FlightAware Discussions

Temperature difference with sunshield

It’s no secret that CYXE Saskatoon can be very cold in the winter, sometimes for several weeks at a time and, as noted in another thread it is surprising how well some electronic equipment can work in such minus 40 degree temperatures.

It’s also no secret that Saskatoon can be very hot in the summer, when it’s not uncommon to see temperatures in the 30C to 35C range. (86F to 95F) During the first summer that I had the receiver and cpu outside on the roof, it failed in extreme heat. Part of the problem was the sun shining directly on the box containing the receiver and the cpu.

A simple sun-shield reduced the direct exposure enough to allow the equipment to continue to function, however I did not take into account the angle from which the evening sun shines in mid to late June.

Since then, the sun-shield has been re-designed and re-made larger, to ensure that the box with the electronics remains in the shade, even in late June evenings when the sun is at its most northerly point.

The shield was cut from a 25.5 by 36 inch sheet of 0.01 inch (0.26mm) aluminium litho-plate, form-fitted to the profile of the edge of the eaves, and held in place by thick double-sided PVA foam tape plus tabs slid under the shingles, along with a few zip-ties for safety. Once all the bending was done, a quick coat of matt-white spray paint ensured that none of our neighbors would suffer an eye injury from the reflection of the sun from a large expanse of shiny metal. The new large sun-shield even helped to alter the pattern of our roof top snow drifts this winter, and prevented the box from being buried under a large drift.


Does the sun shield really make a difference?
It was time for a simple experiment.

I took a box identical to the one that houses the outdoor electronics and secured it on the sunny side of the sun shield and left it for 24 hours, and then read the surface temperature of each box.

The box in the direct sun was at 58.9C(138F) while the box behind the shield had a surface temperature of 41.3C(106F) a difference of 17.6C(32F)

This is the rooftop setup showing both boxes and the sunshield.

and here are the two temperature readings.

The box itself is a 30 calibre polypropylene ammunition box from Princess Auto (Canada) into which has been fitted an aluminium box that holds the electronics. Power is 12v passive power over ethernet, with a 5v 3A DC to DC converter (Hobbyking UBEC)

Inside the box, is an LNA4ALL, followed by a ceramic filter from Adam (9A4QV), followed by a FA ProStickPlus connected to a Nexx WT3020 running Openwrt and Dump1090-Mutability.

Of course, with the LNA4ALL, gain of the receiver is currently set to 13.

3 Likes

this is nice work. passive approaches to cooling are simple and easy to implement. well done

Thanks, the tough part was getting all the angles and folds correct to fit tightly between the roof and the eaves. Fortunately, the aluminium litho plate is cheap when bought from the local metal recycling centre (aka scrap yard) Occasionally, they get a shipment that is defective for printing purposes but makes for fine sunshields or other things.