Colt 1600DX / Colt 2000DX / Hy-Gain 8795 (V) / Lafayette 1800
Midland 7001 Export / Pacific 160 / Superstar 2000 / TriStar 777
| Reading Point | Adjustment | Description | Value |
|---|---|---|---|
| TP1 | CT1 | Band A -80 Ch. | 19.655MHz |
| TP1 | CT2 | Band B -40 Ch. | 19.880MHz |
| TP1 | CT3 | Band C CEPT | 20.105MHz |
| TP1 | CT4 | Band D + 40 Ch. | 20.330MHz |
| TP1 | CT12 | Band E + 80 Ch. | 20.555MHz |
| TP1 | CT5 | Band C CEPT | 20.1035MHz |
| TP2 | T1 | 0utput to RF local oscillator | 37.660-38.100MHz for CEPT |
| TP3 | VCO-Coil | VCO DC Voltage | 2,5 Volt @ 27.175MHz |
| TP4 | CT11 | AM | 10.695MHz |
| TP4 | CT10 | 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 | ||
| T16 | FM Discriminator | ||
| 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 | 26.965 - 27.405MHz for CEPT | |
| T4 | Transmitter Output | 26.965 - 27.405MHz for CEPT | |
| T5 | Transmitter Output | 26.965 - 27.405MHz for CEPT | |
| L16 | Transmitter Output | 26.965 - 27.405MHz for CEPT | |
| CT8 | Transmitter Output USB/LSB | 26.965 - 27.405MHz for CEPT | |
| CT9 | Transmitter Output USB/LSB | 26.965 - 27.405MHz for CEPT | |
| RV2 | Bias Q8 | ||
| RV11 | AM/FM Output Power | 10 Watt | |
| METER | |||
| RV4 | RF Power Meter | ||
| RV8 | RF S-Meter | SSB (USB/LSB) | |
| RV9 | RF S-Meter | AM/FM | |
| . | |||
| RV1 | FM Modulation | +/- 2kHz | |
| RV6 | SSB Modulation | 18 Watt p-p | |
| RV11 | AM Modulation | 90% | |
| RV5 | Carrier at SSB | Adjust for NO Carrier | |
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 (Q18) 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@
