RARR Antennas and Tracking - Revision history

http://www.carnarvonspace.com/wiki/index.php?action=history&feed=atom&title=RARR_Antennas_and_Tracking RARR Antennas and Tracking - Revision history 2026-04-17T14:30:52Z Revision history for this page on the wiki MediaWiki 1.7.1 http://www.carnarvonspace.com/wiki/index.php?title=RARR_Antennas_and_Tracking&diff=2199&oldid=prev Paul: /* Range Rate */ 2007-01-04T01:42:49Z

<p><span class="autocomment">Range Rate</span></p> <table border='0' width='98%' cellpadding='0' cellspacing='4' style="background-color: white;"> <tr> <td colspan='2' width='50%' align='center' style="background-color: white;">←Older revision</td> <td colspan='2' width='50%' align='center' style="background-color: white;">Revision as of 01:42, 4 January 2007</td> </tr> <tr><td colspan="2" align="left"><strong>Line 21:</strong></td> <td colspan="2" align="left"><strong>Line 21:</strong></td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;">After range had been determined, range tones were removed from the coherent link. Range was then maintained by integrating the measured '''range rate''' – the rate of change in the phase of the return signal (Doppler effect) – with previous range measurements.</td><td> </td><td style="background: #eee; font-size: smaller;">After range had been determined, range tones were removed from the coherent link. Range was then maintained by integrating the measured '''range rate''' – the rate of change in the phase of the return signal (Doppler effect) – with previous range measurements.</td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;"></td><td> </td><td style="background: #eee; font-size: smaller;"></td></tr> <tr><td>-</td><td style="background: #ffa; font-size: smaller;">A more precise spacecraft position could be triangulated with up to three ground stations in common view each using one of the three independent VHF transponders carried by the spacecraft<span style="color: red; font-weight: bold;">; each on a different frequency</span>. <span style="color: red; font-weight: bold;">The spacecraft carried only </span>a single S-band transponder; triangulation being of lesser value at lunar distances.<BR></td><td>+</td><td style="background: #cfc; font-size: smaller;">A more precise spacecraft position could be triangulated with up to three ground stations in common view<span style="color: red; font-weight: bold;">; </span>each using one of the three independent <span style="color: red; font-weight: bold;">different-frequency </span>VHF transponders carried by the spacecraft. <span style="color: red; font-weight: bold;">Only </span>a single S-band transponder <span style="color: red; font-weight: bold;">was carried by the spacecraft</span>; triangulation being of lesser value at lunar distances.<BR></td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;">[[The Science of Tracking#Range_Rate:_Phase-rate_measurement|(read more 'Range Rate' detail)]]</td><td> </td><td style="background: #eee; font-size: smaller;">[[The Science of Tracking#Range_Rate:_Phase-rate_measurement|(read more 'Range Rate' detail)]]</td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;"></td><td> </td><td style="background: #eee; font-size: smaller;"></td></tr> </table>

Paul http://www.carnarvonspace.com/wiki/index.php?title=RARR_Antennas_and_Tracking&diff=2198&oldid=prev Paul: /* Range Rate */ 2007-01-04T01:40:19Z

