I think I fixed the DC error issue

1. I added the leap second (leapsecond ?) entry for 2016/12/31, 23:60:00 UTC to daqdrc

[OLD]
set gps_leaps = 820108813 914803214 1119744016;
[NEW]
set gps_leaps = 820108813 914803214 1119744016 1167264018;

2. Restarted FB and all realtime models

Now I don't see any RED light.

I'm afraid that the bidirectional coupler, designed to be 50ohm in/out, disturbs the resonant circuit designed for the EOM which is almost purely capacitive.

One possible way could be to measure the transfer function using the active FET probe from the triple resonant input to the output with the EOM attached.

Another way: How about to measure the reflection before the resonant circuit? Then, of course, there is the triple resonant interface circuit between the power combiner and the EOM. This case, we will see how much power is consumed in EOM and the resonant circuit. Then we can use the previous measurement to see the conversion factor between the power consumption to the modulation depth. Kiwamu may give us his measurement.

jiSome notes on the FSS configuration: ELOG 10321

Very nice! I got excited.

• Don't you ask Calum and co to check the groove size with their microscopes? Just give the samples and the wire.
• Do we want to make a simple "guitar" setup to measure the vibration Qs with Al piece, glass prism, ungrooved Sapphire, this grooved sapphire, grooved ruby, etc?

For a comparison: OMC ELOG 238

It is more accurate to model the physical frequency noises at various places.

cf. See also 40m ALS paper or Shigeo Nagano PDH thesis on https://wiki-40m.ligo.caltech.edu/40m_Library

- The output 4 should be "Laser frequency"

- Seismic path should be excluded from the summing node

- The output after the PMC: "Laser frequency after the PMC"

- "Laser frequency after the PMC" is compared (diffed) with the output 1 "mirror motion in Hz"

- The comparator output goes to the cav pole, the PD, and the PDH gain: This is the output named "PDH Error"

- Tap a new path from "Laser frequency after the PMC" and multiply with the cav pole (C_IMC)
- Tap a new path from "Mirror motion" and multiply with the cavity high pass  (s C_IMC/omega)
- Add these two: This is the output named "Frequency noise transmitted by IMC"

The input impedance of the mixer is not constant. As the diode switches, it changes dynamically. Because of this, the waveform of the LO at the mixer input (i.e. the amplifier output) is not sinusoidal. Some of the power goes away to harmonic frequencies. Also, your active probe is calibrated to measure the power across the exact 50Ohm load, which is not in this case. The real confirmation can be done by swapping the mixer with a 50Ohm resistor. But it is too much. Just confirm the power BEFORE the amp is fine. +/-1dB does not change the mixer function much.

Instead, we should measure
- Orthogonality
- Gain imbalance
of the I/Q output. This can be checked by supplying an RF signal that is 100~1kHz away from the LO frequency and observe I&Q outputs.

Koji, Gautam, Johannes

We quickly checked the situation of the projector in the control room.

- We found that the proejctor was indicating "lamp error".
==> Steve, could you remove the projector from the ceiling and check if it still does not work?
If it still does not work, send it back to the vender. It should be covered by the previous service.

- Zita seemed happy with the DVI output. We tried the dual display configration and  VGA and DVI are active right now.
The DVI output (from RADEON something video card) is somewhat strange. We probably need to look into the video display situation.

Kyle took high quality images of  the three sapphire prisms using the microscope @Downs. He analyzed the images to see the radius of the groove.

They all look sufficiently sharp for a 46um steel wire. Thumbs up.
I am curious to see how the wire Q is with grooved sapphires, ungrooved sapphires, grooved ruby, grooved aluminum stand off, and so on.

As per Steve's request, I've checked the alignment of the IMC and the arms. These three cavities are locked and aligned.

