Building a Balun

After watching TRX Bench on Youtube, I learned how to make a balun. I am still a bit fuzzy on all the technical terms, but it is to convert an unbalanced load to a balanced one, hence BAL-anced to UN-balenced.

It is really neat to see all the different types, and to figure out what you would use them all for. To be honest, I haven’t got it all figured out yet. For now, I’m building baluns for specific antenna projects, where some other HAM has already charted the waters. In theory, then the antenna setup should work, it is only a matter of testing my home made balun.

For this project, I’m making a 1:1 balun, and two 4:1 baluns. The 1:1 is wound on a FT130 and the 4:1’s are wound over a FT140 toroid. Thus the slightly different sizes. I followed the Youtube video pretty closely, although I did use different wire, so I hope that they work well.

I also learned that I can double them, such as these two 4:1 baluns can be put together in series to make a 16:1 balun, or backwards to make a 1:1 balun. Either way, it’s fun to experiment and learn!

Linux – keep it simple.

TS-820 With a Digital Display Problem

It’s been nice playing around with my brother’s TS-520, but I’d like to pick up a radio of my own. I was able to get a TS-820 from a local HAM who was able to help me out with not only a good deal, but extra microphones, an external VFO, and speakers as well!

The 820 did have a bit of an issue with the digital display. When I first started using it, it didn’t read anything, just a few dots. After a while of use, it would start reading, but only 19.000.0 and it was a bit hard to read. Well, after taking a stroll online, I found several people had issues with them over the years, and a few guidelines of things to check.

Fortunately for me, the easy fix was the best. I simply took the TS-820 case off, and removed all the connectors and cleaned them, putting them back into place. Praise God, this worked wonders on the display, and now it tracks with me when I turn the VFO!

I was able to hear a few locals on the 820, but I think I need a better antenna setup for listening on the lower frequencies. I also couldn’t be heard by anyone, so I’ll have to check into that!

Linux – keep it simple.

Server+ beta results are out!

Well, the results for the beta test of the new Server+ (SK1-005) are finally out! And, to God be the glory, I passed! Barely, but I passed!

It took a long time to get the results from this beta test, and after emailing the CompTIA help desk, I learned this was due to Covid-19 delaying the process. Fortunately, they were able to get it done. As well as passing the Server+ exam, this gave me the stackable certification of CompTIA Network Infrastructure Professional and another badge.

The test was very interesting, and of course, due to non-disclosure, I can’t regurgitate the test for you, but in general, it seemed to be rather balanced between Windows and Linux, which was nice. In the past, the tests seemed to be a lot heavier on the Windows side, and it was nice seeing Linux take a more prominent role in the test.

Of all the tests I took, this one seemed to be the most “cumulative”. What I mean is that this test seemed to be a better compilation of previous certificate material (A+, Net+, Sec+, Linux+) than most other tests. Perhaps that is the nature of a tests about servers, since they really are just supped up computers and everything relies on networking and security, as well as a good mix of Linux, as a lot of servers us that OS.

Either way, really relieved to get the reports and find that I did pass the test. It was a bit harder to study for, since, as a beta test, there was no study guide or tutorial to follow. I did study the previous Server+ material to help prep for the test.

Linux – keep it simple.

A Discrete 10 Meter Dipole

I’m a bit new to the HAM radio scene. I’ve been playing around with it for a while, since I got my license back in 2018. For the most part I’ve been on the 2 meter band, and I decided it was time to step it up a notch and try some lower frequencies.

One item that helped push me in this direction was the availability of a TS-520 Kenwood radio that my brother has asked to store at my house. It needed a little bit of work, so I’ve been playing with it a bit, cleaning it up, and decided to try putting it on the air.

Of course, that would mean I need an antenna. So, I decided to purchase a 1:1 balun and set up my own dipole. I could put it out in the yard, we live on an acre and a half, and I’m not ashamed to be a HAM radio enthusiast, but I felt it would look nicer if it was a little more discrete. So, I put it in the attic.

