Radio Boulevard
Western Historic Radio Museum

Classic Pre-WWII Ham Gear - Part 2

1935 - 1941

photo: W6NXW - Gus Gram, Los Angeles, California, ca: 1938 - Rcvr: Breting 14  -  Xmtr:  Homebrew

 The Hallicrafters, Inc.  -  SX-9  -  Contractor: Howard Radio Company

Bill Halligan made several deals with Silver-Marshall Mfg. to start The Hallicrafters, Inc. and began offering receivers in 1933 with the first receiver designs using TRF circuits. Halligan didn't have the necessary licenses to build the radios and sold his early radios by mail. S-M also didn't have the RCA license for Superheterodynes. Since neither S-M nor Halligan had the necessary RCA Superhet license all legal radio building had to be performed by Howard Radio Company (who did have the licenses.) Howard had moved into the Silver plant after RCA sued Silver for building radios without the RCA license. Howard built radios for McMurdo Silver as a contractor. Howard Radio is the most likely contractor for the SX-9 since the early Hallicrafters receivers involved Silver-Marshall and McMurdo Silver. Howard Radio built the Hallicrafters receivers up through the SX-9. By August 1936, Halligan had made his arrangements with Case and had purchased Echophone. Since all of the early Hallicrafters receivers seem to have been built at the Silver-Marshall plant and Howard Radio was the actual RCA-licensed company building radios there, the SX-9 was almost certainly built by Howard Radio. The SX-9 was offered in late-1935 through early-1936 and featured a built-in speaker, nine metal-type tubes and Aladdin iron-core IF transformers in a superheterodyne circuit with bandspread. The first Hallicrafters receivers built without a contractor were the SX-10 and SX-11.  The SX-9 was a significant improvement over earlier TRF models that Hallicrafters had been selling. Its performance is usually rated quite good, even though it still retained a somewhat crude "amateur" appearance.

The Hallicrafters SX-9 was their last contractor-built receiver

A popular RME accessory was the DB-20 Pre-selector, introduced in October 1936. It provided the user with two tuned RF stages ahead of the RME-69 with an advertised gain of 20 to 25 db along with reduction of images. When the RME-69 was used with a DB-20, three tuned RF amplifiers were in operation - sensitivity was incredible and images were no longer an issue. A VHF Converter was also available. RME also offered the DB-20 and the RME-69 installed into one very long cabinet. The matching speaker is mounted in an unusual trapezoid shaped cabinet that allowed for a bench corner to be used for the speaker location and then rectangular equipment cabinets could be butted against each side of the speaker cabinet. Early versions of this speaker cabinet used Rola speakers while late versions used Jensen speakers. In 1939, the RME-70 was introduced and the RME-69 was slowly phased out of production. About 6500 RME-69s were built from 1935 up to about 1940. Shown in the photo above is our 1937 RME-69 SN 1931 with its matching speaker and matching DB-20 Pre-selector. Serial numbers on early receivers are numerical and are probably actual sequential numbers for the quantity of receivers built. Around 1938-39, the serial numbering system was changed to a letter-number combination that probably represents sequentially numbered receivers within specific production runs with the production run identified by the letter used in the serial number.

If you are aligning an RME-69 be aware that it has a decidedly different front-end with no trimmers to compensate for variations in the coil windings of the RF or Mixer sections. This was because the coils were all pre-tuned before assembly and all coils should be identical from receiver to receiver. Whether they have aged the same over the past 70 years is an unknown but most seem to have weathered time quite well. Since the alignment requires some special information, it is lucky that the quirky alignment procedure is in Rider's VOL. X. When aligning the RME-69, it will be noted that the adjustments for the LO are compression trimmer capacitors which are notorious for not "holding adjustment." RME, more than any other communications receiver company, believed that the "ham owners" of their receivers were "tinkerers" - the type that was always adjusting this or aligning that. The fact that the LO might need adjustment every few months didn't bother that sort of owner and apparently didn't bother RME either.

The RME-69 by itself is a typical late-thirties performer, however when rebuilt and aligned, the RME-69 used with the DB-20 preselector is an almost unbeatable vintage receiver. It will be noted that some of the components used in construction are somewhat on "the cheap side." Also, it appears that several parts are just AM BC radio parts that were purchased to construct the receiver. Although Hallicrafters made their reputation on using purchased parts to construct their receivers, RME didn't have that sort of reputation. RME's style of advertising promoted the "engineering" side of design rather than the source or quality of the components used. Still, the RME receivers do perform quite well when rebuilt and aligned correctly.

This RME-69/DB-20 was W7UIZ's first receiver in 1940

W7UIZ's RME-69LS-1/DB-20 Rack Mount

In 1940, Gordon Harris became the youngest licensed ham in the state of Nevada at the age of 12. His father bought him this RME-69 with the LS-1 Lamb Noise Silencer along with the DB-20 preselector and matching speaker - all rack mounted in an RME table-top rack assembly. Quite a receiver for a young ham but Gordon was a genuine enthusiast. Gordon also became Nevada's youngest holder of a FCC First Class Radiotelephone License at the age of 16. He was hired by radio station KOH in 1944, when station manager Bob Stoddard couldn't find any FCC-licensed engineers available due to the demands of WWII. Gordon's "read-the-copy" test was a dismal failure. Those of us who knew Gordon's rapid-fire, whispery voice knew he'd never be an announcer on KOH.  Instead, he was put to work at KOH for his technical abilities, working after school and on weekends. After WWII, Nevada went from the sixth call district to the seventh and Gordon's call became W7UIZ, which he kept until he became an SK in 2012. It's very rare for a ham to have kept his original receiver, especially over a 72 year period of time. I was given Gordon's old receiver by his son in 2015.

