DELF00NLD Site Information Form (site log) International GNSS Service See Instructions at: https://files.igs.org/pub/station/general/sitelog_instr.txt 0. Form Prepared by (full name) : TU Delft GNSS team (gnss-citg@tudelft.nl) Date Prepared : 2023-06-30 Report Type : UPDATE If Update: Previous Site Log : delf00nld_20230417.log Modified/Added Sections : 3.9, 3.10 1. Site Identification of the GNSS Monument Site Name : Delft Four Character ID : DELF Monument Inscription : GPS (mark #16) IERS DOMES Number : 13502M004 CDP Number : (A4) Monument Description : PVC PLATE ON CONCRETE BALUSTRADE Height of the Monument : 0.15 m Monument Foundation : ROOF ON CONCRETE TOWER, FOUNDED ON PILLARS Foundation Depth : 15 m Marker Description : BRASS NAIL Date Installed : 1994-12-30T13:00Z Geologic Characteristic : SAND Bedrock Type : SEDIMENTARY Bedrock Condition : FRESH Fracture Spacing : 0 cm Fault zones nearby : NO Distance/activity : (multiple lines) Additional Information : Point No. in National Triangulation: RD 370351 : The station is operating under responsibility : of the AGRS.NL organisation (MD/KAD/TUD). 2. Site Location Information City or Town : Delft State or Province : Zuid-Holland Country : Netherlands (the) Tectonic Plate : EURASIAN Approximate Position (ITRF) X coordinate (m) : 3924687.742 Y coordinate (m) : 301132.768 Z coordinate (m) : 5001910.798 Latitude (N is +) : +515910.02 Longitude (E is +) : +0042315.30 Elevation (m,ellips.) : 74.4 Additional Information : Former Geodesy building Thijsseweg 11, 5 km : South of the center of town. Motorway A13, exit : Delft Zuid / Technische Universiteit Delft 3. GNSS Receiver Information 3.1 Receiver Type : ROGUE SNR-8000 Satellite System : GPS Serial Number : 175 Firmware Version : 3.2.32.1 Elevation Cutoff Setting : 0 deg Date Installed : 1994-12-30T13:00Z Date Removed : 1995-12-26T23:59Z Temperature Stabiliz. : (deg C) +/- 3.0 Additional Information : (multiple lines) 3.2 Receiver Type : ROGUE SNR-12 RM Satellite System : GPS Serial Number : 222 Firmware Version : 3.2.32.1 Elevation Cutoff Setting : 0 deg Date Installed : 1995-12-27T17:22Z Date Removed : 1997-11-20T16:50Z Temperature Stabiliz. : (deg C) +/- 3.0 Additional Information : Receiver replaced due to failure in DCA unit. 3.3 Receiver Type : ROGUE SNR-12 RM Satellite System : GPS Serial Number : 211 Firmware Version : 3.2.32.1 Elevation Cutoff Setting : 0 deg Date Installed : 1997-11-20T17:06Z Date Removed : 1999-07-08T14:30Z Temperature Stabiliz. : (deg C) +/- 3.0 Additional Information : Firmware change. 3.4 Receiver Type : ROGUE SNR-12 RM Satellite System : GPS Serial Number : 211 Firmware Version : 3.2.32.9 Elevation Cutoff Setting : 0 deg Date Installed : 1999-07-08T15:15Z Date Removed : 2000-07-23T06:30Z Temperature Stabiliz. : (deg C) +/- 3.0 Additional Information : (multiple lines) 3.5 Receiver Type : TRIMBLE 4700 Satellite System : GPS Serial Number : 96517 Firmware Version : 1.20 Elevation Cutoff Setting : 0 deg Date Installed : 2000-07-23T07:00Z Date Removed : 2002-11-18T07:00Z Temperature Stabiliz. : (deg C) +/- 3.0 Additional Information : (multiple lines) 3.6 Receiver Type : TRIMBLE 4700 Satellite System : GPS Serial Number : 96517 Firmware Version : N1.30/S0.00 Elevation Cutoff Setting : 0 deg Date Installed : 2002-11-18T10:30Z Date Removed : 2015-11-27T00:00Z Temperature