The radio itself sits in the laundry room, with a wire that runs up the wall, outside through the old dryer vent (it used to be in a different spot), up the side of the house, and into the roof trusses to the attic area. Our house has a cold roof, so it is not heated and open air.

I made sure to follow the math rules for building it at a length (feet) = 468 / frequency (MHz), giving me a dipole at around 16.5 feet total. The kids helped me hold the wire while I cut it to length, and then I climbed up in the attic to string it up. My brother brought over his antenna analyzer which gave me a little less than 2:1 SWR on 28.4 MHz, which wasn’t perfect, but good enough to get started!

We did a receiving test while he was in the yard with his mobile unit, and I was able to pick him up. I still need a microphone, so I was not able to transmit a reply yet. But, more to follow!

Linux – keep it simple.

Convert AVI to MP4 for Piwigo

As it turns out, Piwigo and AVI files don’t play nicely together. So, I shamelessly ripped off this thread, and wrote a script to automatically convert my camcorder’s AVI files into MP4 videos and put them into my gallery:

#!/bin/bash

echo "Converting videos..."
cd /home/alaskalinuxuser/Videos/
for i in *.avi; do ffmpeg -i "$i" -c:a aac -strict -2 -b:a 128k -c:v libx264 -crf 20 "${i%.avi}.mp4"; done
for i in *.AVI; do ffmpeg -i "$i" -c:a aac -strict -2 -b:a 128k -c:v libx264 -crf 20 "${i%.avi}.mp4"; done

echo "Moving videos..."
mv /home/alaskalinuxuser/Videos/*.mp4 /var/www/html/galleries/camcorder/
cd /home/alaskalinuxuser/Videos/
rm -rf *

chown -R apache:apache /var/www/html/galleries/
echo "Changed owndership"

.....EDITED OTHER FUNCTIONS THAT ARE SPECIFIC TO MY PIWIGO SERVER IMPLEMENTATION.....

exit

Note the double quotes, I learned that this is important because single quotes will not properly handle some characters and spaces in file names. As it turns out, the camcorder we have does not allow you to change the naming convention, nor to use anything other than AVI as the video format.

Linux – keep it simple.

Free QSO Logbook Sheets

As I begin branching out in the amateur radio world, I came to realize that I needed some form of log to capture my contacts. Of course, I found several log books available on Amazon and the like, but as this is a side hobby, I would like to cut down on costs.

There are also several computer programs to handle this, which also are free, in various forms, but the problem with this is that I did not want to be tethered to a computer while I am transmitting or receiving. So, I jump online and searched for any downloadable, printable QSO sheets. Surprisingly, I found none.

If you happen to find some, be sure to let me know in the comments.

However, if, like me, you want to just have some sheets to download and use for yourself, I’ve made a spreadsheet and PDF version that you can readily use and even modify for your own needs. You can download them here and print/use/edit to your hearts content!

Linux – keep it simple.

Adding A Video Plugin To My CentOS Piwigo Server

Previously, I had decided to ditch Google apps, including Google Photos. That meant that I needed a new photo backup solution, of which I have written several articles on this blog. The main portion of the server was Piwigo, a photo viewing/sharing/organizing server that you can view from other devices over the internet. Feel free to check out my previous posts by searching Piwigo to see the setup.

One feature that was missing, however, was the ability to display and view videos. This brought me on a long adventure that I will summarize here, because it wasn’t as easy as it first seemed.

The first thing I needed was to download the right plugin. There were several to pick from, but the one that seemed to be the easiest to integrate was called video-js. I simple logged into my Piwigo server as the administrator and went to the plugins and clicked install. Seemed pretty simple so far….

But, that’s when the problems began.