<p><span class="autocomment">Range Rate</span></p> <table border='0' width='98%' cellpadding='0' cellspacing='4' style="background-color: white;"> <tr> <td colspan='2' width='50%' align='center' style="background-color: white;">←Older revision</td> <td colspan='2' width='50%' align='center' style="background-color: white;">Revision as of 01:40, 4 January 2007</td> </tr> <tr><td colspan="2" align="left"><strong>Line 21:</strong></td> <td colspan="2" align="left"><strong>Line 21:</strong></td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;">After range had been determined, range tones were removed from the coherent link. Range was then maintained by integrating the measured '''range rate''' – the rate of change in the phase of the return signal (Doppler effect) – with previous range measurements.</td><td> </td><td style="background: #eee; font-size: smaller;">After range had been determined, range tones were removed from the coherent link. Range was then maintained by integrating the measured '''range rate''' – the rate of change in the phase of the return signal (Doppler effect) – with previous range measurements.</td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;"></td><td> </td><td style="background: #eee; font-size: smaller;"></td></tr> <tr><td>-</td><td style="background: #ffa; font-size: smaller;">A more precise spacecraft position could be triangulated with up to three ground stations in common view each using one of the three independent VHF transponders carried by the spacecraft; each on a different frequency. The spacecraft carried only a single S-band transponder; triangulation being of lesser value at lunar distances.</td><td>+</td><td style="background: #cfc; font-size: smaller;">A more precise spacecraft position could be triangulated with up to three ground stations in common view each using one of the three independent VHF transponders carried by the spacecraft; each on a different frequency. The spacecraft carried only a single S-band transponder; triangulation being of lesser value at lunar distances.<BR></td></tr> <tr><td>-</td><td style="background: #ffa; font-size: smaller;"> </td><td>+</td><td style="background: #cfc; font-size: smaller;"></td></tr> <tr><td>-</td><td style="background: #ffa; font-size: smaller;"><BR></td><td>+</td><td style="background: #cfc; font-size: smaller;"></td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;">[[The Science of Tracking#Range_Rate:_Phase-rate_measurement|(read more 'Range Rate' detail)]]</td><td> </td><td style="background: #eee; font-size: smaller;">[[The Science of Tracking#Range_Rate:_Phase-rate_measurement|(read more 'Range Rate' detail)]]</td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;"></td><td> </td><td style="background: #eee; font-size: smaller;"></td></tr> </table>

Paul http://www.carnarvonspace.com/wiki/index.php?title=RARR_Antennas_and_Tracking&diff=2197&oldid=prev Paul at 01:39, 4 January 2007 2007-01-04T01:39:32Z

<p></p> <table border='0' width='98%' cellpadding='0' cellspacing='4' style="background-color: white;"> <tr> <td colspan='2' width='50%' align='center' style="background-color: white;">←Older revision</td> <td colspan='2' width='50%' align='center' style="background-color: white;">Revision as of 01:39, 4 January 2007</td> </tr> <tr><td colspan="2" align="left"><strong>Line 17:</strong></td> <td colspan="2" align="left"><strong>Line 17:</strong></td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;">In addition S-band used two higher tones - 500 KHz and 100 KHz - for even more precise range measurement. An '''Ambiguity Resolving Code''' (ARC) was later retrofitted to the S-band system to extend non-ambiguous ranging to almost four times the distance to the Moon. Two pseudo-random codes - 255 bits and 127 bits- were combined with the result being modulated onto the 4 KHz sub-carrier at 4000 bps.<BR></td><td> </td><td style="background: #eee; font-size: smaller;">In addition S-band used two higher tones - 500 KHz and 100 KHz - for even more precise range measurement. An '''Ambiguity Resolving Code''' (ARC) was later retrofitted to the S-band system to extend non-ambiguous ranging to almost four times the distance to the Moon. Two pseudo-random codes - 255 bits and 127 bits- were combined with the result being modulated onto the 4 KHz sub-carrier at 4000 bps.<BR></td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;">[[The Science of Tracking#Continuous-wave_RARR|(read more 'Range' detail)]]</td><td> </td><td style="background: #eee; font-size: smaller;">[[The Science of Tracking#Continuous-wave_RARR|(read more 'Range' detail)]]</td></tr> <tr><td>-</td><td style="background: #ffa; font-size: smaller;"></td><td colspan="2"> </td></tr> <tr><td>-</td><td style="background: #ffa; font-size: smaller;">A more precise position could be triangulated with up to three stations in common view using three independent VHF transponders carried by the spacecraft; each operating on a different frequency. The spacecraft carried only a single S-band transponder; triangulation being of lesser value at lunar distances.</td><td colspan="2"> </td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;"></td><td> </td><td style="background: #eee; font-size: smaller;"></td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;">===Range Rate===</td><td> </td><td style="background: #eee; font-size: smaller;">===Range Rate===</td></tr> <tr><td>-</td><td style="background: #ffa; font-size: smaller;">After range had been determined, range tones were removed from the coherent link. Range was then maintained by integrating the measured '''range rate''' – the rate of change in the phase of the return signal (Doppler effect) – with previous range measurements.<BR></td><td>+</td><td style="background: #cfc; font-size: smaller;">After range had been determined, range tones were removed from the coherent link. Range was then maintained by integrating the measured '''range rate''' – the rate of change in the phase of the return signal (Doppler effect) – with previous range measurements.</td></tr> <tr><td colspan="2"> </td><td>+</td><td style="background: #cfc; font-size: smaller;"> </td></tr> <tr><td colspan="2"> </td><td>+</td><td style="background: #cfc; font-size: smaller;"><span style="color: red; font-weight: bold;">A more precise spacecraft position could be triangulated with up to three ground stations in common view each using one of the three independent VHF transponders carried by the spacecraft; each on a different frequency. The spacecraft carried only a single S-band transponder; triangulation being of lesser value at lunar distances.</span></td></tr> <tr><td colspan="2"> </td><td>+</td><td style="background: #cfc; font-size: smaller;"> </td></tr> <tr><td colspan="2"> </td><td>+</td><td style="background: #cfc; font-size: smaller;"><BR></td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;">[[The Science of Tracking#Range_Rate:_Phase-rate_measurement|(read more 'Range Rate' detail)]]</td><td> </td><td style="background: #eee; font-size: smaller;">[[The Science of Tracking#Range_Rate:_Phase-rate_measurement|(read more 'Range Rate' detail)]]</td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;"></td><td> </td><td style="background: #eee; font-size: smaller;"></td></tr> </table>