Stabiliz. : (deg C) +/- 3.0 Additional Information : (multiple lines) 3.7 Receiver Type : TPS ODYSSEY_E Satellite System : GPS+GLO Serial Number : 323-0386 Firmware Version : 3.5 Mar,16,2011 p1 Elevation Cutoff Setting : 0 deg Date Installed : 2015-11-27T17:00Z Date Removed : 2019-03-29T10:16Z Temperature Stabiliz. : 20.0 +/- 3.0 Additional Information : (multiple lines) 3.8 Receiver Type : TPS ODYSSEY_E Satellite System : GPS+GLO Serial Number : 323-0386 Firmware Version : 3.5 Feb,01,2019 p5 Elevation Cutoff Setting : 0 deg Date Installed : 2019-03-29T10:17Z Date Removed : 2022-02-24T10:55Z Temperature Stabiliz. : 20.0 +/- 3.0 Additional Information : (multiple lines) 3.9 Receiver Type : SEPT POLARX5E Satellite System : GPS+GLO+GAL+BDS+QZSS+IRNSS+SBAS Serial Number : 3048221 Firmware Version : 5.4.0 Elevation Cutoff Setting : 0 deg Date Installed : 2022-02-24T12:00Z Date Removed : 2023-06-30T09:24Z Temperature Stabiliz. : 20.0 +/- 3.0 Additional Information : (multiple lines) 3.10 Receiver Type : SEPT POLARX5E Satellite System : GPS+GLO+GAL+BDS+QZSS+IRNSS+SBAS Serial Number : 3048221 Firmware Version : 5.5.0 Elevation Cutoff Setting : 0 deg Date Installed : 2023-06-30T09:25Z Date Removed : CCYY-MM-DDThh:mmZ Temperature Stabiliz. : 20.0 +/- 3.0 Additional Information : (multiple lines) 3.x Receiver Type : (A20, from rcvr_ant.tab; see instructions) Satellite System : (GPS+GLO+GAL+BDS+QZSS+IRNSS+SBAS) Serial Number : (A20, but note the first A5 is used in SINEX) Firmware Version : (A11) Elevation Cutoff Setting : (deg) Date Installed : (CCYY-MM-DDThh:mmZ) Date Removed : (CCYY-MM-DDThh:mmZ) Temperature Stabiliz. : (none or tolerance in degrees C) Additional Information : (multiple lines) 4. GNSS Antenna Information 4.1 Antenna Type : AOAD/M_T NONE Serial Number : 177 Antenna Reference Point : BPA Marker->ARP Up Ecc. (m) : 0.0000 Marker->ARP North Ecc(m) : 0.0000 Marker->ARP East Ecc(m) : 0.0000 Alignment from True N : 0 deg Antenna Radome Type : NONE Radome Serial Number : Antenna Cable Type : RG214/U TYPE 13 AWG TYPE CL2 (UL) E100316S Antenna Cable Length : 30 m Date Installed : 1994-12-30T13:00Z Date Removed : 1996-03-08T14:59Z Additional Information : (multiple lines) 4.2 Antenna Type : AOAD/M_T NONE Serial Number : 246 Antenna Reference Point : BPA Marker->ARP Up Ecc. (m) : 0.0000 Marker->ARP North Ecc(m) : 0.0000 Marker->ARP East Ecc(m) : 0.0000 Alignment from True N : 0 deg Antenna Radome Type : NONE Radome Serial Number : Antenna Cable Type : RG214/U TYPE 13 AWG TYPE CL2 (UL) E100316S Antenna Cable Length : 30 m Date Installed : 1996-03-08T15:00Z Date Removed : 1996-07-25T09:49Z Additional Information : (multiple lines) 4.3 Antenna Type : AOAD/M_T NONE Serial Number : 243 Antenna Reference Point : BPA Marker->ARP Up Ecc. (m) : 0.0000 Marker->ARP North Ecc(m) : 0.0000 Marker->ARP East Ecc(m) : 0.0000 Alignment from True N : 0 deg Antenna Radome Type : NONE Radome Serial Number : Antenna Cable Type : RG214/U TYPE 13 AWG TYPE CL2 (UL) E100316S Antenna Cable Length : 30 m Date Installed : 1996-07-25T09:50Z Date Removed : 1996-07-30T11:14Z Additional Information : (multiple lines) 4.4 Antenna Type : AOAD/M_T NONE Serial Number : 177 Antenna Reference Point : BPA Marker->ARP Up Ecc. (m) : 0.0000 Marker->ARP North Ecc(m) : 0.0000 Marker->ARP East Ecc(m) : 0.0000 Alignment from True N : 0 deg Antenna Radome Type : NONE Radome Serial Number : Antenna Cable Type : RG214/U TYPE 13 AWG TYPE CL2 (UL) E100316S Antenna Cable Length : 30 m Date Installed : 1996-07-30T11:15Z Date Removed : 1996-08-08T13:29Z Additional Information : (multiple lines) 4.5 Antenna Type : AOAD/M_T DUTD Serial Number : 240 Antenna Reference Point : BPA Marker->ARP Up Ecc. (m) : 0.0000 Marker->ARP North Ecc(m) : 0.0000 Marker->ARP East Ecc(m) : 0.0000 Alignment from True N : 0 deg Antenna Radome Type : DUTD Radome Serial Number : Antenna Cable Type : RG214/U TYPE 13 AWG TYPE CL2 (UL) E100316S Antenna Cable Length : 30 m Date Installed : 1996-08-08T13:30Z Date Removed : 2000-07-23T06:30Z Additional Information : A conical polyester antenna radome is used on : the AOAD/M_T antenna. This is one of the : earlier radome designs, by Danny van Loon, in : 1991. For some time, it has also been used in : the Swedish network, but there it has been : phased out. 4.6 Antenna Type : TRM29659.00 UNAV Serial Number : 93258 Antenna Reference Point : BPA Marker->ARP Up Ecc. (m) : 0.0000 Marker->ARP North Ecc(m) : 0.0000 Marker->ARP East Ecc(m) : 0.0000 Alignment from True N : 0 deg Antenna Radome Type : UNAV Radome Serial Number : Antenna Cable Type : TRIMBLE 14551-00-REVA DCA 0011 Antenna Cable Length : 20 m Date Installed : 2000-07-23T07:00Z Date Removed : 2016-07-13T13:30Z Additional Information : Installed on 2001-11-07T08:30Z (1139/3): : EMP Protector HUBER-SUHNER 34U2.17A : antenna -> ~12 m cable -> EMP Protector : HUBER-SUHNER 34U2.17A -> ~8 m cable -> receiver 4.7 Antenna Type : TRM29659.00 UNAV Serial Number : 0220314044 Antenna Reference Point : BPA Marker->ARP Up Ecc. (m) : 0.0500 Marker->ARP North Ecc(m) : 0.0000 Marker->ARP East Ecc(m) : 0.0000 Alignment from True N : 0 deg Antenna Radome Type : UNAV Radome Serial Number : 0220314044 Antenna Cable Type : TRIMBLE 14551-00-REVA DCA 0011 Antenna Cable Length : 20 m Date Installed : 2016-07-13T13:30Z Date Removed : 2022-02-24T11:00Z Additional Information : antenna -> ~12 m cable -> EMP Protector : HUBER-SUHNER 34U2.17A -> ~8 m cable -> receiver. : A 50 mm spacer was inserted between the antenna : and marker, flush with inner ring in BPA. BPA : has been seriously corroded due to salt-water : conditions in previous installation. 4.8 Antenna Type : SEPCHOKE_B3E6 SPKE Serial Number : 5741 Antenna Reference Point : BPA Marker->ARP Up Ecc. (m) : 0.0000 Marker->ARP North Ecc(m) : 0.0000 Marker->ARP East Ecc(m) : 0.0000 Alignment from True N : 0 deg Antenna Radome Type : SPKE Radome Serial Number : Antenna Cable Type : PRO PUR coaxkabel Low loss N-m to N-m (RG214) Antenna Cable Length : 23 m Date Installed : 2022-02-24T12:00Z Date Removed : CCYY-MM-DDThh:mmZ Additional Information : antenna -> 15 m cable -> EMP Protector : HUBER-SUHNER 34U2.17A -> ~8 m cable -> receiver. : 4.x Antenna Type : (A20, from rcvr_ant.tab; see instructions) Serial Number : (A*, but note the first A5 is used in SINEX) Antenna Reference Point : (BPA/BCR/XXX from "antenna.gra"; see instr.) Marker->ARP Up Ecc. (m) : (F8.4) Marker->ARP North Ecc(m) : (F8.4) Marker->ARP East Ecc(m) : (F8.4) Alignment from True N : (deg; + is clockwise/east) Antenna Radome Type : (A4 from rcvr_ant.tab; see instructions) Radome Serial Number : Antenna Cable Type : (vendor & type number) Antenna Cable Length : (m) Date Installed : (CCYY-MM-DDThh:mmZ) Date