Error issues: None currently identified

The 116MHz version requires:

• the diode multiplier (Sheet 2),
• Logic Stages with 1 divider(IC402) - both inverter packages (IC401/404) required (Sheet 4)
• 2 to 6MHz tripler and filter, (Sheet 9)
• 6MHz low pass filter, (Sheet 9)
• 6MHz filter only (Sheet 5) - optional
• 116MHz BPF, amplifiers, crystal filter and output LPF(Sheets 6 & 7)

The Input Amplifier/Buffer is only required where the available source input is less than +10dBm in level.

The Input Buffer input attenuator (Atten 1) may be used if the drive level available is greater than +10dBm - Adjust the value according to your input signal to obtain +10dBm at the input to the diode multiplier.

Atten 3, between the 110MHz amplifiers should be set to 3dB.

Set Atten 4 following the VHF multiplier chain to 6dB to give around +5dBm into the mixer RF port.

Atten 5, following SJ902, is not used - replace R904 with 0R link

The two stage filter, F6, on Sheet 5, is used to further reduce the unwanted harmonics of 2MHz before the mixer. Link from R904 to the pin 2 pad of M501. On the output side of teh filter replace C504 with a 0R link and strap the signal across to R504. Atten 7 is set to 1dB into the mixer.

Divider 1 (IC402) must be set to divide by 5 to give 2MHz output - hence the jumpers must be programmed as binary 11 (1011) reading in order DCBA. Jumper C (pin 5, SJ3) must be grounded, the remaining 3 taken to the 10k pull-up resistor, R403

Divider Outputs: Divider 1 output (IC402) is taken from pin 13.

Standard ADE-1 mixer required

Tune each filter onto frequency using a signal generator and power meter or spectrum analyser as you go through the construction. This will ease the final tune up. As you complete each chain, adjust it before the mixer is inserted.

For example, build the 110MHz filter, align it, then build the amplifier stages following. Check and re-align. Build the diode multiplier and test through to output of the amplifiers. Set the attenuator values to give approx +5dBm into the mixer. Build the logic stages and check the output is correct in frequency. Build the 2 to 6MHz tripler and check/align it. Using a scope, check that there is a nice square wave output from IC401, pin 2 (may be easier to look at IC402 pin2) Check output of divider through the multiplier - you should see approx +12dBm (>7vp-p) of 6MHz present. At the output of F6 the level will be approx +3dBm. Atten 7 will reduce this level down to approx +2dBm< into the mixer./p>

Build the 116MHz BPF and align it. Once both outputs are optimised, insert the mixer and check the output through the BPF, re-optimising if necessary. Follow through with the remaining filters.

Final alignment should be done on a spectrum analyser. Carefully adjust the trimmer capacitors of the crystal filter for minimum spurii, and maximum wanted signal. The adjustments are iterative, and very small movements make significant differences to the output. You may also find it beneficial to make minor adjustments to the 110MHz filter and the 6MHz filter to get the best rejection of other products.

Typical results are Wanted output: +12 dBm

Spurii < -65 dBc

Harmonics < -43 dBc

Supply voltage - 13.8V DC

Current drawn - 240 mA

Page created 19 May 2008

Page last updated 25 Mar 2012