Collins Military Navy ATC (ART-13) Transmitter and home brew HV/LV/28vdc power supply
The ART-13 Military transmitter was designed for airborne use in aircraft such as the B-29 Superfortress bomber during WW2. It is designed for both CW and AM use and is a real workhorse. The Navy also used this transmitter but changed the designation to ATC. The version I have here is an orginal Navy ATC, however since most people are familiar with the much more common Army Air Corps ART-13, I have used that designation throughout. However, this radio here is a genuine Navy ATC.
One interesting capability of this transmitter is the "autotune" function. What this provides is the ability to select, either from the radio panel or a remote control box, one of ten different channels. The autotune function changed the frequency to the desired one, plus adjusted the transmitter tuning to a preset alignment that had been performed manually when the frequency was originally established. A Collins inovation, the PTO or permability tuned oscillator, was used on this transmitter. This provided a highly accurate/repeatable setting of an adjustable oscillator that allowed precise frequency settings without the need for many crystals such as was the norm with most other military transmitters of the day. This ATC/ART-13 is in its exact military configuration, no internal or external modifications have been made to it. Many knowledgable people will note the tan colored capacitor mounted on the left. This is normal and is provided for by existing terminals for attaching such a condensor to ground. This provided additional loading and gives us a PI output rather than the existing L output. This is very useful particularly on 80 and 40 meters to aid in loading to the more common dipoles of today, as well as harmonic suppression. Some use a variable here, I found a 500mmf hv transmitting (mine is rated at 30kv because that is what I had) works very well for my antenna configuration.
There is a video clip of the ATC/ART-13 in operation in one of the other links on my main page.
The picture shown here is of my ATC/ART-13, along with a HV power supply in top of the ATC/ART-13. The ATC/ART-13 was normally powered by a 28vdc dynamotor that was used to provide the 400vdc and 1150vdc required. Configurations such as mine use a homebuilt power supply that runs off commonly available household 115vac main power. I like lots of indicators so there are quite a few lights on my power supply to denote various conditions of the supply, a white light indicates when the AC power supply is turned on, a green light indicates the ATC/ART-13 has been turned on as well (filaments active), a yellow light indicates that a 30 second timer has completed, which then activates the HV portion of the power supply. This delay is due to the fact that you don't want to accidently apply HV to the transmitter until the filaments of the tubes have had at least 30 seconds to warm up. There is also a toggle to flip between just activating the 400vdc portion, or activating the 400vdc and 1150vdc portions of the power supply. This is because some of the tuneup and alignment is done with only 400vdc, and it is easier to use this arrangement than have to physically disconnect the HV wire from the supply when it is not needed. There are then two more lights,a blue one to indicate the 400vdc portion is in operation and a red one indicating the 150vdc portion is also operating. The two HV sections are only active when the transmitter is actually keyed for transmitting, so the blue and red light go on and off with the keying of the PTT voice system, or when the transmitter is in CW mode. Finally, there are two meters, one that is switch selectable to measure either the HV (1150vdc) or LV (400vdc) sections, and a smaller meter to measure the filament (28vdc) portion. This power supply is capable of going up to 1500vdc, there is a variable adjustment also on the front panel, a variac, that allows adjustment of the primary voltage to the HV transformer, however I normally run the transmitter at it's military level, 1150 volts.
The red light on the ATC/ART-13 panel indicates that the autotune cycle has completed and the transmitter is locked on the desired frequency.
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