开云体育

All: Al has made the Gerber files for his RA8875 display protection board available to all who might be interested. The Gerber files and a documentation file are in the attached zip file. I will also post these in the Files section of the JackAl group. The circuit is sufficiently simple it can also be constructed from perf board. This is the BOM for the PCB, which uses SMD parts. Components are as follows: R1 Thru R5 10 ohms 1206 SMD R7 200 ohms 1206 SMD R6 18 ohms 1206 SMD IC1 – IC4 – RB731U Schottky diode array from Arrow Electronics C1 0.1 uF 1206 C4 10 uF SMD J1 2x5 IDC or equivalent Jack, W8TEE

All: Al and I will be attending Field Day and will be at the Milford Amateur Radio Club (MARC, W8MRC) at Paxton-Ramsey Park just outside the 275 loop, close to Wards Corner exit. We will be using Al's "Luggable Double-Double" Magnetic Loop antenna, shown here (he doesn't like that name...): You'll notice this version has a vacuum variable capacitor (VVC) for tuning. Also note that Al 3-D printed the mounting brackets (in gray). He even has a thumbscrew clamp on the small driven loop! Tuning is done remotely using two encoders and a NEMA 17 stepper motor with controller. While not finished yet, it looks similar to this: You can see the controller hardware in the background. Test thus far shows it has 13dB gain over a reference dipole. Naw...just kidding. Any ML antenna is a compromise, but for many HOA dwellers, it may be the difference between making and not making contacts. Anyway, if you'd like to see it, come to the Park this weekend. We'd love to see you there! Jack, W8TEE Al, AC8GY

Hi Jack, I have the JackAl board installed and working quite well except for the hickups in some areas of the software. I have been reviewing the code but can not figure out if there is a simple way to be able to select USB on 40M for digital modes (FT8). Is there a simple way to fix this so when selecting USB with the button it actually changes the mode? I have tried going to 20M USB and then manually dialing down to 40M but per the code the flip below 10MHZ happens. Farhan's original code allows one to manually select USB if desired along with the auto flips. I also see that you have been involved in several other projects but am wondering when the next code version will be provided to update some of the problem areas. Rick KN4AIE

All: I've been working with a small (2.4") TFT touch screen display for a CW messaging system. The display has 14 pins on the right edge of the display, with their ID's silk screened on the back side of the display. During the course of building the circuit, I probably flipped the display front-to-back...oh, I don't know...about a bazillion times. Al (AC8GY) had a great , but simple, time-saving idea, as shown here: He cut some scrap from an Avery label sheet and just stuck it on the display. Well worth the effort for almost any device that has silk screening on the back but you need to work with it from the front. If need be, it's easy to peel the label off when you're done. Jack, W8TEE

I have a V4 and a V5 for sale. Both have the JackAl board. I also have 5” and 7” displays and the protection boards coming. One JackAl is assembled and the other has all the parts The V4 board has the mini-coax and connectors installed. The JackAls are $110 each and the uBITX are $130 each. Displays $35 each. Can make a package deal. All above are new. Mike AI4NS

----- Forwarded Message ----- From: Albert Peter <albertfpeter@...>To: Jack Purdum <jjpurdum@...>Sent: Thursday, May 30, 2019, 6:55:54 PM EDTSubject: RE: [JackAl] W8TEE Mag Loop Testing I believe he is asking for the inductive reactance at resonance so he can size the capacitors. If that is the case, the following should help: - Range of capacitance required for 1M dia multiple loop - 9.5pF to 90 pF - Approximate inductance at 350KHz – 5.8 microH (measured) - Calculated inductance @ 7 MHz - 5.4microH - Approximate efficiencies: rough calculation approximate only – very difficult to measure. - 7 MHz --~40% - 14mHz ~ 90% Best capacitor type is a split Stator. Hook up the stators in series to get ? the capacitance, but 2X the max voltage. Some of the stator vanes may have to be removed or altered to get the range needed to cover both bands. For one band only, a single stator/ rotor arrangement will work just fine. See attached pic of cap used. If butterfly style can be found this is ideal, but difficult to come by. At the Dayton HamVention I saw none of the butterfly style, but numerous examples of split stator types. Regards, Al AC8GY ----- Forwarded Message ----- From: Kees T <windy10605@...> To: "[email protected]" <[email protected]> Sent: Thursday, May 30, 2019, 2:50:12 PM EDT Subject: Re: [JackAl] W8TEE Mag Loop Testing What is RL on 40m and 20m for the loop ? 73 Kees K5BCQ