EMRFD Message Archive 9134
Message Date From Subject 9134 2013-09-13 20:55:11 Jerry Haigwood The Simple Scalar Network Analyzer (LONG) Hi All,
Introducing the Simple SNA aka The Poor Ham's SNA. Recently Jim Giammanco N5IB and I have been working on a microcomputer controlled SNA that will do automatic frequency scans and data collection. This project grew out of need for this type of instrument at N5IB and W5JH. We have decided to release it into the ham community. On this list, in the files section, under N5IB W5JH Simple SNA, you will find a PDF file that will help you to under the function of this instrument. The unit consists of an Italian microcomputer - the Arduino UNO, a Chinese built AD9850 DDS module, and an interface board designed and built by Jim and I. Interface boards that plug into the Arduino microcomputers are sometimes known as "shields" (I am not sure why). The shield interfaces the Arduino UNO to the AD9850. It also contains a low pass filter and a buffer amp. The gain of the buffer amp is eaten up by attenuators. The attenuators help isolate the AD9850 from the outside world and give the instrument a 50 ohm impedance. Of course before any sweeping or data collection can be done, the microcomputer needs some software. We have provided two functions in the software, a SNA function, and a generator function. The RF output of either function is -10dbm. This is a value low enough to be able to sweep most filters without any worry about damage to components, etc. This software is being released along with the hardware design in hopes that other people will come up with new functions to share with the radio community. The SNA function of this instrument requires a power meter such as the W7PUA/W7ZOI. In fact, this instrument was designed to be used with Bob and Wes' power meter.
So how does it work? If you refer to block diagram of the PDF file mentioned, you will see the typical setup. You will need a PC, a USB cable, a terminal program such as TERM232 for the PC, a +12VDC power supply, a device to test, and the power meter. Connect everything as shown. You turn on the Simple SNA, and then start the terminal program. Press the start button on the SNA and answer the questions. Choose 1 for SNA function, select a starting frequency, select an ending frequency, and select a step size. The program will pause and let you start a capture file on the PC. Hit the enter key and set back and watch it do its job! When you stop seeing anymore data on the screen, you can exit from TERM232 and the data will be saved. To analyze your data, open a spreadsheet such as Excel. Plot the data anyway you like. Make it large, make it small, put in pretty colors, show it to your spouse, kids, dog, etc. ;-) Maybe you decide you don't like the parameters you selected. Just start TERM232 again, press the start button and try it again with different start, stop, or step parameters. The frequency range is 1-30 MHz. Step size is 1 Hz to BIG. You can sweep almost any two port 50 ohm in/out device. Hook it up to your return loss bridge and sweep your antennas, sweep your crystal filters, LC filters, amplifiers, etc.
The generator function allows you to select a starting frequency and step size. You can then step the frequency up/down or change the step size by a factor of 2. It is very simple to use.
A yahoo group has been setup to get the latest software, user manual, news, etc. Here is a link to the group.
< http://groups.yahoo.com/neo/groups/PHSNA>
You are welcome to join and comment. Please enter the poll question about PCBs being made. We need to have a rough count to order boards. Cost of the board will depend on the order quantity.
We hope you guys and gals like it, use it, and modify it. Comments, criticism, pats on the back, kicks in the Bxxx, etc. are welcome.
Jim N5IB and Jerry W5JH
"building something without experimenting is just solder practice"
9135 2013-09-14 05:59:57 Graham Re: The Simple Scalar Network Analyzer (LONG)
Very cool.
I have over the past couple of years done almost exactly the same thing but never progressing beyond on the rough prototype stage of bits and pieces strung together.
Lately, I have been playing around with the Fox Delta Antenna SWR analyzer in a similar fashion. This is a design by Tony I2TZK and sold through Fox Delta as a kit. Similar in concept but uses a PIC, a DDS chip, return loss bridge, with a built in ad8307. While it's primary function is as an antenna swr analyzer it use too can be extended. Simple USB interface but has Windows only software. I have been tinkering away with some Linux software for it but nothing that I want to share as it is very buggy and rough.
