lbr001021.jpg lbr001020.jpg
NRAO webpage for Paul Harden, VLA/EVLA Front End Lab X7142
Last update: 18 NOV 2014
pharden@nrao.edu
National Radio Astronomy Observatory
The Very Large Array (VLA) radio telescope
The Low-Band Receiver (LBR) Pages
 
 
 
 
LBR
 
  ARRAY CONFIGURATION: 
   IN THE "C" ARRAY 
To "B" array Feb. 2015 -- To "A" array June 2015
 
Antenna in the barn: EA23 (VLITE & MJP antenna)
Antenna on the Master Pad: ----
 
                                Antennas with MJP feeds:
EA06, 10, 12, 14, 18, 19, 27 (6 MJPs completed 8/28/2014)
VLITE antennas:
EA01, 05, 06, 10, 11, 12, 14, 19, 23, 27 (10 systems completed 8/25/2014)
 
 
Photo: Autumn in the "C" Array
 
 
 
 
        LBR       
  EA01  
  EA02  
  EA03   
  EA04  
  EA05  
  EA06  
  EA07  
  EA08  
  EA09  
 EA10  
  EA11  
   EA12   
EA13
  EA14  
LBR Serial No.
SN02
SN06
SN26
SN29
SN16
SN14
SN04
SN21
SN30
SN27
SN03
SN01
  SN25  
SN10
VLITE antenna
V5
 
 
 
V8
V3
 
 
 
V4
V9
V1
 
 P-band    LCP 
Tcal      RCP 
13K
14K
15K
14K
13K
19K
14K
18K
21K
22K
18K
17K
18K
21K
14K
14K
14K
20K
17K
16K
14K
10K
14K
14K
14K
16K
14K
14K
P-band
Status
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK 
OK
P-band
dipoles 
aligned
 
aligned
aligned
aligned
 
 
 
 
 
 
aligned
 
 74 MHz    LCP 
Tcal      RCP 
26K
23K
21K
21K
28K
28K
17K
20K
79K
73K
51K
54K
23K
21K
30K
28K
18K
18K
35K
35K
23K
21K
20K
20K
30K
30K
40K
34K
74 MHz
Status
OK
OK
OK
OK
Hi
Tcals
74MHz
 OK
OK
OK
OK
OK
OK
OK
OK 
OK
74 MHz Dipoles
 
 
 
 
MJP
 
 
 
MJP
 
MJP
 
MJP
ESD Boards
 
 
 
 
ESD IN
 
 
 
ESD IN
 
ESD IN
 
ESD IN
Maintenance
Items
 
 
poss.
gain
problems
 
 
 
 
 
 
 
 
 
 
Test Run
Reports
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
 
        LBR       
  EA15  
   EA16  
   EA17  
 EA18
  EA19  
  EA20  
  EA21  
  EA22  
  EA23  
  EA24  
  EA25  
 EA26
  EA27  
EA28
LBR Ser. No.
SN05
SN28
SN17
SN19
SN11
SN24
SN22
SN08
SN12
SN23
SN07
SN18
SN15
SN13
VLITE Antennas
 
 
 
V7
V6
 
 
 
V2
 
  
 
 
 
P-band    LCP
   Tcal      RCP
10K
13K
13K
17K
16K
14K
20K
17K
21K
24K
17K
14K
14K
17K
14K
17K
21K
21K
23K
20K
10K
11K
21K
21K
22K
17K
18K
17K
 P-band
Status
OK
OK
OK
OK
OK
OK
OK
 OK
IN THE
BARN
OK
OK
OK 
OK
OK
P-band 
dipole
aligned
aligned
aligned
 aligned 
aligned
aligned
aligned
aligned
aligned
aligned
74 MHz    LCP
  Tcal      RCP
43K
40K
30K
37K
20K
23K
30K
37K
31K
33K
30K
30K
21K
20K
32K
32K
20K
20K
28K
30K
17K
20K
32K
28K
73K
73K
57K
57K
74 MHz
Status
OK
OK
OK
OK
OK
OK
OK
OK
IN THE
BARN
OK
OK
OK
OK
Hi
Tcals
 74MHz 
74 MHz Dipoles
 
 
 
MJP
MJP
 
 
 
 
 
 
 
 
 
ESD Boards
 
 
 