The attached is the ETMY image with the single arm locked. This was the best I could do. Here is the recipe

• Turn on SP570UZ
• Switch to "M" mode (Manual aperture and exposure)
• Set the aperture to be the widest (smallest F number) and the exposure to be maximum (15 second).
• Switch to AF mode by the lens side switch
• Use the lens dial to adjust the zoom until the OSEMs fill the central 1/3 box (i.e. 1/9 area of the field of view). If you zoom more, you can't focus the spot later.
• Use menu button to switch to ISO1600 (You are now capable to see the beam spot)
• Switch to MF mode by the lens side switch
• Use the lens dial to adjust the focus to have the sharpest image of the spot. This can be achieved at the focal distance of ~1m
• Use menu button to switch back to ISO64
• Push the shutter (I didn't use it, but you should be able to use 2sec timer)

In http://nodus.ligo.caltech.edu:8080/40m/11793 I posted the calibrated PMC free-running displcament with/without IMC locked. Unfortunately, this measurement was done with a part of the IMC electronics not perfect (https://nodus.ligo.caltech.edu:8081/40m/11794). I did the same measurement after the fix, but there is no low freq data http://nodus.ligo.caltech.edu:8080/40m/11795.

Assuming we have the similar error signal leve in the low freq band as The entry 11793, the IMC is considered to be noisier than the PMC between 0.8 and 4Hz. But we should do the same measurement with the current electronics.

The PMC calibration can be found in this entry http://nodus.ligo.caltech.edu:8080/40m/11780

- Is there any machine that can handle 4K? I have one 4K LCD for no use.
- I also can donate one 24" Dell

I also have a functional one on my desk, which has one of the wires repaired.

It seems that FSS slow servo stopped working.

I found that megatron was restarted (by Rana, to finish an apt-get upgrade) on ~18:47 PDT today.

controls@megatron|~> last -5
controls pts/0        192.168.113.216  Mon May 15 19:15   still logged in   
controls pts/0        192.168.113.216  Mon May 15 19:14 - 19:15  (00:01)    
reboot   system boot  3.2.0-126-generi Mon May 15 18:50 - 19:19  (00:29)    
controls pts/0        192.168.113.200  Mon May 15 18:43 - down   (00:04)    
controls pts/0        192.168.113.200  Mon May 15 15:25 - 17:38  (02:12)

FSSslow / MCautolocker were restarted on megatron.

While Gautam is working the restoration of Yarm ASS, I worked on Xarm.

Basically, I have changed the oscillator freqs and amps so as to have linear signals to the misalignment of the mirrors.
Also reduced the complexity of the input/output matrices to avoid any confusion.

Now the ITM dither takes care of the ITM alignment, and the ETM dither takes care of the ETM alignment.
The cavity alignment servos (4dofs) are running fine although the control band widths are still low (<0.1Hz).
The ETM spot positions should be controlled by the BS alignment, but it seems that these loops have suspicion about the signal quality.

While Gautam wa stouching the input TTs, we occasionally saw anomalously high transmission of the arm cavities (~1.2).
We decided to use this beam as this could have indicated partial clipping of the beam somewhere in the input optics chain.

Then the arm cavity was aligned to have reasonably high transmission for the green beam. i.e. Use the green power mon PD as a part of the alignment reference.

This resulted very stable transmission of both the IR and green beams. We liked them. We decide to use this a reference beam at least for now.

Attachment1: GTRX image at the end of the work.

Attachment2: ASSX screen shot

Attachment3: ASSX servo screen shot

Attachment4: Green ASX servo screen shot

Attachment 5: Screen shot of the ASS X strip tool

Attachment 6: Screen shot of the ASS X input matrix

Attachment 7: Screen shot of the ASS X output matrix

I tried a couple of things, but no fundamental improvement of the missing LED light on the timing board.

- The power supply cable to the timing board at c1iscex indicated +12.3V

- I swapped the timing fiber to the new one (orange) in the digital cabinet. It didn't help.

- I swapped the opto-electronic I/F for the timing fiber with the Y-end one. The X-end one worked at Y-end, and Y-end one didn't work at X-end.

- I suspected the timing board itself -> I brought a "spare" timing board from the digital cabinet and tried to swap the board. This didn't help.

Some ideas:

- Bring the X-end fiber to C1SUS or C1IOO to see if the fiber is OK or not.

- We checked the opto-electronic I/F is OK

- Try to swap the IO chassis with the Y-end one.

- If this helps, swap the timing board only to see this is the problem or not.

Basically we use the arm cavities as the reference of the beam alignment. The incident beam is aligned such that the ITMY angle dither is minimized (at least at the dither freq).
This means that we have no capability to adjust the spot poisitions on the PRM, SRM, BS, ITMX optics.

We are still able to minimize A2L by adding intentional asymmetry to the coil actuators.

