The Station At AA8V
Sections 3 and 4

Click on any item in the photo for information on that item, or look in the list below.



Click on any item in the photo for information on that item, or look in the list below.

Introduction:

Section 3 (Left Side of the Photo):
Section 3 is a set of classic Drake Twins, The R-4A receiver and T-4X transmitter. These two work together as a transceiver, and represent the state of the art in 1965. In 1965, this was the kind of gear that royalty and senators used. The T-4X transmitter puts out well in excess of 100W, and, with proper crystals, the pair can operate anywhere in the HF bands, not just the ham bands. Drake gear was used by hams, the military, the commercial sector, and the government. The pair cost $800 in 1965, equivalent to over $6000 in 2016 dollars. This set of twins is fully restored and, though the performance of the pair is not as good as today's modern transceivers (heck, they are 60 years old!), it is still very good, and the pair is a real pleasure to use.

Section 4 (Right Side of the Photo):
Except for the manual T/R switch on the desk, all of the equipment in section 4 is homebrew. The upper shelf of this section contains the AA8V digital VFO-6AG7 Amplifier-6146B amplifier system. The digital VFO is just below the shelf on top of the Wingfoot Exciter "Grid Box". On the desk under the shelf is the Wingfoot VFO Exciter. The VFO tuning control or "Grid Box" is on the left (under the digital VFO), and the main transmitter is on the right. To the right of the shelf, on the desk, are the meters for the Wingfoot Exciter and the Wingfoot 813 Amplifier. The desk contains an Automatic T/R System and the remote mode control for the Wingfoot Exciter.

The AA8V Station
Sections 3 and 4

Drake T-4X Transmitter: The Drake T-4X transmitter was marketed by Drake in 1965. It was reviewed in the May, 1966 issue of QST Magazine. Along with Collins Radio, Drake gear was the finest gear available at that time. In 1965, this was the kind of gear that royalty and senators used. Drake gear was used by hams, the military, the commercial sector, and the government. In 1965 it cost $400, and the power supply was another $100. That is the equivalent of about $3800 in 2015 dollars! It is rated at 200W PEP input, and can operate on the 80m, 40m, 20m, 15m, and 10m band with the supplied crystals. With the addition of extra crystals it can operate, with a few exceptions, anywhere between 1.8MHz and 30MHz. In 1965, it was one of the few transmitters that could, when fitted with the proper crystal, operate on 160m. This particular T-4X has crystals for the 160m and 30m amateur bands. It was completely restored and realigned by me. All electrolytic and paper capacitors have been replaced with modern electrolytic or film capacitors. The power supply, which is a separate unit, has been gutted and rebuilt with a circuit board containing all new resistors, diodes, and capacitors. The circuit board/parts kit is available at a very reasonable price from from The Heathkit Shop, and I highly recommend it. I found this transmitter at a hamfest some 20 years after I purchased the matching R-4A receiver. It was a very, very lucky find! I am still using the same final tubes that were in the transmitter when I got it, and I have a new set of output tubes on hand in case I ever need them. However, since I keep the output down to 100W on CW, rather than driving the finals as hard as I can, I expect them to last a long time.

Digital VFO Keying Amplifier: My digital VFO is keyed so that it doesn't interfere with reception. This keying amplifier allows a single key to key transmitters with either grid block or cathode keying, and allows the same key to simultaneously key the digital VFO. I use it when operating the 6AG7 VFO amplifier or the Johnson Viking Ranger transmitter. It uses a 9V battery, and I have to remember to occasionally change the battery.

MFJ-1700B Receiver/Transmitter Switch: The MFJ-1700B is a pair of six position switches (only one switch is visible in the photo) in a single case originally intended to switch one of six transceivers to one of six antennas. I obtained it from the estate of Tom Carroll, WA8ZGL, one of my dearest friends, now a silent key. It is no longer available, but is essentially two MFJ-1701 antenna switches in a single case. Rather than use the switches as intended, I use them to connect one of six transmitters and one of six receivers to a single T/R relay or switch.. This allows me to change transmitters and receivers without plugging or unplugging any cables. It makes for a neat, clean setup.