The RME-69LS-1 is a very late version of the receiver with the BFO switch being a toggle switch located in the lower left corner of the panel. The Crystal Filter is the late version without the "series-parallel" function. In the lower right corner is the Noise Silencer control. The Lamb Noise Silencer was only used in a few receivers (with the Hallicrafters SX-28 being the best known.) The Lamb NS actually is a tuned-IF noise blanker that works quite well on both voice or cw. It required two extra tubes and one IF tuned transformer. The Lamb NS is built onto a small chassis (which also has the two IF amplifier tubes mounted on it.) The LS-1 version of the RME-69 uses a 6L7 and a 6K7 in place of the older two 6D6 IF amplifier tubes. The Noise Silencer uses a 6J7 and a 6H6.

The DB-20 is a two-stage TRF preselector that was a very popular accessory for the RME-69. This version is rack mounted with a full size 19" front panel. The speaker panel uses the standard 8" Jensen PM speaker with matching transformer. All of the panels are .190" aluminum finished in gray wrinkle paint with engraved nomenclature. Normally, RME didn't provide any panel control information believing that the ham should know his receiver and know the functions of the controls without any nomenclature required. This rack mount RME-69 is somewhat of a departure from that belief and all control functions are well-identified with engraved nomenclature.

Radio Manufacturing Engineers, Inc. was very successful during the 1930s and was certainly a true competitor to the "Big Three" (National, Hammarlund and Hallicrafters.) However, RME didn't evolve from their 1930s design concept and, after WWII, the company began to stagnate. With new ownership under ElectroVoice in the early 1950s, a few newer models emerged. The most famous was the very modern RME-6900. ElectroVoice sold the RME name to G.C. Electronics in 1962. The RME name faded away shortly after.

The Super-Pro used several custom designed parts, including its variable-coupled air-tuned IF transformers, its silver-plated cam-operated bandswitch and its four-gang main tuning condenser and twelve-gang bandspread condenser. Using 16 tubes, the circuit featured double pre-selection on all bands with 25 individual laboratory tuned coils mounted on 20 Isolantite bases, frequency coverage from .54-20MC, amplified AVC, front panel adjustable BFO and 0.5% dial accuracy (incredible for the time.) The variable-coupled IF transformers allowed the user continuously adjustable IF bandwidth from 16KC down to 3KC. Separate RF Gain, IF Gain and Audio Gain controls were used and even a Tone Control was provided. A separate power supply was included in the purchase price (along with a speaker.) The power supply provided three levels of B+ voltage, -C bias voltage and tube heater voltage, all connected to the receiver via a five foot long, nine wire cable that had a special terminal strip type connector on each end. 

The first Super-Pro, commonly referred to as the Model SP-10, used all glass tubes with vented shields on the all but the audio tubes. The audio section including triode connected P-P 42s driven by another triode connected 42 with potted audio transformers with an 8 ohm Z output. Some SP-10 receivers had a 600 ohm Z audio output that added resistors to the audio line output to achieve a 600 ohm Z while utilizing the standard 8 ohm Z transformer. The first, second and third IF transformers were variable-coupled and cam/lever controlled from the front panel Selectivity control. Additionally, the Input and Output IF transformers for the Second Detector and the Output transformer for the amplified AVC were also variable-coupled but adjustable via knurled nuts on threaded shafts that protrude out the top of each transformer housing. The front panel was .190" thick aluminum finished black wrinkle then engraved so the nomenclature would appear bright silver (when it was clean.) The separate power supply was designed to utilize the field coil on the standard 8"speaker (a 12" deluxe speaker was available at $25 extra.) The speaker was just that - a speaker, no cabinet was supplied. The Tuning Meter was not illuminated and had an arbitrary 0 to 5 scale (but with 50 divisions!) Since it measured total IF amplifier plate current, stronger carriers would increase the AVC voltage, reducing the IF gain thus resulting in a lower reading on the meter scale. When tuning in AM stations, one would tune for the lowest reading on the meter. Signal reports were based on the difference between the "no signal" meter reading versus the "signal' meter reading to calculate "db over noise." Bandspread was only operational on the upper three frequency ranges and used a 0-100 logging scale. The crystal filter option was designated with an "X" suffix added to the model type. In mid-1936, an "S" version was offered that had coverage from 1.2 to 40MC with bandspread on all five tuning ranges (identified with an "S" suffix.) This model was advertised extensively in ham magazines of the day. The SP-10 designation is a later identification addition, when new, the receiver was just advertised as the "Super-Pro." The SP-10 was in production for only nine months but, if the SPA is included as a SP-10 receiver, the production lasted about a year and a half.

Hammarlund always used "Series 100" in their advertising but model designations in their sales literature usually are SP-110 or SP-120 with 10 or 12 denoting the speaker size in inches. Model designations also include suffixes that identify the tuning range and installation of a crystal filter - "no suffix" tunes .54 to 20MC, "S" tunes 1.2 to 40MC or "L" tunes 100-400KC and 2.5-20MC. The addition of  an "X" suffix denotes the installation of the crystal filter option. These identifications aren't actually "model numbers" but are really option codes and later Hammarlund documentation does identify these numbers as "code." The serial number on all Super-Pro receivers is located on the rear apron of the chassis, stamped into the metal. Great sensitivity and fantastic audio with continuously variable selectivity make the pre-war Super-Pro receivers a natural for a vintage AM ham station today however they are seldom encountered. Probably because the early models are quite rare and the later 200 Series receivers are usually the military versions that are commonly found in an abused condition requiring extensive electronic and cosmetic restoration. When rebuilt and aligned, the Super-Pro is an incredible performing receiver with tremendous audio capabilities.