I think this is the boot disk failure. I put the spare 2.5 inch disk into the slot #1. The OK indicator of the disk became solid green almost immediately, and it was recognized on the BIOS in the boot section as "Hard Disk". On the contrary, the original disk in the slot #0 has the "OK" indicator kept flashing and the BIOS can't find the harddisk.

If we have a SATA/USB adapter, we can test if the disk is still responding or not. If it is still responding, can we probably salvage the files?
Chiara used to have a 2.5" disk that is connected via USB3. As far as I know, we have remote and local backup scripts running (TBC), we can borrow the USB/SATA interface from Chiara.

If the disk is completely gone, we need to rebuilt the disk according to Jamie, and I don't know how to do it. (Don't we have any spare copy?)

Summary
- CDS Shared files system: backed up
- Chiara system itself: not backed up

controls@chiara|~> df -m
Filesystem     1M-blocks    Used Available Use% Mounted on
/dev/sda1         450420   11039    416501   3% /
udev               15543       1     15543   1% /dev
tmpfs               3111       1      3110   1% /run
none                   5       0         5   0% /run/lock
none               15554       1     15554   1% /run/shm
/dev/sdb1        2064245 1718929    240459  88% /home/cds
/dev/sdd1        1877792 1426378    356028  81% /media/fb9bba0d-7024-41a6-9d29-b14e631a2628
/dev/sdc1        1877764 1686420     95960  95% /media/40mBackup

/dev/sda1 : System boot disk
/dev/sdb1 : main cds disk file system 2TB partition of 3TB disk (1TB vacant)
/dev/sdc1 : Daily backup of /dev/sdb1 via a cron job (/opt/rtcds/caltech/c1/scripts/backup/localbackup)
/dev/sdd1 : 2014 snap shot of cds. Not actively used. USB

https://nodus.ligo.caltech.edu:8081/40m/11640

I further made the burt snapshot directories compressed along with ELOG 11640. This freed up additional ~130GB. This will eventually help to give more space to the local backup (/dev/sdc1)

controls@chiara|~> df -m
Filesystem     1M-blocks    Used Available Use% Mounted on
/dev/sda1         450420   11039    416501   3% /
udev               15543       1     15543   1% /dev
tmpfs               3111       1      3110   1% /run
none                   5       0         5   0% /run/lock
none               15554       1     15554   1% /run/shm
/dev/sdb1        2064245 1581871    377517  81% /home/cds
/dev/sdd1        1877792 1426378    356028  81% /media/fb9bba0d-7024-41a6-9d29-b14e631a2628
/dev/sdc1        1877764 1698489     83891  96% /media/40mBackup

I have replaced the old 11n wifi router (CISCO / Linksys) for the GC network with a new one with 11ac technology.

The new one is a 3band wifi router. Thus it has one 2.4GHz (11n) SSID and two 5GHz (11ac) SSIDs. All these have been set to be hidden. Just come to the 40m and find the necessary info for the connection.

Note that the user id / password for the admin tool have been changed from the default values.

We used to have similar suspension excursion at ETMX. This was the motivation to replace the stand-offs from Al ones to ruby ones. Did the replacement solve the issue at ETMX?

What's the current backup situation?

We also need to copy chiara's root. What is the best way to get the full image of the root FS?
We may need to restore these root images to a different disk with a different capacity.

Is the dump command good for this?

Phenomenal!

My last characterization of the AS55 PD was on Feb 2013. ELOG 8100

There I said the dark noise at the PD output was 16nV/rtHz. I don't have the measurement of the Voltage noise at the output of the demod board.

Note that the PD can only be limited by shot noise when the DC current is larger then 4mA.

The post OS migration admin for nodusa bout apache, elogd, svn, iptables, etc can be found in https://wiki-40m.ligo.caltech.edu/NodusUpgradeNov2017

Update: The svn dump from the old svn was done, and it was imported to the new svn repository structure. Now the svn command line and (simple) web interface is running. And "websvn" was also implemented.

You may want to consult with the cryo Q people (Brittany, Aaron) for a Si QPD. If you want the same QPD architecture, I can look at my QPD circuit stock.

An email has come at 5PM on Dec 3rd.

Once a realtime machine was rebooted, it did not come back. I suspect that the diskless hosts have a difficulty to boot up.

Once the RT machines were back, we launched only the five IOPs. They had bunch of red lights, but we continued to run essential models for the IFO. SOme of the lights were fixed by "global diag reset" and "mxstream restart".