Drake R-4A Receiver: The Drake R-4A receiver was marketed by Drake in 1965. Along with Collins Radio, Drake gear was the finest gear available at that time. In 1965, this was the kind of gear that royalty and senators used. Drake gear was used by hams, the military, the commercial sector, and the government. In 1965 it cost $400. That is the equivalent of about $3000 in 2015 dollars! The receiver can operate on the 80m, 40m, 20m, 15m, and 10m bands with the supplied crystals. With the addition of extra crystals it can operate, with a few exceptions, anywhere between 1.8MHz and 30MHz.. This particular R-4A has crystals for the 160m and 30m amateur bands. It was completely restored and realigned by me. All electrolytic and paper capacitors have been replaced with modern electrolytic or film capacitors. I found this receiver at a hamfest many years ago and had to pay what was, to me at the time, a fortune to get it. But is was well worth it. It is simply one of the finest receivers I have ever used, and has the best AGC that I have ever encountered in a receiver. It is a real joy to use. Some 20 years later I was lucky enough to purchase the matching T-4X transmitter. It was a very, very lucky find! Though the performance of the pair is not as good as today's modern transceivers (heck, they are 50 years old!), it is still very good, and they are a real pleasure to use.

Vibroplex Presentation Bug: When I started out as a ham many years ago, I started with a straight key. However, I quickly switched over to an electronic keyer and paddle. I found a Brown Brothers paddle, which I still have, and it was/is a tremendous paddle. However, in 2012 I decided to try a bug, and I never looked back. It is just plain fun to use! Though a bug takes a lot of practice to use well, I found that my musical talents fit very well with the rhythm of using a bug, and I picked it up fairly quickly. My bug is a Vibroplex Presentation. This has a gold plated top, which looks very nice (and has nothing to do with performance), and jeweled bearings (which have everything to do with performance). The jeweled bearings make the presentation worth the extra money. They allow for very smooth operation with no slop, and the result, if the operator is up to it, is very smooth CW. The weights supplied with this bug, as with all of them, are too light for slower speed operation. I machined a pair of large, brass weights for use with my bug. These allow me to cleanly send as slow as 13 WPM. The weights feature knurled set screws that allow for easy, precise control of the sending speed.

Manual T/R Switch: With some receiver and transmitter combinations I still use a manual transmit/receive switch. The switch switches the antenna from the receiver to the transmitter and vice-versa, and it must be thrown at the beginning and ending of every transmission. Operating with a manual T/R switch really lets you know what it was like to operate in the early days of amateur radio.

Leather Desk Pad: I like to copy down everything on CW 100%, and I use a leather desk pad to provide a good, sound writing surface. Leather pads are expensive, but once you use one you will never go back to anything else. Large leather pads like the one in the photo can be obtained from The Elegant Office.

AA8V 6AG7 VFO Amplifier: The 6AG7 VFO amplifier is a class A RF power amplifier designed to take the signal from the AA8V digital VFO and raise it up to approximately 3W. It contains a built in power supply and operates on the 80m, 60m, 40m, 30m, and 20m bands. It can be used by itself with the digital VFO as a QRP transmitter, or it can be used to drive the AA8V 6146B linear amplifier.

AA8V 6146B Linear Amplifier: The AA8V 6146B linear amplifier is a class AB2 linear RF amplifier. When driven by the 6AG7 amplifier and digital VFOit will produce an output of 50W on the 80m, 60m, 40m, 30m, and 20m bands. The amplifier has a built in power supply with regulated fixed bias and screen voltage (with screen grid protection) and has a single meter that can be switched to read the grid, screen, or plate current.

AA8V Digital Keyed VFO: I designed a digital keyed VFO based on the N3ZI synthesizer board that I use with all of my crystal controlled transmitters, such as the Johnson Viking Ranger and my 6CL6 transmitter. I also use the VFO with my 6AG7/6146B transmitter system. An article on the VFO was published in the January 2014 issue of QST Magazine. The VFO has a resolution of 1Hz, an output of 5 volts peak-to-peak up to 7MHz, and has useful output up to about 30MHz. It features a spotting switch, has 12 different memories, and can also be used as a signal generator. It is keyed via a keying amplifier that also simultaneously keys the transmitter. Keying the VFO keeps it off frequency during receive periods so it doesn't interfere with reception.

Wingfoot VFO Exciter Grid Box/VFO Control: The Wingfoot VFO Exciter uses a Clapp oscillator circuit and has the oscillator LC tuned circuit on a separate chassis called the "Grid Box". The Grid Box is connected to the main transmitter chassis with two coaxial cables. This keeps the tuned circuit away from the heat produced by the exciter, and the result is a VFO with stability rivaling modern solid state transceivers. The Grid Box is built like a tank out of very thick aluminum and uses a very high quality coil, variable capacitor, and very high quality air trimmer capacitors. A National 5 to 1 reduction drive drives the variable capacitor. The VFO operates at 3500kHz on all bands except 30m, where it operates at 3367kHz.