Paul http://www.carnarvonspace.com/wiki/index.php?title=RARR_Antennas_and_Tracking&diff=2196&oldid=prev Paul: /* Range */ 2007-01-04T01:33:52Z

<p><span class="autocomment">Range</span></p> <table border='0' width='98%' cellpadding='0' cellspacing='4' style="background-color: white;"> <tr> <td colspan='2' width='50%' align='center' style="background-color: white;">←Older revision</td> <td colspan='2' width='50%' align='center' style="background-color: white;">Revision as of 01:33, 4 January 2007</td> </tr> <tr><td colspan="2" align="left"><strong>Line 15:</strong></td> <td colspan="2" align="left"><strong>Line 15:</strong></td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;">GRAAR VHF used six '''range tones''' in 5:1 frequency intervals from 20 KHz to 8 Hz. Two tones at a time were used according to spacecraft distance. The '''lower tone''' produced a coarse range reading and the '''higher tone''' a finer resolution. the highest tones were modulated directly onto the carrier but those below 4 KHz were modulated onto a 4 KHz sub-carrier. </td><td> </td><td style="background: #eee; font-size: smaller;">GRAAR VHF used six '''range tones''' in 5:1 frequency intervals from 20 KHz to 8 Hz. Two tones at a time were used according to spacecraft distance. The '''lower tone''' produced a coarse range reading and the '''higher tone''' a finer resolution. the highest tones were modulated directly onto the carrier but those below 4 KHz were modulated onto a 4 KHz sub-carrier. </td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;"></td><td> </td><td style="background: #eee; font-size: smaller;"></td></tr> <tr><td>-</td><td style="background: #ffa; font-size: smaller;">In addition S-band used two higher tones - 500 KHz and 100 KHz - for even more precise range measurement. An '''Ambiguity Resolving Code''' (ARC) was later retrofitted to the S-band system to extend non-ambiguous ranging to almost four times the distance to the Moon. Two pseudo-random codes - 255 bits and 127 bits- were combined with the result being modulated onto the 4 KHz sub-carrier at 4000 bps<span style="color: red; font-weight: bold;">.</span></td><td>+</td><td style="background: #cfc; font-size: smaller;">In addition S-band used two higher tones - 500 KHz and 100 KHz - for even more precise range measurement. An '''Ambiguity Resolving Code''' (ARC) was later retrofitted to the S-band system to extend non-ambiguous ranging to almost four times the distance to the Moon. Two pseudo-random codes - 255 bits and 127 bits- were combined with the result being modulated onto the 4 KHz sub-carrier at 4000 bps.<BR></td></tr> <tr><td>-</td><td style="background: #ffa; font-size: smaller;"> </td><td>+</td><td style="background: #cfc; font-size: smaller;"></td></tr> <tr><td>-</td><td style="background: #ffa; font-size: smaller;"><span style="color: red; font-weight: bold;">A more precise position could be triangulated with up to three stations in common view using three independent VHF transponders carried by the spacecraft; each operating on a different frequency. The spacecraft carried only a single S-band transponder; triangulation being of lesser value at lunar distances</span>.<BR></td><td>+</td><td style="background: #cfc; font-size: smaller;"></td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;">[[The Science of Tracking#Continuous-wave_RARR|(read more 'Range' detail)]]</td><td> </td><td style="background: #eee; font-size: smaller;">[[The Science of Tracking#Continuous-wave_RARR|(read more 'Range' detail)]]</td></tr> <tr><td colspan="2"> </td><td>+</td><td style="background: #cfc; font-size: smaller;"></td></tr> <tr><td colspan="2"> </td><td>+</td><td style="background: #cfc; font-size: smaller;">A more precise position could be triangulated with up to three stations in common view using three independent VHF transponders carried by the spacecraft; each operating on a different frequency. The spacecraft carried only a single S-band transponder; triangulation being of lesser value at lunar distances.</td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;"></td><td> </td><td style="background: #eee; font-size: smaller;"></td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;">===Range Rate===</td><td> </td><td style="background: #eee; font-size: smaller;">===Range Rate===</td></tr> </table>

