lbr001018.jpg
NRAO webpage for Paul Harden, VLA/EVLA Front End Lab X7142
Last update: 24 JUL 2014
pharden@nrao.edu
National Radio Astronomy Observatory
The Very Large Array (VLA) radio telescope
The Low-Band Receiver (LBR) Pages
 
 
 
 
LBR
 
  ARRAY CONFIGURATION: 
   Now in the compact "D" array 
until Sept. 15
See map on right ---->
To "C" array Oct. 2014 -- To "B" array Feb. 2015 -- To "A" array June 2015
 
Antenna in the barn: EA13 
 
                          74 MHz Dipoles are:  DOWN 
Antennas with MJP feeds:
EA06, 12, 14, 19 (as of 7/24/2014)
 
VLITE antennas:
EA06, 10, 12, 14, 23 (installed as of 7/24/2014)
 
 
Photo: VLA in the "D" Array
 
 
 
 
        LBR       
   EA01   
   EA02  
   EA03   
   EA04   
  EA05  
  EA06  
  EA07  
  EA08  
  EA09  
 EA10  
  EA11  
   EA12   
EA13
EA14
LBR Serial No.
SN02
SN06
SN26
SN29
SN16
SN19
SN04
SN21
SN30
SN27
SN03
SN01
SN20
SN10
VLITE antenna
PROPOSED
 
 
 
PROPOSED
VLITE
 
 
 
 VLITE 
PROPOSED
VLITE
 
VLITE
 P-band    LCP 
Tcal      RCP 
13K
14K
15K
14K
13K
19K
14K
18K
21K
22K
20K
17K
18K
21K
14K
14K
14K
20K
17K
16K
14K
10K
14K
14K
15K
19K
14K
14K
P-band
Status
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
IN
 BARN 
OK
P-band
dipoles 
aligned
 
aligned
aligned
aligned
 
 
 
 
aligned
 
 
 
 74 MHz    LCP 
Tcal      RCP 
26K
23K
21K
21K
28K
28K
17K
20K
79K
73K
30K
37K
23K
21K
30K
28K
18K
18K
35K
35K
23K
21K
20K
20K
30K
32K
40K
34K
74 MHz
Status
OK
OK
OK
OK
Hi
Tcals
74MHz
 OK
OK
OK
OK
OK
OK
OK
IN
BARN
OK
74 MHz Dipoles
 
 
 
 
MJP
 
 
 
 
 
MJP
 
MJP
ESD Boards
 
 
 
 
ESD IN
 
 
 
 
 
ESD IN
 
ESD IN
Maintenance
Items
Check
low CAL
 
 
Weak
RCP?
 
Signals
to LOIF
OK
 
 
 
 
 
 
 
 
Test Run
Reports
Low
CAL
Power
OK
OK
OK
OK
Weak
LCP
.51
OK
OK
OK
OK
OK
OK
IN
BARN
OK
 
        LBR       
  EA15  
   EA16   
   EA17   
 EA18
  EA19  
EA20
  EA21  
  EA22  
  EA23  
 EA24  
 EA25  
 EA26   
   EA27   
  EA28  
LBR Ser. No.
SN05
SN28
SN17
SN25
SN11
SN24
SN22
SN08
SN12
SN23
SN07
SN18
SN15
SN13
VLITE Antennas
 
 
 
PROPOSED
PROPOSED
 
 
 
VLITE
 
  
 
 
 
P-band    LCP
    Tcal      RCP   
10K
13K
13K
17K
16K
14K
14K
16K
21K
24K
17K
14K
14K
17K
14K
17K
25K
21K
23K
20K
10K
11K
21K
21K
22K
17K
18K
17K
 P-band
Status
OK
OK
OK
OK
OK
OK
OK
 OK
OK
OK
OK
OK
OK
OK
P-band  DIPOLE 
aligned
aligned
aligned
aligned
aligned
aligned
aligned
aligned
74 MHz    LCP
  Tcal      RCP 
43K
40K
30K
37K
20K
23K
30K
30K
31K
33K
30K
30K
21K
20K
32K
32K
51K
57K
28K
30K
17K
20K
32K
28K
73K
73K
57K
57K
74 MHz
Status
OK
OK
OK
OK
OK
OK
OK
OK
Hi
Tcals
74MHz
OK
OK
OK
OK
Hi
Tcals
  74MHz  
74 MHz Dipoles
 
 
 
 
MJP
 
 
 
 
 
 
 
Proto MJP
(MJP)
ESD Board Installed
 
 
 
 
ESD IN
 
 
 
 
 
 
 
ESD IN
 
Maintenance
Items
 
 
 
Align
dipole
 
Align
dipole
 
 
 
 
 
 
 
 
  Test Run
Reports
OK
OK
OK
OK
Weak
LCP
.46
20MHz
ripple
RCP
OK
OK
OK
OK
OK
OK
OK
OK
lbr001012.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
lbr001011.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-14 --- Ready Spare / at AOC
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
Updated: 3 July 2014
Updated with recent MJP and VLITE installation
POLARIZATION ROSETTA STONE
Low band, VLITE and MJP polarization schemes
 
RCP = IF A/BHoriz. dipoles = VLITE IF 2 = MJP sum
LCP = IF C/DVert.   dipoles = VLITE IF 1 = MJP difference  
lbr001002.jpg
Aerial photo, compact D array
lbr001001.jpg