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observing:ragrav [2016/10/03 01:09] Warren Hankey |
observing:ragrav [2017/04/14 07:44] Elizabeth Iles |
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On the 12m, we use the Field System to record the data to the Mark5 and the HMI antenna interface (on the timeyg VNC server) to control the antenna. The RadioAsdtron group provide a file for HMI as well as a VEX file. | On the 12m, we use the Field System to record the data to the Mark5 and the HMI antenna interface (on the timeyg VNC server) to control the antenna. The RadioAsdtron group provide a file for HMI as well as a VEX file. | ||
+ | |||
+ | ==== Signal path modifications ==== | ||
+ | |||
+ | The receiver cross-over switches have been re-wired to allow additional attenuation in the signal path and/or a reduced supply voltage to the X-band RCP LNA. This is to reduce the signal strength entering the DBBC and hopefully improve phase stability. The S-band cross-over with enables a variable power supply for the LNA when crossed and the X-band cross-over switch will put a (manually configurable) variable attenuator into the X-band RCP signal path after the LNA. The Field System commands to set the 4 possible modes are: | ||
+ | <code> | ||
+ | "x-band rcp lna 20V, atten in | ||
+ | rfpic=cross,direct,* | ||
+ | " | ||
+ | "x-band rcp lna 20V, no atten | ||
+ | rfpic=direct,direct,* | ||
+ | " | ||
+ | "x-band rcp lna variable voltage, atten in | ||
+ | rfpic=cross,cross,* | ||
+ | " | ||
+ | "x-band rcp lna variable voltage, no atten | ||
+ | rfpic=direct,cross,* | ||
+ | </code> | ||
+ | |||
===== Processing the antenna pointing files ===== | ===== Processing the antenna pointing files ===== | ||
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"Take out attenuation in X-band, IF rack | "Take out attenuation in X-band, IF rack | ||
ifpic=*,*,15,15,0,0</code> | ifpic=*,*,15,15,0,0</code> | ||
- | - Modify the DBBC frequencies to include LCP channels: <code>define dbbc014 16273135148x | + | - Modify the DBBC frequencies to include LCP channels, **note the 16273135148x number will be 0000000000x at the start** and is written later (I imagine the time it was executed?) : <code>define dbbc014 16273135148x |
bbc01=798.75,a,4.00 | bbc01=798.75,a,4.00 | ||
bbc02=798.50,a,4.00 | bbc02=798.50,a,4.00 | ||
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lo=lob,7600.00,usb,rcp,off | lo=lob,7600.00,usb,rcp,off | ||
enddef</code> | enddef</code> | ||
- | - Lastly, add the checkmk5 procedure: <code>define checkmk5 16273141501x | + | - Lastly, add the checkmk5 procedure: <code>define checkmk5 16273141501x |
scan_check | scan_check | ||
!+1s | !+1s | ||
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Watch out for the spacecraft signal in the spectrum analyser, check both polarisations using ''ifpic=xr'' (RCP), ''ifpic=xl'' (LCP). Make notes in the log on signal strength etc. | Watch out for the spacecraft signal in the spectrum analyser, check both polarisations using ''ifpic=xr'' (RCP), ''ifpic=xl'' (LCP). Make notes in the log on signal strength etc. | ||
+ | |||
+ | The attenuator values can be changed using the "rfpic=<xband>,<sband>", replace xband and sband with either "direct" (no attentuation) or "cross" for variable attenuation (Check with yg staff regarding the voltage of the variable attenuation). (Arwin) | ||
===== After the observations ===== | ===== After the observations ===== | ||
- In the PCFS, stop the power monitoring with a <code>iread@</code> | - In the PCFS, stop the power monitoring with a <code>iread@</code> |