Intro

    The 430 and sband radar was used to range to various satellites

23aug16: 430
17nov16: 430
11dec16: 430
10-13feb17: 430
08mar17:  sband

23aug16:

Link to data files:
link to plasma line movie

    The table below shows the satellites that were looked at and their predicted positions. sat # 1..3 were what was looked for. 3a.. 4 were found while we left the telescope pointing in sat 3 direction for about 1 hour.

Setup:

• 430 radar:
• 10ms ipp, 440 usec rf pulse, 2 usec baud, clp random code
• The 10ms ipps were continuous in time, but they were not synchronized to the 1 second tick (tied to the hydrogen maser). So absolute time of day was determined by a less accurate method. We should figure a way to synchronize the transmitter ipp pulses to the hardware tick.
  
• Datataking:
• 500 kHz bw,  2 usec sampling.
• 10 sec scans (1000 10ms ipps)
• We should have run just one long scan.
• Starting a new scan every 10 seconds caused a 50ms break in the recorded data (but the tx continued to run on the 10ms ipp cycle.
• radar interface file format sent to disc.
• Ended up with 6 output files. The 1st 3 had satellite data:
  

• File Ind	name	Last Write Date (AST)	SAT found
  0	s3106_20160823.000	10:20:06	SAT 1
  1	s3106_20160823.001	10:44:29	SAT 2
  2	s3106_20160823.002	11:08:53	SAT 3

  
  

Processing:

• Idl scripts were written to process the data.
• Select the file for a satellite
• scan the file for scan start times
• compute location in file for expected transit
• read 6000 records about this position.
• there were 2 ipps/rec so we had 12000 ipps. at .01 secs each , this was 2 minutes of data.
• plot the voltages for an ipp close to transit. find the range bins for the undecoded data
• compute the power over these range bins for each of the 12000 ipps (no decoding)
• Plot the total power and fit a gaussian to find the ipp of the peak
• this did not work on the sat 3 (because of saturation).
• for 1 minute (6000 ipps) about the peak ipp, decode and compute spectra for 51 heights about the expected range.
• For the gps satellites, the round trip time was on the order of 134ms. For decoding the tx samples were 13 ipps before the height data.
  
• there were 220 tx samples, so a 256 point fft was used.
• this gave 500/256=2kHz resolution. At 430 MHz this is 1.4 km/sec. for a satellite around 750km its orbital velocity is about 7km/sec.
• We ended up with an spectral density array: spcBufAr[256/freq,51/heights,6000/ipps]

Sat 1: GPS_BIIF-2_37753 (prn 01)

• Found in file Ind 0
• the plots show the echos from sat1 (.ps) (.pdf)
• Page 1: Undecoded data
• top: voltage vs range number for ipp with max echo
• each range bin is 2usec (.3km). range 0 started at 600 usecs (90km).
• the echo appeared 13 ipps after the tx ipp.
  
• the echo started in range bin 2018.
• middle: power  in ipp vs range number (db scale)
• bottom: power in echo vs ipp number
• the power in range bins 2012 thru 2237 was averaged for each ipp and then plotted.
• A gaussian was fit to the result (red) to find the ipp of transit.
• Page 2: Decoded data, spectra computed
• Top: 5 spectra around echo height 2018 from ipp with max echo
• Green is the range 2018 of the peak. It is about 40 db above Tsys. The other ranges don't decode, but you can see the clutter from the echo spread across the band.
• 2nd: linear blowup showing the baseline of the height 2018, and the other ranges that didn't decode.
• 3rd: additional blowup in freq. The echo is in the DC channel.
• bottom: Plot the DC channel for height 2018 for all ipps. This shows the beam pattern.
• The dips are where new scans started. there is an each 50ms, so the echo does not end up in the same channel for 1 ipp.
  

Sat 2: GPS_BII-04_20302

Not seen

Sat 3: CryoSat2_3650

• This is a leo satellite (735 km). It is found in file 2
• the plots show the echos from sat3 (.ps) (.pdf)
• Page 1: Undecoded data
• top: voltage vs range number for ipp with max echo
• each range bin is 2usec (.3km). range 0 started at 600 usecs (90km).
• The returned in the same ipp as the transmit pulse.
  
• the echo started in range bin 2141
• The a/d is 12 bits. The signal saturated (2047/-2048).
  
