Does anybody know the bandwidth of the Voyager 2 radio receiver's front-end?
I know that the current data rate of the receiver is of order tens of bits per second, and I have one estimate of 18 Hz. Could that be correct?
$\begingroup$
$\endgroup$
5
-
$\begingroup$ Do you mean the antennas themselves (very broad!) or the transmission line, or the receiver front end, or baseband? This may be related: Frequency responses of Voyager's S-band high gain antenna's feed-horn and receiver front end & IF? and there may be some helpful information there as well even though there's no answer yet. $\endgroup$– uhohCommented Nov 19, 2020 at 6:35
-
$\begingroup$ Thank you. The receiver front end. Is it 18 hz? $\endgroup$– JohnCommented Nov 20, 2020 at 22:10
-
1$\begingroup$ Okay I've updated your question, and I think I can add an answer by tomorrow, but someone may beat me to it. Thanks! $\endgroup$– uhohCommented Nov 21, 2020 at 1:25
-
1$\begingroup$ Thanks!!!!!!!!! $\endgroup$– JohnCommented Nov 21, 2020 at 2:59
-
$\begingroup$ This is Space SE, we can't expect everyone to be an expert in telecommunications! The OP has asked to the best of their knowledge and we now understand that while there is a capture range is 100 kHz the actual signal is far narrower and defined by other parameters which change over the course of the mission. OP has accepted the answer, it doesn't seem productive to close the question as "need details or clarity", in this case those are things that can be posted as additional answers, which if course is prevented if the question is closed! $\endgroup$– uhohCommented Nov 28, 2020 at 5:19
Add a comment
|
2 Answers
$\begingroup$
$\endgroup$
1
This is an interesting but challenging question. I've found the following footnote on page 39 of Voyager Telecommunications, DESCANSO Design and Performance Summary Series, Article 4 Section 7.2.6 Voyager 2 Procedures to Compensate for Voyager 2 Receiver Problem and so am posting as a partial answer for now. I will have to dig deeper and then update accordingly.
4The term “best-lock frequency” in a phase-locked loop refers to the frequency the loop would naturally oscillate at with no input. When the receiver loop is receiving an uplink carrier exactly at BLF (the center of its band- width), the loop would indicate a zero static phase error telemetry measurement. The bandwidth of a healthy Voyager receiver is about 100 kHz, as compared with 100 Hz for the receiver with the failed tracking loop.
This does not mean the received signal can be 100 kHz wide, but I think it means that if a narrow signal were within this range, and the receiver were working properly, it could be locked on to and decoded.
Again, partial answer only for now...
Experts feel free to comment, edit, or post a better answer.
-
$\begingroup$ @Albert thanks to you too, it's an interesting question! By the way I am not at all sure this is the final and complete answer, so I'd recommend that you don't click accept right away. Other answers may be posted still, and someone may find fault in this one as currently written. Perhaps consider un-clicking accept and waiting a few more days? $\endgroup$– uhohCommented Nov 22, 2020 at 0:34
$\begingroup$
$\endgroup$
7
Does anybody know the bandwidth of the Voyager 2 radio antenna?
Well there are different bandwidths for different functions. This summary of Voyager's telecommunications systems by JPL's Deep Space Communications and Navigations Systems Center of Excellence (DESCANSO) claims Voyager has 4 main functions for communication. They are carrier tracking (Doppler), command, telemetry, and ranging. NASA's webpage on Voyager's Instrument Information states,
. . . the carrier tracking loop bandwidth was 18 Hz, and the ranging channel noise bandwidth was 1.5 MHz.
EDIT: I initially thought that the OP was asking about the frequency of Voyager's communications system. So I might as well add that information too.
The uplink frequency Voyager receives (Earth to Voyager) is 2113.3 MHz. These are the downlink (Voyager to Earth) frequencies of both Voyager 1 and 2:
Voyager 2 uses a frequency of 2295 MHz (S-band) or 8415 MHz (X-band).
-
2$\begingroup$ It would also be good to add at least some actual value for either a bandwidth or a bandpass to your answer in order to address the question as asked. $\endgroup$– uhohCommented Nov 20, 2020 at 0:06
-
1$\begingroup$ Oh. Okay. I was thinking of data transfer bandwidth.. $\endgroup$– Star ManCommented Nov 20, 2020 at 0:17
-
1$\begingroup$ This doesn't answer the question. $\endgroup$ Commented Nov 20, 2020 at 19:17
-
$\begingroup$ @user253751 I have edited the answer. $\endgroup$– Star ManCommented Nov 20, 2020 at 21:31
-
1$\begingroup$ PLL (loop) bandwidth isn't the same as signal bandwidth $\endgroup$ Commented Nov 20, 2020 at 21:44