cumbria designs




The X-Lock 3 VFO Stabilizer

This compact microprocessor design brings crystal referenced stability to free running VFOs. Accepting an RF input of a few hundred mV over a frequency range of a few 10s of kHz to over 50MHz, the X-Lock continuously measures the host VFO's frequency. By comparing consecutive measurement results the X-Lock computes a variable correction voltage which when applied to a compensation circuit within the VFO, corrects drift.

A tri-colour LED indicates lock state and through two small tactile switches, the X-Lock can be personalised to suit operator preferences and the characteristics of the host VFO.

This latest version also features two modes of RIT operation to provide consistent lock points over the frequency excursions that occur during Tx/Rx changes. Supplied as a kit only, the X-Lock has been successfully applied to hundreds of commercial and home built designs.

"Will it work with my radio?"

If your radio has a free running VFO and there is room to install the X-Lock then the answer is almost certainly yes! Take a look at our X-Lock Solutions page to see how it has already been used across a range of popular HF equipment.

  • Operation to 50MHz
  • High Impedance JFET Input
  • Adjustable Control Voltage Rate
  • Adjustable Post Tuning Delay
  • Automatic or External RIT Modes
  • Tri-Colour Status LED
  • +12V Operation, 30mA
  • Size (mm) L60 x W40 x H15
  • Correction Circuit parts included
  • 14 Page assembly and instruction manual

Download the X-Lock Manual in pdf format.

X-Lock 3.0 Manual

Price 36.90 Inclusive of VAT at 20%

(30.75 ex-VAT)