• 2nd: power  in ipp vs range number (db scale)
• 3rd power in echo vs ipp number
• the power in range bins 2141 thru 2364 was averaged for each ipp and then plotted.
• bottom: blowup of frame 3 (power  vs ipp)
• The main beam and even part of the first sidelobe has clipped.
• You can see a number of sidelobes.
• There is another echo 5200 ipps (52 seconds) before this echo.
  
• Page 2: Decoded data, spectra computed
• Top: 5 spectra around echo height 2018 from ipp with max echo
• Green is the range 2141 of the peak. It is about 45 db above Tsys. The other ranges don't decode, but you can see the clutter from the echo spread across the band.
• 2nd: linear blowup showing the baseline of the height 2018, and the other ranges that didn't decode.
• bottom: additional blowup in freq. The echo is in the DC channel.

Sat 3A: sidelobe of sat 3.

• sat 3a appeared 1 min 27 secs before sat 3. it was found at a range of 856.2 km (sat 3 was at  732.3). It is a sidelobe from the ground screen from sat 3..
  
• the plots show the echos from sat3a (.ps) (.pdf)
• Page 1: Undecoded data
• top: voltage vs range number for ipp with max echo
• each range bin is 2usec (.3km). range 0 started at 600 usecs (90km).
• The returned in the same ipp as the transmit pulse.
  
• the echo started in range bin 2553/2554
  
• 2nd: power  in ipp vs range number (db scale)
• 3rd power in echo vs ipp number
• the power in range bins 2553 through 2777  was averaged for each ipp and then plotted.
• it is much weaker that sat 1 or 3.
  
• bottom: blowup of frame 3 (power  vs ipp)
• There is no main lobe. The satellite is passing through sidelobes.
  
• Page 2: Decoded data, spectra computed
• Top: 5 spectra around echo height 2554  from ipp with max echo
• Green is the range 2554 of the peak.
• 2nd-4th: a single frequency channel vs ippnum was plotted for 5 heights:
• 2nd: chan 0: the peak height is range 2554. Range 2553 comes later (since it is closer)
• 3rd: chan 2kHz: range 2554 is strongest
• bottom: chan 4kHz: not much power seen
• The strongest echo was range 2554 in freq chan was 2kHz. The object has a radial component and it is moving toward us.
• If it is the same object we can compute the angle it was seen from the radar..
• r1=732.3 km .. range to satellite at transit
  
• r2=856.2 km .. range to object 87 secs earlier.
  
• rE=6376.518 km.. earth radius to ao focus (jpl ephem).
  
• angle r1 pointing direction to r2 direction from center of earth:
• th=acos((r1+re)^2 + re^2 + r2^2)/(2*(r1+re)*re)) = 3.776 deg
  
• angle r1 pointing direction to r2 direction  from telescope:
• to 2nd range from telescope pointing direction: acos(r1/r2)=31.2 deg
• This is a sidelobe from the ground screen:
• The edge of the dish is at za=35
• the angleof the  edge of the dish from vertical  is 55 degrees
• the ground screen is tilted 25  degrees back  from the vertical
• So it point 55=25= 30 deg before the pointing direction (when looking due east)
• We measured an offset of 31.2 degrees. so it's the ground screen 

Sat 3b: possible sidelobe of 3?

• sat 3b appeared 52  secs before sat 3. it was found at a range of 747.3 km (sat 3 was at  732.3).
  
• the plots show the echos from sat3b (.ps) (.pdf)
• Page 1: Undecoded data
• top: voltage vs range number for ipp with max echo
• each range bin is 2usec (.3km). range 0 started at 600 usecs (90km).
• The returned echo is from the same ipp as the transmit pulse.
  
• the echo started in range bin 2191
  
• 2nd: power  in ipp vs range number (db scale)
• 3rd power in echo vs ipp number
• the power in range bins 2191 through 2411  was averaged for each ipp and then plotted.
• it is much weaker that sat 1 or 3.
  
• bottom: blowup of frame 3 (power  vs ipp)
• kind of looks like a main beam with sidelobes, but the sat did not pass through the center of the main beam.
  
• Page 2: Decoded data, spectra computed
• Top: 5 spectra around echo height 2191 from ipp with max echo
• Green is the range 2191 of the peak.
• 2nd-4th: a single frequency channel vs ippnum was plotted for 5 heights:
• 2nd: chan 0: the peak height is range 2191. the other ranges have little power
• 3rd: chan 2kHz: not much power.
  
• bottom: chan 4kHz: not much power seen
• If it is the same object we can compute the angle it was seen from the radar..
• r1=732.3 km .. range to satellite at transit
  
• r2=747,2 km .. range to object 87 secs earlier.
  
