CAKE Session Oct 27 2018
CAKE Session Oct 27 2018
We recoved quickly from the shock of finding the Abbey closed by following Cap’s suggestion to move to Coffee Junction- it worked out fairly well but the table was not large enough for all and I deeply regret not paying sufficient attention due to all who showed up. We were delighted to welcome David KG6IRW (Elecraft’s widely traveled Impresario) and (Elecraft’s expert Metrologist) Rene K6XW. Also with us were Cap KE6AFE, John N5HPB, Eric KK6IZY, Richard K8SQB, Glen KG0T, Reed N1WC, Gary K6PDL, Peter K6UNO and your scribe Ron W6WO.
Richard vividly described GeoCaching as a fun hide and seek game. It has evidently become a very popular outdoor recreational activity where participants use a Global Positioning System (GPS) receiver or mobile device to hide small devices called “geocaches”, at specific locations marked by coordinates all over the world. I recommend that you check Wikkipedia for more detail and I have included a picture for Short Skip of two examples Richard showed us.
Rene brought a high power RF dummy load made by an amateur friend to professional standards. We could compare the degree of professionalism to the images seen at the presentation of the Hubble Telescope the previous night. Thanks to Don K6GHA and members of the SLVARC for arranging that event. We discussed using modern high power ceramic resistors instead of the carbon types Hams have used for decades. Rene also showed us a rare random noise voltmeter made by Bruel & Kjoer.
The discussion on resistors meshed well with Ron’s current activities. You may recall he has an objective of measuring ESR of capacitors using a N2PK VNA. To be brief, VNA accuracy is dictated in large measure by the precision of calibration components. A 49.9 Ohm 1% leaded resistor is unsuited to accurately measuring the milliOhms of capacitor ESR. If (like Ron) you think of resistors in terms of color coded bands its time to review the current state of the art ! A great place to start is by downloading the eBook “The Ultimate Guide to Resistors” from the Riedon web site. Ron is waiting on a 50 Ohm +/- 0.01 % SMD component and a careful layout of a test fixture with gold plated connectors is in progress. To determine the accuracy being achieved also requires some reference components with accurate values down to a few tens of milliOhms There is an amazing selection of them on Mouser or Digikey. Stay tuned if interested.
Peter you will recall is also interested in resistors from a perspective of noise and distortion at audio frequencies. The Riedon guide shows that noise associated with alternative resistor technologies can differ by as much as 30 dB. In the context of noise, Glen mentioned how misleading it is to refer to recovering signals below noise without reverence to Shannon’s Law (note the word “Law” not theory). Eric gave some hints about improving inter-network latency, pity IP V6 didn’t survive.
Finally our CAKE sessions probably began about 18 years ago, and it seems time to celebrate. It would be appropriate to hold a party in Watsonville at a time Eric WA6HHQ (co-originator of the CAKE idea). will be able to join us. Let’s see if we can make this happen.
Our next session will be on Nov 10 I will determine if the Abbey will be available so please assume so unless you hear to the contrary.