AMSTUDIO

THE WB2FCN "AM" OPERATING STUDIOS

STUDIO "A"

Studio "A" is a modest system, consisting of E.F. Johnson equipment. The exciter is the Johnson Pacemaker,

with amateur band coverage of 80 through 10 meters, modes are AM/CW/SSB, power output is 50 watts approximately for CW/SSB/AM. The amplifier is the Johnson Thunderbolt, sporting a pair of 4-400As' running class AB2 and class C. The antenna tuner is the Johnson 1 KW Match-Box, which feeds the 80 meter dipole array with open wire feed-line. The receiver is a Hallicrafters SX-101 MK3. Here is an "AD" from the 1950s' for the Exciter/Amplifier pair.

I got both of these items by bidding on E-bay on the internet. The Pacemaker came in blowing fuses and of

questionable operation. I had to replace all the Electrolytics in the power supply, and there were a few tubes plugged into the wrong sockets, as well as some tubes that were just plain bad. I replaced all the tubes in the unit with new ones, and went through the alignment procedure only to find I had no grid drive to the 6CL6, I found there was a burned out resistor that goes to the balanced modulator output coil which provided B+ to the balanced modulators, result no output from modulators = no grid drive to the 6CL6. After replacing the resistor, the unit was then aligned per the manual on all bands. The power output in cw mode is close on to 65 watts, SSB seems to work a little better and gives 75 Watts Peak, with the LO AM mode giving a carrier output of 35 watts. The chassis and front panel were quite clean when the unit arrived, and just needed a little dusting to brighten things up. Here is the picture of the unit as received from the E-Bay seller.

The Thunderbolt Amplifier was another matter entirely! This one was on E-Bay as totally non-working needing lots

of TLC to bring it back to life. Here are a few pictures of the unit as shown on E-Bay!

The unit was shipped without the owner taking any pains to prevent further damage to the unit. As a result when it

arrived the cabinet was bent, The RF input coil was broken from its mounting, one 4-400 tube socket was broken in half

right down the middle (probably from the dropping). Both, tuning and loading caps had bent plates, the plate blocking

caps were broken in half and there were no tubes in the unit. The E-bay seller promised to send them along, "IF HE

COULD FIND THEM"! I guess he is still looking because he hasn't answered any of my Email requests since he got

his money for the unit. I had to straighten out the lumps in the case/cover and then strip it down to "bare metal" and

repaint it. There weren't any feet left on the case so I substituted #5 rubber Stoppers for the feet. I also had to make

some screws long enough to hold the cabinet to the chassis. I completely rebuilt the input switch assembly from some

old switch parts and using 2-56 brass hardware to hold the contacts on the ceramic wafers, the center section was a

real "BEAR" as it was the shorting type 6 positions.

Here is the rebuilt Thunderbolt, after rebuilding and cleaning it up, and installing all new tubes in it.

The Kilowatt Match-Box also came from E-Bay, But arrived in excellent shape exactly as described and working

great. Here is the E-Bay picture.

STUDIO "B"

Studio "B" consists of the retired "Marine Radio" set AN/SRT-3 transmitter, which was designed for operation on the frequencies of from .35 Mhz to .515 Mhz. I got this unit on E-Bay as well. It has been modified to cover the most popular frequencies on 160 meter AM- Fone, and is currently set up for 1.850 Mhz , 1.880 Mhz , 1.890 Mhz , 1.950 Mhz , and 1.980 Mhz. It is a (5) five channel transmitter with a power output of 300 Watts on AM. It came with provisions for Modulated CW but no audio chain for AM, So I assembled one and installed it in the cabinet that houses the 0 - 1500 volt D.C. high voltage power supply. The frequency control circuits were retuned to cover 160 meters and the antenna system is a vertical approximately 47 feet high with a radial system consisting of 50 ft lines radiating out from the base of the antenna.

Here are a few pictures from the E-bay auction.

This unit came without any tubes, missing the side panels, and otherwise just as seen here, there was also no documentation with the unit. I had to "BUZZ" out the circuitry using a Simpson VOM and an audio generator and

audio signal tracer. I ended up with a reasonable schematic of the transmitter as I had it. I then received a copy of

a radio marine magazine from Marc VE3GIX, which confirmed my attempt to describe the unit from tracing circuits.

The info allowed me to finish the wiring for the transmitter and gave me insight into what had to be done to put this

grand old transmitter on 160 Meter AM. This is a Crystal control or Master Oscillator type transmitter. The oscillator

tube is a RCA 807, the Buffer stage is another RCA 807, and the final amplifier stage is a pair of VT4C/211 triodes

with 1250 VDC on the plates at maximum 450 Milliamps plate current. After cleaning the unit up inside (It was extremely DIRTY from long storage) I powered it up, changed the frequency to 160 meters. I had to build a 1300 volt power supply and also a voice audio chain to drive the 150 Watt modulation transformer, which was originally used for MCW with a 500 cycle 115VAC signal.

Here are some pictures of the finished transmitter, the new HV power supply and the modulator input driver.

STUDIO "C"

Studio "C" consists of the ubiquitous BC-610-E model. I had this transmitter for about 10 years and used it for AM/CW work on 80-40-20 meters. The old unit runs a reasonable 400 watts output. I loaned this unit to a friend and it

made the move from Buffalo, N.Y. , to Schenectady, N.Y. where it resided for 22 years, at the end of which time it came back to me none the worst for wear. I had to disassemble the power supply deck to clean some rust from the under-side and primed it with rust inhibitor and put it back together. This BC-610-E is all original/stock with the BC-614-E speech amplifier assembly and the BC-939-A antenna tuner and still operates on 80-40-20 meters however it is setup for AM only operation. There are two receivers for this system 1 SP-600JX17 and 1 BC-312 for a total "Military" AM HF station. The antenna system consists of several 44 foot long-wire antennas oriented to the "Cardinal Points" for 360 degree coverage.

