Showing posts from October, 2016

More Junk Box Rigs

FPM20 Rebirth of the hallicrafters FPM300 11/09/2016 ~ More progress.  TodayI installed a few more controls and am closing in on having the complete front panel in working order.  73's Pete N6QW  11/08/2016 ~ More on the Front Panel  Since we already voted there is no guilt in working on the rig. The Tuning dial has been added and some more video of the rig.   73's Pete N6QW  11/07/2016 ~ Building the front panel. Today I began work on the front panel. With my manual 3 axis mill (yes I have both a manual and 3 axis CNC mill) I made the cut outs for the display and S Meter. There is also a short movie. The final size will be 4 inches high by 10 inches wide by 12 inches deep. 11/5/2016 ~ More work and headed toward an enclosure! Today I did some work on the power supply board and that is now complete. It seems like the original designer's utilized several unique voltages on the main board such as 12.6 VDC, 3.6 VDC. 12 VDC and 6 VDC. I have a built a power supply board that n…

Rig Photos


That's All Folks!

This is the latest and last posting on this blog. There will be no further blog entries!

Keep on melting solder.

Pete N6QW

What is a VFO (variable frequency oscillator)?

The Variable Frequency Oscillator ~ aka "Grief in a Box". Whether you have an appliance radio (store bought) or one that you made with your own hands somewhere buried in the innards is a variable frequency oscillator.  However if you are running a single channel fixed frequency device such as a crystal controlled transmitter or receiver then maybe that is not the case. The acid test is if you move a knob or mouse pointer and you are able to change the frequency, then you have a VFO. A special case may be the VXO which is a variable crystal oscillator which uses the properties of a quartz crystal to shift its frequency of oscillation over a small range. But the VXO usually has a knob adjusting a variable capacitor or a pot controlling a voltage variable capacitor. But I really want to focus on the knob turning, mouse pointing variety of variable frequency oscillator. There are various ways to generate a variable frequency starting with the very early approach involving analog…