Paul http://www.carnarvonspace.com/wiki/index.php?title=RARR_Antennas_and_Tracking&diff=2195&oldid=prev Paul: /* Range */ 2007-01-04T01:32:30Z

<p><span class="autocomment">Range</span></p> <table border='0' width='98%' cellpadding='0' cellspacing='4' style="background-color: white;"> <tr> <td colspan='2' width='50%' align='center' style="background-color: white;">←Older revision</td> <td colspan='2' width='50%' align='center' style="background-color: white;">Revision as of 01:32, 4 January 2007</td> </tr> <tr><td colspan="2" align="left"><strong>Line 15:</strong></td> <td colspan="2" align="left"><strong>Line 15:</strong></td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;">GRAAR VHF used six '''range tones''' in 5:1 frequency intervals from 20 KHz to 8 Hz. Two tones at a time were used according to spacecraft distance. The '''lower tone''' produced a coarse range reading and the '''higher tone''' a finer resolution. the highest tones were modulated directly onto the carrier but those below 4 KHz were modulated onto a 4 KHz sub-carrier. </td><td> </td><td style="background: #eee; font-size: smaller;">GRAAR VHF used six '''range tones''' in 5:1 frequency intervals from 20 KHz to 8 Hz. Two tones at a time were used according to spacecraft distance. The '''lower tone''' produced a coarse range reading and the '''higher tone''' a finer resolution. the highest tones were modulated directly onto the carrier but those below 4 KHz were modulated onto a 4 KHz sub-carrier. </td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;"></td><td> </td><td style="background: #eee; font-size: smaller;"></td></tr> <tr><td>-</td><td style="background: #ffa; font-size: smaller;">In addition S-band used two higher tones - 500 KHz and 100 KHz - for even more precise range measurement. An '''Ambiguity Resolving Code''' (ARC) was later retrofitted to the S-band system to extend non-ambiguous ranging to almost four times the distance to the Moon. Two pseudo-random codes - 255 bits and 127 bits- were combined <span style="color: red; font-weight: bold;">and </span>the result <span style="color: red; font-weight: bold;">was </span>modulated onto the 4 KHz sub-carrier at 4000 bps.</td><td>+</td><td style="background: #cfc; font-size: smaller;">In addition S-band used two higher tones - 500 KHz and 100 KHz - for even more precise range measurement. An '''Ambiguity Resolving Code''' (ARC) was later retrofitted to the S-band system to extend non-ambiguous ranging to almost four times the distance to the Moon. Two pseudo-random codes - 255 bits and 127 bits- were combined <span style="color: red; font-weight: bold;">with </span>the result <span style="color: red; font-weight: bold;">being </span>modulated onto the 4 KHz sub-carrier at 4000 bps.</td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;"></td><td> </td><td style="background: #eee; font-size: smaller;"></td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;">A more precise position could be triangulated with up to three stations in common view using three independent VHF transponders carried by the spacecraft; each operating on a different frequency. The spacecraft carried only a single S-band transponder; triangulation being of lesser value at lunar distances.<BR></td><td> </td><td style="background: #eee; font-size: smaller;">A more precise position could be triangulated with up to three stations in common view using three independent VHF transponders carried by the spacecraft; each operating on a different frequency. The spacecraft carried only a single S-band transponder; triangulation being of lesser value at lunar distances.<BR></td></tr> </table>

Paul http://www.carnarvonspace.com/wiki/index.php?title=RARR_Antennas_and_Tracking&diff=2194&oldid=prev Paul: /* Range */ 2007-01-04T01:31:34Z

