G4DYA

I'm attempting to provide cooling for a BBAI in a Seeed case. Without the end plates, two 5V 25mm fans side-by-side works well.

First, I installed the AI but didn't use star washers next to the board - components are too close for comfort. Instead I used two star washers between the standoffs and the case. I didn't use the nylon standoff at all because there's a chip capacitor very close to the hole.



Next I stuck two fans to the Kiwi board and connected them to the bottom of the 5v barrel jack. I added a bit of draught excluder to the side of one fan.



Then connected the Kiwi to the AI.



Then stuck the lid on. Without anything at the end I held it together with Gaffa tape!



This arrangement keeps the CPU temperature well below 50° C. With the end plates on, it obstructs the airflow quite badly and is noisy. Next step is to try some sort of mesh grille. After that, I might try some sort of conduction cooling with chunky slabs of copper inside and heatsinks outside.

73,
Richard G4DYA

There doesn't seem to be anything wrong with the PCTEL GPS-TMG-40N antenna's current draw. The data sheet says <=40 mA, and I've just measured mine at 23 mA, both well within the Kiwi's 50 mA current limit.

On second thoughts, I don't think my antenna is going deaf at times. The Kiwi seems to struggle to acquire sats when the server has been running for a few hours. Last night it had 11-12, but by this morning it was down to six. On restarting the server it immediately came back to 11-12. If this is a bug, I suspect it's been there a while.

This is what my shadow map looks like after 18 hours. As expected, there's not much low-elevation stuff in some directions because of trees. In other directions, where the optical horizon is 20+ km away, satellites are being received at elevations as low as 3°. The 'polar hole' is clearly visible.

Just to add to this dormant thread, yesterday I installed a PCTEL GPS-TMG-40N antenna with low-loss feeder and it certainly does the trick. I went for the 40 dB version so there's plenty of signal in hand to feed a 4-way passive splitter when I get one. I'm somewhat screened by tall trees in the south-west quadrant, so don't get many low-elevation signals from there.

The KiwiSDR GPS software only seems to allow a maximum of four Galileo satellites in the 12 channels. Is this intentional? While it all works fine, it would be nice if the limit could be raised - either by allowing more than four Galileo sats, or by allowing more than 12 channels. Also, surely there isn't much point in scanning for QRZZ satellites in Region 1?