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Lbandcircular

MtPleasant26m.Lbandcircular History

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February 26, 2013, at 04:58 AM by JMc -
Changed lines 4-7 from:
  1. The tone port (A2 in rack 3) injects left-hand circular into the L band feed. Tune sig gen (the SML) to 1/2 of central sky frequency (e.g. for a 1400 MHz centre frequency this would be 700 MHz).
  2. Select the L band receiver and start with agilent set to the standard frequency of 4.1 GHz.
to:
  1. The tone port (A2 in rack 3) injects left-hand circular into the L band feed. Tune sig gen (the SMY) to 1/2 of central sky frequency (e.g. for a 1400 MHz centre frequency this would be 700 MHz).
  2. Select the L band receiver (http://ra-wiki.phys.utas.edu.au/index.php?n=MtPleasant26m.OTTER)) and start with agilent set to the standard frequency of 4.1 GHz (http://ra-wiki.phys.utas.edu.au/index.php?n=MtPleasant26m.OscillatorControl).
Changed lines 10-11 from:
  1. Make sure that for the Agilent setting used above that the SMY required for the frequency translator is not within any of the undesirable LO ranges as listed on the yellow sheet attached to the frequency translator.
to:
  1. Make sure that for the Agilent setting used above that the SML required for the frequency translator is not within any of the undesirable LO ranges as listed on the yellow sheet attached to the frequency translator.
Changed lines 23-26 from:
  • On the main menu for the receiver PC select the expansion port and make sure that the quadrature hybrid is OUT.
  • Toggle the switch between direct and crossed and adjust the attenuation in the IF strip so that the level of the tone on the spectrum analyser is the same when “direct” as “crossed”. It is important that these are as accurate as possible, so once you have it roughly right on 10 dB per division use 3 dB per division or 1 dB per division to get the tone level the same to better than 1 dB.
  • When the switch is “direct” the attenuation on the expansion port changes the level of the signal on A4 (marked RHC)
to:
  • Using the OTTER interface (http://ra-wiki.phys.utas.edu.au/index.php?n=MtPleasant26m.OTTER), make sure that the quadrature hybrid is OUT.
  • Toggle the switch between direct and crossed and adjust the attenuation in the IF strip so that the level of the tone on the spectrum analyser is the same when “direct” as “crossed” (http://ra-wiki.phys.utas.edu.au/index.php?n=MtPleasant26m.OTTER). It is important that these are as accurate as possible, so once you have it roughly right on 10 dB per division use 3 dB per division or 1 dB per division to get the tone level the same to better than 1 dB.
  • When the switch is “direct” the attenuation changes the level of the signal on A4 (marked RHC)
March 08, 2012, at 03:02 AM by 131.217.6.6 -
Changed lines 12-20 from:

These undesirable LO ranges are (taken from yellow post-it note 08/03/2012): 560–512 MHz 373–395 MHz 280–296 MHz 224–236 MHz 186–198 MHz

to:

These undesirable LO ranges are (taken from yellow post-it note 08/03/2012):
560–512 MHz
373–395 MHz
280–296 MHz
224–236 MHz
186–198 MHz

March 08, 2012, at 03:01 AM by 131.217.6.9 -
Changed lines 10-11 from:
  1. Make sure that for the Agilent setting used above that the SMY required for the frequency translator is not within any of the undesirable LO ranges as listed on the yellow sheet attached to the frequency translator (could someone specify them here please?)
to:
  1. Make sure that for the Agilent setting used above that the SMY required for the frequency translator is not within any of the undesirable LO ranges as listed on the yellow sheet attached to the frequency translator.

These undesirable LO ranges are (taken from yellow post-it note 08/03/2012): 560–512 MHz 373–395 MHz 280–296 MHz 224–236 MHz 186–198 MHz