<p><span class="autocomment">Range</span></p> <table border='0' width='98%' cellpadding='0' cellspacing='4' style="background-color: white;"> <tr> <td colspan='2' width='50%' align='center' style="background-color: white;">←Older revision</td> <td colspan='2' width='50%' align='center' style="background-color: white;">Revision as of 01:31, 4 January 2007</td> </tr> <tr><td colspan="2" align="left"><strong>Line 15:</strong></td> <td colspan="2" align="left"><strong>Line 15:</strong></td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;">GRAAR VHF used six '''range tones''' in 5:1 frequency intervals from 20 KHz to 8 Hz. Two tones at a time were used according to spacecraft distance. The '''lower tone''' produced a coarse range reading and the '''higher tone''' a finer resolution. the highest tones were modulated directly onto the carrier but those below 4 KHz were modulated onto a 4 KHz sub-carrier. </td><td> </td><td style="background: #eee; font-size: smaller;">GRAAR VHF used six '''range tones''' in 5:1 frequency intervals from 20 KHz to 8 Hz. Two tones at a time were used according to spacecraft distance. The '''lower tone''' produced a coarse range reading and the '''higher tone''' a finer resolution. the highest tones were modulated directly onto the carrier but those below 4 KHz were modulated onto a 4 KHz sub-carrier. </td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;"></td><td> </td><td style="background: #eee; font-size: smaller;"></td></tr> <tr><td>-</td><td style="background: #ffa; font-size: smaller;">In addition S-band used two higher tones - 500 KHz and 100 KHz - for even more precise range measurement. <span style="color: red; font-weight: bold;">A pseudo-random </span>'''Ambiguity Resolving Code''' (ARC) was later retrofitted to the S-band system to extend non-ambiguous ranging to almost four times the distance to the Moon. <span style="color: red; font-weight: bold;">This </span>was modulated onto the 4 KHz sub-carrier at 4000 bps. </td><td>+</td><td style="background: #cfc; font-size: smaller;">In addition S-band used two higher tones - 500 KHz and 100 KHz - for even more precise range measurement. <span style="color: red; font-weight: bold;">An </span>'''Ambiguity Resolving Code''' (ARC) was later retrofitted to the S-band system to extend non-ambiguous ranging to almost four times the distance to the Moon. <span style="color: red; font-weight: bold;">Two pseudo-random codes - 255 bits and 127 bits- were combined and the result </span>was modulated onto the 4 KHz sub-carrier at 4000 bps.</td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;"></td><td> </td><td style="background: #eee; font-size: smaller;"></td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;">A more precise position could be triangulated with up to three stations in common view using three independent VHF transponders carried by the spacecraft; each operating on a different frequency. The spacecraft carried only a single S-band transponder; triangulation being of lesser value at lunar distances.<BR></td><td> </td><td style="background: #eee; font-size: smaller;">A more precise position could be triangulated with up to three stations in common view using three independent VHF transponders carried by the spacecraft; each operating on a different frequency. The spacecraft carried only a single S-band transponder; triangulation being of lesser value at lunar distances.<BR></td></tr> </table>

Paul http://www.carnarvonspace.com/wiki/index.php?title=RARR_Antennas_and_Tracking&diff=2193&oldid=prev Paul at 01:26, 4 January 2007 2007-01-04T01:26:02Z

