ARS K8JLY operates from the second floor of the Historic Smith Mill located in Jackson Township, Ohio. Constructed in 1925 the building features post and beam interior supports and unique tile exterior walls. The primary photo shows the north side of the mill and the 600 ohm ladder line from a 135' Center fed Zepp. The feeders enter the wall at the second floor ceiling height. The 6" spacing is maintained throughout the feed system from antenna through grounding switch and to the overhead bus work that allows connection to any of the four vintage transmitter antenna tuning units.
1930s VINTAGE AMATEUR RADIO EQUIPMENT
The vintage Amateur radio gear looks right at home in the old mill.|
Tnx for looking
K8JLY - Cid Vance
STATION 1 -- 250TH
TRANSMITTER: I refer to this rig as the W3VNE Transmitter as it was originally constructed by W3VNE (Silent Key) in1938. I purchased the unit on eBay 12 years ago. The restoration process took about 2 years and began by reverse engineering each section. This process produced accurate schematic diagrams for each piece and assisted in understanding the builders control logic. Transmitter line up: 6L6 Osc, 807 Multiplier, 3C24 driver and two 250TH's in the final amplifier. The original modulator was not included when I purchased the transmitter. I suspected the space above the low voltage power supply was where it might have been located. Using period correct components and methods I constructed the Speech Amplifier and Modulator on a common chassis which also included the speech amplifier power supply. Tube line up is all triode: The microphone is fed directly to the first of three 56 speech amplifier tubes with the last driving a pair of 2A3's which drive a pair of 805's. Operating paramaters are for approximately 600 watts DC input to the class-C R.F. amplifier. The class B modulator is capable of delivering in excess of 300 watts audio. Power Supplies : A low voltage power supply provides necessary power to the exciter with the exception of the 3C24 Driver which obtains 1250 volts from the medium voltage power supply. This 1250 volt supply also powers the modulator 805's. The High Voltage power supply provides 2250 volts to the the final amplifier. A separate supply provides fixed bias for the 250TH finals. Due in part to poor gain from my crystal microphones it was necessary to construct a pre-amp using a 6SF5 triode. The addition of this outboard pre-amp insures sufficent microphone gain to the modulator speech amplifier.
RECEIVER: Hallicrafters SX-28 early version circa 1939.
MICROPHONE: Astatic Model 30
The two photos give a good view of the operating station and transmitter. The open wire feed lines can be seen behind the transmitter as well as the home made antenna grounding switch. Although it might not be the best set up, a separate antenna is used for the receiver. This was done to elimnate the need for an antenna relay.
STATION 2 -- T20 / TZ20
TRANSMITTER: The following photos are of a second vintage transmitter that I finished restoring and put on the air January 2nd - 2015. I refer to this transmitter as the "T-20 Transmitter". This homebrew rig was purchased at an estate auction in nearby Creston, Ohio about 20 years ago. Three rack sections contain the power supply, modulator and RF section As with my earlier project it was necessary to reverse engineer each section, generate schematics and try to understand the connection and control logic the original builder had in mind. The original tube line up was: RF Section: 6V6 Osc., 6L6 Dblr, 807 Driver, (2) T-20's P-P final amplifiers. Modulator: 6SJ7 - 6C5 - 6V6 - (2) 6L6's , 80 Speech amp power supply, 5Z3 6L6 plate supply. Power supply for the RF Section: (2) 816's HV Rectifiers, 5Z3 LV Rectifier.
The original modulator with 6L6's did not seem capable of modulating the T-20's. There was no data on either driver or modulation transformers making it impossible to see how they would have matched the Class C amplifier load. I constructed a new speech amplifier / modulator using the original chassis and front panel using period correct components. The revised tube line-up is as follows: 6SF5 - Mic-input, 6J5 - 6J5 - (2) 45's P-P driving a pair of Taylor TZ-20's P-P. The new modulator contains a 5Z3 rectifier for speech amplifier and driver tubes as well as a 6X5 bias rectifier for the T-20 finals.
The power supply for the RF section was also re-constructed with a simplified arrangement and included a 12VDC relay for PTT operation. The unit provides 750 volts for the TZ-20 modulator and T-20 final tubes. A low voltage section provides 420 volts for the 6V6 - 6L6 and 807 driver.
