Monday, March 28, 2016


...More tubes for the collection...or to make a VU meter when I have time.

Needed two, bought 4, just in case, luckily only one failed testing.

Testing another:

and the last one:

...looks around 10 "dashes" in difference between these two tubes, in any case it's not a measuring instrument and can be corrected on the control circuit. Also no precision supply used.... only 84 Vac from 230 to 12 --- 12 to 115-0-115 transformer arrangement (using only one 115v output):

Have a nice week!

Monday, March 14, 2016

Pi day and the Pi blade server

It looks today is Pi day, it also looks like nowadays everyday is day of something...

In any case will share here my Pi in blade server version....

The Pi was supposed to be inside another box to be used as an SDR receiver but didn't liked the DVB card quality (RF wise) and now was converted to a NAS...

Keep in mind this is the Raspberry and not the Pi constant with approx value of:  3.141592653589793238462643383279502884197169399375105
(give it or take)

On to the most interesting photos:

The full enclosure:

 Power supply:
The disk array (external storage):
Chassis interconnect:
Power line and boot device slot:
Easy access for maintenance:
The CPU blade:

.... so now you know how to get your blade chassis... in the nearest poundo shop for arround 1.5 Eur...

Have a nice week!

Sunday, March 13, 2016

9 Digit VFD frequency counter (PLJ-9VFD)

Received this last week and this Saturday tried to confirm it's working:

..after power on:

frequency of 8.514 Mhz and 620 Hz

It's a simple, VFD display, frequency counter that I got from a popular biding site and was delivered from the far Est for less than the price of the individual components (14.00 Eur).

The test fixture, connected to the VFO of the VLF receiver testing board:

The backside picture:

On the left, the power supply and on the right, signal input.

The only pitfall is the manual, you have to download and it's in Chinese, in any case enough to understand the basics. It will be used only as frequency counter for a future project.

Have a nice weekend!