<p></p> <table border='0' width='98%' cellpadding='0' cellspacing='4' style="background-color: white;"> <tr> <td colspan='2' width='50%' align='center' style="background-color: white;">←Older revision</td> <td colspan='2' width='50%' align='center' style="background-color: white;">Revision as of 01:26, 4 January 2007</td> </tr> <tr><td colspan="2" align="left"><strong>Line 9:</strong></td> <td colspan="2" align="left"><strong>Line 9:</strong></td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;">The '''S-band antenna''' consisted of twin 4.2m (14ft) parabolic dishes operating at around 2500Mc with a beamwidth of 2.5&deg;. One dish transmitted and the other received; the separation of transmit and receive functions decreased noise feedback on the receive dish. Both VHF and S-band antennas had 10Kw transmitters.</td><td> </td><td style="background: #eee; font-size: smaller;">The '''S-band antenna''' consisted of twin 4.2m (14ft) parabolic dishes operating at around 2500Mc with a beamwidth of 2.5&deg;. One dish transmitted and the other received; the separation of transmit and receive functions decreased noise feedback on the receive dish. Both VHF and S-band antennas had 10Kw transmitters.</td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;"></td><td> </td><td style="background: #eee; font-size: smaller;"></td></tr> <tr><td>-</td><td style="background: #ffa; font-size: smaller;">Tracking was accomplished by a '''coherent''' (continuous) link from the ground station to the spacecraft and back to the ground station. <span style="color: red; font-weight: bold;">Spacecraft </span>transponder frequency conversion ratio <span style="color: red; font-weight: bold;">complied with </span>the <span style="color: red; font-weight: bold;">international IFF standard – </span>240:221. Initially the GRARR S-band frequency conversion was downwards but later it was inverted to be compatible with the Apollo USB systems.</td><td>+</td><td style="background: #cfc; font-size: smaller;">Tracking was accomplished by a '''coherent''' (continuous) link from the ground station to the spacecraft and back to the ground station. <span style="color: red; font-weight: bold;">The spacecraft </span>transponder frequency conversion ratio <span style="color: red; font-weight: bold;">followed </span>the 240:221 <span style="color: red; font-weight: bold;">international IFF standard</span>. Initially the GRARR S-band frequency conversion was downwards but later it was inverted to be compatible with the Apollo USB systems.</td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;"></td><td> </td><td style="background: #eee; font-size: smaller;"></td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;">=== Range ===</td><td> </td><td style="background: #eee; font-size: smaller;">=== Range ===</td></tr> </table>

Paul http://www.carnarvonspace.com/wiki/index.php?title=RARR_Antennas_and_Tracking&diff=2192&oldid=prev Paul at 01:23, 4 January 2007 2007-01-04T01:23:58Z

<p></p> <table border='0' width='98%' cellpadding='0' cellspacing='4' style="background-color: white;"> <tr> <td colspan='2' width='50%' align='center' style="background-color: white;">←Older revision</td> <td colspan='2' width='50%' align='center' style="background-color: white;">Revision as of 01:23, 4 January 2007</td> </tr> <tr><td colspan="2" align="left"><strong>Line 9:</strong></td> <td colspan="2" align="left"><strong>Line 9:</strong></td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;">The '''S-band antenna''' consisted of twin 4.2m (14ft) parabolic dishes operating at around 2500Mc with a beamwidth of 2.5&deg;. One dish transmitted and the other received; the separation of transmit and receive functions decreased noise feedback on the receive dish. Both VHF and S-band antennas had 10Kw transmitters.</td><td> </td><td style="background: #eee; font-size: smaller;">The '''S-band antenna''' consisted of twin 4.2m (14ft) parabolic dishes operating at around 2500Mc with a beamwidth of 2.5&deg;. One dish transmitted and the other received; the separation of transmit and receive functions decreased noise feedback on the receive dish. Both VHF and S-band antennas had 10Kw transmitters.</td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;"></td><td> </td><td style="background: #eee; font-size: smaller;"></td></tr> <tr><td>-</td><td style="background: #ffa; font-size: smaller;">Tracking was accomplished by a '''coherent''' (continuous) link from the ground station to the spacecraft and back to the ground station. <span style="color: red; font-weight: bold;">The spacecraft </span>transponder <span style="color: red; font-weight: bold;">operated according to </span>the international IFF standard – 240:221. Initially the frequency conversion was downwards but later<span style="color: red; font-weight: bold;">, </span>to be compatible with the Apollo USB <span style="color: red; font-weight: bold;">transmissions, GRARR spacecraft frequency conversion was downwards</span>.</td><td>+</td><td style="background: #cfc; font-size: smaller;">Tracking was accomplished by a '''coherent''' (continuous) link from the ground station to the spacecraft and back to the ground station. <span style="color: red; font-weight: bold;">Spacecraft </span>transponder <span style="color: red; font-weight: bold;">frequency conversion ratio complied with </span>the international IFF standard – 240:221. Initially the <span style="color: red; font-weight: bold;">GRARR S-band </span>frequency conversion was downwards but later <span style="color: red; font-weight: bold;">it was inverted </span>to be compatible with the Apollo USB <span style="color: red; font-weight: bold;">systems</span>.</td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;"></td><td> </td><td style="background: #eee; font-size: smaller;"></td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;">=== Range ===</td><td> </td><td style="background: #eee; font-size: smaller;">=== Range ===</td></tr> </table>

