left: 0; top: 0;">AkaSci 🛰️</a><div><a href="https://mstdn.social/@zazoobred/112110469269323316" rel="in-reply-to">in reply to</a><ul><li></ul></div></section><article><p><a href="https://mstdn.social/@zazoobred">@zazoobred</a> <br>Yes, Voyager comms has to compensate for Doppler, which can shift the X-Band 8.415 GHz downlink carrier by up to 1.3 MHz. Receiver tracking loops do that.</p><p>Interestingly, Voyager 2, due to a failed tracking-loop capacitor, cannot track uplink signals beyond +-100 Hz offset. So, transmission from earth (at 2.1 GHz) is pre-compensated in frequency, taking earth's rotation, orbital speed and Voyager 2 temperature into account.</p><p>See <a href="https://fosstodon.org/@AkaSci/110832414978433970" rel="nofollow noreferrer">https://fosstodon.org/@AkaSci/110832414978433970</a> for some more info.</p></article><footer><a rel="bookmark" href="https://gnusocial.jp/conversation/2823373#notice-5656020">In conversation</a><time datetime="2024-03-21T21:26:55+09:00" title="Thursday, 21-Mar-2024 21:26:55 JST">about 11 months ago</time> <span>from <span><a href="https://fosstodon.org/@AkaSci/112110598062386825" rel="external" title="Sent from fosstodon.org via ActivityPub">fosstodon.org</a></span></span><a href="https://fosstodon.org/@AkaSci/112110598062386825">permalink</a><h4>Attachments</h4><ol><li><article><header><div>Domain not in remote thumbnail source whitelist: cdn.fosstodon.org</div><h5><a href="https://fosstodon.org/@AkaSci/110832414978433970">AkaSci 🛰️ (@AkaSci@fosstodon.org)</a></h5><div> from <span>AkaSci 🛰️</span></div></header><div>Attached: 1 imageTo make matters worse, only 1 of 2 receivers on Voyager 2 is healthy, but a fault prevents it from accurately tracking the receive signal. Signal frequency varies due to the rotation of the earth (doppler) and receiver temperature. V1 can track signals that are off by +-100,000 Hz, but V2 can only handle +-100 Hz. For V2, tx from earth is pre-compensated in freq, taking earth rotation and V2 temp. into account.https://descanso.jpl.nasa.gov/DPSummary/Descanso4--Voyager_new.pdf
#Voyager
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AkaSci 🛰️ (akasci@fosstodon.org)'s status on Thursday, 21-Mar-2024 21:26:55 JSTAkaSci 🛰️
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- Artem Ignatyev
@zazoobred
Yes, Voyager comms has to compensate for Doppler, which can shift the X-Band 8.415 GHz downlink carrier by up to 1.3 MHz. Receiver tracking loops do that.
Interestingly, Voyager 2, due to a failed tracking-loop capacitor, cannot track uplink signals beyond +-100 Hz offset. So, transmission from earth (at 2.1 GHz) is pre-compensated in frequency, taking earth's rotation, orbital speed and Voyager 2 temperature into account.
See https://fosstodon.org/@AkaSci/110832414978433970 for some more info.
In conversationabout 11 months ago from fosstodon.orgpermalink
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  AkaSci 🛰️ (@AkaSci@fosstodon.org)
  from AkaSci 🛰️
  Attached: 1 image To make matters worse, only 1 of 2 receivers on Voyager 2 is healthy, but a fault prevents it from accurately tracking the receive signal. Signal frequency varies due to the rotation of the earth (doppler) and receiver temperature. V1 can track signals that are off by +-100,000 Hz, but V2 can only handle +-100 Hz. For V2, tx from earth is pre-compensated in freq, taking earth rotation and V2 temp. into account. https://descanso.jpl.nasa.gov/DPSummary/Descanso4--Voyager_new.pdf #Voyager 3/n

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