However, there is no better feeling than building your own and make it do the kind of tricks you want it to do. I am a long time fan of the Arduino having a whole handful of boards and projects.
Count me in for one of the PCB's if you get that far. I have downloaded the PDF file you have uploaded and I think I will at least get out some of my other bits and pieces and prototype something based on your design as it does interesting and has potential. Tony's well done Antenna SWR analyzer aside, anything base around the Arduiono will have a lot of interest.
Incidentally, I tried the link to your new Yahoo group but came up with a "page missing" error as though it doesn't exist. I will try later.
cheers, Graham ve3gtc
On 13-09-14 01:29 AM, Jerry Haigwood wrote:
Hi All,
Introducing the Simple SNA aka The Poor Ham's SNA. Recently Jim Giammanco N5IB and I have been working on a microcomputer controlled SNA that will do automatic frequency scans and data collection. This project grew out of need for this type of instrument at N5IB and W5JH. We have decided to release it into the ham community. On this list, in the files section, under N5IB W5JH Simple SNA, you will find a PDF file that will help you to under the function of this instrument. The unit consists of an Italian microcomputer - the Arduino UNO, a Chinese built AD9850 DDS module, and an interface board designed and built by Jim and I. Interface boards that plug into the Arduino microcomputers are sometimes known as "shields" (I am not sure why). The shield interfaces the Arduino UNO to the AD9850. It also contains a low pass filter and a buffer amp. The gain of the buffer amp is eaten up by attenuators. The attenuators help isolate the AD9850 from the outside world and give the instrument a 50 ohm impedance. Of course before any sweeping or data collection can be done, the microcomputer needs some software. We have provided two functions in the software, a SNA function, and a generator function. The RF output of either function is -10dbm. This is a value low enough to be able to sweep most filters without any worry about damage to components, etc. This software is being released along with the hardware design in hopes that other people will come up with new functions to share with the radio community. The SNA function of this instrument requires a power meter such as the W7PUA/W7ZOI. In fact, this instrument was designed to be used with Bob and Wes' power meter.
So how does it work? If you refer to block diagram of the PDF file mentioned, you will see the typical setup. You will need a PC, a USB cable, a terminal program such as TERM232 for the PC, a +12VDC power supply, a device to test, and the power meter. Connect everything as shown. You turn on the Simple SNA, and then start the terminal program. Press the start button on the SNA and answer the questions. Choose 1 for SNA function, select a starting frequency, select an ending frequency, and select a step size. The program will pause and let you start a capture file on the PC. Hit the enter key and set back and watch it do its job! When you stop seeing anymore data on the screen, you can exit from TERM232 and the data will be saved. To analyze your data, open a spreadsheet such as Excel. Plot the data anyway you like. Make it large, make it small, put in pretty colors, show it to your spouse, kids, dog, etc. ;-) Maybe you decide you don't like the parameters you selected. Just start TERM232 again, press the start button and try it again with different start, stop, or step parameters. The frequency range is 1-30 MHz. Step size is 1 Hz to BIG. You can sweep almost any two port 50 ohm in/out device. Hook it up to your return loss bridge and sweep your antennas, sweep your crystal filters, LC filters, amplifiers, etc.
The generator function allows you to select a starting frequency and step size. You can then step the frequency up/down or change the step size by a factor of 2. It is very simple to use.
A yahoo group has been setup to get the latest software, user manual, news, etc. Here is a link to the group.
< http://groups.yahoo.com/neo/groups/PHSNA>
You are welcome to join and comment. Please enter the poll question about PCBs being made. We need to have a rough count to order boards. Cost of the board will depend on the order quantity.
We hope you guys and gals like it, use it, and modify it. Comments, criticism, pats on the back, kicks in the Bxxx, etc. are welcome.
Jim N5IB and Jerry W5JH
"building something without experimenting is just solder practice"
9136 2013-09-14 10:56:01 Richard Johnson Re: The Simple Scalar Network Analyzer (LONG)
In the new yahoo format can some one ive me a hint as to were the "files" are?
Thanks much.
rich9137 2013-09-14 11:58:11 Robert Bennett Re: The Simple Scalar Network Analyzer (LONG)