Henning, DK5LV's PICASTAR build
Henning is progressing well with his modular PICASTAR buildup. Best to let Henning describe his progress so far: <vk3pe>
April 4th, 2011
as promised, enclosed are a few photos of my build, which is still not completed yet.
I learnt about the PIC A STAR project during the "UKW Tagung" Weinheim from Achim Vollhardt DH2VA a long time back. But doing my own pcb´s using these very thin tracks seemed undoable to me. So I was very pleased, that You made commercial done pcb´s
After I got the boards the first assembling of boards went on quite quickly. I only needed help from one of my co-workers at my QRL to do the soldering of the DDS, DSP and CODEC, as my attempts were not successful.
I even destroyed one DDS may be due to some errors in the supply voltage connections when trying to power them up again. This error came up after Günter Wahl, DL5SDC asked me for help, as his DDS did not work. I visited him in our summer 2009 at his home.
After some problems even my DSP-LED got the pulsing light (LED) showing that the DSP is working.
Butler and DDS then were tested, using another (known) working PIC I programmed using a slightly modified source code from Andreas Stefan DL5MGD (his AD 9951 DDS project) --- see his German web page (DL5MGD.de) and my article about my DDS in VHF communications magazine.
Due to other tasks the project stopped for a while
In our summer last year (2010) I started to build the chassis The case has the
dimension 270 mm wide, 115 mm height, 300 mm deep.
Front- and back panel (2 mm thick aluminium) are screwed to the chassis (3 mm aluminium) using aluminium corner material (20 * 20 * 2 mm)
From old crates I got this nice rounded corner
aluminium into which I can slide aluminium sheets (1 mm thick, unless I mill
the sides to 1
mm) ) for the bottom cover, sides and top.
In also designed the front panel using the programme
"Frontdesigner 3.0 from ABACOM. Getting the positions of the holes correct
to fit the PnM board to the front panel was a bit of pain due to the different
scales (metric and imperial) but fortunately with the programme I can switch
between both scales. After a lot of print outs on paper all holes seemed to
be at the right
I then printed the front panel on paper glued it on a aluminium sheet and then made the milling on our QRL´s milling machine... I think up to five attempts until I got everything right The holes for the LED´s were then drilled using our table top drilling machine.
The "final" front panel will be engraved and milled using our "new" CNC-Machine in my QRL.
Next step: downloading of the source code into the PnM: I am using the IK6FWJ loader, as my COM 1 port on my PC is not working.
I will see ikf I can "revive" one of my old computers in order to run IF cal.
DSP tests 05 were successful, after some trouble I also could download the firmware into the PnM and then in a next step form PnM into the DSP.
Too nice to hear the hi hi on the audio!!!! (using my communication test set Stabilcok 4040)
Assembly of the IF amp and DSP into its housing should be not a big problem... but before I wanted to test the performance of the tow board together.
And then the problems started. See my findings in my folder in the yahoo ham radios group...
After a lot of discussion with Bob Dalley M0RJD
I found my solution, sensitivity on the IF board (sensitivity = -103 dBm/ 20m
dB SINAD; meaning -123 MDS only for the IF Amp, NOT for the complete receiver!)
may be not sufficient to get the spec´s from G3XJP but let´s see.
So integration goes on, as the attached photos show. see also pdf drawing of panel here
Click for larger picture !
To see how other builders are doing their assembly is also a good help to me. May be other builders will also get some inspiration from my build!
P.S. this morning (April 201) I was successful in doing my first IF amp cal using the software from DL4JAL. May be not in all satisfactory, as at input levels (to my IF amp) above -40 dBm I see "pumping", IF AGC voltage is 2.45 V, but from about -110 dBm to this level the audio is constant .