• rE=6376.518 km.. earth radius to ao focus (jpl ephem).
  
• angle r1 pointing direction to r2 direction from center of earth:
• th=acos((r1+re)^2 + re^2 + r2^2)/(2*(r1+re)*re)) =  1.267 deg
  
• angle r1 pointing direction to r2 direction  from telescope:
• to 2nd range from telescope pointing direction: acos(r1/r2)=11.5  deg
• not sure what could be creating this sidelobe

Sat4: unknown sat

• sat 4 went through the beam  at 15:00:17.52.   This is 8 minutes after sat 3.
  
• the plots show the echos from sat4 (.ps) (.pdf)
• Page 1: Undecoded data
• top: voltage vs range number for ipp with max echo
• each range bin is 2usec (.3km). range 0 started at 600 usecs (90km).
• The returned echo is from the same ipp as the transmit pulse.
  
• the echo started in range bin 2493
• The real component of the voltage shows a modulation during the rf pulse. this means that the object has a radial velocity component.
  
• 2nd: power  in ipp vs range number (db scale)
• 3rd power in echo vs ipp number
• the power in range bins 2494 through 2712  was averaged for each ipp and then plotted.
• The main beam is about 19db above the 1st sidelobe. Looks like the satellite went through close to the center of the main beam.
  
• Page 2: Decoded data, spectra computed
• Top: 5 spectra around echo height 2493 from ipp with max echo
• Green is the range 2493 of the peak. The other colors are adjacent ranges.
• 2nd: blowup in amplitude
• bottom: blowup in frequency.
• the * mark 1.9 kHz channels.
• the echo is more than 1 channel wide --> object has a radial velocity.
• Page 3: plot freq chan power vs ipp for multiple channels
• each frame is a different frequency channel from the spectra -2kHz to +4kHz in 2 kHz steps
• within  a frame the power from the channel is plotted vs ipp #.
  
• The colors are plots for 5 ranges about the peak range.
• The power in range 2493 is the same for 0KHz and 1.95 KHz. So we measure a radial velocity of about .975 KHz
• A doppler shift for .975 KHz is: 680 meters /second
• What is it?
• the range at za=9.395 deg was 837.9 km. At transit this would be cos(9.395)*837.9=826.7 km altitude
• At 826 km altitude, a satellite should have a tangential velocity of around 7.4 km/sec
• looking from 9.4 deg za would give a radial velocity of: sin(9.4)*7.4=1.2 km/sec
• We measure a doppler shift of .68 km/sec.  half of the expected velocity.. but..
• we are moving at about 40000km/day or .5 km/sec because of the earth rotation.
  
• This happens to be in the same direction as the satellite, so the sat actual velocity would be about 1.1 km/sec.. close to the expected value.
  
• Could this be a sidelobe of sat 3? Probably not since we have such a well defined main beam shape.
  

Summary

    The table below has the measured results

161117: 430 sat passes

• 430 ch used.
  
• got ephemeris from horizons and used it to track sat while transmitting.
  
• used about 300 KWatts..
• clp, 10ms ipp, 440 usec rf pulse, 2usec baud.
• used sbraw 1 .. 9999999 bufs, 4000 2usec samples, clp
  
• round trip time around 135 ms.
  
• usrp: 25 MHz bw.
  
• ri: 500 kHz bw.. sample 600 to 8600 usecs,
• In the previous runs, the receive window had 3000 samples (at 2usec sampling):
• For 17nov16 i  increased the receive window to 4000 (2 usec samples).
  

• There were two files generated during the run : .000 and .001..
• I concatenated them into 1 file (xxx_all.000)  to make it easier to process (records can get split between the files).
• The xxall.000 file is about 3.2 gbytes.
  

161211 (AST): 430 sat passes

    The experiment was scheduled for 20:00 to 23:00 (ast) 161211. We looked at 4 satellites:

Setup:

• Downloaded ephemerides from jpl horizons (apparent ra,dec)
• We tracked tdrs_3, navstart_68, beidou_m3
  
• For lageos we positioned the telescope to:
• az=58.711, za=15.8140  
• and then let the satellite pass through the beam.
• platform was positioned to 1256.22 and then the tiedown tracking was turned off.
• platform was with about .02 ft for entire run..
• tx:
• Used ipp of 11.1 milliseconds for all 4 satellites.
• This made sure the echo did not come during the tx pulse..
• coded long pulse, 440 usec rf pulse, 2 usec baud.
  
