SuperStar 3900

Alan 87
Alan 8001
Cobra 148GTL-DX
Eagle 2000
Galaxy DX99V
Mirage 88
Sommerkamp TS-790DX
SuperStar 390FM (New)


I make a special EPROM expansion board that will add 4 more bands to many radios that use either Binary or BCD programming, it also adds a 10KHz shift function as well, click here to find out more.

It will give 1 band down, 1 band up, UK 40 (up 64 channels without Alpha ch hops), NZ 40 (down 63 channels) and 10KHZ shift.

On a 40 channel radio it will give coverage from 26.335 to 28.005 (including the normal low,mid and high bands of 26.515-27.855), that is a total of 167 channels !

I can also make a custom board upon request which will give whatever frequency range you want (within the limits of the radio).


Circuit Theory

PLL Circuitry. PLL is an abbreviation of the phase-locked loop which is fundamentary composed of a closed loop feedback citcuit. The feedback component is the balance of frequency drift and the PLL circuit acts to cancel it out. To detect out the frcquency drift of the PLL output, a fixed reference ocillator (10 kHz, 1/1024 divided down from 10.240 MHz) is compared constantly with the input frequency (10 kHz). The input frequency is obtained by dividing the VCO frequency. A functionalI block diagram is provided below under "PLL Circuit" for the easier understanding.

Off-Set frequency oscillator IC10. The off-set-frequency oscillator IC10 oscillates at 14.460 MHz for all band. Switching between these oscillating frequencies is made by biasing the diodes D34 to D36.
The off-set frequency signal is obtained at IC10 Oscillator and flows into IC10 Mixer where it is beat with the VCO signal. The VCO signal is obtained from the following:
f vco = foff-set + Nfr
Where, f vco = VCO frequency, N = programming code for divider output, and fr = referency frequency step (10kHz).

i.e.: At channel #1 in band A, and band corresponding N code is 91:
f vco = 14.010 + 91 x 0.01 = 14.920MHz.

Since the mixer output determined by two factors the off-set frequency output (dependent on band selector switch) and the VCO output, the mixer output contains the subtracted frequency of 0.91 to 2.25 MHz. These frequencies appears in pin #2 of IC5, and divided by the programmable divider in IC5 down to 10 kHz which is compared with another 10kHz signal obtained from the reference oscillator TR24 (10.240MHz).
The VCO output is mixed with the off-set frequency signal and applied to the TX mixer IC9 through band-pass filters.
i.e. At channel 1 in band A, and AM band, the TX mixer IC9 accepts 14.920 + 10.695MHz = 25.615MHz is TX frequency.
When receiving channe 1 in band A (26.065MHz), the 1st RX mixer TR18 accepts 15.370 local ignal at its base, and converts down it down to 10.695MHz IF (for AM/FM mode, this is the 1st intermediate frequency). TR18 off-sets the 10.695MHz signal so that TR30 can oscillate at 10.6975MHz for LSB.

Adjustment


Test equipment required:
Power Supply: 13,8 VFrequency CounterDummy Load 50 ohmOscilloscope
DC AmperemeterRF SSGAF SSG

Preparation alignment:
ClarifierMid.
SQ GAINMax.
AF GAINMax.
RF GAINMax.
MIC GAINMax.
MOD, S/RFS/RF
NB/ANLOff
BandD
Channel19
Reading PointConditionAdjustmentProcedure
PLL
IC5 Pin 3-Check10.2400MHz
TP2Band:D, Ch.:40L175,0 Volt
TP3-L18Maximum on Oscilloscope
OSCILLATOR
IC10 Pin 9AML1916.9400MHz
IC10 Pin 9USBL2016.9425MHz
IC10 Pin 9LSBL2116.9375MHz
IC10 Pin 9TX AMVR2116.9400MHz (TX-Frequency)
TP5TX AML2610.6950MHz
TP6RX USBL2710.6925MHz
TP6RX LSBL2810.6975MHz
TP5TX USBVR7SSB Modulator Balance
RECEIVER
RX AML6 L7 L8RF Input
RX AML10 L11 L12AM/FM/SSB IF
RX AML3 L4AM/FM IF
RX FML5Discriminator Coil (FM Demodulator)
TP1RX USBL1 L2Noise Blanker IF
RX USBVR3SSB Squelch
RX AMVR4AM/FM Squelch
AM/FM S- MeterRX AMVR1
SSB S- MeterRX SSBVR2
TRANSMITTER
TP9 (+) TP8 (-)Bias DriverVR1110mA
TP9 (+) TP7 (-)Bias FinaleVR10100mA
TP9 (+) TP7 (-)Bias FinaleVR20100mA
TX AML42Maximum
TX AML43Mixer Coil (VCO-frequency input)
TX AML44Mixer Coil (TX-carrier 10.695MHz input)
TX AML40 L42Maximum RF output
TX AML33Minimum Harmonic
TX AMVR1315 Watt (30 Watt with Dual Finale output) AM/FM
TX USBVR1220 Watt (40 Watt with Dual Finale output) SSB (ALC)
TX AMVR1490% AM-Modulation (AMC)
TX FMVR52 kHz FM-Deviation
TX CWVR16CW Tone (Not in all model`s)
Power MeterTX AMVR8

Microphone Connection

PinDescription
1Ground
2Microphone
3TX Key (Connect to Ground)
4Speaker (Connect to Ground)


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