PCB

All posts tagged PCB

Here is an active antenna for higher LF and MF frequency range using an U310 N-Channel JFET as amplifier.
Antenna are based on a la8ak (sk) design. It has a decent performance given its small size.
However, on lower LF and VLF range it performs poorly.

A little tip for anyone interesting using this design or similar designs. Do not power it by a noisy switching power supply. Switching noise will go straight into the receiver.

 

Bias tee PCB

Bias tee PCB

 

Left: Remote amp. with telescopic car whip Right: Bias tee

Left: Remote amp. with telescopic car whip Right: Bias tee

 

Remote amp. and antenna

Remote amp. and antenna

 

 

Bias tee mounted in a nice box

Bias tee mounted in a nice box

 

Blue LED in remote amp. shows that power is present. Green LED on bias tee indicates normal current load.

Blue LED in remote amp. shows that power is present. Green LED on bias tee indicates normal current load.

 

Remote antenna amplifier schematic

Remote antenna amplifier schematic

 

Bias tee schematic

Bias tee schematic

 

Bought this nice media interface of eBay for around 33USD and I must say I’ve got value for my money.
It does not have any brand but it is marked as the moddel CH-528 though.
Anyway, it can read several kinds of memory cards, it has several usb ports and audio jacks in its front.
What makes it very useful for me is that I now can connect both old IDE drives and newer SATA drives on the fly without opening my computer or rebooting. This is a very good thing as friends and family constantly drops by with a “computer problem” which needs to be rectified. Hooking up a drive for data recovery is now very easy.

Here’s some pix…

Box
Cable for external drives
Front view

Rear view

Power, SATA, USB x 2 & Audio cables

Lid removed

Upper PCB removed

Another close up with the upper PCB removed

Unit in place

Simultaneously testing a IDE & SATA drive

View of disk manager with SD card, USB pen drive, IDE & SATA drive

 

Here is a line of homebrew circuit board that I have made for a amplifier project I am working on. (Which by the way takes forever to comlete 🙂  )
These boards are designed by Dominique F1FRV which have laid down a tremendous effort in designing these boards.
Dominique has done some minor changes to the design since these boards were made, so cards made by his latest instructions will look a bit different from these.

Have been working on a crowbar circuit for my universal high voltage power supply for some time now.
And here is a early preview of the circuit. This unit is meant to bolt right on top of my 5kV 100uF filter capacitor.
As the picture shows I have cut a air gap into the PCB to strengthen the isolation between high an lo- voltage areas on the card.

HV crowbar unit

Here is the schematics of the circuit. And I must emphasize, this circuit is not fully tested yet!!!
Crowbar circuit