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PA-1 

 12  

TRANSMIT-RECEIVE ["T-R"] SWITCHING CONSIDERATIONS: 
 

T-R switching of a single antenna with a 2 Meter transceiver and the PA1 RF 
amplifier may be accomplished in any of these ways:   
 

1. Internal connections to your transceiver, making use of its built-in T-R  
switching circuit or relay.   

 

2. External T-R relay controlled by transceiver microphone switch or relay  
line.    

 

3. RF-activated T-R switch such as the Ramsey RFS-1 kit.  

 

4. PIN-diode T-R switching.  

 
 You have to make your own decision about whether to tie into any of the  
internal circuitry of your transceiver. It depends on how comfortable you are in 
doing so, how dependent you are on factory or professional service, and the 
policy of the service center on modified equipment.   
 
We developed the RFS-1, T-R relay kit exactly for those situations where PA1 
operation is needed but there is reluctance to make additional connections in 
and out of a costly hand-held transceiver. The RFS-1 kit is very economically 
priced and includes a heavy-duty 12-volt relay. Sorry, but we cannot make the 
PC board or individual parts available separately from the entire RFS-1 kit. 
 
The use of PIN diodes for T-R switching is discussed amply in recent editions of 
the ARRL Handbook and in ham radio magazine articles. A practical circuit 
requires two suitable PIN-diodes, RF chokes, bias supply and either a quarter- 
wave line or tuned circuit for receiver isolation.    

Содержание PA1

Страница 1: ...nd connectors Informative manual answers questions on theory hookup and uses enhances resale value too Maximum output of 35 40 watts max drive of 8 watts Mounts in any small aluminum case which then w...

Страница 2: ...tion Detector ML Music Lights Kit LC1 Inductance Capacitance Meter RAMSEY AMATEUR RADIO KITS HR Series HF All Mode Receivers QRP Series HF CW Transmitters CW7 CW Keyer QRP Power Amplifiers RAMSEY MINI...

Страница 3: ...y 6 Parts Layout Diagram 6 Schematic Diagram 7 Testing 11 Troubleshooting 11 Transmitting Receiving 12 Customizing 13 Installation 13 Operating Your PA1 13 Warranty 15 KIT ASSEMBLY AND INSTRUCTION MAN...

Страница 4: ...ur final T R installation to boost those hard to copy signals We ask you to understand that the VHF Power Transistor that is the heart and soul of this circuit cannot be guaranteed beyond careful test...

Страница 5: ...kside of the board to prevent the part from falling out before soldering The part is then soldered securely to the board and the remaining lead length is then clipped off PA1 PARTS LIST 1 PA1 Printed...

Страница 6: ...er step Right now simply position it in place and observe how far its flat leads extend toward the input and output pads Scribe a line into the tinned pads at each end of these two leads as a guide to...

Страница 7: ...PA 1 7...

Страница 8: ...you can see some finished work on your PC board this is a good time to begin making and installing the three coils and RF Choke 9a Cut a 1 length of 18 tinned bare wire and form it as shown making a g...

Страница 9: ...12b Install the RF choke 13 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 t...

Страница 10: ...ps 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 outp...

Страница 11: ...r a sudden peaking of RF output C2 has the most direct and critical control over the driving of Q1 3 After some power output is noted from peaking C2 then adjust both C3 and C4 for maximum output Then...

Страница 12: ...in doing so how dependent you are on factory or professional service and the policy of the service center on modified equipment We developed the RFS 1 T R relay kit exactly for those situations where...

Страница 13: ...ll have as much fun using your amplifier as you had building it INSTALLATION NOTES 1 The best location for the relay is as close to the PA1 amplifier PC board as possible with a short solid connectio...

Страница 14: ...ent right from the start CONVERSION STEPS 1 Lift the ground side of the RF choke 2 Solder a 1 amp diode s cathode lead banded end directly to the emitter ground connection of the RF power transistor K...

Страница 15: ...ur abilities please return it for a complete refund The PA1 kit is designed for the advanced builder who appreciates the convenience of having all the hard to get parts available from one reliable sou...

Страница 16: ...y and Instruction manual for RAMSEY MODEL NO PA1 2 METER RF POWER AMPLIFIER KIT RAMSEY ELECTRONICS INC 590 Fishers Station Drive Victor New York 14564 Phone 585 924 4560 Fax 585 924 4555 www ramseykit...

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