User manual RAMSEY PA1

[. . . ] 2 METER RF POWER AMPLIFIER KIT Ramsey Electronics Model No. PA1 Give your handheld a big boost with this economical power amplifier kit. Thousands have built and enjoyed this kit; one magazine review even said, "probably the best bargain in Ham radio!" · · · · · · · · · · Works with any radio; mobile, fixed or handheld 8 to 10 times the power gain: 10 watts out for every 1 watts in, 20 watts out for every 2 watts in, 30 watts out for every 3 watts in!Easy connection to a radio Operates on 12 - 14 volts DC, draws a maximum of 5 amps Just add a T-R relay, case, Pre-amp if desired and connectors Informative manual answers questions on theory, hookup and uses enhances resale value, too! [. . . ] Using the #18 enameled wire, wind a 5-turn coil for L3. The inside diameter is also 1/4", the turns should be close-wound, and the ends should be 1/4-inch long. Using a small knife or sandpaper, scrape the insulation from each end, tin the bare ends with solder, and gently bend the ends as needed so the coil sits in its position correctly and neatly. Install L3. L3 side view L 3 to p v ie w 12a. The RF choke consists of a ferrite bead with 6 holes. It is easily made by passing or "lacing" 5 turns of the #24 bare wire through its holes. This will fill 5 holes with a lead coming out at each end. (Note that trying to fill the 6th hole would cause both wire ends to come out of the same end of the ferrite bead. ) Trim the ends to 1/4" and bend as needed for neat installation. RFC 1 12b. Install bypass capacitor C7, . 01 uf (marked . 01 or 103 or 10 nf) from the DC voltage pad to the ground plane. VERY IMPORTANT: PLEASE READ!The RF Power Transistor MUST be mounted to its heatsink (usually the metal case enclosure) B-E-F-O-R-E it is soldered to the circuit board. This is necessary for the sake of your investment as well as the health of the transistor. It is VERY easy to crack the transistor's case and break off the leads if you attempt to tighten the nut AFTER soldering. As has been explained, Ramsey Electronics' warranty on this transistor covers ONLY fresh, nonsoldered units which prove to be electrically defective before any installation attempt. So. . . NOW is the time to decide how you are going to enclose your PA1. If that decision is still to come and you wish to experiment with the performance of the PA1 before designing a finished accessory such a "docking booster", then PA-1 · 9 make a suitable HEATSINK for Q1 and install it before proceeding. A piece of heavy aluminum or copper the same size as the PA1 circuit board will work fine. Even when securing Q1 to such a heatsink, do not use too much force. Observe the correct orientation of Q1 on the actual circuit board when mounting it to the heatsink. The collector lead (output side) has a 45-degree cut that is plainly visible. Pre-tin both the upper and lower surfaces of all four leads of power transistor Q1. After reviewing the mounting information, mount Q1 to its heatsink or section of metal enclosure. After double-checking the orientation of the collector lead, solder all four Q1 connections. [. . . ] Connect the remaining end of the 500 ohm pot through a 51 ohm resistor to a neatly routed wire to the +12 volts DC input to the PA1. Set up a 0-100 milli-ammeter or VOM to monitor Q1's collector current. Keeping your tests short, adjust the 500 ohm pot for about 50 mA of collector current. Do not exceed 100 mA! PA-1 · 14 PA1 WARRANTY NOTICE: The PA1 kit is the only item in the entire Ramsey product line that is not covered under any warranty. [. . . ]