Ham Intern. Concorde III / Jumbo III / Multimode III
Oscillator frequencyVCO-frequency = Oscillator
frequency (Q2) - FIN
VCO-frequency = 20.105MHz -
2.55MHz = 17.555MHz @ Ch.1 Band 40
Output from BPF (T1 / T2) =
Oscillator frequency (Q2) + VCO-frequency
Output from BPF (T1 /
T2) = 20.105MHz + 17.555MHz = 37.660MHz @ Ch.1 Band 40
RX and TX
frequency = Output from BPF (T1 / T2) - IF-frequency
RX and TX
frequency = 37.660MHz - 10.695MHz = 26.965MHz @ Ch.1 Band
40
Programming Chart for PLL02A
| Band | Ch. | FIN | P0 | P1 | P2 | P3 | P4 | P5 | P6 | P7 | P8 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 40 | 1 | 2.55MHz | 1 | 1 | 1 | 1 | 1 | 1 | X | X | X |
| 40 | 2 | 2.54MHz | 0 | 1 | 1 | 1 | 1 | 1 | X | X | X |
| 40 | 3 | 2.53MHz | 1 | 0 | 1 | 1 | 1 | 1 | X | X | X |
| 40 | 4 | 2.51MHz | 1 | 1 | 0 | 1 | 1 | 1 | X | X | X |
| 40 | 5 | 2.50MHz | 0 | 1 | 0 | 1 | 1 | 1 | X | X | X |
| - | |||||||||||
| 40 | 40 | 2.11MHz | 1 | 1 | 0 | 0 | 1 | 0 | X | X | X |
| - | |||||||||||
| -80 | X | X | X | X | X | X | X | X | 0 | 0 | 1 |
| -40 | X | X | X | X | X | X | X | X | 0 | 0 | 1 |
| 40 | X | X | X | X | X | X | X | X | 1 | 1 | 0 |
| 80 | X | X | X | X | X | X | X | X | 1 | 1 | 0 |
| 120 | X | X | X | X | X | X | X | X | 1 | 1 | 0 |
Adjustment
| Reading Point | Adjustment | Description | Value |
|---|---|---|---|
| PLL | |||
| TP2 | VCO-Block Coil | VCO Voltage | 4 Volt @ 27.185MHz |
| OSCILLATOR | |||
| U1 Pin 3 | Check | Reference Oscillator | 10.240MHz |
| TP1 | CT1 | RX AM -80 Band | 19.880MHz |
| TP1 | CT2 | RX AM 40 and -40 Band | 20.105MHz |
| TP1 | CT3 | RX AM 80 Band | 20.330MHz |
| TP1 | CT4 | RX AM 120 Band | 20.555MHz |
| TP1 | CT5 | RX LSB 40 Band | 20.1035MHz |
| TP3 | CT7 | TX AM | 10.695MHz |
| TP3 | CT8 | RX LSB | 10.692MHz |
| Adjustment | Description | Value | |
|---|---|---|---|
| RECEIVER | |||
| T8 | RF Input | ||
| T9 | RF Input | ||
| T10 | RF Input | ||
| T11 | 1. IF | 10,7MHz | |
| T12 | 1. IF | 10,7MHz | |
| T13 | AM IF | 455kHz | |
| T14 | AM Detector | 455kHz | |
| T6 | SSB IF | 455kHz | |
| T7 | SSB Detector | 455kHz | |
| T18 | FM Discriminator | 455kHz | |
| RV6 | SSB AGC | ||
| RV10 | Squelch | ||
| TRANSMITTER | |||
| T1 | PLL Output to Converter | 37.660 - 38.100MHz for CEPT | |
| T2 | PLL Output to Converter | 37.660 - 38.100MHz for CEPT | |
| T3 | Transmitter Output AM | 26.965 - 27.405MHz for CEPT | |
| T4 | Transmitter Output AM | 26.965 - 27.405MHz for CEPT | |
| T5 | Transmitter Output AM | 26.965 - 27.405MHz for CEPT | |
| CT6 | Transmitter Output USB/LSB | 26.965 - 27.405MHz for CEPT | |
| RV2 | Bias Q8 | ||
| RV11 | AM/FM Output Power | 10 Watt | |
| RV3 and RV9 | SSB Modulation | 18 Watt p-p | |
| RV1 | FM Modulation | +/- 2kHz | |
| RV12 | AM Modulation | 90% | |
| RV5 | Carrier at SSB | Adjust for minimum carrier leakage | |
| METER | |||
| RV4 | RF Power Meter | 10 Watt | |
| RV7 | RF S-Meter | SSB (USB/LSB) | |
| RV8 | RF S-Meter | AM/FM |
| Pin | Description |
|---|---|
| 1 | Microphone |
| 2 | Ground |
| 3 | Speaker (Connect to Ground) |
| 4 | TX Key (Connect to Ground) |
Quieting of AM reception and
improving gain of incoming signals is a common request from radio operators. In
the first stages of the HF input 2SC1675 transistor can be found. This
transistor is responsible for the amplification of a small detected signals. A
problems exist if the transistor itself is noisy as is such the case of the
2SC1675 when compared to other low noise packages. Along with the amplification
of the incoming signals is transistor noise. Replacement of this transistor with
a higher gain, lower noise transistor greatly improves the signal to noise ratio
of your receiver.
We will use an 2SC2999 transistor that has higher gain
lower noise characteristic. Replace the 2SC1675 (Q16) with an 2SC2999 (or similar low noise and high gain transistor) to achieve
this improved signal to noise ratio.
Re-Adjust T8 and T9 / T10
The gain
will improved with more than 6dB with the same signal to noise
ratio.
@DréCB/19MIR000=27.805Mhz./USB&6635Khz./LSB@
