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| My layout (1st attempt) |
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| Designer's layout (2nd attempt) |
Its amazing to think that layout made that much difference but this is the world of RF where crazy things happen all the time.
Sunday, December 13, 2015
Antenna Pre-amp - Part 2 - Second Attempt
As I noted in my last post, I was fairly sure my pre-amp was not working correctly and I was going to try to recommended layouts from the designer (as indicated by another hobbyist who drew up the layout and posted it here). Here are the two layouts, side by side:
The big difference between the two designs is the amount of ground plane on the top layer. Both designs have the entire backplane acting as a ground and I mistakenly thought this would be enough. The designer's layout has most of the top layer also acting as ground. And as you might suspect, it made a world of difference. 80mA steady-state current (both with and without input and output termination) and cool to the touch with a nice, big heat-sink.
Its amazing to think that layout made that much difference but this is the world of RF where crazy things happen all the time.
Its amazing to think that layout made that much difference but this is the world of RF where crazy things happen all the time.
Saturday, December 05, 2015
Rental Beast
I had a business trip last week to Seattle and due to my route cutting through the mountains in winter, I asked for an all-wheel drive rental car. What I got was a beast.
Aside from needing to get over the mountains, this was exactly the wrong car to drive in a dense urban area, park in a garage with narrow spots, and try to make get back home through rush hour traffic.
But this is not a story about the mismatch between large vehicles and Seattle. This is a story about buttons.
I have never been a car with so many buttons. Quick, think of a feature a "fancy" car might have.
I'm not talking about things like powered seats, sunroof, and Sirrus/XM radio. Or even things like heated leather seats, built in GPS, back-up camera, push-button start or triple-zone climate control.
I'm talking about dynamic cylinder shut-down to increase fuel economy (we got over 19 MPG on the highway), cooled leather seats, and automatic windshield wipers that figured out how often they needed to swipe on their own.
And a vault hide your phone and connect to the media system while your in the store? It had that too.
Aside from needing to get over the mountains, this was exactly the wrong car to drive in a dense urban area, park in a garage with narrow spots, and try to make get back home through rush hour traffic.
But this is not a story about the mismatch between large vehicles and Seattle. This is a story about buttons.
I have never been a car with so many buttons. Quick, think of a feature a "fancy" car might have.
I'm not talking about things like powered seats, sunroof, and Sirrus/XM radio. Or even things like heated leather seats, built in GPS, back-up camera, push-button start or triple-zone climate control.
I'm talking about dynamic cylinder shut-down to increase fuel economy (we got over 19 MPG on the highway), cooled leather seats, and automatic windshield wipers that figured out how often they needed to swipe on their own.
And a vault hide your phone and connect to the media system while your in the store? It had that too.
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