Shown in the top photo is the 1936 "Super-Pro" SP-10 SN:576 receiver that was used at WMI, a Lake Erie ship-to-shore radio station located in Lorain, Ohio. This receiver was totally restored to original, "as delivered to WMI" condition and its performance is terrific with powerhouse audio. The lower photo is our 1937 SP-100X SN:3387 receiver that was originally owned by Pacific Gas & Electric Co. and it has also been totally restored to original. Performance is phenomenal and the receiver is pleasure to use. More information on the "200 Series" Super-Pro further down this webpage.

For the ultimate source of detailed  information on the Pre-WWII Hammarlund Super-Pro receivers, including Product History, Estimated Production, Serial Number Assignments, Performance and Restoration, use the Home/Index at the bottom of this page and then click on "Hammarlund Mfg. Co., Inc. - The Incredible Pre-War 'Super-Pro'" - there are three parts to this article.  

The Hallicrafters, Inc.

SX-11
 

The SX-11 was a major step forward for Hallicrafters. As a continuation of the design and manufacturing style that was used with contactors, Hallicrafters' engineers designed the SX-11 to be built from purchased parts that could be assembled into a first-rate communications receiver. The SX-10 and SX-11 were the first receivers that Hallicrafters built without the use of contractors. The SX-11 boasts several firsts for the company. It was Hallicrafters' first receiver with Push-Pull audio output, first with a tuning-eye tube, first to use a separate speaker. The 11 tube superheterodyne circuit also has such unusual features as variable injection BFO, 0-200 bandspread scaling, illuminated main dial, 6L6 tubes in the P/P audio output (14 Watts of audio) plus the fabulous styling that remained in the Hallicrafters line for the next several years. The SX-11 evolved during production with early versions sporting SX-9 type knobs and several circuit differences from the later versions. From the factory, the SX-11 was housed in a metal enclosure painted black wrinkle but the advertised SX-11 was also sometimes pictured in an after-market, shielded (copper sheeting on the inner surfaces,) solid-walnut cabinet. These wooden cabinets were not a Hallicrafters' product but were available from various "jobbers" during the thirties and the cabinet dimensions allowed installed several other makes and models of receivers.

Sears-Roebuck - "Silvertone"  Model 5656A - built by Howard Radio Co.

During the thirties, Sears-Roebuck got into the communications receiver market by offering a few different models that were built for them by Howard Radio Company. Their Silvertone Model 5656A was offered in 1937. The 5656A had a similar appearance to some of the very early Howard-built Hallicrafters receivers, particularly the SX-7 receiver. The 5656A receiver was an eight tube superhet with three tuning bands covering .55 to 18.0 MC. Also included was variable coupled IF for adjustable selectivity, an eight inch diameter tuning dial with multi-colored scales that somewhat compensated for the lack of a bandspread, an AVC switch with separate Sensitivity Control (IF Gain) and a built-in 8" Jensen speaker. It is likely that the screen-grille was originally flocked with some kind of mohair as was typical of the screen grilles of the day. The BFO was built on a separate small chassis that was "cable connected" to the receiver chassis. The 5656A provided the basic communication necessities and performance that was adequate for many entry-level hams. The 5656A was fairly popular and can be spotted sometimes in vintage ham station photos.

In 2003, back when I had the Western Historic Radio Museum as a real "brick and mortar" museum in Virginia City, Nevada, I was contacted by a ham collector that also happened to be a medical transport pilot for the most of the Western USA. He would fly people from Western rural areas into larger metropolitan areas for non-emergency hospital treatments or appointments. The radio deal was that in a few weeks he was going to be flying from his SoCal home-location up to Nevada to do a "pick up" and transport that person from a rural location in Nevada into one of the Reno hospitals. He wanted to come to Virginia City afterwards since the medical transport was a "drop off" and he only had his return trip to SoCal left. He had brought along the 5656A for me to purchase. This all came off without a hitch and the receiver was delivered as expected.

I performed a complete restoration on this 5656A about 2006. I had to have four knobs cast from one of the good condition originals. At the time Larry Bordonaro, now "Antique Radio Knobs.com", was just starting out and did custom knob casting in plastic material that looked just like bakelite. His knob castings were first-rate (Larry is still in business - 2024.) I had to rebuild the tuning system that relied on a pinch-wheel working against a plastic drive disk. Internally, the paper capacitors were restuffed with polyfilms and out-of-spec resistors replaced. I did a full alignment and the 5656A was working about a well as it could considering its design limitations.

The 5656A, at first glance, seems to be a typical AM-BC-SW entertainment radio that would have been for the consumer market and probably offered as a console model radio. The circuit does have a TRF amplifier stage and a single IF amplifier stage. The chassis was professionally converted by Howard Radio to have all of the basic necessities of a ham receiver. The BFO chassis is an obvious addition but it's well-designed and functions quite well.   >>>

Why did James Millen Leave National? - James Millen left National in May 1939, officially to form his own company, James Millen Mfg. Co., but here's what Millen himself had to say about his leaving, as told to John Nagel K4KJ and reported in Nagel's "Brief History of the National Company, Inc."