Following the video-js documentation, I set all my settings under the settings tab, and then moved over to the synchronization tab. I was immediately greeted by yellow triangles because ffmpeg, mediatool, ffprobe, and exiftool were not found. So, I jumped into the terminal, but found that those packages don’t exist in CentOS’s yum repositories. A little bit of internet searching lead me to do this (wish I had written down the reference) :

# yum install mediainfo
# rpm -Uvh http://li.nux.ro/download/nux/dextop/el7/x86_64/nux-dextop-release-0-5.el7.nux.noarch.rpm
# yum install ffmpeg ffmpeg-devel -y
# yum install perl-Image-ExifTool.noarch

After installing those packages, now I could go to the synchronize page and received no errors. Unfortunately, after setting the synchronization settings to my liking, pressing submit returned only this error: “You ask me to do nothing, are your sure?”

So, after more web searching, I went to the video-js plugin issue tracker and found others with the same problem. Included was also a fix by a user named ipsedix: https://github.com/xbgmsharp/piwigo-videojs/issues/162#issuecomment-605990233

Back at the command line again, I jumped into my MariaDB like so:

[root@localhost alaskalinuxuser]# mysql -u root -p
Enter password: 
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 1302
Server version: 5.5.65-MariaDB MariaDB Server

Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MariaDB [(none)]> SHOW DATABASES;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| piwigo             |
| test               |
| uloggerdb          |
+--------------------+
6 rows in set (0.01 sec)

MariaDB [(none)]> USE piwigo;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
MariaDB [piwigo]> SHOW TABLES;
+-------------------------------+
| Tables_in_piwigo              |
+-------------------------------+
| piwigo_caddie                 |
| piwigo_categories             |
| piwigo_comments               |
| piwigo_config                 |
| piwigo_favorites              |
| piwigo_group_access           |
| piwigo_groups                 |
| piwigo_history                |
| piwigo_history_summary        |
| piwigo_image_category         |
| piwigo_image_format           |
| piwigo_image_tag              |
| piwigo_image_videojs          |
| piwigo_images                 |
| piwigo_languages              |
| piwigo_old_permalinks         |
| piwigo_plugins                |
| piwigo_rate                   |
| piwigo_search                 |
| piwigo_sessions               |
| piwigo_sites                  |
| piwigo_tags                   |
| piwigo_themes                 |
| piwigo_upgrade                |
| piwigo_user_access            |
| piwigo_user_auth_keys         |
| piwigo_user_cache             |
| piwigo_user_cache_categories  |
| piwigo_user_feed              |
| piwigo_user_group             |
| piwigo_user_infos             |
| piwigo_user_mail_notification |
| piwigo_users                  |
+-------------------------------+
33 rows in set (0.00 sec)

MariaDB [piwigo]> UPDATE piwigo_config SET value="a:0:{}" WHERE param="vjs_sync";
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

MariaDB [piwigo]> exit
Bye

Now we were getting somewhere! Unfortunately, because I had over 1000 videos in the server, I kept getting errors and time outs. This caused the process to fail repeatedly when I try to synchronize. It would usually only get through the first 200 or so videos before stopping. So, as a quick and dirty fix for that I unchecked the setting to “Overwrite existing posters”. This way, even though it would time out or fail, it would make the posters (thumbnails) for about 200 videos before it quit. Then all I had to do was run the synchronization process five or six times to get them all done!

Linux – keep it simple.

“Dude”, a 3D low poly man

Well, I guess I got a little board after finishing my last project. Usually I move right into some other project, but at the moment, I am lacking inspiration on what to do next. So, in the meantime, I decided to work on my low poly skills, namely, the art of character creation and rigging.

Rigging is the addition of a skeleton to the model so that they can be manipulated or animated. As you can see from “Dude”, he is able to move about and be articulated into any natural (and some unnatural) positions, such as running, pointing, kneeling, and being pushed backwards.

Perhaps the most interesting feature was that I gave him an articulate hand. He doesn’t have all 5 fingers, but he has a thumb, a pointer finger, and then three “connected” fingers on each hand. This allows for the pointing motion and some other articulate movements such as picking things up, or pushing buttons and holding objects like controllers.

