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Novemeber 2017 - Antenna Analyzer

Oct 24th 2017, 18:00

rrmccabe

Joined: Apr 20th 2011, 19:52
Total Topics: 0
Total Posts: 0
Anyone in the process of building this kit?

I ordered the board from QRP guys and parts on a slow boat from China via Ebay.

Have to say the assembly manual is going to be the biggest challenge as its missing info, has incorrect values in the schematic (which they warn you) and assembly photos using boards from other kits that look close but are not.

In the end I will probably end up with more money in it than its worth but looked like a fun project.
Nov 18th 2017, 12:19

WA7SDI

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
I have just completed the Arduino Antenna Analyzer in November 2017 QST! It is an amazing little piece of equipment!! works great!
There are a few problems, yes!!! but easy to overcome! I am not a computer guy and in this area is where I had the most problems but managed to muddle through. This is (not a beginners project)! but easy enough with a little experience and patience. I had a few questions for Jack but did not get a reply thru e-mail, I am sure he must be a busy man. all that being said! This is a worthwhile project and I would like to see more projects like this in QST!
Please remember Jack and Farrukh put in a lot of time on this and gave it to us all for FREE!!
Happy building and 73 Paul WA7SDI.
.
Dec 7th 2017, 09:21

rrmccabe

Joined: Apr 20th 2011, 19:52
Total Topics: 0
Total Posts: 0
Hey Paul, thanks for the reply. I am at the same point with Jack and no replies.

My analyzer seems to function but does not display SWR correctly. On a dummy load it reads well but on a real antenna with 1.5:1 SWR it is off the charts. Have yet to figure it out.

I appreciate the efforts for the project but think the league should have vetted the project better before publishing it.
Dec 7th 2017, 20:03

W1VT

Super Moderator

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
SWR analyzers have issues when there are nearby transmitters present--the simple diode detectors can't tell the difference between the reflected signal and a strong radio signal picked up by the antenna. One way to see how bad things are is to connect a 50 ohm load and a diode detector directly to the antenna.

Zack Lau W1VT
ARRL Senior Lab Engineer
Dec 8th 2017, 16:25

rrmccabe

Joined: Apr 20th 2011, 19:52
Total Topics: 0
Total Posts: 0
That is not the case with this one. Connecting a 270 non inductive resistor to it should give me approx a 5:1 SWR but shows 300:1. 50 ohm resistor looks good. Something obviously is wrong.
Dec 9th 2017, 08:56

W1VT

Super Moderator

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
https://www.youtube.com/watch?v=LUbt3W4hnTE
KE4EST has a video of his version of this project. He says he has compared it against an SWR meter.

https://groups.yahoo.com/neo/groups/SoftwareControlledHamRadio/info
Not only is there discussion about this project on this Yahoo forum, but Jack, one of the project designers, can be reached here.

Zack W1VT
ARRL Senior Lab Engineer
Dec 10th 2017, 09:20

rrmccabe

Joined: Apr 20th 2011, 19:52
Total Topics: 0
Total Posts: 0
Thanks. Jack did respond to my email but no resolutions as of yet.
Dec 30th 2017, 10:33

N7XAU

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
Clicked the link for the Yahoo group but it says it does not exist?
Dec 30th 2017, 16:44

W1VT

Super Moderator

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
Yes, it looks like someone pulled the plug on that group. It is still listed on my list on Yahoo groups menu bar but I get that error too.
Jan 5th 2018, 06:11

VK5TM

Joined: Jul 17th 2010, 12:34
Total Topics: 0
Total Posts: 0
They moved to Groups.io
Jan 10th 2018, 08:14

rrmccabe

Joined: Apr 20th 2011, 19:52
Total Topics: 0
Total Posts: 0
I scrapped the project. I will be 100 before they get back to me. Two thumbs down on this one to ARRL for not vetting this better. The manual should have been an indicator of the rest of the project. The BOM still has incorrect signal generator board listed in it. I brought it to their attention after having to reorder a different type and its still has not been fixed.
Jan 10th 2018, 08:57

cdegrassi

Joined: Feb 21st 2014, 23:41
Total Topics: 0
Total Posts: 0
Hello, I have assembled everything, but there is an issue with the SD card reader not being recognized. Anybody having same issue? Any solutions?
Also the BOM and the schematics in the assembly manual have lots of discrepancies (resistors values, device types, etc) Which one should we follow? BOM or Schematics?

Thank you
Jan 11th 2018, 08:58

rrmccabe

Joined: Apr 20th 2011, 19:52
Total Topics: 0
Total Posts: 0
I don't remember any resistor values being wrong but as I said the signal generator (one of most expensive parts) was wrong for sure. My SD card reader worked fine. My only issue was the indicated SWR was wrong on anything except a 1:1 match.
Jan 11th 2018, 15:07

cdegrassi

Joined: Feb 21st 2014, 23:41
Total Topics: 0
Total Posts: 0
Well R6, R10, R13,R15,R17 are 1K on the BOM and 2K2 on the schematics, R12,R14,R16 R18 are 2K on the BOM and 3k3 on the schematics. R18 is listed on the BOM but then on the schematics it says "Not Installed".
I know that for you all experts in electronics this is nothing, but for the less gifted it cna get very confusing.
Same happened with the 409er VFO project in a previous QST.
I understand and appreciate the free time that was put in developing a publishing this projects, but the initial excitement of assembling such a wonderful project (and others) gets bursts pretty quickly when things are not working and the only help (manuals and schematics) are inconsistent.
Again, thank you for the time and knowledge, but if it is published on QST it should follow some minimal quality control. My 2c.

I would also suggest the use a code repository like github or bitbucket to allow contributors to easily post code and manuals updates. We have a great community of amateur radio people, we should make partecipation and contribution to these awesome projects easier, ecourage sharing and make user support each other in a more accessible way,

Cheers
Jan 16th 2018, 09:54

W1VT

Super Moderator

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
When I first started working for the ARRL back in 1986 I'd compare schematics to the submitted project and send a list of the discrepancies to the editors. But, that was before the Internet and Social Media--back then the only computer we had in the lab was a 4,77 MHz IBM PC running a program for generating printed circuit board artwork. There were no web pages that had links that constantly needed to be fixed by lab staff. If only I had invested all my money in Apple back then....

These days, I'd assume an editor working at home can do a better job of comparing a circuit board against a schematic than someone who has to constantly answer the phone in the lab.

Zack Lau W1VT
ARRL Senior Lab Staff.

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