The suspension were damped. We could restore the IMC lock. The locking became OK and the IMC was aligned. The REFL spot came back.

At least, I could confirm that the WFS ASC signals were not transmitted to c1mcs. There must be some disconneted links of IPC.

Interesting. My understanding is that this is close to signal recycling, rather than resonant sideband extraction. Is that correct?

For signal recycling, we need to change the resonant condition of the carrier in the SRC. Thus the macroscopic SRC length needs to be changed from ~5.4m to 9.5m, 6.8m, or 4.1m.
In the case of 6.8m, SRC legnth= PRC length. This means that we can use the PRM (T=5%) as the new SRM.

Does this T(SRM)=5% change the squeezing level?

In fact, that is my point. If we use signal recycling instead of resonant sideband extraction, the "tuning" of the SRC is opposite to the current setup. We need to change the macro length of the SRC to make 55MHz resonant with this tuning. And if we make the SRC macro length together with the PRC macro length for this reason, we need to thing again about the mode matching. Fortunately, we have the spare PRM (T=5%) which matches with this curvature. This was the motivation of my question. We may also choose to keep the current SRM because of its higher T and may want to evaluate the effect of expected mode mismatch.

I personally don't like the idea of having sendmail (or something similar like postfix) on a personal server as it requires a lot of maintenance cost (like security update, configuration, etc). If we can use external mail service (like gmail) via gmail API on python, that would easy our worry, I thought.

I know it, and I don't like it. DokuWiki seems to allow us to use an external server for notification emails. That would be the way to go.

I'm planning to construct a beat setup between the PSL and AUX beams. I am going to make it in the area shown in a blue square in the attached photo. This does not disturb Johannes' and PSL setups. The beams are obtained from the PBS reflection of the PSL and the dumped beam of the aux path (0th or 1st order beam of the AOM).

The beat setup has been made on the PSL table. The BS and the PD were setup. The beat was found at 29.42degC and 50.58degC for the PSL and AUX crystal temperatures, respectively.
We are ready for the EOM test. I have instruments stacked around the PSL table. Please leave them as they are for a while. If you need to move them, please contact with me. Thanks.

A picked-off PSL after the main modulator was used as the PSL beam. This was already introduced close to the setup thanks to the previous 3f cancellation test ELOG 11029. The AUX beam was obtained from the transmission of 90% mirror. Both paths have S polarization. The beams are combined with a S-pol 50% BS. The combined beam is detected by a new focus 1GHz PD.

The PSL crystal temp (actual) was 50.58degC. The AUX crystal temp was swept upward and the string beat was found at 50.58degC. After a bit of alignment, the beat strength was -18dBm (at 700V/A RF transimpedance of NF1611) .

I've packaged an AP1053 in a Thorlabs box. The gain and the input noise level were measured. It has the gain of ~10 and the input noise of ~0.6nV/rtHz@50MHz~200MHz.

Details

AP1053 was soldered on Thorlabs' PCB EEAPB1 (forgot to take a picture). The corresponding chassis is Thorlabs' EEA17. There is a 0.1uF high-K ceramic cap between DC and GND pins. The power is supplied via a DC feedthru capacitor (Newark / Power Line Filter / 90F2268 / 5500pF) found in the WB EE shop. The power cable has a connector to make the long side of the wires detachable. Because I did not want to leave the RF signal path just mechanically touched, the SMA connectors were soldered to the PCB. As the housing has no access hole, I had to make it at one of the sides.

The gain of the unit was measured using the setup shown in the upper figure of Attachment 2. When the unit was energized, it drew the current of about 0.1A. The measued gain was compensated by the pick off ratio of the coupler (20dB). The gain was measured with the input power of -20, -10, 0, 10, and 15dBm. The measurement  result is shown in Attachment 3. The small signal gain was actually 10dB and showed slight degradation above 100MHz. At the input of 10dB some compression of the gain is already visible. It looks consistent with the specification of +26.0dBm output for 1dB compression above 50MHz and +24.0dBm output below 50MHz.