Low poly art is interesting. There are so many “flavors” of it. Some low poly is focused on more of a “cartoon” look. Others are actually high poly objects with a small color pallet to produce a low poly feel. Yet some actually go for a square or “Lego” style. What I’ve done here is given the model sharp, angular features with no texture. The clothes are simply a change of the surface color of those polygons, rather than having a mapped skin with details.

I like this style and I’m trying to see what I can do with it. Hopefully a little practice will improve my skills.

Linux – keep it simple.

Fix a Nabi Big 20 HD Tablet that cannot connect to FUHU servers!

I recently got a Nabi Big 20 HD tablet to use as a camera viewer in a nursery at our church. The only problem was, when I turned it on, it kept giving me an error, stating that I had to hook up to the wifi, and that the FUHU servers had a problem. Essentially, since Fuhu went out of business, you can’t connect to the fuhu servers.

Since you can’t connect to the servers, setup can’t be completed, and this 20″ tablet became a 20″ paperweight. Obviously, that would not do, so I figured out how to use fastboot mode, TWRP, and the advanced file manager to delete the unneeded junk to make the tablet functional again. Below are my instructions, performed from a Linux computer. You could do this from Windows as well, if you download the right tools.

Before you begin, you will need the TWRP recovery image, which you can get from here: http://www.mediafire.com/folder/rul6liygr1rw3/Nabi_big_20_hd_tablet or from https://forum.xda-developers.com/android/development/recovery-nabi-bigtab-hd-20-t3035372

  1. Power off the tablet.
  2. Hold the volume up and power on buttons, and release them when you see the menu options.
    NOTE: This is actually fastboot mode!
  3. Perform an OEM unlock
alaskalinuxuser@alaskalinuxuser-OptiPlex-7010:~$ fastboot oem unlock
...
(bootloader) Showing Options on Display.
(bootloader) Use device keys for selection.
(bootloader) erasing userdata...
(bootloader) erasing userdata done
(bootloader) erasing cache...
(bootloader) erasing cache done
(bootloader) unlocking...
(bootloader) Bootloader is unlocked now.
OKAY [ 13.625s]
finished. total time: 13.625s
alaskalinuxuser@alaskalinuxuser-OptiPlex-7010:~$
  1. After this it reboots and starts up again, so power off the tablet.
  2. Hold the volume up and power on buttons again, release them when you see the menu options.
    NOTE: Once again, this is actually fastboot mode!
  3. Flash the recovery image.
alaskalinuxuser@alaskalinuxuser-OptiPlex-7010:~/Downloads$ fastboot flash recovery recovery.img
target reported max download size of 643825664 bytes
sending 'recovery' (8646 KB)...
OKAY [  0.313s]
writing 'recovery'...
OKAY [  0.314s]
finished. total time: 0.627s
alaskalinuxuser@alaskalinuxuser-OptiPlex-7010:~/Downloads$ 
  1. From the still open menu, use the volume keys to scroll down to “recovery mode” and press the power button once to choose it. NOTE: it will show the NABI screen, then reboot into TWRP. Unfortunately, ADB does not work in this version of TWRP.
  2. Go to “Mount” and check “System” and then click to disable MTP.
  3. Press the home key or back key to get back to the main menu.
  4. Click “Advanced”.
  5. Click “file manager”.
  6. Scroll to “priv-app” and select it.
    Click on each of these items and choose to delete them:
    fuhu_addapps2.apk
    fuhu_appzone2.apk
    fuhu_drmmanagerservice.apk
    fuhu_nabiaccountmanager.apk
    fuhu_nabiupdater.apk
    –Personally, I just deleted all “fuhu” apps in this folder, but I think you only need those ones.
    Then in the “app” folder, delete all the fuhu apps. Yes, I’m pretty sure you need to delete all of these ones.
  7. Select the home or back button to get to the main TWRP screen.
  8. Reboot to system.
  9. Enjoy!
    NOTE: It should start up, and may go through the Google setup (if you never started it before), and then will drop you off in “parent mode”.

