“Those who hear not the music, think the dancer mad”
MultiPig LPF Kit

MultiPig+ Kit - Part 2


Time to make some more progress with the MultiPig+ started in Jan 2005.

Low Pass Filter Kit

30 toroids, 40 capacitors and a lot of winding, some during lunch hours! One way of making the lunchtime Jacket potato more interesting; after all there had to be something that would..

Transmitter Kit

MultiPig Transmitter Kit
Transmitter Kit

Although now practiced in winding coils, the counting can still catch me out, generally when winding a bifillar multi tap toroid, and after it has been soldered in and the leads neatly trimmed. Which turned out to be "very" hard to cleanly remove. But apart from that, construction proceeded very smoothly. Testing, unlike the Golden Ale will have to wait until the rest of the rig is completed, although I think the memory of the toroid struggles will remain longer than the memory of the beer. "Best served cold", the clues, dear reader, were there..


30 toroids, 30 trimmers, 50 capacitors, 20 plug in connectors 130 parts, 320 solder joints. Several sessions accompanied by SSB, Pedigree, Bunzel vending machine tea, Jacket potatoes, Fursty Ferret and Haddock 'n chips were required to complete the board.

Toroid winding tips

“Gentlemen start your winding..”

1. Wind the first three turns, just to get the wire to grip, then counting from zero carefully wind the required number of turns, when completed remove the first 3 turns from the end you started at, then presto you will be left with the correct number of tight neat turns.
2. Carefully sew the wire through the core being careful to avoid getting kinks in the wire.
3. Blu tack can be used to hold a toroid, or other component while soldering.
4. If the wire is heat strippable, then heat the end with an iron and use a pool of solder on the wire to burn and tin the wire at the same time.
5. Check for continuity.
6. Once soldered into position, check the windings, then reheat the joints, while pulling the wire tight with pliers. This will get the wires, tight and the toroid securely held to the board.
7. Check and triple check the number of turns, before cutting the wires flush to the board.

MultiPig BPF Kit

Revisiting the PLL

The PLL can use either a 12Mhz or 10Mhz crystals. Mine has a 12Mhz crystal, as previously noted this caused some confusion during the initial testing!
Now, for the Direct Conversion experiments I need to produce a frequency which does not include an IF offset.

Clock / PLL divide by = Reference Frequency

12090000 / 2048 = 5903.3203125

Then we can calculate the PLL HEX switch settings..

For a target frequency of 7.035Mhz

7035000 / 5903.3203125 = 1191.7022

Bin = 10010100111

XOR with 1111111111111 = 1101101011000

HEX = 1B58

Reverse for SW1 - SW4 switch settings = 85B1

MultiPig BPF Complete
BPF Complete

Read more in MultiPig+ Kit Part Three