Tuesday, August 26, 2014

Scope bandscope adapter

...Just some modules glued togetter:

 Signal on display is from a QRSS Kit at 14.200Mhz...

 placed very close to input since there's no positive gain in the circuit and the mixer was homebuilt.
 Lower channel is the trigger. Log detector is an AD8307 and IF filter (10Mhz) is incorrectly terminated....
(add: made some measurement: vpp on the ramp for the vfo is 3.44V. Min vfo freq is: 4.174Mhz and max vfo is: 4.196Mhz, that is around 22Khz and makes 2.44Khz by division. I was thinking the peak was a bit large but in fact should be correct)

...plenty of room to improve....

And... have a nice week!

Thursday, August 21, 2014

New oscilloscpe - Rigol DS1052E

...Yes, my third oscilloscope. First one, the "Kiotto" brand (nice crap of tech support) died some time ago. Then I bough a second hand "Hameg" HM307:

 (in need of some maintenance but still functional as long as I let it warm) which is on main shack.

This new "Rigol", I'v been thinking in getting it for almost a year, now was the time.
Here it is in all it's glory:

I am more productive building without an oscilloscope, only for some circuits that the wave form is important it will help me a lot, like the one in the picture.

Yes, if you want to know, the fan is noisy (I've seen server's less noisy) and yes you need to read the manual for more complex functions, for the default one just press the auto button. No, I will not try the 100Mhz hack for it....for now.
The scope comes with two test probes good to 6 Mhz.
The trace it's not as responsive as a crt scope but crt's can't do fft transformations or math on the input signals either.

I am almost sure the old Hameg will live longer since it can be repaired, the new modern equipments as soon as they have a problem, it's just a matter of sending to the bin.

Have a nice weekend!

Thursday, August 07, 2014

Front panel method

Decided for the first time to make a nice front panel, well, at least was the first time I succeed doing so.
Interesting enough is I made the front panel and a box before actually the equipment beeing fully operational and tested, so, now I have to make it work!

 The way as I made this was: made all the holes to the components, LCD and buttons, then printed the front panel as an overlay (trust me, it's better to print first and cut last, so you don't have to print many tests).
Before applying the paper I spayed prime on the aluminum panel, after dried used paper glue to fix and set the paper on top. Finally some varnish was spayed to give a more glossy look.

Because the prime was grey and the paper very thin (normal print paper) it got a slightly grey tone.
Another issue was on turnng the nuts of the buttons, with a plier, some small scratches were made.

The project it self is an arduino to select the frequency of the airband receiver I bough in 2013 in the Cork Ham radio rally, this one:

This receiver frequency is set inside by means of dip switchs on a MC145151 PLL and the idea of the project is to have an external box controlling the PLL so it can rapidly change frequency without opening the box.
Right now the code to select the frequency is working, only missing the output part and cabling to the PLL circuit. When finish will be posted here.

Have a nice weekend!