At this point, I recommend installing a regular launcher, such as Trebuchet, Apex launcher, Nova launcher, etc. I used Apex launcher personally, because you can “hide” unwanted apps, and I use it to hide the unwanted Nabi apps. You should be able to see the Chrome browser in the parent mode window, use that to download the apk for the launcher you want (or use the Google account if you set up an account).

Once a launcher is installed, press the home key, and choose to always use the launcher you installed. You can now use this tablet as a regular Android tablet.

TWRP does have the option to install SuperSU and root the device. That’s completely up to you. Kingo Root also works incredibly well on this tablet. It will be stuck on Android 4.4.2, so it is a little outdated, but seems to work rather well. It was designed for gaming, so it is pretty powerful for as old as it is.

Linux – keep it simple.

Let’s Encrypt with DDNS on CentOS 7

My new A+ rating for my personal web server, with certificates from Let’s Encrypt!

A while back, I started using CentOS, with Apache, to host my own website. As I talked about here on this blog, the website is for my Piwigo server, which is a Google Photo’s alternative. My pictures from my phone are backed up to my home server automatically, and the Piwigo server acts as an interface where people with appropriate passwords can log in and see the photos. Typically, just me and my wife.

One problem that I had, however, was difficulty getting a certificate from a CA (Certificate Authority), and I had to use a self signed certificate. This worked great, to be honest, except that some browsers have a pesky “this is not secure” message that you had to accept alot. It got old if I was showing some one, either client or friend, the setup but had to acknowledge a big security warning.

So, I set out once again to try to get that fixed. I heard a lot of good things about Let’s Encrypt, the free, open source encryption method, and that they now support DDNS, so I thought I’d give it a try. So, logging into the terminal, I followed the instructions, and got this in the terminal:

[root@localhost alaskalinuxuser]# certbot --apache
Saving debug log to /var/log/letsencrypt/letsencrypt.log
Plugins selected: Authenticator apache, Installer apache
Starting new HTTPS connection (1): acme-v02.api.letsencrypt.org

Which names would you like to activate HTTPS for?
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
1: alaskalinuxuser.ddns.net
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Select the appropriate numbers separated by commas and/or spaces, or leave input
blank to select all options shown (Enter 'c' to cancel): 1
Obtaining a new certificate
Performing the following challenges:
http-01 challenge for alaskalinuxuser.ddns.net
Cleaning up challenges
Unable to find a virtual host listening on port 80 which is currently needed for Certbot to prove to the CA that you control your domain. Please add a virtual host for port 80.

This was a bit confusing to me, since I could browse to my own website on port 80. But, fortunately, I found the answer here: http://tomaskalabis.com/wordpress/letsencrypt-unable-to-find-a-virtual-host-listening-on-port-80/

So, I made a new file at /etc/httpd/conf.d/alaskalinuxuser.conf and filed it in with this:

<VirtualHost *:80>  
    ServerAdmin alaskalinuxuser@fastmail.com
    ServerName alaskalinuxuser.ddns.net
    ServerAlias alaskalinuxuser.ddns.net
    DocumentRoot /var/www/html 
</VirtualHost>

After that, I exited nano and restarted the httpd daemon, and was able to re-run certbot:

[root@localhost conf.d]# certbot --apache -d alaskalinuxuser.ddns.net
Saving debug log to /var/log/letsencrypt/letsencrypt.log
Plugins selected: Authenticator apache, Installer apache
Starting new HTTPS connection (1): acme-v02.api.letsencrypt.org
Obtaining a new certificate
Performing the following challenges:
http-01 challenge for alaskalinuxuser.ddns.net
Waiting for verification...
Cleaning up challenges
Deploying Certificate to VirtualHost /etc/httpd/conf.d/ssl.conf
Redirecting vhost in /etc/httpd/conf.d/alaskalinuxuser.conf to ssl vhost in /etc/httpd/conf.d/ssl.conf

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Congratulations! You have successfully enabled https://alaskalinuxuser.ddns.net

And now I have a CA vouching for my web server!

Linux – keep it simple.