Removed : (CCYY-MM-DDThh:mmZ) Additional Information : (multiple lines) 5. Surveyed Local Ties 5.1 Tied Marker Name : BIG ASTRON. PILLAR Tied Marker Usage : FOOTPRINT Tied Marker CDP Number : (A4) Tied Marker DOMES Number : 13502M001 Differential Components from GNSS Marker to the tied monument (ITRS) dx (m) : 1.818 m dy (m) : 0.958 m dz (m) : -1.584 m Accuracy (mm) : 1 mm Survey method : TRILATERATION/TRIANGULATION/LEVELLING/GPS CAMP. Date Measured : 1994-04-19 Additional Information : Checked twice per year using a local survey, : but only significant changes will be reported 5.2 Tied Marker Name : GPS (mark #15) Tied Marker Usage : FOOTPRINT Tied Marker CDP Number : (A4) Tied Marker DOMES Number : 13502M003 Differential Components from GNSS Marker to the tied monument (ITRS) dx (m) : 0.807 m dy (m) : -1.748 m dz (m) : -0.524 m Accuracy (mm) : 1 mm Survey method : TRILATERATION/TRIANGULATION/LEVELLING/GPS CAMP. Date Measured : 1994-04-19 Additional Information : Checked twice per year using a local survey, : but only significant changes will be reported 5.3 Tied Marker Name : EUREF/GPS (mark #18) Tied Marker Usage : FOOTPRINT Tied Marker CDP Number : (A4) Tied Marker DOMES Number : 13502M002 Differential Components from GNSS Marker to the tied monument (ITRS) dx (m) : 1.596 m dy (m) : 12.563 m dz (m) : -2.121 m Accuracy (mm) : 1 mm Survey method : TRILATERATION/TRIANGULATION/LEVELLING/GPS CAMP. Date Measured : 1994-04-19 Additional Information : Checked twice per year using a local survey, : but only significant changes will be reported 5.4 Tied Marker Name : GPS (mark #19) Tied Marker Usage : FOOTPRINT Tied Marker CDP Number : (A4) Tied Marker DOMES Number : 13502M005 Differential Components from GNSS Marker to the tied monument (ITRS) dx (m) : 3.344 m dy (m) : 10.491 m dz (m) : -3.358 m Accuracy (mm) : 1 mm Survey method : TRILATERATION/TRIANGULATION/LEVELLING/GPS CAMP. Date Measured : 1994-04-19 Additional Information : Checked twice per year using a local survey, : but only significant changes will be reported 5.5 Tied Marker Name : GPS (mark #20) Tied Marker Usage : FOOTPRINT Tied Marker CDP Number : (A4) Tied Marker DOMES Number : 13502M006 Differential Components from GNSS Marker to the tied monument (ITRS) dx (m) : 9.491 m dy (m) : -0.936 m dz (m) : -7.480 m Accuracy (mm) : 1 mm Survey method : TRILATERATION/TRIANGULATION/LEVELLING/GPS CAMP. Date Measured : 1994-04-19 Additional Information : Checked twice per year using a local survey, : but only significant changes will be reported 5.6 Tied Marker Name : GPS (mark #21) Tied Marker Usage : FOOTPRINT Tied Marker CDP Number : (A4) Tied Marker DOMES Number : 13502M007 Differential Components from GNSS Marker to the tied monument (ITRS) dx (m) : 12.008 m dy (m) : -7.080 m dz (m) : -9.073 m Accuracy (mm) : 1 mm Survey method : TRILATERATION/TRIANGULATION/LEVELLING/GPS CAMP. Date Measured : 1994-04-19 Additional Information : Checked twice per year using a local survey, : but only significant changes will be reported 5.x Tied Marker Name : Tied Marker Usage : (SLR/VLBI/LOCAL CONTROL/FOOTPRINT/etc) Tied Marker CDP Number : (A4) Tied Marker DOMES Number : (A9) Differential Components from GNSS Marker to the tied monument (ITRS) dx (m) : (m) dy (m) : (m) dz (m) : (m) Accuracy (mm) : (mm) Survey method : (GPS CAMPAIGN/TRILATERATION/TRIANGULATION/etc) Date