June 16, 2010, at 05:54 AM by 131.217.6.6 -
Changed line 41 from:
14064.18469.68754391 | 31dBvt13bBrett16th June
to:
14064.18469.6875439131dBvt13bBrett16th June
June 16, 2010, at 05:36 AM by 131.217.6.7 -
Added line 41:
14064.18469.68754391 | 31dBvt13bBrett16th June
May 07, 2010, at 05:38 AM by 131.217.6.9 -
Changed line 40 from:
-------Brett5 May
to:
14004.1580212.37541532dBvt10jBrett5,7 May
May 05, 2010, at 03:37 AM by 131.217.61.178 -
Added line 40:
-------Brett5 May
April 29, 2010, at 01:40 AM by 131.217.6.7 -
Changed line 39 from:
14004.1580212.37541828 dBfringe checkJay, Eric29 Apr
to:
14004.1580212.37541828 dBfringe checkJay, Eric29 Apr
April 29, 2010, at 01:40 AM by 131.217.6.7 -
Changed line 39 from:
14004.1580212.37541860 Db
to:
14004.1580212.37541828 dBfringe checkJay, Eric29 Apr
April 29, 2010, at 01:35 AM by 131.217.6.6 -
Changed line 39 from:
14004.1580212.375
to:
14004.1580212.37541860 Db
April 29, 2010, at 01:31 AM by 131.217.6.6 -
Added line 39:
14004.1580212.375
April 26, 2010, at 12:58 PM by 131.217.240.6 -
Changed lines 20-21 from:
  1. Move the phase shifter in. While its moving watch the IF1 tone in the passband. As it reduces, stop moving, increase the tone strength and start moving again. If the tone increases, move back. Once you have found the spot which is a minimum, stop. Then move the shifter all the way in. Make note of how many steps to move from the minimum to the “IN” limit. Now move the shifter out this many steps and stop. Change the level of the injected tone at this minimum point so that it just shows up. Now change to IF2 with the spectrum analyser. The level should be about 20 dB or more higher than IF1. It is worth letting the phase shifter travel through its full range as there may be multiple nulls, before tuning to a final value. This is quite a slow process as the phase shifter has a total of about 750 steps and moves slowly.
to:
  1. Since the injected tone is left-circularly polarized, select which channel you want to be the right-hand circular and adjust the phase shifter position to minimise the tone in it. To do this go through the following steps
    • Move the phase shifter in. While its moving watch the IF1 tone in the passband.
    • If it reduces to the point where it is hard to distinguish from the background noise stop moving, increase the tone strength and start moving again.
    • If the tone starts to increase in strength, move back. Once you have found the spot which is a minimum, stop.
    • Move the shifter all the way in. Make note of how many steps to move from the minimum to the “IN” limit.
    • Move the shifter out this many steps and stop. You may want to refine the minimum position by moving 10–20 steps either side of the minimum to see if you can find a better position. Keep note of the number of steps from the “IN” limit”.
    • Change the level of the injected tone at this minimum point so that it just shows up. Now change to IF2 with the spectrum analyser. The level should be about 20 dB or more higher than IF1.
    • It is worth letting the phase shifter travel through its full range as there may be multiple nulls, before tuning to a final value. This is quite a slow process as the phase shifter has a total of about 750 steps and moves slowly.
April 26, 2010, at 12:53 PM by 131.217.240.6 -
Changed lines 10-11 from:
  1. Make sure that for the Agi when converted back to 1152 in the frequency translator that you are not using an undesirable LO as listed on the yellow sheet attached to the frequency translator.
to:
  1. Make sure that for the Agilent setting used above that the SMY required for the frequency translator is not within any of the undesirable LO ranges as listed on the yellow sheet attached to the frequency translator (could someone specify them here please?)
Changed lines 13-20 from:
  1. Using the spectrum analyser look at the generated tone using a narrow span (1–2 MHz).
  2. On the main menu for the receiver PC select the expansion port and make sure that the quadrature hybrid is OUT.
  3. Toggle the switch between direct and crossed and adjust the attenuation in the IF strip so that the level of the tone on the spectrum analyser is the same when “direct” as “crossed”. It is important that these are as accurate as possible, so once you have it roughly right on 10 dB per division use 3 dB per division or 1 dB per division to get the tone level the same to better than 1 dB.
  1. Switch the quadrature hybrid in (now it shouldn’t make any difference whether the switch is set to “direct” or “crossed”.
  2. Move the phase shifter in. While its moving watch the IF1 tone in the passband. As it reduces, stop moving, increase the tone strength and start moving again. If the tone increases, move back. Once you have found the spot which is a minimum, stop. Then move the shifter all the way in. Make note of how many steps to move from the minimum to the “IN” limit. Now move the shifter out this many steps and stop. Change the level of the injected tone at this minimum point so that it just shows up. Now change to IF2 with the spectrum analyser. The level should be about 20 dB or more higher than IF1. It is worth letting the phase shifter travel through its full range as there may be multiple nulls, before tuning to a final value.
to:
  • Using the spectrum analyser look at the generated tone using a narrow span (1–2 MHz).
  • On the main menu for the receiver PC select the expansion port and make sure that the quadrature hybrid is OUT.
  • Toggle the switch between direct and crossed and adjust the attenuation in the IF strip so that the level of the tone on the spectrum analyser is the same when “direct” as “crossed”. It is important that these are as accurate as possible, so once you have it roughly right on 10 dB per division use 3 dB per division or 1 dB per division to get the tone level the same to better than 1 dB.
  • When the switch is “direct” the attenuation on the expansion port changes the level of the signal on A4 (marked RHC)
  1. Switch the quadrature hybrid in. Now it shouldn’t make any difference whether the switch is set to “direct” or “crossed” (which presumably means that the cross-over switch is prior to the input to the Hybrid).
  2. Move the phase shifter in. While its moving watch the IF1 tone in the passband. As it reduces, stop moving, increase the tone strength and start moving again. If the tone increases, move back. Once you have found the spot which is a minimum, stop. Then move the shifter all the way in. Make note of how many steps to move from the minimum to the “IN” limit. Now move the shifter out this many steps and stop. Change the level of the injected tone at this minimum point so that it just shows up. Now change to IF2 with the spectrum analyser. The level should be about 20 dB or more higher than IF1. It is worth letting the phase shifter travel through its full range as there may be multiple nulls, before tuning to a final value. This is quite a slow process as the phase shifter has a total of about 750 steps and moves slowly.
Changed lines 24-31 from:

Simon - 15 November 2004, Ammended by Brett, Nov 17 2006.

to:

Last editted April 2010.

Settings for various L-band circular polarization experiments

NOTE: The phase shifter steps should be given from the inner limit.

Frequency (MHz)Agilent (GHz)SMY (MHz)Balancing Attenuation (dB)Phase shifter stepsTone isolationExperimentPersonDate
14004.158029.2541818 dBvt14gJohn, Simon26 Apr 2010
April 26, 2010, at 04:48 AM by 131.217.62.41 -
Changed lines 4-13 from:
  1. The tone port injects LHC into the L band feed
  2. Tune sig gen to 1/2 of central sky frequency
  3. Select L band receiver and start with agilent at 4.1 GHz
  4. Choose Agilent frequency for reasonably flat pass band on both linears over the band width of observation
  5. Make sure that when converted back to 1152 in the frequency translator that you are not using an undesirable LO as listed on the yellow sheet attached to the frequency translator.
to:
  1. The tone port (A2 in rack 3) injects left-hand circular into the L band feed. Tune sig gen (the SML) to 1/2 of central sky frequency (e.g. for a 1400 MHz centre frequency this would be 700 MHz).
  2. Select the L band receiver and start with agilent set to the standard frequency of 4.1 GHz.
  3. Choose Agilent frequency for reasonably flat pass band on both linears over the bandwidth being observed.
  4. Make sure that for the Agi when converted back to 1152 in the frequency translator that you are not using an undesirable LO as listed on the yellow sheet attached to the frequency translator.
Changed lines 23-25 from:

Simon - 15 November 2004, Ammended by Brett, Nov 17 2006.

to:

Simon - 15 November 2004, Ammended by Brett, Nov 17 2006.

April 25, 2010, at 01:02 AM by 131.217.240.21 -
Changed lines 1-32 from:

How to setup circular polarization with the L-band system :


1) The tone port injects LHC into the L band feed

2a) Tune sig gen to 1/2 of central sky frequency

2b) Select L band receiver and start with agilent at 4.1 GHz

2c) Choose Agilent frequency for reasonably flat pass band on both linears over the band width of observation

2d) Make sure that when converted back to 1152 in the frequency translator that you are not using an undesirable LO as listed on the yellow sheet attached to the frequency translator.

3) Balance the inputs to the quadrature hybrid :

  a) Using the spectrum analyser look at the generated tone using a
     narrow span (1–2 MHz).
  b) On the main menu for the receiver PC select the expansion port and
     make sure that the quadrature hybrid is OUT.
  c) Toggle the switch between direct and crossed and adjust the
     attenuation in the IF strip so that the level of the tone on the
     spectrum analyser is the same when “direct” as “crossed”.  It is
     important that these are as accurate as possible, so once you
     have it roughly right on 10 dB per division use 3 dB per
     division or 1 dB per division to get the tone level the same to
     better than 1 dB.

4) Switch the quadrature hybrid in (now it shouldn’t make any difference

  whether the switch is set to “direct” or “crossed”.

