Panadaptors

The panoramic spectrum display, invented by Marcel Wallace in the 1930's, provides a radio operator with a graphic display of radio signal amplitudes at frequencies close to the  signal to which his radio is currently tuned.  This allows the operator to observe arrival of new signals, presence of interfering signals, or existence of nearby spectral regions with more or less signal traffic.  The panoramic display is normally used as an accessory to a communications receiver, thus the coined name "panadaptor".  Wallace's company, Panoramic Radio Corporation, of New York City, was the primary promoter of  panoramic radio displays during the 1930's and most of the 1940's.  After the second world war, Panoramic Radio expanded its line of  spectrum analysis devices to find further applications in radar, sonar and acoustics both as a laboratory tool and for operational use.  Panoramic later was acquired by Singer and Singer in turn by Empire......and I have lost track of this evolution. Many other firms built panoramic signal displays during the subsequent cold war years.  Spectrum analysis for panoramic display is now performed digitally as part of the signal processing in some modern (costly) receivers.  This website is focused on the beginnings of panoramic radio displays.





1942 Panoramic SA-1 and SB-1 Radio Spectrographs         

An early panadapter  featuring a 5 inch CRT  was pictured in QST for March 1942, page 16, but not identified.  It is now known to be a Panoramic model SA-1.  The author has aquired a Panoramic SB-1, Type T200  which is a utility spectrum analyzer version of the SA-1, incorporating an untuned mixer input stage for use with an external heterodye oscillator.   An SA-1 Type T200 unit, being restored by a collector in the UK, is shown below, with the author's SB-1 on the right. Both units are identified as "Panoramic Radio Spectroscope" on the front panel.  The SB-1 unit also bears the name "Panoramoscope" on its rear panel identification tag. The names "Panoramic Adaptor",  and "Panalyzor"  were apparently not used until later (SA-3, SB-3) units in the 1943-44 era.  A photo showing a similar unit also appears in  "The Secret Wireless War" by Geoffrey Pidgeon, page 99.

               SB-1 Photo
                                                          SA-1                                                               SB-1

This SB-1 analyzer was apparently built during the third quarter of 1942, as indicated by date codes on most of its RCA  metal, octal-based tubes. The SB-1 has an enameled metal horizontal scale mounted in front of the CRT,  while the SA-1 is equipped with a green plastic graticule against the CRT screen (similar to the graticule on later model SA-3 equipment), suggesting later manufacture.

1942 Panoramic SA-2A Radio Spectrograph

    The SA-1 analyzers were as large (17"w x 9"h x 13" d) and heavy (    lbs) as many radio receivers.  The model SA-2 version of the Radio Spectrograph was apparently intended to be smaller, as an accessory to a radio, rather than a competitor for bench space. Photographs of smaller (unidentified) units appeared in QST for March and July, 1942 .  A Panoramic model SA-2A Radio Spectroscope has been found.  This unit is very similar to the unit described in QST, July 1942, but has its two-inch CRT mounted in a separate "doghouse" connected to the main unit by a multi-conductor shielded cable.


 
                                       SA-2A


  This two-piece unit, is apparently a commercial model, produced for the Navy at the outbreak of  the war. The only indication of Navy purchase is the US and Anchor engraved on upper right corner of the nameplate.

                                 

Production date of this unit is estimated as the second half of 1942.  Tubes in the unit bear May-June 1942 date codes.  The two patents stamped on the plate - 2,273,914 and 2,279,151 - were awarded on February 4 and April 7, 1942.  The next panoramic reception patent awarded to Marcel Wallace and Panoramic radio was  number 2,312,203, awarded February 23, 1943.  It seems reasonable to infer that if this unit had been manufactured after February 1943,  their latest patent would have been cited on the nameplate.

The commercial heritage of the SA2A is further demonstrated by the component layout and the commercial components, such as waxed paper capacitors. Not visible, in this picture, are the capacitors hidden underneath the terminal board and inaccessible without major disassembly. This is not an easy unit to repair.
                                  SA2A bottomview

1943 Panoramic SA-3  Panoramoscope

The later model analyzer,  incorporating a 3 inch CRT, a spacious chassis, and mil-spec style components and component layout was the model SA-3,   initially called a "Panoramoscope".  Note the difference in layout and wiring.
   

The commercial side of the SA-3 family included five models (as of 1945), with more added during the next 20 years. Models were distinguished by Type numbers indicating maximum sweepwidth and sometimes suffixes to denote different input IF frequencies within a Type.

