My photography portfolio has moved to a new location and has been updated with my latest work. You can find it directly here or via the Photography link on my home page. Have a look, would love to hear from you!
By the end of March 2023 I will end my Smugmug subscription. The necessary content revision has been completed as of today.
If you have bookmarked content of mine on the Smugmug site (photos.addieleman.nl or addieleman.smugmug.com), you will have to go to my home page and find the web pages from there.
On November 10, 2021 I registered as a Dutch “radiozendamateur” (ham) with callsign PA8L. You might hear me on the bands, for now mostly on HF, but that can change quickly because I’m exploring this wonderful world of radio communication.
You can also find me on qrz.com.
Power supply annex battery charger 13.8 V
This is a design for a 13.8 V power supply that can charge a sealed lead battery and simultaneously power equipment with a 13.8 V nominal supply voltage. Maximum current is 1.5 A and this can be delivered continuously, even when the output is short-circuited. Output current will be limited further when the regulators run too hot.
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Loop antenna for medium wave with remote tuning
A tuned loop is a very effective antenna for medium wave reception in an area with man-made noise. However, using such a loop in close proximity to a laptop computer with an SDR (software-defined radio) is not a good idea because the loop will pick up interference from the computer. Therefore I decided to build a loop antenna with remote tuning by varicaps (varistors if you prefer that term), picking up the idea from T.J. Nelson’s article. That way you can move the loop antenna to a spot further from the computer and possibly a spot with lower interference. Outside is best, so I’ll be aiming to build something that can withstand inclement weather (within reason!).
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SMC Pentax 3.5/28 compared to other 28mm lenses
There isn’t much to be had in the way of native 28mm lenses for Sony FE cameras. Of course, Sony offers the FE 2/28 and I’ve tried that one out several times but couldn’t bring myself to buy it. I just don’t like its rendering, the pictures are dull and lifeless to my eyes. That only leaves legacy lenses as prime 28mm options. Continue reading “SMC Pentax 3.5/28 compared to other 28mm lenses”
Leitz Summicron-R 2/50 vs. Zeiss Loxia 2/50 quick and dirty comparison
Recently a Leitz Summicron-R 50mm 1:2 fell into my lap; it was my father’s and I’d completely forgotten about it until my mother asked me what to do with it.
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Minolta Panorama Head
I didn’t know it even existed: a Minolta Panorama Head.
An American lens, the Minolta MD W.Rokkor-X 28mm 1:2.8
Today I received this nice sample of the MD W.Rokkor-X 28mm 1:2.8, the American version with white “Rokkor-X” lettering. The search for the other Americans continues…
A lens of unknown origin
Does anybody know who manufactured this? Just curious…
Update: got an answer, read on!