The noise level was characterized with the setup shown in the bottom figure of Attachment 3. The noise figure of the amplifier is supposed to be 1.5dB above 200MHz and 3.5dB below 200MHz. This is quite low and the output noise of AP1053 can not be measured directly by the analyzer. So, another LN amplifier (ZFL-500HLN) was stacked. The total gain of the system was measured in the same way as above. The measured noise level was ~0.7nV/rtHz between 50MHz and 200MHz. Considering the measurement noise level of the system, it is consistent with the input referred noise of 0.6nV/rtHz. I could not confirm the advertized noise figure of 1.5dB above 200MHz. The noise goes up below 50MHz. But still 2nV/rtHz at 3MHz. I'd say this is a very good performance.

I could not understand why 'netgpibdata' scripts are missing in "scripts/general" folder on pianosa... Where did they go???

Also, I found that the PROLOGIX GPIB-LAN controller for crocetta (192.168.113.108) is no longer working. I need to reconfigure it with "telnet"...

crochetta was reconfigured to have 192.168.113.108. It was confirmed that it can be used with netgpibdata.py

Configuration: I have connected my mac with the unit using an Apple USB-Ethernet adapter. The adapter was configured to have a manual IP of 192.168.113.222/255.255.255.0. "netfinder.exe" was run to assign the IP addr to the unit. It seemed that NVRAM of the unit evaporated as it had the IP of 0.0.0.0. Once it was configrued, it could be run with netgpibdata as usual.

> So my question is - should we just cut the PCB trace and add this series resistance for the 4 ALS signal channels, and THEN measure the THD?

GO A HEAD

Last night I worked at the PSL table for the modulation depth measurement for an aLIGO EOM. Let me know if the IFO behavior is unusual.

What I did was:

• Cranked up the HEPA speed to 100
• Placed an aLIGO EOM in the AUX beat path (south side of the PSL laser). (It is still on the PSL table as of Feb 20, 2018)
• Closed the PSL shutter
• Turned off the main Marconi forr 11MHz. The freq and output power of this marconi have not been touched.
• Turned off the freq generation unit
   
• Worked on my measurement with the spectrum and network analyzers + aux marconi.
   
• Turned down the HEPA speed to 30
• Turned on the freq generation unit
• Turned on the main Marconi
• Opened the PSL shutter => IMC locked

aLIGO EOM crystal replacement

• The entire operation has been performed at the south flow bench @40m.
• We knew that the original crystal in the aLIGO EOM we are testing has some problem. This was replaced with a spare RTP crystal.
• Once the housing was removed, it was obvious that the crystal has a crack (Attachment 1).
  It seemed that it was produced by either a mechanical stress or a thermally induced stress (e.g. soldering).
• I wanted to make sure the new crystal is properly aligned interms of the crystal axis.
  The original crystal has the pencil marking at the top saying "Z" "12". The new (spare) crystal has "Z" and "11".
  So the new crystal was aligned in the same way as the original one. (Attachment 2)
• I took an opportunity to measure the distribution of the electrode lengths (Attachment 3). The lengths are 14, 5, and 14mm, respectively.

aLIGO EOM test: Setup

• The modulation signal was supplied from an aux Marconi.
• Between the Marconi and the EOM, a 20dB coupler (ZFDC-20-5) was inserted. There the Marconi was connected to the output port, while the EOM was to the input port. This way, we can observe how much of the RF power is reflected back to Marconi.
• The beat setup (40m ELOG 13567) was used for the measurement. The EOM was placed in the beam path of the beat setup in the PSL side.
• To eliminate the modulation sidebands of 11MHz and 55MHz, the 40m Marconi and the freq generator were turned off (in this order).
• The nominal amplitude of the carrier beat note was -15dBm ~ -16dBm.
• The cable from the source to the EOM was ~3m. And the loss of this cable was ~0.4dB.

Measurement

• The EOM had three input ports. 

1. 9MHz input - In reality, there was no matching circuit.
2. Center port - matched at 24.1MHz and 118.3MHz. 24.1MHz port has no amplification (just matching), and 118.3MHz is resonant.
3. 45.5MHz port - resonantly matched at 45.5MHz

• The Marconi output power was set to be +13dBm. For the 45MHz measurement, 20dB attenuator is inserted right next to the Marconi so that the VSWR seen from the Marconi was improbed. (Marconi did not like the full reflection of unmatched circuit and shutdown due to the protection function.)
• The amplitude ratios between the sidebands and the carrier were multiplied by a factor of 2, to obtain the modulaiton depths. ( BesselJ(1,m)/BesselJ(0,m) ~ m/2 )
   
• The result is found in Attachment 2.
  • The center port showed the modulation response of 0.7mrad/V and 15mrad/V for 24.1MHz and 118.3MHz, respectively. This suggests that the amplification factor for 118.3MHz is ~x21.
  • The VSWR of the center port is below 1.5 at the target frequencies. That's as tuned in Downs and has not been changed by the crystal replace.
  • The 45MHz port has the modulation response of 0.034mrad/V. This later tuned out that the amplification of ~x19. The circuit is well matched at the resonant frequency.
     
