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Microwave Mortuary

Note to Mortuary contributors: please consider that your boss may not find your submission in the best interests of your Big Company. Once in a while we get a "please remove my submission" email, try not to send us anything that you might regret.

Note to Big Companies: Don't blame us for posting your spectacular failures, we only post what your employees send us. On the other hand, please don't rip off Microwaves101 pictures for presentations without permission, that's bad manners. Maybe it's time for some training!

Note to Mortuary fans: In many cases, if you click on pictures on this page you can see higher resolution images.

January 2021: Jacob from The Netherlands writes:

"Last week I bought a broken Spinner BN 534218 dummy load. This is a rather well known 400 Watt 50 Ohms dummy load. Since it was broken, the price was right. ;-) My idea was to repair it using a chip resistor instead of the original 'odd' wedge shaped resistor. But after opening the dummy load, there was no 'wedgy' resistor! Since the mechanical construction is very nicely made, I guess there are two types of 400 Watt models. With the 'wedgy' resistor or with a chip resistor. The failure of the resistor is easy so spot I guess. ;-) I don't know if the resistor failed due to overloading or that the dummy load failed within the normal operational limits. But the absence of a copper heat spreader under the resistor is likely the cause of the failure due to a hotspot. Therefore I planned to place a copper heat spreader and two 250 Watt 100 Ohms resistors in parallel. Therefore the hotspot is 'split in two' to reduce the hotspot load. Also a copper plate will be added to improve heat spreading since copper is much ‘faster’ than aluminium. And I'm seriously considering integrating a power sensing diode/capacitor circuit for the connection of an external power meter. ;-)"

 

December 2020: jumpers from Bob, who says " I found these jumpers on the back panel of a freshly calibrated PNA-X. The jumper with the blue caps is the new replacement jumper and there as an example of what it should look like.

May 2020:  Here's a fried FET, from the collection of the Unknown Editor. From the individual source vias and the way the nitride is pulled back, you can tell it is a millimeterwave effort.  The way the busbars are so far from the active channels, you know a microwave guy did not argue enough over the layout design rules. 

August 2019:  The following pictures come in from Bernd: 

It is the result of connecting a log-periodic antenna system based on a FR4 substrate to a 50 watt amplifier at 1.7GHz. I think it's interesting to see what branches of the array had burnt. With this photo everyone is seeing how these antennas work and which are the elements which are used for a given frequency. In a log periodic system only a few elements contribute gain as it can be clearly seen.

Thank you, Bernd!

 

 

July 2019: We love attending IMS, and we love to meet with our friends and fans.  And it's great that some suppliers offer free beer on the exhibit floor, so long as everyone remembers to be careful. Here's a picture of an accident at a booth that could have been prevented. Pro tip: don't assume you can use the display table-top as a place to set your beer when you fawn over the sample hardware...

Want more? Check out the Microwave Mortuary Archives!

Author : Unknown Editor

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