User manual RAMSEY PA1

[. . . ] 590 Fishers Station Drive Victor, New York 14564 Phone (585) 924-4560 Fax (585) 924-4555 www. ramseykits. com PA-1 · 3 PA1 AMPLIFIER All of us at Ramsey say THANKS for your interest in building the world's most popular 2 Meter amplifier project. Successful construction and installation of your PA1 amplifier can give your handheld 2 Meter transceiver an RF power boost beyond the performance of many fixed and mobile units. BEFORE you begin building your PA1, we ask you to read the warranty information on page 14 and think about a few details in advance: The PA1 is a true "Ham Radio" kit project which presumes the expertise that goes along with your license. You need to know how to "tack solder", wind simple VHF coils per our directions, and how to finish your PA1 with suitable enclosure, connectors, T-R switching and I/O wiring. [. . . ] It is easily made by passing or "lacing" 5 turns of the #24 bare wire through its holes. (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. 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. 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. The final circuit-wiring steps consist of the CORRECT installation of two small 47 or 56 pf disc capacitors. This step is more critical than many builders may realize, because excess lead-length of C5 and C6 will reduce power output and induce feedback!The bodies of C5 and C6 should fit snug against Q1 and you should see little or no capacitor wire lead at all!Install C6, just like C5. FINAL PC BOARD WIRING BEFORE TESTING: 18. Use good-quality coax terminated to fittings for your own application. Install coaxial input and output lines. Take a moment now to review your work. This effort can actually improve performance as well as make you proud of your work and enhance the resale value of your amplifier. There should be NO evidence of excessive wire length or roughlooking solder joints. PA-1 · 10 INITIAL TESTING · · · · · Required for testing: 1 to 5 watt 2 Meter transmitter or transceiver. [. . . ] 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. Because of the variety of ways in which this kit can be constructed and mounted mechanically, we cannot offer any kit repair service. So, if this kit appears too complex for your abilities, please return it for a complete refund. [. . . ]