• The linearity was checked with the 45MHz port (Attachment 3). The input power (idrectly connected to the EOM without 20dB attn) was varied between -17dBm to +13dBm. There was no sign of non linearity.
   
• The modulation response at 24MHz was compared at various input ports. (Attachment 4)
  • The input signal was amplified tobe 23dBm by ZHL-3A for better sideband visibility. The actual amplifier output was ~30dBm, and a 6dB ATTN was used to improve the VSWR to protect the amplifier.
  • The 9MHz port showed 3.6mrad/V and 1.8mrad/V with the port unterminated and terminated, respectively. This factor of two difference is as expected.
    This 1.8mrad/V is roughly x2.6 higher compared to the one of the matched 24/118MHz port. This is close number to the ratio of the plate sizes (14mm/5mm = 2.8).
  • With the current condition, the 9MHz (unterminated), 9MHz (terminated), 24/118MHz, and 45MHz ports requires 22dBm, 27dBm, 36dBm, and 21dBm to realize the current modulation depth of 0.014 at 24MHz.
  • Comparing this matched 9MHz performance, the amplification of the 45MHz port at 45MHz was determined to be ~x19.
     
• Considering these results, the modulation response of the center port at 24MHz seems too low. We don't want to supply 36dBm for the 0.014rad modulation (nominal number for H1).
  Here are some thoughts:
  • Use the 45MHz or 9MHz port for 24MHz modulation. Probably the unit is unmatched but, we can come up with the idea to improve the VSWR at 24MHz somehow?
  • Redistribute the plate length to have better modulation at 24MHz. Can we achieve sufficient modulation capability with the frequency of the long and short ports swapped? We hope that we don't need to start over the matching of the 24/118MHz again because the capacitances of the ports are almost the same.

I have been working on the aux beat setup on the PSL table between 9PM-3AM.

This work involved:

- Turning off the main marconi
- Turning off the freq generation unit (incl IMC modulation)
- Closing the PSL shutter

After the work, these were reverted and the IMC and both arms have been locked.

The new matching circuit was tested.

Results:

f_nominal  f_actual  response    required mod.  drivng power
 [MHz]      [MHz]    [mrad/V]     [rad]         needed [dBm]
  9.1       9.1        55         0.22      =>   22
118.3     118.2        16         0.01      =>    6
 45.5      45.4        45         0.28      =>   25
 24.1       N/A         2.1       0.014     =>   27

Comments:

- 9.1MHz and 118.3MHz: They are just fine.

- 24.1MHz: Definitely better (>x3) than the previous trial to combine 118MHz & 24MHz.
  We got about the same modulation with the 50Ohm terminated bare crystal (for the port1).
  So, this is sort of the best we can do for the 24.1MHz with the current approach.
  The driving power of 27dBm is required at 24.1MHz

- About the 45MHz
  - The driving power of 27dBm is required at 24.1MHz
  - The maximum driving power with the AM stabilized driver is 23dBm, nominally to say.
  - I wonder how we can reduce resistance (and capacitance) of the 45MHz further...?
  - I also wonder if the IFO can be locked with reduced modulation (0.28 rad->0.2 rad)
  - Can the driver max power be boosted a bit? (i.e. adding an attenuator in the RF power detection path)

Why is MC2 LR so different from the others???

I suspect that the LD of the aux laser is dying.
- The max power we obtain from this laser (700mW NPRO) is 33mW. Yes, 33mW. (See attachment 1)
- The intensity noise is likely to be relaxation oscillation and the frequency is so low as the pump power is low. When the ADJ is adjusted to 0, the peak moved even lower. (Attachment 2, compare purple and red)
- What the NE (noise eater) doing? Almost nothing. I suspect the ISS gain is too low because of the low output power. (Attachment 2, compare green and red)