ESD IN
ESD IN
 
 
 
ESD IN
 
 
 
ESD IN
 
Maintenance
Items
 
 
 
 
 
 
 
 
Rework,
tune
dipole
 
 
 
 
 
  Test Run
Reports
OK
OK
OK
OK
OK
OK
OK
OK
IN THE
BARN
OK
OK
OK
OK
OK
lbr001014.jpg
Where are the receivers?
Click on map to enlarge
Low frequency (50-500 MHz)
astronomy at the
Very Large Array radio telescope
Socorro, New Mexico

The Low Band Receiver (LBR) project
lbr001013.jpg
Above shows the bandwidths of the LBR filters and the dipoles, as measured on the antenna. It appears the current dipole response is not a limiting factor to the overall channel bandwidths. The dipole bandwidth corresponds to the LBR bandwidth at about SWR 5:1 or less.
A joint project of the NRAO and the U.S. Naval Research Laboratory (NRL)
NRL Press Release
"Scientists Bring Low-Frequency
'First Light' to the
Jansky Very Large Array" 
GENERAL INFORMATION
TECHNICAL
 
          LBR Photo Gallery
 
 
 
   Photos Page 1: Some general VLA shots
   Photos Page 2: Low Band Receivers
      Completed LBR receiver
      Build/Construction details of receiver & assemblies
      The old "Legacy" receivers
  Photos Page 3: LBR Installation
      LBR receivers on the antennas and in the array
      The Climb to the Apex and LBR Installation
      Deploying the 74 MHz dipoles
   Photos Page 4: More low-band
      The Experimental "box" or "Bazooka" dipoles (Ant. 5)
      Moving Ant. 25 (with LBR) with the transporter
      LWA-2 station at end of VLA North arm
   Photos Page 5: Low band dipoles and baluns
      Photos of the legacy, bazooka and MJP dipoles
      Photos of the old vs. new balun boxes
LBR Documentation
       LBR Production drawings & schematics
       Design, Development and Conceptual drawings
       List and links to LBR system drawings
Receiver Test Data
Updated: 23 April 2014 with latest lab test results 
     Bench tests for gains, P1dB, dynamic range, LCP/RCP isolation  
     Hot/cold LN2 load tests for Trx, Tcal, Tsys and Noise Figure
.pdf format   (best for printing)
.xlsx format (source spread sheet)
LOW-BAND OPERATIONAL STATUS
RECEIVERS IN THE LAB/SPARES
SN-09 --- Rebuilt to production gains/Tcal standards; has bad CAL noise switch
SN-12 --- From EA23 in barn; Tcal values lowered, added ESD Board.  Ready to reinstall EA23
SN-20 --- From EA13; Tcal checkout and add ESD Protection Board; READY SPARE
VLA ARRAY & LBR STATUS
NRAO Press Release (Dec. 2013)
"New System Makes Two Telescopes In One" (VLITE)
4/P Band Bandpass Plots 
Band pass plots are run weekly on all EVLA antennas for RFI mitigation and  a good litmus test of 4/P band performance. 
Plots are here on EVLA Filehost:
\\Filehost\evla\techdocs\RFI\rfi-survey\plots\evla-bandpass\p-band
(cut & paste into Filehost; not linkable from website)
Select latest date or date desired.
QUICK LOOK TECHNICAL MANUAL
Overview of the NRL/NRAO Low Band System
Updated Feb. 2014
POLARIZATION ROSETTA STONE
Low band, VLITE and MJP polarization schemes
 
X = LCP = IF C/DVert.   dipoles = VLITE IF 1 = MJP diff
Y = RCP = IF A/B Horiz. dipoles = VLITE IF 2 = MJP sum
  
Latest System Updates (as of 11/05/14)
Updated the array map to show VLITE and MJP antennas, and now in C array
EA26 - Polarization swapped to normal
EA13 - Replaced receiver for possible Tcal/CAL switching problem
EA18 - Moved from Master Pad to SW arm
EA23 - Moved to barn
lbr001004.jpg lbr001003.jpg
"C" array "back end"
Pictoral Diagrams of Low Band Polarization
LO and IF flow through the EVLA system (includes VLITE)
NEW
lbr001002.jpg lbr001001.jpg
P-band
74MHz
MJPs