I got a new Rev 5.2 board, myVNA .54 software, USB Configure 2.5 and "latest" Windows 7 drivers. All in the hope that this error will go away. It does not. I...
Hi Jim, If you really want help with this problem, you might start by answering Dave's specific questions that he asked you about a week ago. You might also...
Jim, There is no issue with the design. A properly assembled and configured VNA works from the first try. And you did not tell if your both detectors are not...
Jim Ok, so we can infer from the fact that you are using 5.2 that you are using a USB interface. We might also presume that you have programmed the board...
Hi guys, I know the VNA design and hardware works, it is mine the one which doesn't. Most likely it is a soldering or component issue. However a cryptic...
Hi Jim, ... Dave has a debug guide at his website that you might check out. Have you tried toggling the ADC lines and observing the results as Ivan suggested? ...
Hi Jim Either there was a timeout in the reading of the ADC or there has been some fundamental breakdown in the communications. The software starts an ADC...
Yes, the ADC's toggle. The ADC2 timeout message is gone after reflowing that area. I get the signal generator outputting the right frequency with about 2Vpp....
... The RF DDS level is 1 Vpp into 50 ohms - i.e. a properly built detector RF input or a terminator. This might explain the ADC under/over range. Paul N2PK...
Hi Dave, Thanks for your last email (and previous ones too) which helps me understand better what its going on. I have good quality USB cables and I have...
Hi Jim Always ADC2? In that case I think you need to hang a scope on the control lines of the ADC. Compare the waveforms to the datasheet or the timings...
Dave, See my previous email: The time-outs do not show any more. The ADC issue now (independently whether one or the other is in thru or reflect mode) has to...
Hi Jim Ok, under or overrange probably means one of two things 1. it really is too high or low an input (not likely) 2. (more likely) the data being clocked in...
Jim, 1. check the reference +2.5V voltage on the failing ADC chip. 2. Make sure the ADC inputs are biased with approximately +3V each with the Detector input...
Ivan, In both ADCs, the inputs (pins 5 and 6) are at 4.9 volts. That is also the voltage at the + input (pin 3) of all four LT1677 opamps. Strange. However I...
Paul, Dave, Ivan: Ok, Got rid of the under/over range alerts. Next time, prior to solder, I'll wash the PCB more thoroughly. At the suggestion of Ivan, I have...
See if the Mixer IC is soldered well, and check the values of the 1K load resistors in the mixer shoulders. Regards, Ivan VE3iVM ... From: "jghbeta"...
Hi Ivan, Paul, Dave The VNA is finally working. The ADC timeout and under/ over range errors were due to poor soldering caused by my insufficient washing of...
Here's a couple of non-RF applications for the VNA. I'm working on a MOSFET audio power amp design, and one of the challenges is testing the frequency...
I'm interesting in either a complete N2PK VNA or a partial kit of parts that may be collecting dust in someone's shack in order to align some NQN bandpass...
... Paul, I have two, and could loan you one for the task if you'd like. Actually, you'll never build a better piece of test equipment though. W4ZCB...
*Hi Jeff: I had my share of bad luck last night. My Dell laptop was hard to open and after looking at the problem I had broken off a small piece of the bracket...
I kinda do what you are asking for. After I get myVNA set up in the mode and the way I want it I then quit myVNA, from a command prompt: regedit browse to: ...
Thanks Paul, That’s a good plan. I can do the export. In my case, it’s worth the work. Getting the VNA setup with all the stuff to return it must take...
To All, The new president of Yahoo, Carol Bartz, appears to be shutting down Yahoo departments in an attempt to save money, perhaps prior to selling...
