Glenn, VK3PE's Combo STAR build

* BLOG *

12th Dec 2009

My own build is currently using a PICnMIX for testing but will eventually use a colour TFT display when it is developed fully. (see further down)

The TFT under development is based on a Sony PSP1000 type display (actually a "Sharp" brand display with no touchscreen) or other similar 4.3" displays. The Sharp is often available very cheap on eBay. However, the development is not yet finished (By Ian, Chris and Gerard) so don't rush out to buy a display quite yet !


As of 9th Dec 2009, After about 15 hours of assembly, (Combo PCB only) it has been receiving signals OK off air. Last item of the build is the BPF coils, then I will do the PA's etc.

Click for larger pictures.



21st Dec 2009

I now have the TFT display running using the Combo Trxavrb PCB plus another developmental PCB (tftpcb) The tftpcb was designed by Chris Stake and software by Gerard.

The case I am going to use is now an ex commercial case as it matches exactly that used on picastar #2 (of 4 !)

24th Dec , 2009

My Combo is now installed in a case, along with a prototype TFTPCB (colour display) driven by a Trxavrb PCB included on the Combo pcb panel.

It's a little hurried at this point as I want to prove all PCB's and it needs a tidy up of wiring !

This is a non touch screen display and the little buttons down the side emulate the touchpads. Each side of the display are 'icons' showing the function of the pads. These are full definable for function by the builder using Ian, G3VPX's, Hobcat setup program.

At this point, this TFT is experimental only. Only a few prototype PCB's exist for software development but as you can see, it is going well. Alternately, the "Electronics Assembly" display can be used now but is very expensive.

Click for big picture 4.3" TFT here,

20th Feb, 2010. 5" TFT now fitted

The case I am using is pretty tight inside. The Combo PCB stretches from front to back of the case so front panel space, although appearing large, is restricted by the PCB being behind it under the screen. The combo pcb is mounted upside down under a chassis in the case. The small control is the MENU encoder, while the Mic socket is yet to be mounted. I may also fit 4 more encoders, but not decided as yet.

The Power amps and low pass filter are mounted behind the display.

The TFT is fitted with double sided tape onto a home made PCB that also has 2 columns of press button switches to emulate the touch screen. The little PCB mounted on the rear is a prototype TFT interface pcb.

This is a 4.3" TFT, I have a 5" display also to try. See below...........

The protective covering is still fitted to the screen reducing picture clarity.

The switches used are commonly available tactile type with a 6mm shaft. They are quite small diamater though and not suited to a front panel "push" action. The bottom left side, one up, has a small cap on it to increase the diameter.

I used a cap which is avilable in Australia from P/N SP-0596.

This appears to be a C&K part, check Farnell # 1886423. The C&K number is 46580200 and has 0.1" hole. It's also available from Mouser in the USA or Digikey # CKN1113. The cap needs to be drilled out though to suit the switch here. I found a 3.2mm drill did the job. Get a few extras when you buy them !


This is the top, showing PA's and LPF. Still to be tidied up ! A fan will be fitted at rear with auto control, eventually.

The bottom. The case is a bit small (short), as the Combo PCB just fits with about 1mm to spare, front and rear. This was at testing stage only.

Click to enlarge

Comparison of my PICaSTAR #2 and #4 (Combostar Ver BB)

Case size is 280W x 145H x 300D (mm)

In case you are wondering, #1 is a home brew PCB version, and #2 is the initial Combo version. Yes, I have FOUR Picastars although #1 has had a few parts removed and #3 currently has no PA's. They are in #4

I still have to do some tidying up and need to make front panel lettering for ComboBB (#4) etc.

29th December, 2009:- Combo "BB" made its first QSO's on 40m and 80m !


31st Dec, 2009:- Finally got around to doing the CAL_IF. After the usual fiddle getting communications under Qbasic, the CAL was run successfully. There were no problems adjusting the Pots. as required. It was not done at 14MHz as I don't have the BPF coils wound yet, so will need to do it again later.

20th Feb, 2010, I have now fitted a 5" TFT display in place of the 4.3" type: < click on pictures for larger view >

The pictures do not do the colours justice. (white balance not correct on camera)

If you compare the 4.3" type further up the page, the 5" type is mainly wider and a little taller. This meant a major re-make of the front panel.





More pictures soon

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created 10th Dec, 2009