                      Type                     Input IF Frequency                               Maximum Sweepwidth

                      T-50                         450 - 480 kc.                                              50 kc.
                      T-100                       450 - 480 kc.                                              100 kc.
                      T-200                       450 - 480 kc. or 21.4Mc                             200 kc.
                      T-1000                     5.25  Mc, 10.2Mc, 10.7Mc, or 21.4MC     1 Mc.
                      T-2000                     21.4 or 30 Mc                                             2 Mc
                      T-3000                     21.4 Mc or 30 Mc                                       3 Mc
                      T-6000                     30 Mc.                                                        6 Mc
                        (Note: in the ancient era of panadaptors, MHz and kHz had not been invented yet, and frequencies were measured in Mc and kc.)

Contemporary receivers with IF in the 450 - 480 kc range included the Hallicrafters SX-28, the Hammarlund Super PRO, and the National HRO  plus many other receivers.  These receivers also existed, either unchanged or repackaged, under multiple military nomenclatures.  The Hallicrafters S-27 and S-36 VHF receivers used a 5.25 Mc. IF.  The General Radio P540  UHF/microwave receiver  (better known as AN/APR-4) used a 30 MHz IF.  Nems Clarke receivers, built during the 1950's,  used 21.4 Mc IF.  A later panadaptor model, the SA-8 Type T-100, could be ordered with 500 Kc IF for use with the 1950's era Collins receivers.

Many military versions of the model SA-3 appeared, starting in 1943.  These units were apparently the first to be called  "Panoramic Adaptor". Shortening of this name to "Panadaptor" is probably attributable to the military operators and technicians using them. A Navy technical manual for the model RBY was released June 30,1943 and an Army technical manual, TM11-446 for the BC-1031 and BC-1032 members of the SA-3 family,  was released July 30, 1943.

Military nomenclatured versions of the SA-3 family include:

                   BC-1031-A
                   BC-1031-B
                   BC-1032-A
                   BC-1032-B
                   RBU
                   RBV
                   RBW
                   RBY
                   RCC
                   RCX
                   RDK

SB-3 Panalyzor

An apparently later evolution of the SA-3 family, was the SB-3 "Panalyzer" shown below.  A Panalyzer added an untuned mixer stage to allow use of an external oscillator to translate input signals to the input center frequency of the panadaptor which followed. 
                                       



Postwar  Panoramic PCA-2  /  Hallicrafters  SP-44

 After the end of WWII, with loss of military orders and shrinking staff, Panoramic attempted to sell radio amateurs on the virtues of their product.  They produced Model PCA-2, with a 2 inch CRT and electrically very similar to the 1942  model SA-2A.  A similar model was made under contract for Hallicrafters who marketed it as the Hallicrafters SP-44.  Internally, the component layout and parts quality of these units regressed from the mil-spec quality of the SA-3 units above to more closely resemble the SA-2A.  There are at least three different schematics from this family of panadaptors, with minor variations in the power supply circuits and in the biasing of the reactance tube modulator.

         


Hallicrafters  S-35 Panoramic Receiver

This panoramic receiver, consisting of a Hallicrafters SX-28 receiver in a common cabinet with a panadaptor distinguished by a 5 inch CRT, was shown in Hallicrafters pages in the 1945 Radio's Master catalog and other Hallicrafters advertising of the period.  The front panel of this panadaptor does not resemble any of the contemporary Panoramic models, although the tube lineupand circuitry  is suggestively similar to that of the SA-1/SB-1 units. (This comment on circuitry based on a schematic published in  Radio News Magazine, March 1945).

                           

The author has not yet found anyone who owns or has even seen a Hallicrafters S-35 or a manual for one.  Possibly the S-35 was a prototype, built in unsuccessful competition with Panoramic for a military contract.  This possibility is suggested by comparison with the Navy Type RBY-1,. built by Panoramic and sharing its cabinet with a Hallicrafters SX-28.

                         RBY-1
                                                                                                       NAVY  RBY-1  , by Panoramic with SX-28

About this webpage.

 This webpage is a result of an information search that began when the author purchased the SA-2A panadaptor shown above.  Neither the author or the seller realized the age of the unit or the sparcity of available information.  Over a period of 18 months, much panadaptor information has been found, through the generous assistance of many hams, collectors and librarians.  Some misinformation has also been encountered, offered in the belief that it was true.  In the course of  returning the SA-2A to operation, the author has done enough reverse engineering to create a  pseudo-manual for the unit, but a copy of the manufacturers manual has never been found.  This webpage is an offering of some of the panadaptor history that was found during the search.

The author wishes to thank the many people who have contributed information to his search, including:
    Anthony Norden
    Ben Hall
    David Stahl
    Dave Doughty
    Joe Lutz
   
John Bauer
    Alan Douglas
    Ray Robinson
    Phillip McCoy
    Ron Hershey
    Don Merz
    King County Library
    Oberlin College Library
    University of Washington Library
    and offers appologies to any who I have omitted.
   
   



----------More to come -----------------
This webpage is a work in progress.  Comments, corrections, and added information are welcomed.
Thanks for your visit.
Chuck McGregor,  N7RHU   email address current at QRZ.com