National had been successfully building its reputation as a top shortwave communication receiver company. The sales and designs coming out of National were at the cutting edge. Unfortunately, the majority share holder at National Company, one Warren Hopkins, wanted National to suddenly change directions. Hopkins wanted Millen to switch emphasis from shortwave communications equipment and go into the consumer "home radio market." Hopkins thought this change would expose more of the public to National products by supplying "Wards" or "Sears" with home radios. Millen was adamantly against National changing direction. He had worked for the past eleven years to put National as the leader in shortwave communication receivers and, to Millen's dismay, it seemed that Hopkins (and perhaps some others in the company) wanted to abandon this successful business position. Millen resigned but National never went into the home consumer radio market at that time. Demands from WWII in Europe resulted in huge orders for HRO receivers which rendered the argument for change moot. Years later, in retrospect, Millen believed that Hopkins' position stemmed from a desire to maximize his stock value because of his ultimately terminal health issues and had nothing to do with National's long-term success.

Another version was related to me by George Meier based on what some of Millen's close friends told him.

It seems that Millen had gone to Washington D.C. to discuss the use of the HRO receiver in the military. At the meeting, Millen supposedly represented himself as president of National. Millen's "high profile" at National (and in National's advertising) did seem to promote the belief that Millen was "in charge" so apparently the "Washington crowd" believed that they were dealing with National's CEO. Somehow word got back to William Ready (the actual president of National Company) who, for some reason, was livid. During the meeting at National (upon Millen's return) Millen was asked to resign, which he did. It seems like an over-reaction on Ready's part, especially since the National-Millen publicity promoted the impression that "Millen was the CEO" through most of the thirties.

This Washington DC story has some problems however. Millen was de facto running National. If it had been a problem for William Ready, one would think he would have brought it to Millen's attention years earlier. Millen was "high profile" because he literally was the only one at National that communicated to the amateur public. Millen actually personally answered many of the letters that came into National from hams around the country. He had a monthly open letter to hams that ran in QST magazine. Millen personally traveled around the country visiting hams and gathering information on what hams wanted from National. According to John Nagel, Millen along with his personal assistant, Frances Bearse, really did "run" National in the thirties. If Millen had represented himself as National's president in Washington D.C., it doesn't seem like it would have been much of a problem since he was, in fact, running the company.

To leave the successful position that Millen had at National, with his very "high profile" personality, must have been the result of a serious internal conflict. However, one should remember that Millen was still a young man when he left National. Perhaps the conflict with Hopkins was enough to force Millen's resignation and allow him to become the CEO of his own company, James Millen Mfg.Co. and not have to deal with the "Hopkins" of the corporate-world.

Pierson left Patterson Radio Company in 1937 and simultaneously purchased all of Patterson's communications receiver manufacturing business, including the rights to continue building the PR-15. Since assembly of the receiver was accomplished at the Gilfillan Brothers plant in Los Angeles, the transfer of Patterson's communications business to Pierson really didn't affect the construction of the receiver. Other than the name change to Pierson-DeLane (after Pierson partnered with his investor, business adviser and VP, a Mr. DeLaplane,) the PR-15 appearance remained unchanged although there are a few examples around that are gray rather than black wrinkle finish. Pierson-Delane did advertise the PR-15 installed in a floor model cabinet but whether any were sold or survive is unknown (Patterson did offer the PR-15 as a console radio with slightly different frequency coverage and controls. At least one sold and is owned by Stan Carter. It's a beautiful radio presentation, no doubt.) Pierson continued to build the Patterson PR-15 under the Pierson-DeLane name until about 1939. Pierson-DeLane then started manufacturing two-way radios up until they went out of business in 1943. Emmitt Patterson continued to build some consumer radios but eventually quit the radio business entirely in 1939.

Note that this PR-15 (it's a Patterson) doesn't have the manufacturer's name on the dial. Instead the original owner's name, ~ Charles Morrison ~, has the place of honor. Charles Morrison was W6JVJ and he lived in and around Los Angeles, California. He had been a professional shipboard radio operator in the late-twenties and saw duty on the S.S. City of Los Angeles and possibly also on the S.S. City of Honolulu. Both ships were owned by the Los Angeles Shipping Company and were passenger ships that sailed between LA and Honolulu. Morrison moved to New Mexico in 1930 to work for Western Airlines but was back in LA within a few months, working for Pan-American Airlines. Morrison had an earlier, two letter ham call that is unknown. Morrison was an active ham into the 1990s. But how did Morrsion get his name on the dial mask? Upon close examination after a good cleaning, it appears that the Patterson company name was carefully removed and " ~ Charles Morrison ~ " was artistically hand-lettered in matching silver paint. Several of Morrison's papers with the manual were included with the receiver and they all have calligraphic lettering galore applied, so he would have been more than capable of doing this "name change" himself. Guy Morrison, Charles Morrison's son, donated his father's Patterson PR-15 receiver to WHRM in 2018.

Designed by Ray Gudie, the Breting 14 circuit is almost identical to its predecessor, the Breting 12. The "14" sold for just over $100 and that price also included a chrome-plated chassis with P/P audio using a triode-connected 6F6 driver and triode-connected Push-Pull 6F6 output tubes. The magnificent mirrored dial inside an almost Art Nouveau style bezel also featured an edge-lighted translucent plastic tubular rotating dial-drum scale for band-in-use readout and a red translucent pointer is backlit onto the logging scale (the same style bezel though slightly smaller was used by Patterson for their PR-15 receiver.) The "R" meter also had an edge-illuminated translucent scale. Certainly the dazzling dial illumination during operation gave the Breting 14 an impressive bench presence that hopefully made up for some of its design idiosyncrasies. However, that fabulous front panel infatuation soon vanished when the owner needed access to the chassis for routine tube testing or minor adjustments. The cabinet has no lid and requires complete removal for any sort of "top of the chassis" checking. The cabinet is only mounted with four large thumbscrews but a lid still would have been more convenient. The bottom cover is attached by way of the metal glides that when threaded into the chassis mounting brackets not only hold the bottom cover in place but also act as feet.