Measured : (CCYY-MM-DDThh:mmZ) Additional Information : (multiple lines) 6. Frequency Standard 6.1 Standard Type : INTERNAL Input Frequency : (if external) Effective Dates : 1994-12-30/CCYY-MM-DD Notes : (multiple lines) 6.x Standard Type : (INTERNAL or EXTERNAL H-MASER/CESIUM/etc) Input Frequency : (if external) Effective Dates : (CCYY-MM-DD/CCYY-MM-DD) Notes : (multiple lines) 7. Collocation Information 7.1 Instrumentation Type : GPS Status : PERMANENT Effective Dates : 1998-08-17/CCYY-MM-DD Notes : IGEX experiment. Receivers: : 1. 1998-08-17/1999-02-17 ASHTECH GG24C : 2. 1999-02-17/CCYY-MM-DD JPS LEGACY GGD 7.x Instrumentation Type : (GPS/GLONASS/DORIS/PRARE/SLR/VLBI/TIME/etc) Status : (PERMANENT/MOBILE) Effective Dates : (CCYY-MM-DD/CCYY-MM-DD) Notes : (multiple lines) 8. Meteorological Instrumentation 8.1.1 Humidity Sensor Model : HMP233 Manufacturer : VAISALA Serial Number : P0120011 Data Sampling Interval : 60 sec Accuracy (% rel h) : 1 % rel h Aspiration : NATURAL Height Diff to Ant : 1.6 m Calibration date : 1993-09-12 Effective Dates : 1994-04-19/1999-12-31 Notes : Electronics: Vaisala Humidity and Temperature : Transmitter HMP233; HUMICAP H-Sensor. : 1% accur. between 0 and 90% RH. : 2% accur. between 90 and 100% RH. 8.1.x Humidity Sensor Model : Manufacturer : Serial Number : Data Sampling Interval : (sec) Accuracy (% rel h) : (% rel h) Aspiration : (UNASPIRATED/NATURAL/FAN/etc) Height Diff to Ant : (m) Calibration date : (CCYY-MM-DD) Effective Dates : (CCYY-MM-DD/CCYY-MM-DD) Notes : (multiple lines) 8.2.1 Pressure Sensor Model : PTB200A Manufacturer : VAISALA Serial Number : 692620 Data Sampling Interval : 60 sec Accuracy : 0.12 hPa Height Diff to Ant : -2.65 m Calibration date : 1993-09-12 Effective Dates : 1994-04-14/1999-12-31 Notes : Electronics: Vaisala Pressure Transmitter : PTB 200A; pressure sensor below GPS antenna 8.2.x Pressure Sensor Model : Manufacturer : Serial Number : Data Sampling Interval : (sec) Accuracy : (hPa) Height Diff to Ant : (m) Calibration date : (CCYY-MM-DD) Effective Dates : (CCYY-MM-DD/CCYY-MM-DD) Notes : (multiple lines) 8.3.1 Temp. Sensor Model : HMP233 Manufacturer : VAISALA Serial Number : P0120011 Data Sampling Interval : 60 sec Accuracy : 0.1 deg C Aspiration : NATURAL Height Diff to Ant : 1.6 m Calibration date : 1993-09-12 Effective Dates : 1994-04-14/1999-12-31 Notes : Electronics: Vaisala Humidity and Temperature : Transmitter HMP233; Pt 100 RTD 1/3 DIN 43760B 8.3.x Temp. Sensor Model : Manufacturer : Serial Number : Data Sampling Interval : (sec) Accuracy : (deg C) Aspiration : (UNASPIRATED/NATURAL/FAN/etc) Height Diff to Ant : (m) Calibration date : (CCYY-MM-DD) Effective Dates : (CCYY-MM-DD/CCYY-MM-DD) Notes : (multiple lines) 8.4.x Water Vapor Radiometer : Manufacturer : Serial Number : Distance to Antenna : (m) Height Diff to Ant : (m) Calibration date : (CCYY-MM-DD) Effective Dates : (CCYY-MM-DD/CCYY-MM-DD) Notes : (multiple lines) 8.5.x Other Instrumentation : (multiple lines) 9. Local Ongoing Conditions Possibly Affecting Computed Position 9.1.1 Radio Interferences : CELL PHONE ANTENNA Observed Degradations : NONE Effective Dates : 1997-03-25/CCYY-MM-DD Additional Information : Located on South tower, 100 meters from GNSS : antennae, transmitting in a 240 degrees sector. : The GNSS antennae are located in a 120 degrees : sector not covered by the GSM system. Test at : 5 meters from the GSM antenna have shown no : degradation of the GPS, so it is very unlikely : that the GPS is affected. 