RECEIVER: Hallicrafters SX-17
MICROPHONE: Astatic D-104
STATION 3 -- 50T
TRANSMITTER: This homebrew transmitter constructed in 1935 was based on the new Eimac 50T triode. The 50T was Eimac's second tube and was introduced in 1934. Described as a scaled down version of their 150T it was soon replaced by the 100T series triodes. I purchase this transmitter through eBay in 2011. While in storage at the original owners location acid leaking from batteries stored above caused considerable damage to the Antenna Tuner, Final Amplifier, Exciter and Modulator sections. Replacement panels were constructed locating metering and controls in the same position as original. Chassises were fabricated from 16 gauge galvanized steel. The transmitter is assembled in a 72" open rack. Tube line-up is as follows: Exciter - 6L6 Crystal Controlled Oscillator, 6L6 Buffer, 807 Driver. Final Amplifier - Eimac 50T (Presently using an Eimac 100TH as I do not have a good 50T). Modulator - 57, 56, 56, (2) 45s, (2) TZ-20s. Low Voltage Power Supply - (2) 5Z3s. High Voltage Power Supply - (3) 83s MV.
RECEIVER: NATIONAL HRO - 1935
MICROPHONE: Astatic D104 circa 1933
STATION 4 - TW75 / CW
TRANSMITTER: This transmitter was from the estate of K8EGU. Based on the circuit, type of construction and the use of a Taylor TW-75 triode in the final indicates it was built in the early 1930's. Constructed on a 3" x 10" x 17" steel chassis with a 1/4" x 10-1/2" high x 19" wide masonite front panel. Some parts were missing. Documenting what was left of the original wiring indicated the circuit consisted of a 6C5 / 6J5 Oscillator, 6L6 multiplier / driver and the TW-75 Taylor as final amplifer. Plug-in coils were used in all stages. Oddly, there was no provision for crystal control. Reconstruction consisted of removing and cleaning all salvagable components. The oscillator and multiplier sockets were moved to the existing holes in the rear to promote a more logical cirucit / flow. The chassis was refinished with black wrinkle finish. The masonite front panel was carefully cleaned and left in original condition. The meter on the left displays oscillator plate and final grid current. The right hand meter indicates TW-75 plate current. The bottom section is the power supply and was assembled from period correct components. A 5Z3 supplies 300 vdc to the oscillator and multiplier. Plate voltage for the Taylor TW-75 is supplied by (2) 866 mercury vapor rectifiers. The top section is a simple antenna tuner built on a wood chassis with masonite front panel. It can easily be configured for series or parallel feed.
RECEIVER: PATTERSON - PR-10 1932
SKCC - 14287
At present my C.W. skills are a bit lacking, but I can be found fumbling around on 40 meters.
1923 AWA STATION
Transmitter: Original (4) tube C.W. Transmitter as described in QST and the 1923 edition of Radio Simplified. The transmitter was purchased at auction. Original wiring was carefully documented. All components were disassembled, cleaned and inspected. The porcelain tube sockets manufactured for General Electric by Westinghouse Electric were the type specified by RCA for use on the new UV-202, 5-watt transmitting tube introduced in 1922. The transmitter is of Hartley design. Information in the early publications described using up to (4) tubes in parallel as this unit was built. The powersupply with the exception of the filter capacitors was constructed from period components and assembled on a 3/16" thick bakelite chassis. The transmitter is keyed through the center tap of the 7-1/2 volt filament winding. Antenna coupling was tapped to each end of the tank coil through separate variable capacitors series feeding my 135' double Zepp.
Receiver: Regenerative detector with (2) A.F. stages assembled from salvaged period correct components. The coils were wound on a 3" diameter micarta form and spans from 1300 to about 4000 khz. Originally I wanted to use one of the Reinartz radios from my collection (I have seven). None would tune 160 meters let alone the 80 meter band. The Reinartz circuit introduced in 1922 was described as one of the best for C.W. operation.
Operation: It was my intent to have the station up and running for the AWA Bruce Kelley Memoriable 1929 QSO party scheduled for December 10-11 and 17-18. Tuning the transmitter was a real learning experience. Using my grid dip meter to adjust the taps on the tank coil I finally got it in the area of the C.W. portion of the 80 meter band. I had to cheat and use my frequency counter to land between 3550 and 3580 khz. Once things settled down the four 202's did pretty well and frequency held close to my settings -- as long as I did not breath or touch anything!! At any rate I managed to make two QSO's on Sunday December 18. For now I consider that success!
QSL: In searching out early components and pieces of information on this early equipment a QSL card was offered for sale on eBay. This was not just any QSL! It was a QSL card sent from 8DKM Akron, Ohio to 4FT Wilimington, N.C. dated November 27th, 1923 confirming their QSO on 170 meters! As you can see 8DKM was running a transmitter using (4) UV-202's and his receiver was described as a Reinartz with Detector and (2) A.F. My original QTH was Akron, Ohio so I took the short drive to the address listed on the QSL card. I am sure the neighborhood had changed considerably since 1923, and not necessarily for the better. I took a moment to take a couple of pictures of the house and thought how it must have been 93 years ago when 8DKM was pounding away on C.W. with homebrew gear similar to my 1923 station
Thank's for looking . . . 73 Cid K8JLY