• rcv window: 600 to 8600 usecs
• cal 9000 to 9800 usecs (400 samples.. 200 cal on, 200 cal off).
  
• ri:
• crr1 -> 500 kHz base band filters -> ri.
• requested 999999 records.. so there is not ipp gaps because of program switching.
• Note: ri recording didn't start till 21:42.. fifo_data program on aeron had to be restarted (/etc/rc.local)
• usrp:
• crr2 -> combiner (with tx samples) -> mixer (30->260 hiside lo) -> usrp
• started around 20:45
• datataking:
• sbraw 1
• tx Power..
  
• 320-> 350 Kw for navstar, lageos, beidou
• 1.1MW for tdrs_3
  

Timeline (ast times..)

• 20:45 tracking tdrs_3
• 1 MW transmitting
  
• usrp data was recording..
  
• ri data recording didn't start till 21:42
• didn't see anything on the oscilloscope. telescope at za=18deg21
  
• 21:00 setup square law detector with 1ms time constant, 500 kHz bw  to see if we could see something on scope.
• This was independent of the regular data acquisition.
• nothing obvious seen
  
• 21:02 pulled out code for a minute or two
• switched square law filter 500 KHz -> 5kHz
  
• still didn't see much on oscilloscope... maybe a small bump at satellite range.
  
• 21:09:06  moved off in za by .5 degrees then back on by 21:10
• you can see this move on the za vs hour plots (see below).
  
• saw the small bump in sqlaw signal go and then come back.. saw we were hitting the satellite.
• 21:15  can now see the echo on the oscilloscope voltage trace (that goes to ri recording..). za about 14deg.
• 21:42  finally got the ri recording going.. the data above was only recorded on the usrp.
• 22:00  start moving to navstar 68 (gps satellite)
• sat at za=19.9 till it came into the beam
• 430 tx power reduced to 340KW
  
• 22:03 satellite came into the beam.
• 22:11 added 3db to ri signal path (so the echo wouldn't saturate the a/d).
• 22:15 usrp took out 9db in tx sample path.. reducing the tx power caused the tx samples to be same size as receive data (we want the tx samples to stick up more so we can more easily find the start of each ipp).
• 22:21 start moving to tdrs_3
• put 10db in ri signal path (so we don't saturate).
  
• using gps satellite levels and ratio of range: (20k/6k)^4=123. (in power). sqrt for voltage.. so factor of 11 ..
• 22:26 sitting waiting for leo to pass through the beam
• 22:37:xx   on oscilloscope (voltages) saw satellite pass through the beam.
• Not as strong as gps satellite had been.. the sizes must be different.
• 22:42: start moving to beidou_m3
• 22:45   tracking beidou_m3.. strong echo on the oscilloscope.
• 23:00   done.
  

Data:

• There were 4 files generated during the run : .000 thru .003.. (the 1st 3 2.2 GB. the last 1.4 GB)
  
• I concatenated them into 1 file (s3106_20161211_all.000)  to make it easier to process (records can get split between the files).
• The s3106_20161211_all.000 is 7.4 GB/
  

Plots:

• Plotting the ephemeris file info for each satellite (.ps) (.pdf)
  
• Plotting the measured az,za for the run (.ps) (.pdf)
• 
  

170210-13 430 sat passed

Setup

• Downloaded ephemerides from jpl horizons (apparent ra,dec)
• platform was positioned to 1256.22 and then the tiedown tracking was turned off.
• tx:
• ipp, data window, power depended on satellite (see timeline below)
• coded long pulse, 440 usec rf pulse, 2 usec baud.
  
• tx window, data window, cal window (200 samples cal on , 200 cal off  800 usec total)
• see timeline for levels for each satellite.
  
• ri:
• crr1 -> 500 kHz base band filters -> ri.
• requested 999999 records.. so there is not ipp gaps because of program switching.
• gio on
• See timeline for levels for each satellite.
  
• usrp:
• crr2 -> 260Amp -> combiner (with tx samples) -> mixer (30->260 hiside lo) -> usrp
• datataking:
• trkinit ch, be sure dome at stow.
• make sure platform at ref position then stop tiedown tracking.
  
