Palomar PTR130K  Please note I am in the process of documenting information on these transceivers for those interested. This information may have errors at this time.

The PTR130K was an HF transceiver, I designed as a consultant, for Palomar Electronics. It was never manufactured in large quantities. It was started a little to late at a time when Palomar Electronics was loosing it main source of revenue, the sale of solid state HF power amplifiers, as a result of new (1977)  FCC rules.

The control for the radio is a simple calculator chip that was made by Mostek. The logic is simply making use of the numbers fed to the display when calculations are made.

Synthesizer

The synthesizer is a dual loop system.

 The primary loop consists of the circuits including oscillator Q207 and ICs U207, U210, U211, U215, U216, U218. This loop generates frequencies from 45 to 74 MHz corresponding to radio frequencies of 1 to 30 MHz. The basic tuning of this loop is controlled by the tens, and ones MHz decades and the  hundreds and tens KHz decades. Note: Ones KHz and the hundreds Hz decades also cause changes in the tuning of this loop, these lower decades should be set to zero when testing this loop.

The secondary loop consists of the circuits including oscillator Q200, and ICs U208, U217, U205? (SL1640), U212, U213. Its loop oscillator tracks the primary loop tuned by D20? (6510 not D204 which tunes the primary oscillator).  The signal produced by the oscillator  Q200 is buffered by the SL1610 U?? and mixed with the signal output from the primary loop. With both loops locked and the ones KHz and the hundreds Hz decades set to zero the desired output from U205? (SL1640) would be 3.960 MHz.  This signal is divided by two in U219 and applied to the programmable divider U208. U217 is a  phase detector that compares the output from U208 to 4.95 KHz, derived from the reference oscillator (990 KHz) divided by 200 in U212 and U213. The filtered phase detector output locks the secondary loop to  primary loop output - U208 division ratio * 4.95 KHz by fine tuning the primary oscillator via D202.

 The final LO output frequency (secondary loop frequency) is the primary loop frequency - the mixer output frequency which is set by the division ratio of U208. Therefore: Increasing the division ratio of U208 by one would reduce the output frequency by 9.9 KHz. There are adders  at the program jam inputs of the primary loop programmable dividers ( U??? {CD 4049} and U207) that cause its output frequency to increase  by 10 KHz for each 9.9 KHz added to the secondary loop. The net result of this is that the output frequency steps in 100 Hz steps as the division ratios  of U208 and U207 are incremented.

Notes

• First IF 40.040 MHz
• LO2 Frequencies  40.495 MHz and 39.585 MHz
• Second IF 455 KHz.
• Synthesizer ref oscillator 990 KHz
• Primary synthesizer loop tuning range 45 to 74 MHz.
• Secondary loop output tuning range 41.04 to 70.04 MHz.
• Secondary loop mixer output range ( when locked) 3.960 to 3.9699 MHz

Schematics

• Controls
• Front Panel
• Power Amplifier
• Receiver Exciter
• RF Filters
• Synthesizer