First Generation PA

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The Quantar First Generation UHF Power Amps cover UHF R1, R2, R3 and R4. R0, 380-433 MHz, was a slight redesign, and it is covered else where.

Basics

The Basic module is pictured below.

First Generation PA Layout

The major parts of the PA are

  • Printed circuit board
  • Intermediate PA
  • Final PA
  • Circulator
  • Low Pass Filter

Each of these parts varies depending on the range of the PA.

Band IPA FPA Circulator LPF
R1 TLE9150 TTE6321 5884911T04 TTE6331
R2 TLE9150 TTE6322 5884911T04 TTE6332
R3 TLE9160 TTE6323 5884911T18 TTE6334
R4 CLE6090 TTE6342 5884911T18 TTE6334

The IPA module is a 10 W output that feeds into the FPA. Note the schematic diagram has some errors on it regarding a 30-35W output from the IPA. This is an error as it's from the 25W UHF PA diagram.

The FPA module consists of two parallel PA strips with two FET's each for a total of four devices. Each strip is addressed as "A" and "B" in the radio for the current monitoring of the PA.

Unfortunately there is no diagram of the IPA or FPA modules.

Note there is no CPU or even much digital circuitry in the PA. All metering is done via the exciter CPU mostly using an analog input and switches (U4103/4) to switch this input between different voltages on the PA.

The exciter controls the output power by an analog output (V_CONT) 0-5v from the CPU. This voltage is then used to control a couple transistors (Q4100 & Q4101) making the V_OMNI voltage that varies the first stage in the Intermediate PA.


The complete schematics are PNG format and are also available as a PDF

Pictures

This is a UHF R2 Generation 1 PA I took pictures of.

Conversions

Converting from a R1 to R2 is quite easy.