• sbraw 1

• use sbraw 1
• need to change ipp, rcv windows for different objects. see table above
  

Timeline:

Navstar - 48 (gps svn 44)

• 10feb17 00:34 -> 01:00
• pointing:
• pnt ephm ld 2 /share/obs4/usr/s3106/navstar_48_170210.ao
  pnt tr 1 2 -cR
• running at
•  360 KW.
• ri:
• ipp 9500 usecs (echo 5.5 -> 3.5 ms)
• datawin: 600 usecs -> 8200 usecs (90-1230km)
• calWin   :8600 ->9400 usecs (200smp on, 200smp off at 2usec smpl)
  
• usrp: standard setup. 25 Mhz bw.
• 00:32 start taking data
• ri data: /share/aeron01
• s3106_20170209.000  (till 00:47)
• s3106_20170209.001  (till 01:00). this has the two pointing crosses
• usrp data:
• in directory:/data0/ch/2017-02-10T04-31-12   (2017-02-10T03-15-31 just test files)
  
• 00:47  started new ri file.. 2nd file contains 2 pointing crosses:
• crosses:
• each strip is 1 degree (great circle) center of the tracking position.
• Each strip duration is 1 minutes (at a constant rate along the strip).
  
• az strip (neg to positive az .. -.5 deg to + .5 deg).
  
• za strip (net to position za  .. -.5 deg to +.5deg)
• cross 1: (all times ast .. utc-4)
  
• az: start 00:48:15
• za: start 00:49:40
• cross 2:
• az start  00:51:06
• za start  00:52:31
• Cross notes:
• need to correct for the round trip time when computing the pointing offset.
• The telescope moved between tx and rx times (because of the round trip time).
  
• 00:53  move back to track the object till 01:00
• 01:00   stopped observing.

EGS

• 10feb17 15:39:32.317
• leo. sitting at az:231.510, za: 8.102 (max elevation from robert's page).
• platform height 1256.22. then stopped tiedowns.
  
• 15:30 start datataking
• power levels 370 KW
• ri levels 200 mv pk to pk on scope with envelope mode
• usrp noise: pk to pk +/- 400 counts
• ri setup:
• ipp 13000 usecs (echo 9933 usec)
  
• datawin: 3000 usecs -> 12000 usecs (450 - 1800 km)
• calWin   :12100 -> 12900 (200smp on, 200smp off at 2usec smpl)

• 15:39.xx   saw echo on scope. Looks like it might have saturated to +/- 2.5 volts of the ri.

TDRS3

• continues from egs run. datataking was left running. ri setup the same.
  
• 15:45    start to move to tdrs3 position
• pnt ephm ld 2 /share/obs4/usr/s3106/tdrs_3_170210.ao
• pnt tr 1 2 -cR
• tx about 1.4 MW
• 15:52:xx  saw it come into the beam (20deg za)
• 15:52:xx
  
•  after it came into the beam, i added 3db of attenuation to the ri signal.
• also added 5db attenuation to the usrp transmitter samples (since now at 1.4MW).
• 16:29  tx power 1.287MW.. forward,reverse power varies some as we track the ch in za (standing waves in waveguide)
  
• signal getting stronger as we come down in za
• 18:06  tx power 1.46 MW
• 18:07  start doing crosses. this is about 247 MB into file .007
• +/-  .5 deg per strip. each strip 1 minute
• cross1:
• azstart: 18:10:07
• zastart: 18:11:31
• cross2:
• azstart: 18:12:56
• zastart: 18:14:21
• cross3:
• azstart: 18:15:45
• zastart: 18:17:10
• 18:18:10   go back to tracking tdrs-3
• 18:25    stopped datatking
• with tiedown tracking off, platform had risen 3.2 cm (no problem  for lambda=70cm)
  
• datafiles:
• ri: s3106_20170210.000 to .007
• usrp: /data0/ch/2017-02-10T19-29-17 to 2017-02-10T21-29-17 (3 hour directories).

Lageos-1

• ri setup:
• ipp 11000 usecs, echo at 7693.
• datawin: 2000 usecs -> 10000 usecs (300-1500 km)
• calWin   :10100 to 10900 (200smp on, 200smp off at 2usec smpl)
• leo. sitting at az=310.889, za=18.4130
• should have been at az=301.889, za=18.4130.. i permuted 301 to 310.. so we saw no echo..
• did not see the echo on the oscilloscope.
  

