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Saturday, March 22, 2008

Saturday, March 15, 2008

Long-haul WiFi - new developments

Returning to the WiFi topic, here is the new antenna development that I had promissed in the early post, once the dual "cantenna" design was finished.

The dual cantenna is quite efficient, as I realized by connecting it to reasonably distant access points (in excess of 200 meters, with many obstacles between, including houses). By verifying the antenna efficiency was the expected, I assumed that in better conditions the range could be far greater, by establishing a link between two antennas of this type or other type of optimal configurations.

However, I knew I could push it a little further, so I decided to buy a 12 euro 45 cm dish from a regular satellite TV system, and the materials to build a biquad feed. I installed the dish on top of the tripod used for the cantennas, and attached the biquad feed (built according to these instructions) to it:



Monday, January 7, 2008

Water Fuel Cell - DC voltage results

Today I performed some tests measuring gas production with DC voltage. The tests were performed in order to obtain aproximately the same consumed power, namely 22 Watts.

DC test performed:


High frequency test (100 KHz) at same voltage:


The DC test shows a clear increase in efficiency (almost 25%) relative to the pulsed electrolysis.
Still to compare these results with low pulse frequencies (it is likely that power losses are quite high at 100 KHz).

Sunday, January 6, 2008

Water Fuel Cell - more results

For one measurement taken without the inductor coil, we have the following values:

Friday, January 4, 2008

Water Fuel Cell - measured results

I performed two consecutive runs without changing the conditions. The data obtained is as follows:

Considering that it consistently took 4 minutes to produce 80 ml of H2 + O2, this
gives a rate of 1.2 litres/hour of H2 + O2.

Water Fuel Cell - back to business

After reparing the WFC and adding extra safety measures, here is the entire setup producing hydrogen at 12 Volts DC and 1.94 Amps. Next I will provide a grid with measured values, including gas volume:


Thursday, January 3, 2008

Water Fuel Cell - cleaning the mess and repairing the electrolyser

After yesterday's mishap, and of realizing how lucky I was to still be in one piece, it is time to take a deep breath and after looking into what went wrong, follow all the safety measures to prevent one such event from ever happening again.

I started by getting a new lid for the electrolyser and putting a new seal rubber in it, this time with two clamps instead of one. Now only the clamps are used for holding the lid. The original ring around the lid was discarded. By itself this doesn't provide extra protection against an explosion, apart from the slight probability of the lid popping out in one piece instead of fragmenting into several pieces (today I still found fragments of the lid in distant corners of the room).