CAKE summary for March 11 2017
On this glorious Spring morning we were happy to hold our regular session in the courtyard of The Abbey coffee shop.Taking time out from their routines were Ward AE6TY, Fred KJ6OOV, Kerry K3RRY, John N5HPB, Tom KW6S, Don K6GHA, Reed N1WC and Ron W6WO.
Ward is searching for fundamental equations that govern the behavior of filters. Ron recently logged into a webinar on the subject which showed exotic simulation tools, clearly understanding the equations is a tall order. Good luck and keep us posted Ward.
Soldering small components with inaccessible contacts can be a challenge. Ward recommended the use of solder paste and baking in an oven. A few experiments first was recommended.
The mystery item was an image of part of the 40m band provided by Fred. We saw bands of high level noise each roughly 50kHz wide. Fred told us these appear regularly around 4:30 AM and cease around noon. Fred’s loop antenna provided some sense of direction. Many suggestions came forth but were inconclusive. If anyone reading this can offer ideas please contact Fred.
Fred had questions about feeding Off Center Fed antennas. These are often called “Windoms”following the article by L G Windom W8GZ in QST1929. It is a subject Ron has studied extensively and deserves more space than is appropriate in these notes. The following articles are highly recommended.
1. Impedance Characteristics of Harmonic Antennas by W4UCW in QST Feb 1954
2. The OCF Antenna – some less explored facets by W4RNL (no date)
3. Articles by W6WO in QEX March/April 2009, Nov/Dec 2011
Several guys had been to the Foothill flea market that morning and displayed their treasures. Among these were a couple of useful coax switches and a vacuum relay switch. Don was attracted by a couple of high current ammeters; old style but useful as well as being decorative. Kerry (in his inimical hi-tech and professional fashion) showed how he was rewiring his garage. Ron showed the replacement synthesizer kit obtained for the QRPLabs U3S digital mode beacon TX (subsequently built and operational).
Thanks go to all who have supported these sessions for well over a decade and to those who often comment from afar. We welcome questions and will do our best to attend to them.
Our next CAKE session will be on the 25th and we hope to BCNU