Tuning Dial Vernier Variations - The original bandspread was mechanical and was a vernier mechanism that allowed several turns of the main dial in slow-motion and then, if tuning in the same direction continued, a direct drive type of fast tuning engaged allowing quick placement of the tuning condenser to the desired location. If the direction of tuning was reversed, then the "slow-motion" re-engaged for several turns again and then the fast tuning again engaged. This allowed all fine tuning to be accomplished with just one dial. On the receiver shown in the photos, SN:49555, the vernier tuning control is accomplished using the knob on the lower right side of the panel. The vernier action is by a tuning belt that runs from a large pulley on the tuning condenser shaft mounted just behind the logging dial to a very small diameter pulley on the vernier shaft. The belt is a type of small diameter, tightly coiled spring that is very flexible and able to provide its own tension. This vernier control is obviously very different in design and also "Rube Goldberg" in its crude implementation. The construction of the vernier drive appears to be original due to the way the pulley is mounted to and as an integral part of the logging dial. The construction of the small vernier shaft while crude appears original. The small pulley is actually made from a plaskon control knob that has a groove machined into its perimeter. The operation of the spring belt was somewhat noisy. The entire vernier mechanism design and construction looks like a prototype and not something that would found in a production receiver. Other changes in this receiver are that the RF Gain control occupies the BFO switch location and, as mentioned, both of the BFO controls are located underneath the cabinet and original holes in the bottom plate indicate these locations are original to this receiver. The original artwork shown RF Gain control position is occupied by the Tone-AC switch in SN:49555. All of the wiring looks original and has the "patina of age" appearance. The mechanical differences look original albeit crude in workmanship.

Breting 14 AX and Another Vernier Tuning Variation -  In 1938, a circuit change in the Noise Silencer prompted a designation change to "Breting 14 AX" but the documentation for this change was never published. The common belief was that the 6H6 duplex diode was changed to 6C5 triode however the circuit modification was much more elaborate and actually used the 6C5 as the R-meter amplifier (how the BFO tube could double as the R-meter amplifier was a mystery when examining the schematic.) Additionally, the last IF amplifier tube was changed from a 6L7 to a 6K7 and Crystal Filter modified so that the 432kc crystal could be mounted under the chassis. The mirrored dial was changed to "14 AX." The vernier tuning was also changed. As mentioned above, the first vernier was a dual-speed mechanism on the main tuning shaft. SN:49555 has the lower right-most knob and a belt system. There was another vernier version on the 14 AX that used a rubber drive wheel and utilized the knob that had been for the Crystal Filter (which, of course, was also then relocated to the lower left-most control.) Lack of any Breting detailed documentation or documentation of any upgrades is a problem common to the all subcontractors that were building their radio receivers at Gilfillan. It's also quite likely that Breting offered the "14" in a floor console cabinet as he had with the "12." Very few built and there are few-to-no survivors. Also, some 14 AX versions show up with gray cabinets. Some may even have silk-screened control nomenclature.

Utah Radio Products Company  -  UAT-1 "Add-A-Unit" Amateur 80 Watt Transmitter Kit

Utah Radio Products sold many different types of radio components from the 1920s up into the 1950s. Although mainly known for loudspeakers in the 1920, Utah also produced various type of transformers and chokes along with many other radio components. In 1937, Utah introduced the "Add-A-Unit" series of transmitter kits. There were five different kits that could be purchased with the designation being "Kit No.1," "Kit No. 2," etc., up to "Kit No. 5."

Kit No. 1 was an 80 Watt input power transmitter that used a metal 6L6 crystal controlled oscillator and two parallel connected metal 6L6 tubes as the PA. Plug-in coils had to be wound as part of the kit construction with plans for coil sets covering 160M, 80M, 40M and 20M. Additionally, Utah would supply construction details on 10M coils on request. Three coils comprise each set with an oscillator coil, a PA input coil and a PA output coil. Four pin Hammarlund forms are used for the oscillator and PA input coils and a Hammarlund large five pin coil is used for the PA output coil. The PA output is link-coupled to either an antenna that is cut for a specific operating frequency or to an antenna matching device. Power supply is built-in and uses all Utah "iron." Price was $49.75

Kit No. 2 was a 50 Watt Modulator priced at $44.50. Kit No.3 was the Antenna Coupler priced at $13.95. Kit No. 4 was a 500 Watt input RF amplifier priced at $49.75. Kit No. 5 was a 250 Watt Class B Modulator priced at $49.75. When all five kits were assembled together, the builder ended up with a 500 Watt AM-CW transmitter.

The idea of "Add-A-Unit" was driven by the Depression and the fact that most hams didn't have the money to purchase all of the kits simultaneously. A prospective builder could start with Kit 1 and probably Kit 3, which would result in an 80 Watt CW crystal-controlled transmitter that could be matched to several types of antennae. Later, Kit 2 could be added for AM operation. Then perhaps last, Kit 4 and Kit 5 could be added giving the builder a complete 500 Watt AM-CW transmitter with the purchase spread out over the time necessary.