STUDIO "D"

Studio "D" consists of the (PW) station equipment, the line-up there is EICO equipment running between 45 and 65 watts. This studio has a pair of exciters, (1) EICO 723 AM/CW transmitter at 60 watts input CW and about 50 watts on AM. There is also (1) EICO 720 AM/CW transmitter at 90 watts input on CW and about 70 watts on AM. The frequency control can be either FT-243 crystals (XTAL) or the EICO 722 VFO, which covers 80 through 10 meters, it has a provision for external keying to enable the VFO before the transmitters so as not to require a clamp tube in the 723, and also works with the 720 which has a clamp tube in the circuitry. The modulator is an EICO 730 which is a multi-impedance output modulator at the 50 watt level. This particular 730 has been modified in accordance with the "MOD" suggestions of "WB3HUZ" to open up the 730 and make it a more "Broadcast Quality" sounding modulator/transmitter.

This transmitter system works in conjunction with one of a pair of R-390A receivers at the station. The R-390A receiver

is on what I call my Omni-Directional Antenna, Both actually, and works great in conjunction with the EICO gear, as

I use Studio D for AM and CW, and the R-390A has the 100 Hz mechanical filter position and wide and narrow audio positions, which is outstanding for CW work with crowded conditions. The Antenna used by the transmitters is a center-fed dipole, fed with open wire feed-line and tuned with an E.F. Johnson 275W Match-Box with the external SWR meter and Directional coupler. The R.F. output of both EICO transmitters is switched so that there is always an E.F. Johnson Low-Pass filter in-line. I've got an EICO 717 Keyer and a Vibroplex Key for my high speed "ANTICS" at the low end of 40/20 Meters on CW, at around 7030/14030 Mhz. Drop in sometime if I'm on and give me a call, I'll slow down or speed up as required for us to have an enjoyable "QSO".

Studio "E"

Studio E is the latest addition(4/25/2001) to the WB2FCN BoatAnchor AM/CW stations, and is a

most unlikely acquisition. The station consists of a Hallicrafters SX-101A Mark1 Receiver, a Hallicrafters

HT-32A Exciter/Transmitter and a Hallicrafters HT-33 Mark1 Linear Amplifier.

The SX-101 Mark3 receiver covers 160 through 10 meters, AM/CW/SSB modes and has the 100 KC

calibrator installed. I got this unit from an E-bay auction long before the feeding frenzy had start there and

the seller was reading the lable on the rear of the chassis and posted it as an HA-5 VFO. He didn't know if

it worked or not only that it was heavy. I got it for $90.00 and had to pay 45.00 to have it shipped from the

California coast the Buffalo. When it arrived I thought there had been a mistake as the box was "HUGE", I

checked the shipping tag and it was mine, when I opened it up there inside was the SX-101A, I contacted the

guy and told him he sent the wrong item as I bid on an HA-5. His response was that is what it is and told me

to check the label on the back of the unit, I did, sure enough there was a marking on the back that said HA-5

I said thanks and sorry for my mix-up. I put it on a variac and brought it up, let it warm-up at 70 volts for about

30 minutes then turned it full on and put my shop antenna into the unit and preceeded to listen to the "Guys" on

3885 AM while I cleaned the dust, of which there was very little, off the unit. I replaced a single number 47 bulb

and that was the total extent of work on the receiver.

The HT-32A exciter/transmitter was acquired on E-bay recently (April 2001) from Pittsburg,PA. I bid on it

was the highest bidder but it didn't make the reserve. I then bid on the HT-33 amplifier and won it, the same

seller had both items, and offered me the exciter at the last bid price since I was taking the amplifier, and he

really wanted to get rid of both units. When I first saw the units up close in Pittsburg (We drove down) I was

amazed that I even bid on them they were saturated with years of dust, and I figured I would be getting them

in shape for the next six months. Boy was I wrong! I carefully removed the exciter from its case "Hefted" it

to the work bench and started cleaning out the dust, it took an HOUR to get all of it off the exciter I then gave

it the eye-ball treatment I looked things over carefully no obvious changes, Hum lets warm it up. I put the exciter

on the variac set the voltage at 60 volts, went for coffee, when I came back down everything was on and the fan

was running, I decided to bring it up to full A.C. input volts turned on the calibrate position and on the spectrum

analyzer saw the output on 7290. Yeah, quick check of the bands showed output on all 80 through 10 meters.

Inserted a wattmeter in the line to the dummy load and checked for power output, oh well can't have everything,

the power out was a whopping 15 watts on all bands, Humm I checked the voltages on the various stages, and

monitored the drive levels all the way from the sideband generator to the 6146 output tubes all correct, ok I

changed the 6146s (a pair) and started again. This time in CW mode I got 55 watts out on all bands, I put cleaner

on the bandswitch sections all the way to the output tubes, and checked again, checked my manual reprint from

"BAMA" and decided to peak the driver coils up as I had changed the output tubes. A good tweaking and the

output was right at 70 watts for all bands and I was HAPPY, not bad at all total time on the bench was about

4 hours and the exciter was working. I got on 7290 and got a few signal reports, and with the band being very

unpredictable I still got good signal reports from the guys on 40 meters, went to 10 AM and worked a station

in Texas and decided to tackle my next job!

--... ...-- DE Jim WB2FCN