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2: Receiver Local Oscillator Alignment:
The main Receiver VCO is set to a frequency which is center of the programmed frequencies, By using the
m6m-5k.bin EPROM [Generated from VK2DOT RT85 Software or other software] – set to channel 48
[53.225Mhz].
Connect the frequency counter to J365. The frequency counter should read 74.625Mhz.
Connect DC Voltmeter between ground and TP701. On 10 Volt Range.
With the correct alignment tool on all ferrite cores adjust the ferrite cores – the ferrite slugs are easily
broken.
Adjust L702 such that the DC voltage at TP701 is centered on 3.5V for all programmed channels
(i.e. some above 3.5V and some below 3.5V). Voltages will swing between 2 Volts and 4 Volts.
NOTE:
f= (RX freq - 21.4MHz) +- 244Hz : for V HF(HB) and UHF
or
f= (RX freq + 21.4MHz) +- 244Hz : for VHF{LB}
52.525Mhz = Tx frequency then 73.925Mhz = Rx Oscillator frequency.
3: Transmitter VCO Alignment:
Ensure that the exciter output is disconnected at J366.
Connect the frequency counter to J366. The transmitter output local oscillator frequency will be at
the transmitter frequency. Ie for channel 48 will be 53.225Mhz when transmitting.
******
A:
The main transmitter VCO should be adjusted on the highest transmitter programmed frequency.
Adjust channel to channel 38 [53.975Mhz].
With DC Voltmeter still connected between ground and TP701 and on 10 Volt Range; Key the
transmitter and adjust L702 to give 4.0 Volts at TP701.
B: Connect DC Voltmeter between ground and TP101. On 10 Volt Range.
With the correct alignment tool on all ferrite cores adjust the ferrite cores – the ferrite slugs are
easily broken.
Operate the PTT button. Check the voltage at TP101 and re-adjust L107 for a voltages
around 4.5V for the TX channel. Release the PTT button.
4: Transmitter Driver Alignment:
Connect a DC voltmeter to pin 2 of CM101. Set channel to center frequency. Ie. channel 48 [53.225Mhz].
Adjust CV102 for a dip between two peaks.
Midland 70-066 low Band Conversion to 6 Meters: Synthesizer Part 2
Page 2.13
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