Sennheiser G1, 2, 3 wireless systems
These cables cost from around £26 to buy in the UK.. This one cost a little over £14 to make myself.. And apart from the Sennheiser type locking jack, which are available from that popular online auction site (£3)! Most of the parts came from the rather excellent Audiospares. Not to be confused with the well respected but also 'well expensive' Studiospares!
Sennheiser G2 belt pack transmitter pin out

Neutrik angled Silent Jack, Sennheiser (type) locking 3.5mm stereo Jack Plug, Lynx 6mm instrument cable and heat shrink tubing..
I use a DI box to secure the jack plug whilst soldering the connections..
Often overlooked with Neutrik connectors.. You must remove (snip off!) the spacer to accommodate thicker cable (6mm in this case)
Like so..

Neutrik angled Silent Jack..
All done!