Reply To: Antenna Analyzer shown by W4PID Dick Hataway
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Thanks for pulling all this together. As you have pointed out, much of the hardware is a bit hard to find now.. the red board was once available from QRP guys but that is no longer the case. The DDS ( signal generator module ) is now both difficult to find and expensive. The diode bridge has been replaced with a MMIC style bridge in later units, etc etc. As of around mid 2019 the design finally stabilized and now is somewhat different than originally published by Jack and Al. John Price’s software had become the basic standard I believe for the unit, although there are multiple versions of the software out there, all of which use Jack’s original code with some additional flavors added. The software is fairly easy to modify if someone wants to try to change some things.
Boards likely will have to be ordered new now. There are gerber files available for the latest board, and the cost for a mass order is pretty small if there is club interest.
The CPU (Mega 2560 Pro Mini) appears to be still available on Ebay and Amazon for around $17 from clone suppliers. It takes a great deal of study to make sure the one that is advertised on the web will work, pin for pin, with the unit used in Jack’s article.
The DDS I settled on was the AD9850. This was due to lack of availability for the 9851 and cost. A fellow in W5 land came up with an adapter board that converted the 9850 pinout to match Jack’s red board as well as other boards of the time. The one I and many others used is the dreaded Type 1 DDS discussed in the notes you found, but made not so dreaded by the adapter board.
My display came from MCUFriend. I think this may be the most difficult part to source now. A note to the .io group mentioned below might be the best course of action to find a suitable display. note that the gerbers that are available use the old board as a standard so there will have to be intense study to make sure the pinout is correct, etc.
With those parts hurdles crossed, I set out to put together an analyzer.
I have about 22MB of files on my computer re this project. There is a group on the web, SoftwareControlledHamRadio@groups.io , that has this and many other very interesting projects under discussion at all times. I suggest a digest version if you want to see only one email a day from them. There are several offspring of this group discussing in detail many of the projects that originate here. You can google SoftwareControlledHamRadio@groups.io and find the group, join, and become over run with all the fun.
If there is sufficient interest among club members to build an antenna analyzer, then I would be glad to put up the files I have on a Google Drive for a limited period of time so folks could download and follow my notes on the project. They are not organized, as I have not worked on the project since 2019 sometime. I suggest in addition to Dave’s info, you check out