Wingfoot VFO Exciter: The Wingfoot VFO Exciter is a remarkable transmitter built and designed by Jim Trutko, W8EXI, in the late 1950s with the help of the Goodyear Aerospace Corporation, where Jim worked. Jim passed the transmitter on to me when he retired and I restored it. It features an ultra stable VFO with stability comparable to modern transceivers. This is achieved by placing the frequency determining components on a separate chassis or "Grid Box" connected to the exciter by coaxial cables. The exciter uses timed sequence keying which gives it exceptional keying, and it operates on the 80m, 40m, 30m, and 20m amateur bands. The output is continuously adjustable from 3W to 27W via a variable screen voltage regulator circuit on the 2E26 final amplifier. The power supply for the exciter is a separate unit that rests on the floor. A separate remote mode switch is used to control the exciter. The "Wingfoot" name comes from the Wingfoot trademark that the Goodyear Tire and Rubber Company has used for years.

AA8V Automatic T/R System: To make operation with my vintage receivers and transmitters as easy as with modern transceivers, I designed a solid state T/R system that places the station in transmit mode automatically when the key is pressed, and holds it in transmit mode for an adjustable time after sending ceases. I use this system with the 6x2 and SX-96 receivers, and the 6AG7/6146, Wingfoot VFO, and Johnson Viking Ranger transmitters. The key is plugged into the front of the unit, and then the unit is connected to the key jack of the transmitter. It can accommodate both negative and positive keyed transmitters. The back of the system has a normally off 120V AC outlet and a normally closed RCA jack. A Dow-Key 120V coaxial antenna relay is plugged into the 120V AC outlet, and the mute circuit of the vintage receiver is connected to the normally closed RCA jack. When the key is pressed, the 120V outlet is turned on, activating the T/R relay, and the normally closed circuit is opened, muting the receiver. A red light turns on indicating that the system is in transmit mode. An adjustable timer keeps the circuit in transmit mode for a short time after sending ceases. The T/R circuit can also be switched off if desired, or manually switched to transmit mode. Besides controlling the transmitter and T/R system, the key also keys a sidetone generator with adjustable pitch and volume controls. The sidetone can be turned off with a switch if desired.

Wingfoot VFO Exciter Meters: In most vintage transmitters a single switched meter is used to measure the final amplifier grid, screen, and plate currents. The Wingfoot VFO Exciter instead uses three separate Weston meters to simultaneously measure all three currents. Purchased new back in the 50s and 60s, Weston meters would have been very expensive (back in 1967 a single meter cost $14.40 or about $100 today!), but they were also available surplus at very reasonable prices, so using three meters wasn't quite as extravagant as it might seem. The top meter measures grid current (10mA full scale), the middle meter screen current (10mA full scale), and the bottom meter plate current (100mA) full scale. When the entire Wingfoot system is in use, all six meters kick up and down with keying, and are a wonder to behold. The entire operation of the system can be assessed with a single glance at the meters.

Wingfoot 813 Amplifier Meters: In most vintage amplifiers a single switched meter is used to measure the final amplifier grid, screen, and plate currents. The Wingfoot 813 Amplifier instead uses three separate Weston meters to simultaneously measure all three currents. Purchased new back in the 50s and 60s, Weston meters would have been very expensive (back in 1967 a single meter cost $14.40 or about $100 today!), but they were also available surplus at very reasonable prices, so using three meters wasn't quite as extravagant as it might seem. The top meter measures grid current (100mA full scale), the middle meter screen current (100mA full scale), and the bottom meter plate current (500mA) full scale. When the entire Wingfoot system is in use, all six meters kick up and down with keying, and are a wonder to behold. The entire operation of the system can be assessed with a single glance at the meters.

Manual T/R Control for the Wingfoot VFO Exciter: The Wingfoot VFO Exciter uses a remote mode switch to control the exciter. Three modes are available: Operate, Standby, and Spot. In Standby mode only filament voltages are applied to the exciter. This keeps the system warmed up. Also, a 120V AC outlet on the Wingfoot exciter, used to switch a remote T/R coaxial relay, is turned off. In Spot mode, all stages operate except for the final amplifier. The120V AC outlet is also turned on. This places the entire system in transmit mode (except for the final amplifier) and allows the operator to key the transmitter and listen to the signal in the receiver, without putting a signal on the air. This is called "Spotting" the signal in the receiver. In Operate mode all stages are activated, including the final amplifier, and the 120V outlet is turned on, placing the entire system in transmit mode. The remote control is fitted with an internal relay that operates on 120V that can switch the mode remotely from Standby to Operate. A remote-remote control! When plugged into the Automatic T/R system, the Wingfoot VFO system can be automatically switched from Standby to Operate at the touch of the key. Spot mode must still be entered manually via the knob on the remote control.

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