Elecraft AT1 41 dB Step Attenuator - Manual

Elecraft • www.elecraft.com • 831-662-8345
E L E C R A F T A T 1 S t e p A t t e n u a t o r
Assembly and Operating Manual
E740101: Revision A, September 7, 2006
Copyright © 2006, Elecraft; All Rights Reserved
Introduction
The Elecraft AT1 is a versatile and accurate HF/VHF step attenuator that permits selecting any level of attenuation between 0
and 41 dB in 1 dB steps. The AT1 features an unusually high upper power limit of 2 watts, making it ideal for many
applications where attenuators with a lower power rating cannot be used such as at the output of a QRP transmitter for QRPp
experimentation.
The AT1 step attenuator is designed to be used as a stand-alone unit. Optionally, it may be built into existing equipment or an
enclosure of your choice. See Assembly Options on page 2 for more information.
The AT1 uses no surface-mount technology, so it’s an ideal project for first-time builders.
Specifications
Size: 5-3/8” x 2-11/16” (13.7 cm x 6.8 cm)
Range: 0 to 41 dB in 1 dB steps
Accuracy: Below 50 MHz: ± 0.25+0.01(A) dB
54 to 200 MHz: ± 0.50+0.01(A) dB
Where A is the attenuation selected in dB
Tools Required
You will need the following tools to build this kit:
• Fine-tip soldering iron. Recommend a temperature-controlled soldering station with 700 to 800°F tip (370-430°C).
• IC-grade solder (Kester #44 or equivalent). Small diameter solder (e.g. .031”) is easiest to work with on small
printed circuit boards. DO NOT use acid-core solder, water-soluble flux solder, additional flux or solvents.
• Diagonal cutters.
• Needle-nose pliers.
Parts List
We recommend that you do a complete inventory before beginning assembly. The inventory helps you correctly identify all
the parts to avoid mistakes during assembly.
Identifying Parts
The resistors in this kit all have value stamped on their bodies. For example, a 39-ohm resistor may be stamped “39Ω”.
Others, like the 910 ohm resistors may be marked with numbers similar to color codes. For example, a 910-ohm resistor may
be marked “911” indicating 91 x 10 or 910 ohms. In those cases the numbers you should find on the part are shown in
parenthesis after the value. There will be other numbers and letters stamped on them as well. You can ignore them. As long
as you find the numbers given, you have the right part.
Reference. Designator Description Qty
Part
Number
Misc. AT1 Step Attenuator printed circuit board 1 E100309
J1, J2 BNC Connector, PC Mount 2 E620020
R1, R3, R4, R6 910 Ω (911) 1W Resistor 4 E500256
R2, R5 5.6 Ω (5R6) 1W Resistor 2 E500257
R7, R9 300 Ω (301) 1W Resistor 2 E500258