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PR20—1 

 

220 MHz 

LOW NOISE 

PREAMP 

KIT 

16 db Gain, 1 db Noise Figure 

Runs on 9 to 15 VDC 

Hi-Q tuned input to reduce 
overload 

Small size to fit in any rig 

The most popular preamp kit in 
the USA! 

Easy 15 minute assembly 

Perk up your reception  on 220 MHz with this easy-to-build and install kit. 
Works well with any radio - especially effective in repeaters. Rugged design 

using a microwave transistor outperforms units costing triple the price! 
 
                                                                    

Kit No. PR20 

Summary of Contents for PR20

Page 1: ...mall size to fit in any rig The most popular preamp kit in the USA Easy 15 minute assembly Perk up your reception on 220 MHz with this easy to build and install kit Works well with any radio especiall...

Page 2: ...s may be designed for either RF or audio use and may be either tuned or broadbanded The Ramsey Low Noise PR10 20 and 40 Preamplifiers for 144 220 and 440 MHz respectively differ from our popular SA7 a...

Page 3: ...a bipolar silicon NPN low noise UHF VHF amplifier in a TO 92 case suitable for service up to 5 GHz with maximum device dissipation of 600 milliwatts Q1 has a very low noise figure determined by the bi...

Page 4: ...isc capacitor may be marked 01 103 or 10nF C5 RESISTORS 1 470 ohm yellow violet brown R1 1 100K ohm brown black yellow R2 OTHER COMPONENTS 1 PRX printed circuit board 1 shielded adjustable coil L1 mar...

Page 5: ...PR20 5 RAMSEY PR20 PRE AMP PARTS LAYOUT NOTE FOR PR 20 Disregard C6...

Page 6: ...he first try For your convenience the PC board is considerably enlarged While working with a small PC board such as the PR20 a miniature vise plus a magnifier may prove very helpful In all steps below...

Page 7: ...tion Press the transistor in place firmly with finger pressure so that a minimum amount of wire leads are exposed above the PC board In soldering do not be afraid to apply enough heat to make good cle...

Page 8: ...opriate part installations Correct parts placement checked PC board soldering checked touched up if needed INPUT AND OUTPUT CONNECTIONS Use short pieces of miniature coax such as RG 174 to connect the...

Page 9: ...is is a low noise preamp don t look for an imaginary increase in noise level or waste time trying to make a strong repeater signal seem stronger CAUTION Under no circumstances should transmitter RF ev...

Page 10: ...e Use good quality miniature coaxial cable STRONG SIGNAL OVER LOADING If you live in a situation where there are very strong nearby stations you may experience overloading of the receiver to which the...

Page 11: ...ures an on board battery supply adjustable gain control heavy duty whip HF VHF mode switching and jack for using external antennas T R SWITCHING CONSIDERATIONS FOR TRANSCEIVER OPERATION If you wish to...

Page 12: ...Other maximum ratings Collector to Base Voltage 25 V Collector to Emitter Voltage 12 V Base to Emitter Voltage 3 V Maximum Collector Current 70 mA Standard replacements ECG10 or SK9139 You may of cour...

Page 13: ...gth of resistors or capacitors Erratic operation will be traced to poor input output or voltage connections or a faulty solder connection CONCLUSION Please make sure your preamplifier is working as or...

Page 14: ...so with very low noise plus the convenient AC power supply BNC I O connectors and LED ON OFF indicator of the Ramsey PR2 available factory wired The PR2 uses advanced microwave MMIC for signal to nois...

Page 15: ...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 BE return...

Page 16: ...Professional FM Stereo Transmitter RAMSEY RECEIVER KITS FR1 FM Broadcast Receiver AR1 Aircraft Band Receiver SR2 Shortwave Receiver SC1 Shortwave Converter RAMSEY HOBBY KITS SG7 Personal Speed Radar...

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