Data:

    Links to data files: (times  are AST .. UTC-4)

• 20170210:
• navstar-48  tracking (.000)
• navstar-48   crosses (.001)
• 20170210: 
  
• 15:30  to 18:07 (files 000 to 006) 14Gb)
  
• 18:07 to 18:24 (crosses while tracking tdrs-3) (2Gb)
  

Plots:

• Plotting the ephemeris file info for each satellite
  
• 170210  navstar-48 (svn 44) (.ps) (.pdf)
• 170210  egs (.ps) (.pdf)
• 170210  tdrs-3 (.ps) (.pdf)
• 170213  lageos-1 (.ps) (.pdf)
  

170308: satellite ranging with sband tx.

    On 08mar17 the sband transmitter was used in bistatic mode (with gbt) to range various satillites.
The satellites of interest were:

    The setups attempted were:

• cw mode no doppler
• phase encoding with .05 usec baud

Trouble with the sband software:

• The sband software always starts the tx and rx cycles on a hardware 1 second tick.
  
• The starting phase of the pncode generator is set so that:
• the code phase at the rx tick after the rtt  has the correct phase.
• It also computes the fractional baud at the receive tick
  
• The computation is needed for mono and bistatic runs.
• part of the checking in the module ensures that  the echo has not completely passed before the receive starts (this is only a problem for mono static runs). 
• The bug is that the part of the code doing the checking does not know that it is a bistatic or monostatic run... so it always applies the check.
  
• Our problem was that the .1 second round trip time was generating an error saying that the receive cycle was starting after all of the echo was passed (only true if it had been monostatic) (more info)
  
• a work around was found during the run, but it's implementation caused other problems (pointing).
• we switched to use the telescope program ephemeris tracking, but when restarting the sband software, it reset the pointing back to the sband software...
  

What we ended up doing:

• data was taken with the jpl backend at gbt.
  

The plots show the tracking and tx power for the run (.ps) (.pdf):

• page 1: az,za, ra,dec for entire run
• top: feed azimuth (srcaz-180) for the day
• the dashed lines show the times when we were supposed to be tracking the different satellites.
• 2nd frame: za for the run
• 3rd frame: apparent ra the telescope was pointing at
• The black line is the ra the telescope pointed  at.
• the solid colored lines show the ra for the various satellites from the ephemeris  files.
• bottom frame: apparent dec
• black line: telescope dec
• colored lines: satellite decs from ephemeris fiels
• page 2-4 pointing error, transmitted power
• page 2: lageos-2 pointing error and tx power.
  
• We sat at an az,za for lageos -2.
  
• It went through the beam at 21:39:50 utc
• the transmitter was at 486 KWatts
• We were transmitting CW (no coding).
• GBT may not have been tracking lageos-2 at 21:39:50 (on the phone i was told they would get there a little late).
  
• page 3: navstar 18 pointing and transmitter power.
• the transmitter was running cw during navstar 18.
  
• The sband pointing software updates the ra,dec and rates once a minute from the ephemeris file.
  
• The problems we had with the short round trip times caused the rates to be set to 0.
  
• the sawtooth pattern is the 1 minute ra,dec updates with rates=0.
• the dashed green lines show when the minimum error occurred each minute.
• the dashed red lines show the location of the 3rd and 4th sidelobes of the sbn horn (about 125 asecs at za=18 degrees).
• joseph's cw echo from navstar 18 occurred during these minima. He was seeing the echo in the 3rd and 4th sidelobes of the telescope.
  
• page 4: sbs pointing error and transmitter power.
• This is a blowup showing when we were tracking sbs-1: 22:44:31 to 22:53:06 UTC
  
• the transmitter was in CW during this time.
• there was no transmitter power between 22:48:28 to 22:51:09 (we had a tx trip).
• We finally got the coding working  at the end of sbs's run.. but i hadn't noticed that during the debugging i had disabled the tracking. So there was no ranging results.'
• joseph's cw results are during this tracking period. He also saw the tx dropout.
  

GBT JPL backend results:

    Joseph sent an email and some plots showing the results from the jpl backend at gbt for lageos-2,navstar 18 and sbs-1

Joseph's plots from  jpl backend

• navstar 18 cw plots (.png)
  
• sbs-1 cw plots (.png)

Summary

• We were transmitting CW (486KW) when LAGEOS-2 went through the beam at 21:39:50 AST.
• gbt may not have been tracking lageos-2 at the time.
• NAVSTAR 18 was seen in the 3 and 4th sidelobe during a cw transmission
  
• SBS-1  was tracked 22:44:31 till 22:53:06
• the transmitter was in CW mode at 560KW
• there was transmitter dropout 22:48:28 thru 22:51:09
• The spectra were seen in the jpl backend at gbt.
• The fixes for the sband software to track close by objects needs to be tested.
  

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