Shown to the left is the UAT-1 80 Watt transmitter and a copy of Kit 3 Antenna Coupler. The coupler requires balanced feed line going to a dipole antenna. I usually can get about .6amps of RF antenna current. I had a two-way QSO with K7RLD (Washington state) with this set-up. K7RLD was using his Utah UAT-1 transmitter. Probably the first two-way UAT-1 QSO in several decades.

Bliley Electric Company
 

Did you ever wonder what the granted ham frequencies were before WWII? Shown to the right is a 1939 multi-color chart put out by Bliley Electric Company, the famous quartz crystal manufacturer.

160M band shows 1750kc up to 2050kc. It was the popular Phone band because it could be used by newly licensed hams (Class B.) 50kc was CW only. The 1936 ARRL HB shows the lower end of 160M was 1715kc at that time.

80M was the same frequencies as today but was CW only except for 100kc Phone for Class A licenses.

40M was the same frequencies as today but was totally CW only.

20M covers 14.0mc up to 14.4mc and only had a small 100kc section for Class A Phone. The remaining 300kc was CW only.

10M was from 28.0mc up to 30mc and allowed Class B licenses to operate Phone from 28.5mc up to 30mc. 500kc was CW only.

"Restricted Phone" indicates Class A license. "Unrestricted Phone" was for Class A or Class B licensees. Class A required one year experience and a more difficult test. Class B required no experience and a less difficult test. Class A, B or C had a 10wpm code test requirement. Class C license was the same privileges as Class B but testing was administered by mail and volunteer examiner.

1938 DD-1  SN: H-80596

 The Hallicrafters, Inc. - Skyrider Diversity DD-1
 

In 1936, James Lamb and James McLaughlin custom-built an elaborate dual-diversity receiver for XE1G, Dr. James Hard, a wealthy and enthusiastic ham in Morelos, Mexico. In 1937, McLaughlin and Karl Miles, Chief Engineer for Hallicrafters, designed a version of the XE1G receiver for production. Hallicrafters began advertising the Dual Diversity DD-1 in June 1938. The dual diversity design utilized a shared local oscillator to provide single dial tuning which drove the seven-gang tuning condenser. Main tuning is accomplished with the left-side dial and bandspread uses the right-side dial. The massive Yaxley-built push-button switch assembly controlled AC power and bandswitching. The four meters monitored signal levels in each receiver, the signal balance between the two receivers and the common AVC line in S-units. 26 tubes are used in the DD-1, including the four VHF 1851 RF amplifier tubes which allowed the receiver to tune up above 40MC.

The table version was to sell for about $300 for the basic receiver without the Power Supply, Power Amplifier, Diversity Action Meters or speaker, (these accessories increased the basic price by $120.) The DD-1 Console version included the fabulous 15" Jensen Ortho-Dynamic High Fidelity Speaker in a Hagstrom-designed Deco-styled Bass Reflex cabinet along with a matching wooden top housing the diversity action meters. The DD-1 Power Supply and Power Amplifier chassis were stowed on shelves built into the rear of the speaker console. The DD-1 Console was priced at $500 - nearly the price of a new Chevy coupe in 1938. The prices escalated to $627 for the table version and an incredible $720 for the second production run models sold in 1939.

Not surprisingly, the DD-1 was only seriously advertised for about six months (last QST ad was 1/39) but the DD-1 was shown in the Hallicrafters' line-up in the 1940 ARRL Handbook (certainly prepared for publication in late-1939.) Total production is thought to be around 120 receivers. As a specialized receiver it confirmed that Hallicrafters' engineers were capable of sophisticated designs but this "over-the-top" creation certainly wasn't what the Hams of the late thirties would have purchased for their station receiver.

The DD-1 shown to the left is SN 80596, the highest known serial number from the initial production run. This DD-1 was on display in our Western Historic Radio Museum from 2006 until we closed the museum in 2012. With the move to Dayton, the DD-1 was located upstairs for ten years. The photo to the left is from May 2022 and shows the DD-1 in its new location downstairs where it has much better visibility.
 

  For the ultimate information source on the Skyrider Diversity DD-1 including Estimated Production, Serial Number Assignments, Performance, Known DD-1 Serial Numbers, Photo Gallery of other DD-1 receivers, History of Diversity Reception plus many details on our Restoration of our DD-1 SN:H-80596.....use the Home/Index at the bottom of this page and go to "Hallicrafters Dual Diversity Receiver, the DD-1."    

During WWII, the U.S. Navy had HQ-120X versions built for them by Hammarlund. That receiver was designated as the RBG/CHC-46140. The circuit was somewhat revised and the tube line-up was extensively changed (and reduced to 11 tubes,) the S-meter was replaced with a Super-Pro S-meter, capacitors were militarized, oil-filled units while the transformers and chokes were all hermetically-sealed (potted) units. The RBG was also physically larger than the HQ-120X with the depth of the receiver extended by about two inches. The ham band calibration bandspread was changed to Navy frequencies and the audio output impedance changed to 5000Z ohms. There was a matching loudspeaker designated as CHC-49154 (eight inch diameter speaker.) The initial contract (in 1941) was for the USN through General Electric Mfg Co. with Hammarlund as the manufacturer of the RBG receiver. The second contract was in 1943 with Hammarlund as the contractor directly for the USN. These receivers were the RBG-1 and RBG-2. More details on the RBG versions can be found in "WWII Communications Equipment" - use the Home/Index at the bottom of this page to navigate to that three-part article, Navy gear is covered in Part 1.

