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The Sylvania Manual HF Receiver R-1451 & R-1451A

This is a mid-sixties era solid-state BA.  It still has 6 tubes, the nixies in the frequency readout.  Photos by Robert Nickels, Roy Wildermuth, Todd Roberts and me.  According to the tags, the earlier R-1451 was part of the "Water Boy 1" system, while the R-1451A was part of the WLR-6.  The R-1449 VLF receiver is part of the same systems.

The R-1449 is allegedly a repackaged CE/Watkins-JohnsonI 357.  The R-1451 also has modules similar to the R-1449, and may be a repackaged CEI/W-J or other manufacturer's receiver.

Additional front panel detail photographs here and here.

Basic specs are:

0.5 to 32 MHz in 6 harmonically-related bands.  There is an AFC circuit that can be tuned to lock the frequency on any 100 Hz multiple.

Single conversion 0.5-8 Mhz,  double conversion above 8 Mhz.

IF filters for 16, 8, 4, 3 (ISB only), 2, 1 and 0.1 KHz bandwidths.  Clevite ceramic filters are used for 16, 8, 4, and 2 KHz.  Collins mechanicals are used in the ISB module.  The 1 and 0.1 KHz bandwidths are obtained with single crystal filters.  A broadband 455 KHz IF output is provided on the rear panel, in addition to separate AM/CW/LSB and USB audio outputs.

AM, CW/SSB, ISB and (R-1451A only) "FMA" modes.

The model number is not stated on R-1451 serial number 4.  Each individual module and circuit board is also serialized in single digits.  The label plate says "Sylvania HF Manual Receiver, Part of Water Boy 1 System".

The tag for this R-1451A shows it as part of WLR-6 ESM suite.

Another interesting feature is a retractable spinner-crank on the inner tuning knob.  The outer knob is slow speed reduction tuning, inner knob high speed tuning, and pull the spinner from the center of the inner knob -- it extends on an arm for really high speed tuning.   Interior construction is modular, but very cramped.

Sylvania made and prototyped other HF receivers.  Examples include the R-1414 and an even earlier 26-tube receiver similar to the R-390 or R-725/URR.

Michael O'Beirne, G8MOB, has pointed out many similarities between the R-1451 and the Telefunken E-863.  Both have harmonically related bands, 100 Hertz AFC, and Nixie tube frequency readouts.  The E-863 is also listed as a surveillance or communications receiver.  The IF frequencies are different, and the E863 lacks the R-1451's lowest MF band.  There may be a relation between them..........
Telefunken E-863

Please contact me, Robert Nickels, Roy Wildermuth, and Todd Roberts if you have any additional information on this series of radio.

Josh Rovero,
Aug 5, 2011, 4:05 PM
Josh Rovero,
Aug 5, 2011, 4:05 PM