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So you may remember that over a year ago I showed a small board that I designed to use as a step calibrator. I could not get that board to work after I had assembled one. Without a working prototype I couldn't say that I had designed the board properly though I suspected then, and have since confirmed, that the problem was in soldering the tiny PE4302 ics. So I recently tried again - and again - and again to get the board working. Yesterday I finally (with my last PE4302) I got it working! I have decided to redesign some for the next iteration. The original one used an unproven amp circuit which I have abandoned in favor of MMICs So when I finish designing this new board (which preserves the working attenuator sections of the old board) and get it back from China, I will try to hand assemble it and test it. Then we can get a quote on having the boards made (and populated). I believe the price of this has come way down in the last few years for small orders of assembled boards. Jim

All: 1) I have assembled the grounding plate using the supplied two 6” X 9” copper circuit boards. I do not think I could get a respectable cut of the copper with the tools I have available. I overlapped them slightly. To make sure the grounding is adequate, considering running a bead of solder along the overlap line? 2) I have not attached the grounding plate to the cabinet yet in the event it needs to be moved around a bit. 3) Does the NANO and the base need to be electrically isolated, or can I sit the base directly on the grounding place. 4) I think Jim mentioned using hot glue for some of the attachment. In what settings is this kosher? Use glue on the NANO? Thanks, John Sent from the all new AOL app for iOS

All: It begins. Follows is an initial salvo of questions. I will strive to remain efficient and organized. 1. The parts included two 6 inch X 9 inch copper-plated circuit boards. I plan to fashion them to cover the floor of the cabinet, overlapping a bit in the middle to fit. 2. Use 6 in number, one-half inch metal (not brass, came with the parts collection) stand-offs to attach the circuit boards to the cabinet. 3. Use the short, supplied jumpers to attach the copper ground plane to the front and back cabinet panels. Use the stand-offs as the site to connect the jumpers to the ground plane. 4. Hold on cutting holes in the cabinet front panel (for switches, LCD, etc) for now to prevent internal component spacing problems. Wisely suggested by Jim. 5. Next target is the NANO. Please critique strongly. Standing by. John Sent from the all new AOL app for iOS

This update includes instructions for both types of relays. The performance hit for the inexpensive relay is minor, but some may want the more expensive Ducommun RF relay. I also put a copy on the website: http://radiosky.com/jovecal/JOVECal1_Manual.pdf I will be in Hawaii for most of July. Aloha, JS

Added layout photo and table with all the connections (minus the RF ones). It is really not that much wiring JS

All, The primary goal of the DIY calibrator project was to keep the cost as low as possible. The JC1 protocol DIY calibrator meets that goal. Jim Sky’s goal was to make it low cost, self contained, buildable by most, and with Jim’s new software it can characterize itself based on the SDRuno power meter as suggested by Dick Flagg. There is no need for further characterization and self characterization will be used by each builder. These calibrators are based on hobby level parts and connectors and are not able to withstand shipping trauma. There isn't and never has been a minimum sensitivity goal established for Jove observatories. Currently there is a wide observed variation of spectrographs due to the lack of calibration. JC1 prototype DIY calibrator is the perfect low-cost calibrator to help solve that issue. Any other high-cost versions can be put in our back pocket if for some reason a higher-cost calibrator becomes justified. For the upcoming eclipse project, time is closing in and it takes time to order parts and assemble the calibrator. A survey identifying the number of JC1 prototype DIY units to be constructed would be a good next step. Thanks. Larry K4LED

Does this mean that everyone that builds one will have to ship it to Dave for verification? I wish I would have just built the prototype only. I’m thinking I should withdraw the Beta #1 version and Jove can go with the prototype to simplify and speed up the project. Verification didn’t seem necessary with the MK I or II we just accepted it as good enough. We also have to ask why no one else took the initiative to build one. Larry

See attached. Larry K4LED

Using the Noise Source Characterizer with the Jove Cal Step Calibrator The Jove Cal 1 (JC1) needs to be calibrated at the maximum output level it will use. For the MKII this was about 100MK, which after being subjected to fourteen 3 dB attenuation steps yields a temperature of 6100 degrees K. which is well below the galactic background levels. This suggests that 100 MK is a reasonable maximum output temperature to shoot for. In the MKII the custom noise module is adjusted to this value during manufacture. JC1 uses a noise source that is much hotter than 100MK, about 7 billion K! A total of 63 dB of attenuation is available from the step attenuator modules in the MKII design. We only need 42 dB of attenuation for our step calibration. The JC1 can use some of the left over 21 dB of attenuation to bring the maximum calibrator output level down to near 100MK. With my JC1 prototype, adding 19 dB of attenuation brought the temperature down to 104MK. The NSC is perfect for determining the amount of attenuation needed. You simply connect NSC to SDRuno using an SDRPlay receiver that is fed by the calibrator. Typing an attenuation level (half dB increments) into NSC's Set Attenuation box and pressing the button updates the attenuation level in the calibrator and the temperature can be read. Hitting the R button after setting each trial attenuation level will expedite your process as it can take several seconds to overwrite your previous moving average. When you are finished making adjustments, click the Reset button in the JOVE Cal Comms box. This will reset the antenna switch in the JC1. You now have two important pieces of information that must be manually input into the RSS calibrator panel; the actual maximum temperature that you achieved, and the attenuation that must be applied to reach this maximum calibration level. Jot these numbers down and close SDRuno and the NSC program. Open RSS and select Calibrate from the top menu. The calibration window will appear. Set the Com Port if it throws an error. Under Options select Set Calibration Point. Enter the maximum calibration level you achieved. You will notice that the scale is redrawn with new temperatures for each calibration step. Select Options / Set Calibrator Min Attenuation. Enter the amount of attenuation you used to achieve the max calibration level you wanted. The Min Attenuation value is stored in the JC1 (always 0 in the MKII) EEPROM. That is it. You can now run calibrations.