The HQ-120X was the first of a long line of "HQ" receivers built by Hammarlund specifically for the ham market. Shown in the left photo is a black finish HQ-120X with the unusual rack-mount option with an extended front panel and rear dust cover but with feet on the bottom to allow table-top use. The right photo shows the HQ-120X in the standard table cabinet with the later production gray finish option. By 1942, the gray finish had become standard and black finish was a special option.

Sears-Roebuck - Silvertone  STANDBY - Model 5752 - built by Howard Radio Co.
 

The Model 5752 is a nine tube, single preselection superhet with two IF amplifiers, crystal filter, electrical bandspread, R-meter, switchable AVC, BFO with front panel frequency adjustment and a single-ended 6V6 audio output all built onto a copper plated chassis. Tuning range is in five bands covering .55mc up to 40mc. An external speaker was required. Dials were illuminated but the R-meter wasn't. Dates from 1939 to 1940. The Model 5752 was built for Sears by Howard Radio Company.

One certainly notices the similarity of the Silvertone STANDBY's appearance to that of the Radio Manufacturing Engineers RME-69. It had to be a deliberate design "copy" of the RME-69 but what would have been the reason? A clue might be in the name "STANDBY." At the time, many hams believed they should never be without receiving capability. If the main receiver was down for repairs, then the "standby" receiver could be used. The active and prepared ham would always have a "standby" receiver. If the station receiver was a RME-69 or RME-70, then this Sears "look-alike" would blend in and appear to be another RME product. It seems unlikely that Sears' "RME-69 look-alike" would have been styled to fool someone into thinking this Howard-built receiver came from RME, especially at the price Sears was selling it for. It's more likely that the designers imagined that a ham looking for an inexpensive "standby" receiver would find the Model 5257 appealing because of its familiar appearance.

No restoration has happened on this "STANDBY" receiver,...at least, not yet. One can note that to the left of the tuning dial escutcheon there is a small red pilot lamp jewel. This superfluous addition will be removed as soon as work starts on this receiver. It's obvious that some mechanical rework is going to be required since the dials are obviously tilted somewhat. More to come,...

This Silvertone STANDBY receiver had belonged to KB6BKN Walt Schivo (in fact, Walt has a photo of this receiver on his QRZ page.) For a while, there were some Internet postings about this very same receiver with speculation that it was a RME product. Walt sold a lot of his gear to Ham & HiFi about five years ago and that's where I found the receiver in July of 2019. Once I had the receiver and could thoroughly examine it didn't take too long to discover that it had been built by Howard Radio Company.

Silvertone STANDBY Model 5752 built by Howard Radio Co.   ca: 1940

RME-69 look-alike, minus the RME price,...and performance

Meissner was primarily known for coil and transformer components. They had been purchased by the famous transformer company, Thordarson out of Chicago shortly after WWII (and Thordarson had been purchased by Maguire Industries at the same approximate time.) Meissner was located in Mt. Carmel, Illinois. Through the late-thirties and on-through WWII, Meissner was a top supplier of components and equipment. Meissner offered a variety of electronic kits that included many radio receivers, lots of test equipment and ham equipment. The two main ham receivers were the Traffic Scout and the Traffic Master. Meissner offered the buyer a few options when purchasing the Traffic Scout kit. The complete kit including cabinet and panel was identified as Kit No.10-1169 and the selling price was $65.10. The Traffic Scout kit without the cabinet or panel was identified by Meissner as Kit No.10-1170 and sold for $58.50. The panel by itself was $2.10 and the cabinet by itself was $5.10. These were net prices and options shown in the 1940 ARRL Handbook with "list" prices being much higher. List price for the complete kit, No.10-1169, was $108.50. The Traffic Scout cabinet is fairly large with dimensions of 10.5"H x 19"W x 13.75"D and the weight of the complete receiver is about 40 pounds. For 1941-42, Meissner offered both the Traffic Scout and the Traffic Master fully assembled with tubes included. These were called "Laboratory Built Receivers" and were complete and ready to be used. Of course, the price was substantially higher than the kit versions.

Interesting side note,...Meissner Mfg. Co. and Thordarson were merged post-WWII. Thordarson had been purchased by Maguire Industries shortly after WWII. In 1952, Meissner was called "Thordarson-Meissner" for a while. Meissner coil boxes will be found that are marked Thordarson-Meissner and also other boxes will have Meissner Division of Maguire Industries. Meissner was gone by about 1960. Thodarson reformed and is still in business in Las Vegas, NV as a custom transformer builder.

Hallicrafters published that 50,000 SX-28s (and SX-28As) had been built by 1946, however the serial numbers seem to indicate a production figure of about half that amount, around 27,500 receivers. Nowadays, many SX-28s and SX-28As are still being used in vintage AM ham stations because of their fabulous audio quality and classic "good looks." Most ham AM operators find the sensitivity, selectivity and stability quite acceptable for communications on vintage AM nets today. The SX-28 (SN H-151197) shown above belonged to W3ON, John Ridgway (SK), who purchased it new in February 1942. In 1997, at age 85, John sold his receiver to me saying, "...it's so damn heavy, I can't even turn it on its side anymore." The W3ON SX-28 is in superb, all-original condition and is an excellent example of how the pre-WWII SX-28 looked when new.

For the ultimate source in detailed information on the SX-28 and SX-28A history, production and engineering changes, dating by serial number information, competition comparisons use the Home/Index at the bottom of this page and click on "Hallicrafters SX-28, a Pre-war Masterpiece" - this is a three-part article. 

