• High gain - 20 dB Broadband coverage. • Excellent review in Feb. 90, 73 Magazine. • Two stage feedback design ensures stable operation. • Runs on 12-15 VDC @ 15 mA. • Complete with applications and hook-up instructions. BROADBAND RF PREAMP ———— 100 KHz - 1.3 GHz Perk up that old receiver! Great for scanners, TV sets, frequency counters, shortwave sets, anywhere a stable 20 dB gain is needed! SA7—1 Kit No.
SA7 INTRODUCTION: A "preamplifier" gives an initial boost, measured in decibels, to the level of a signal before it is processed by tuned circuits, filters, amplifiers, mixers, detectors or other circuit stages. Preamps may be designed for either RF or audio use and may be either tuned or broadbanded. The SA7 is indeed a "general purpose" RF pre-amplifier. While we realize that most users understand the term "broadband", we understand that some of you would appreciate some clarification.
PARTS SUPPLIED WITH SA7 KIT Capacitors 1 2.2 pF capacitor [axial style, green body with red bands] (C6) 1 4.7 or 5 pF disc capacitor (C1) 3 .01 uF disc [marked .01 or 103 or 10 nF] (C2,3,5) 1 4.
REQUIRED, NOT SUPPLIED 8-15 VDC power source your choice of power on-off switching RF input and output connectors (your choice of type) enclosure of your choice, if SA7 is not mounted inside receiver or counter, etc.
SA7 PRE-AMP ASSEMBLY PROCEDURE Soldering 15 parts to a PC board is not a big job, but good performance of the SA7 requires attention to keeping all leads as short and neat as possible. The order of the parts installation is not critical for this and other small kits, so the purpose of following the suggested order of assembly is just to make it as easy as possible for you to get the right parts in the right holes.
5. Install C5, .01 uF. Notice that C5 lines up with the DC voltage supply points on the PC board. If you have your red (+) and black (-) supply wires ready, they could be installed now while correct polarity is on your mind. 6. Install R4, 1K ohms (brown-black-red). Note that this resistor is installed vertically, with the resistor body closest to Q1. 7. Install C4, the one electrolytic capacitor. Make sure polarity is correct. 8. Install R5, 100 ohm (brown-black-brown). 9.
Installation of C6 and R6. The style of these components might be new to you, but don't be concerned. We'll get them in right. Having installed all the conventional resistors according to color code, note that the remaining resistor-like part is marked with 6 bands; the first two at one end should both be red. This is the 2.2 pF axial capacitor. Install it between Q1 and R3, taking care that the capacitor body is as close as possible to the PC board. 13. C6, 2.2 pF capacitor installed.
Procedure for installing SMT R6: 1. Unpack from cardboard protective holder and study how R6 is made, using the magnifier if necessary. 2. Notice that both ends are metallic - these are the soldering points. 3. Lightly pre-tin the PC board trace points where R6 is to be positioned. Do not make too heavy a solder build up. 4. Holding R6 in position with tweezers, touch one end and the PC trace with the soldering tip. The solder should flow nicely.
USING YOUR SA7 PRE-AMP The very best way to find out what your SA7 can do, and also cannot do, is to set one up right from the beginning with the input and output connections most practical for your uses. If you are building it with no specific or "dedicated" use in mind, we suggest that you setup its connections to serve as a sort of quickconnect test instrument. Try it out in a variety of situations.
FINAL NOTES ABOUT BROADBAND PRE-AMPS Yes, the Ramsey SA7 or PR2 RF pre-amp will give that promised boost to the signal strength of that distant FM broadcast station that your wife, sister or dad wants to tune in without so much static.
BROADBAND "ACTIVE ANTENNA" For situations where a short or indoor receiving antenna is needed, the SA7 preamp will give considerably improved performance even if the antenna is little more than a collapsible whip or short length of wire.
Adding a tuned RF input SA7 ANT Freq. = SA7—12 1 6.
WARNING: Under no circumstances should transmitter power be applied to the SA7. Although this seems common-sense, most receivers are in transceiver configuration and one slip of the mike key will blast your little SA7 to La-La Land.
The Ramsey Kit Warranty Please read carefully BEFORE calling or writing in about your kit. Most problems can be solved without contacting the factory. Notice that this is not a "fine print" warranty. We want you to understand your rights and ours too! All Ramsey kits will work if assembled properly. 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.
Ramsey Electronics project kits are packed with pride in the USA. If you believe we packed an incorrect part or omitted a part clearly indicated in your assembly manual as supplied with the basic kit by Ramsey, please write or call us with information on the part you need and proof of kit purchase 3. FACTORY REPAIR OF ASSEMBLED KITS: To qualify for Ramsey Electronics factory repair, kits MUST: 1. NOT be assembled with acid core solder or flux. 2. NOT be modified in any manner. 3.
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