5) Move the phase shifter in. While its moving watch the IF1 tone in the passband. As it reduces, stop moving, increase the tone strength and start moving again. If the tone increases, move back. Once you have found the spot which is a minimum, stop. Then move the shifter all the way in. Make note of how many steps to move from the minimum to the “IN” limit. Now move the shifter out this many steps and stop. Change the level of the injected tone at this minimum point so that it just shows up. Now change to IF2 with the spectrum analyser. The level should be about 20 dB or more higher than IF1. It is worth letting the phase shifter travel through its full range as there may be multiple nulls, before tuning to a final value.

6) Now try injecting into a broadband radiator at the vertex. You should have similar size tones in IF1 and IF2.

to:

How to setup circular polarization with the L-band system :


  1. The tone port injects LHC into the L band feed
  2. Tune sig gen to 1/2 of central sky frequency
  3. Select L band receiver and start with agilent at 4.1 GHz
  4. Choose Agilent frequency for reasonably flat pass band on both linears over the band width of observation
  5. Make sure that when converted back to 1152 in the frequency translator that you are not using an undesirable LO as listed on the yellow sheet attached to the frequency translator.
  6. Balance the inputs to the quadrature hybrid :
    1. Using the spectrum analyser look at the generated tone using a narrow span (1–2 MHz).
    2. On the main menu for the receiver PC select the expansion port and make sure that the quadrature hybrid is OUT.
    3. Toggle the switch between direct and crossed and adjust the attenuation in the IF strip so that the level of the tone on the spectrum analyser is the same when “direct” as “crossed”. It is important that these are as accurate as possible, so once you have it roughly right on 10 dB per division use 3 dB per division or 1 dB per division to get the tone level the same to better than 1 dB.
  7. Switch the quadrature hybrid in (now it shouldn’t make any difference whether the switch is set to “direct” or “crossed”.
  8. Move the phase shifter in. While its moving watch the IF1 tone in the passband. As it reduces, stop moving, increase the tone strength and start moving again. If the tone increases, move back. Once you have found the spot which is a minimum, stop. Then move the shifter all the way in. Make note of how many steps to move from the minimum to the “IN” limit. Now move the shifter out this many steps and stop. Change the level of the injected tone at this minimum point so that it just shows up. Now change to IF2 with the spectrum analyser. The level should be about 20 dB or more higher than IF1. It is worth letting the phase shifter travel through its full range as there may be multiple nulls, before tuning to a final value.
  9. Now try injecting into a broadband radiator at the vertex. You should have similar size tones in IF1 and IF2.
April 25, 2010, at 12:57 AM by 131.217.240.21 -
Added lines 30-35:

6) Now try injecting into a broadband radiator at the vertex. You should have similar size tones in IF1 and IF2.

Simon - 15 November 2004, Ammended by Brett, Nov 17 2006.

April 25, 2010, at 12:57 AM by 131.217.240.21 -
Added lines 1-29:

How to setup circular polarization with the L-band system :


1) The tone port injects LHC into the L band feed

2a) Tune sig gen to 1/2 of central sky frequency

2b) Select L band receiver and start with agilent at 4.1 GHz

2c) Choose Agilent frequency for reasonably flat pass band on both linears over the band width of observation

2d) Make sure that when converted back to 1152 in the frequency translator that you are not using an undesirable LO as listed on the yellow sheet attached to the frequency translator.

3) Balance the inputs to the quadrature hybrid :

  a) Using the spectrum analyser look at the generated tone using a
     narrow span (1–2 MHz).
  b) On the main menu for the receiver PC select the expansion port and
     make sure that the quadrature hybrid is OUT.
  c) Toggle the switch between direct and crossed and adjust the
     attenuation in the IF strip so that the level of the tone on the
     spectrum analyser is the same when “direct” as “crossed”.  It is
     important that these are as accurate as possible, so once you
     have it roughly right on 10 dB per division use 3 dB per
     division or 1 dB per division to get the tone level the same to
     better than 1 dB.

4) Switch the quadrature hybrid in (now it shouldn’t make any difference

  whether the switch is set to “direct” or “crossed”.

5) Move the phase shifter in. While its moving watch the IF1 tone in the passband. As it reduces, stop moving, increase the tone strength and start moving again. If the tone increases, move back. Once you have found the spot which is a minimum, stop. Then move the shifter all the way in. Make note of how many steps to move from the minimum to the “IN” limit. Now move the shifter out this many steps and stop. Change the level of the injected tone at this minimum point so that it just shows up. Now change to IF2 with the spectrum analyser. The level should be about 20 dB or more higher than IF1. It is worth letting the phase shifter travel through its full range as there may be multiple nulls, before tuning to a final value.

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Page last modified on February 26, 2013, at 04:58 AM