Some of the tubes that had been used in the NC-100XA were updated in the NC-200 circuit with the most obvious change being the replacement of the push-pull 6F6 tubes with push-pull 6V6 beam-power pentodes delivering about 8 watts of audio power. Additionally, the RF amplifier and one of the IF amplifier tubes were changed from 6K7 tubes to 6SK7 tubes. AVC and BFO functions used 6SJ7 tubes to replace 6J7 tubes. The old 80 rectifier was replaced with a 5Y3G. The NC-200 eliminated the interstage coupling transformer formerly used and replaced it with a phase-inverter circuit that repurposed one of the triodes of the 6F8 tube. Twelve tubes total were used in the NC-200's single-preselection superheterodyne circuit. The IF was changed from National's usual 456kc to the industry standard 455kc. A new 455kc Crystal Filter was incorporated into the circuit and featured a six-position switch to select various stages of selectivity along with a Phasing control. The S-meter used a new Marion Electric model that had a square flange although the scale inside is the same as the older, round flange meters. The S-meter toggle switch that was used on the NC-100A receivers was replaced with a switch that was incorporated into the RF Gain control. Only when the RF Gain was at maximum (full CW) was the S-meter switch actuated (of course, the AVC had to be switched on for the meter to read signal strength.) A series valve (clipper) type Noise Limiter and a variable Tone control were also part of the circuit although both of these improvements had been incorporated into the last of the NC-100XA receivers. Battery operation was possible utilizing the seven pin auxiliary socket located on the rear apron of the chassis. The NC-200 sold for $147 in 1940. National listed the models as NC-200TG (without matching speaker) or NC-200TS (with matching speaker.) Also, with R substituted for the T if the model was rack mount style. There was also a "TGM" version that eliminated the bandspread and was probably for commercial or military applications.

Most of the pre-war NC-200 receivers were built within two production runs identified by letter prefixes and starting with the letter C. Run C, probably started in September 1940 and probably produced just under 1000 receivers since the serial numbers go up into the mid-900s. Run D probably started around mid-1941. It also seems to have produced fairly high quantities of NC-200 receivers, probably around 800 to 900 receivers. Run E was probably started sometime in 1942 and ran thru most of WWII. Run E was used for the remainder of the NC-200 family which included the WWII NC-200FG that eliminated the ham band spread feature. This receiver later became the NC-240C. When the AM BC band was replaced with a 200kc to 400kc band, the receiver was designated NC-240CS. Production run F seems to have been shared with the NC-240CS and the post-war NC-240D (early versions only - later NC-240D receivers use a seven digit SN.) Ultimately, around 1800 pre-war NC-200 receivers were probably produced thus making those versions fairly uncommon.

Silver Anniversary NC-200 - In December 1940, National introduced the Silver Anniversary NC-200. But,...whose anniversary was it? Surprisingly, it wasn't National's. December 1940's QST was a special issue that celebrated QST's "Silver Anniversary" (25 years) with a silver cover on the magazine and with the inside loaded with articles on the origin of ham radio, the ARRL and QST. On the back-inside cover, National had a full-page ad that introduced the Silver Anniversary NC-200. The ad states that this special version of the NC-200 was "Dedicated to amateurs on the twenty-fifth anniversary of their own QST. A toast to QST, the ARRL and the Amateur!" This version of the NC-200 had a special NC-diamond insignia installed that had "SILVER ANNIVERSARY" embossed around the perimeter. The special NC-diamond was also installed on the matching loudspeaker housing. Additionally, the receivers were equipped with special brown bakelite knobs and a brown bakelite S-meter housing. Also, the special NC-diamond, the tuning knob's skirt and all of the control nomenclature plates were finished in "gold tone." National wasn't consistent in the Silver Anniversary trim however and some receivers will be found with off-white or cream color dials, black knobs or a very light gold tone finish. Only the "Silver Anniversary" <NC>  diamond insignia remained consistently installed throughout production. Silver Anniversary NC-200 receivers were built during the early-production of run "C" and into mid-production of run "D." Though it would seem like both Standard Finish and Silver Anniversary models would have been available during this time period, it's very possible (and reported serial numbers seem to confirm) that only Silver Anniversary models were produced for a considerable time period. Shown above is a Silver Anniversary NC-200 model with the serial number C-536 and probably dates from early-1941.

References:

1. "Communications Receivers - The Vacuum Tube Era, 1932-1981"  by Raymond S. Moore - Undoubtedly the best reference book on tube-type superheterodyne communications receivers. History of receivers and the companies along with circuit description and photos of each receiver. Four editions have been printed.

2. "Shortwave Receivers Past & Present - Communications Receivers 1942-1997"  by Fred Osterman - Excellent reference book on later communications receivers. Includes many foreign makes. Circuit descriptions, photos, prices.

3. "Los Angeles Radio Manufacturing - The First Twenty Years" by Floyd Paul - Details the history of Gilfillan Bros., Inc and their licensing relationship with RCA. Many smaller LA companies are also covered.

4. QST, Radio News and Shortwave Craft magazines from 1928 up to 1948 - These vintage magazines are excellent sources for contemporary reviews of equipment and pre-production articles by the designers. Advertisments are invaluable for dating and development of the model line.

5. Operator's Instructions, Factory Manuals, Rider's Troubleshooting Manuals - Original manuals are excellent sources for circuit descriptions, design intentions and performance expectations. Many times the same information is included in the appropriate Rider's Troubleshooting Manual.

6. Radio Manufacturer's of the 1920s - Vol 2. by Alan Douglas - History on Howard Radio Company and many other early radio manufacturers. Three volumes were published.