9.1.x Radio Interferences : (TV/CELL PHONE ANTENNA/RADAR/etc) Observed Degradations : (SN RATIO/DATA GAPS/etc) Effective Dates : (CCYY-MM-DD/CCYY-MM-DD) Additional Information : (multiple lines) 9.2.1 Multipath Sources : ROOF Effective Dates : 1994-12-30/CCYY-MM-DD Additional Information : Flat roof with concrete balustrade at right : angles with the roof, and several 90 degrees : corners. Medium multipath effects have been : observed. 9.2.x Multipath Sources : (METAL ROOF/DOME/VLBI ANTENNA/etc) Effective Dates : (CCYY-MM-DD/CCYY-MM-DD) Additional Information : (multiple lines) 9.3.x Signal Obstructions : (TREES/BUILDINGS/etc) Effective Dates : (CCYY-MM-DD/CCYY-MM-DD) Additional Information : (multiple lines) 10. Local Episodic Effects Possibly Affecting Data Quality 10.1 Date : 1997-03-25/CCYY-MM-DD Event : Cell Phone transmission started, see 9.1.1 10.2 Date : 2001-11-07/CCYY-MM-DD Event : EMP Protector HUBER-SUHNER 34U2.17A installedin : the antenna cable 10.x Date : (CCYY-MM-DD/CCYY-MM-DD) Event : (TREE CLEARING/CONSTRUCTION/etc) 11. On-Site, Point of Contact Agency Information Agency : Delft University of Technology : Department of Geoscience and Remote Sensing : (GRS) Preferred Abbreviation : DUT Mailing Address : Stevinweg 1 : 2628 CN Delft : Netherlands (the) Primary Contact Contact Name : TU Delft GNSS team Telephone (primary) : +31 15 2784907 Telephone (secondary) : Fax : E-mail : gnss-citg@tudelft.nl Secondary Contact Contact Name : GI-RD Telephone (primary) : +31 6 52481939 Telephone (secondary) : Fax : E-mail : rd@kadaster.nl Additional Information : (multiple lines) 12. Responsible Agency (if different from 11.) Agency : (multiple lines) Preferred Abbreviation : (A10) Mailing Address : (multiple lines) Primary Contact Contact Name : Telephone (primary) : Telephone (secondary) : Fax : E-mail : Secondary Contact Contact Name : Telephone (primary) : Telephone (secondary) : Fax : E-mail : Additional Information : (multiple lines) 13. More Information Primary Data Center : DUT Secondary Data Center : BKG URL for More Information : http://gnss1.tudelft.nl/dpga/ Hardcopy on File Site Map : ./dpga/station/Delft.html Site Diagram : ./dpga/station/Delft.html Horizon Mask : (Y or URL) Monument Description : (Y or URL) Site Pictures : ./dpga/station/Delft.html Additional Information : No obstacles above 0 degrees of elevation, : except for a small rod (anti lightening) 1.5 m : West of the antenna, and two small 1.5 m high : masts 9.5 m South-East and 14 m South-West of : the antenna. : More pictures available on the web-site. : For more information (in Dutch) see also the : official station we Antenna Graphics with Dimensions SEPCHOKE_B3E6 --------------- <-- 0.1550 / \ | | +-----------------------------------------------------+ <-- 0.1080 TCR | | | | | | | | +-----------------+-----------------+-----------------+ <-- 0.0480 BCR | | | | | | +--------x--------+ <-- 0.0000 BPA=ARP (5/8" thread might differ from BPA!) NOM=NRP <-- 0.1210 --> <-- 0.3630 --> Changes: 16-Sep-2020: ARP changed from BAM to BPA ARP: Antenna Reference Point L1 : L1 Phase Center L2 : L2 Phase Center TCR: Top of Chokering BCR: Bottom of Chokering BPA: Bottom of Preamplifier