Paul http://www.carnarvonspace.com/wiki/index.php?title=RARR_Antennas_and_Tracking&diff=2191&oldid=prev Paul at 08:03, 3 January 2007 2007-01-03T08:03:00Z

<p></p> <table border='0' width='98%' cellpadding='0' cellspacing='4' style="background-color: white;"> <tr> <td colspan='2' width='50%' align='center' style="background-color: white;">←Older revision</td> <td colspan='2' width='50%' align='center' style="background-color: white;">Revision as of 08:03, 3 January 2007</td> </tr> <tr><td colspan="2" align="left"><strong>Line 2:</strong></td> <td colspan="2" align="left"><strong>Line 2:</strong></td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;">[[Image:RARR-VHF.jpg|left|thumb|RARR VHF antenna]]</td><td> </td><td style="background: #eee; font-size: smaller;">[[Image:RARR-VHF.jpg|left|thumb|RARR VHF antenna]]</td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;"><BR><BR></td><td> </td><td style="background: #eee; font-size: smaller;"><BR><BR></td></tr> <tr><td>-</td><td style="background: #ffa; font-size: smaller;">The GRARR VHF and S-band antennas were driven by identical hydraulically-powered [[Tracking Antenna Mounts|X-Y mounts]] with digital angle encoders accurate to &plusmn;0.1&deg;.</td><td>+</td><td style="background: #cfc; font-size: smaller;">The GRARR VHF and S-band antennas were driven by identical hydraulically-powered<span style="color: red; font-weight: bold;"><BR></span>[[Tracking Antenna Mounts|X-Y mounts]] with digital angle encoders accurate to &plusmn;0.1&deg;.</td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;"></td><td> </td><td style="background: #eee; font-size: smaller;"></td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;">The '''VHF antenna''' was a 8.4m (28ft) square array of cavity-backed slots operating at about 150Mc. The array was later upgraded to backward-scatter dipoles. The antenna had a beamwidth of 16&deg; and was often used as an acquisition aid for the narrower beamwidth S-band antenna.<BR></td><td> </td><td style="background: #eee; font-size: smaller;">The '''VHF antenna''' was a 8.4m (28ft) square array of cavity-backed slots operating at about 150Mc. The array was later upgraded to backward-scatter dipoles. The antenna had a beamwidth of 16&deg; and was often used as an acquisition aid for the narrower beamwidth S-band antenna.<BR></td></tr> </table>

Paul http://www.carnarvonspace.com/wiki/index.php?title=RARR_Antennas_and_Tracking&diff=2190&oldid=prev Paul: /* Angle */ 2007-01-03T08:00:44Z

<p><span class="autocomment">Angle</span></p> <table border='0' width='98%' cellpadding='0' cellspacing='4' style="background-color: white;"> <tr> <td colspan='2' width='50%' align='center' style="background-color: white;">←Older revision</td> <td colspan='2' width='50%' align='center' style="background-color: white;">Revision as of 08:00, 3 January 2007</td> </tr> <tr><td colspan="2" align="left"><strong>Line 25:</strong></td> <td colspan="2" align="left"><strong>Line 25:</strong></td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;"></td><td> </td><td style="background: #eee; font-size: smaller;"></td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;">===Angle===</td><td> </td><td style="background: #eee; font-size: smaller;">===Angle===</td></tr> <tr><td colspan="2"> </td><td>+</td><td style="background: #cfc; font-size: smaller;">Angle tracking was acheived using a monopulse technique where each antenna independantly compared four different off-axis beams simultaneously; the VHF using the four quadrants of the square plane, and the S-band with the four apertures of the receive horn.</td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;"><BR></td><td> </td><td style="background: #eee; font-size: smaller;"><BR></td></tr> <tr><td> </td><td style="background: #eee; font-size: smaller;">[[The Science of Tracking#Angle:_Relative–phase_measurement|(read more 'Angle' detail)]]</td><td> </td><td style="background: #eee; font-size: smaller;">[[The Science of Tracking#Angle:_Relative–phase_measurement|(read more 'Angle' detail)]]</td></tr> </table>

Paul