User manual RAMSEY DDF1

[. . . ] DOPPLER DIRECTION FINDER RADIO DIRECTION FINDER KIT Ramsey Electronics Model No. DDF1 Get in on the fun of radio direction finding (RDF) with this super kit !The latest in affordable Doppler direction finding equipment available in a complete kit form . . this one even includes the receiving antenna. A must for the "fox hunter" at an unheard of price! · · · · · · · · Elegant and cost effective design thanks to WA2EBY ! [. . . ] Identify and install small signal diode D1, 1N4148 (glass bead type with polarity band). There is another plated through hole inside the silkscreen for R16 that is not the installation hole. Install R11, another 33K ohm (what were those colors). . . . (orangeorange-orange). Install a 324 Op amp in the U1 position, paying attention to the correct part placement. Let's finish up the components on the "component" side of the circuit board. 83 for the final component on the main board component side, install C38 (. 01uF) (marked . 01 or 103 or 10nF). DDF1 · 22 Whew!Take a few minutes now to double check your work, especially the placement of the polarized and orientation specific components. The next time we re-visit this board we'll be ready to energize the circuit, so this is your last chance to "get it right the first time" and avoid timely circuit troubleshooting. Remember that time spent here can save a lot of time (and expense!) when the unit is initially turned on. In the final assembly steps for the DF main board, the components will be mounted to the SOLDER SIDE of the circuit board (aren't you glad you didn't jump ahead)!This will allow for correct orientation of the controls through the case assembly. These controls and displays will be the ones you'll be looking at for years to come, so take your time to ensure proper positioning of each component. Moving to the solder side of the circuit board, identify the locations for S1 (power), S2 (scan stop), and S3 (phase invert). Carefully insert the slide switches into position (one at a time is fine) in the S1, S2, and S3 positions. Ensure that each switch is mounted flush to the circuit board, and solder into place. The switches are DPDT type, so "up down" orientation is not critical. Check the placement of each switch by "test fitting" the circuit board into the upper half of the case assembly and observing the switch position. Take care not to "skew" the switch as it may bind during normal operation. Identify the 10K trimmer potentiometer (labeled 10K or 103 on the side of the pot). Note that the silkscreen for this part (and R19 and 36) is on the component side of the PC board. Install this potentiometer from the solder side of the circuit board in the R50 position. Check the parts placement diagram for correct placement if you are unsure. [. . . ] The very fact that your kit includes this new manual is your assurance that a team of knowledgeable people have field-tested several "copies" of this kit straight from the Ramsey Inventory. If you need help, please read through your manual carefully, all information required to properly build and test your kit is contained within the pages!DEFECTIVE PARTS: It's always easy to blame a part for a problem in your kit, Before you conclude that a part may be bad, thoroughly check your work. Today's semiconductors and passive components have reached incredibly high reliability levels, and its sad to say that our human construction skills have not! [. . . ]