A Telegram Network for Ham Radio

| categories: code, software, amateur radio

A few weeks ago I launched the QTC-Net Project. Which is a Telegram Network between Ham Radio operators.

http://www.qtc-net.org/

The Idea was simply this:

  • 4 operators A, B, C and D. A has a message for D.
  • A is talking to B, telling him the message B then puts the message in the network
  • C is talking to D, C will fing the message to D in the network and tells it D

Coding such a thing is more difficult than it looks like. especially if it should be decentralized, unencrypted (ham radio requirement), and easy to use.

so we will se what the future brings... :)


Features for a Sonic Screwdriver

| categories: hardware, misc

In this post I will collect ideas what we can build into a sonic screwdriver today, to make it a really useful tool.

  • TV-B-Gone the famous TV on off switch is easy to integrate, and makes a good effect.
  • A mechanical screwdriver (nothing special)
  • A laser pointer
  • A flashlight
  • A pen
  • A USB storge
  • A small radio scanner
  • A voltagetester
  • Some capacitive buttons on the side to control screwdriver functions
  • morse code controlled embedded shell
  • a sound amplifier that you can use for various things even for finding telephone cables
  • motion sensors and blinking leds
  • screwdriver OS
  • mp3/ogg player
  • a recording and playback device
  • speed indicator
  • electronic compass
  • GPS sensor with cw output
  • infrared temperature sensor
  • crypto infrastructure (signing and encryption of data)
  • optical mouse pointer
  • a camera
  • some sort of status display or laser beamer
  • a wire cutter
  • add on interfaces....

so far, I'm sure i will get more ideas soon....


Debian Architectire Change i386 to AMD64

| categories: hardware, software

Last week I upgraded the Debian System on my Laptop from i386 to AMD64. Some people may say: "this never works" but from a technical point of view it should not be a problem in a well packaged linux environment, so I started to try it out.

Basically you have to exchange every binary on the system with the 64bit version. which means that you have to reinstall every package on the system. All of the config files user data and some databases in /var should stay as they are.

My first Problem was the Kernel. My original Kernel that I used was 32 bit only. The Debian AMD64 Kernel freezes during Hardware detection. I think there is some problem with the Firmware Loader infrastructure and 64bit. ifconfig does not return when the firmware cant be loaded. (note to myself: report that to the kernel people) The compiler suite could only produce 32 bit binarys and therefore 32 bit kernels by default. I think there is a way to let it produce 64 Bit binarys but I simply used the Kernel from a grml life system.

After I could boot a 64bit system I was able to debootstrap a new Installation to the harddisk, download a kernel source and compile a fresh 64 bit kernel.

I then installed the same packages on the bootstrapped system as there are on the original one. therefore I fetched a package list with aptitude, stripped out all automatic installed packages and did an apt-get install on the bootstrapped 64bit system. Sorry that I cant write down every command I used for this but I didn't make to many notes, but you are surely an awakened head so you may figure out the right shell commands for yourself.

I planned to use /etc and /home as well as the mountpoints in /media as they are. /var needs to be migrated for the LDAP Database Log, Cups and Mysql. /usr/src and /usr/local schould be delivered from the i386 System. All the other Files should come from the new system. In /etc the /etc/ld.so.conf.d should come from the new system, the passwd and group should come from the old one, especially the passwd is a bit tricky.

Because some of the users are installed dynamically, userids change from the old system to the new one. A good solution would have been to copy the passwd directly after bootstapping, but i missed that point, so I had to adopt all the userids of the existing (amd64) system users to the UIDs on my old system. I did that with "find -uid" by finding all filed owned by all old uids, giving them a temorary new uid. I then mapped all temporary uids to the old (i386) passwd database. With that two step process I ensured that I do not switch an existing uid to another one I have to chane later.

I later discovered that the alternatives system is also messed up a bit at the moment, I have to fix that, but it does not harm operations at the moment.

After copying all the files together all I had to do was to make the new system bootable, create a new initrd, recompile any customized packages (like wmii-hg) reboot, and experience the really fast amd64 performance.


The Vertical Dipole

| categories: hardware, amateur radio

I plan for a while to try out another vertical concept, since I figured out, that my 6.5 Meter Vertikal having some trouble coming to its full performance because my Truck roof is definately not enough for Bands below 17 Meters.

The Question of the right radials on a multiband vertical is a good question, it should be \$\frac{1}{4} \lambda\$ most of the designs simply add verticals for each band to the design. You could also use an earth tuner to match your antenna to your vehicle, note to me: schedule some experiments with earth tuners on the sidecar radio outfit.

An other way is to look how dipoles are tuned and adapt it to a groundplane antenna. So you can use some radials with exactly the same length as the antenna, and than feed it with a balancer unit. I did it with my antenna, and it worked almost well, almost because the 1:1 voltage Balun I used maybe was not the best choice, but it worked anyway. The main problem I had with the groundplane design where the radials. 6.5 Meter to every direction means lots of extra space around my truck, I can't reduce length with couls because the coilsize debends on the frequency. And the only Idea I had for the mechanic of the radials was the use of tensioned wire.

So I need a design which is playing without radials! A vertical Dipole for example. With a feed in the middle. There is a vertical \$\frac{1}{2} \lambda\$ monoband design available in Rothammels Antenna book which feeds the antenna with koax cable right through the bottom dipole element. The design is basically the same as with a normal dipole exept that it is vertical and the feed is not coming from the side. So should be capeable of multiband work by adding some sort of Balun some sort of Tuning to the feed point.

This raises to questions: How to tune, and how to do the Mechanics. The Mechanics question was solved by ordering a Havy Duty 10 M GFK Mast at dx-wire.de. the mast costs about 70 € but alows rapid development of different antenna designs with much cheaper materials than the aluminium tubing, I used since then. I can now use old RG213 Coax cable or speaker cable as antenna element for example. I also ordered the portable 10m version from dx-wire which soon will improve my portable antenna situation soon.

The next problem to solve was the matching problem. I want something which I can control from the shack. It is possible to place a symetric autotuner at the feed point i decided against to make the feedpoint simpler and lighter. If you match in the schack you have higher losses on the Koax cable. The choice which death to die was finally made by the large collection of available Unsymetric autotuners, and the time i had available. I can still add some extra antenna tuning in the next project, when I know how the whole thing plays. Ham Radio is still an experimental Service, so what.

I build an antenna with two 3,65 m long elements. This length should work from 10-15 Meters. it is a little bit to short for 17-20 and 20 Meters. At 40 meters there is still a little less than \$\frac{1}{4}\lambda\$ left, but a single element is to short. On 80 Meters such an antenna will be some sort of wet towel, but still better (longer) than my other 80m solutions.

IMG_20130801_220331

IMG_20130801_220355

I decided to use RG213 cable for the upper element. The schielding radiates the waves the inner conductor is left unconnected. The case of the Feed is made of waste pipe and sealed cable feedthroughs.

IMG_20130801_205416

The lower antenna element is a bit more tricky, I stripped 3.65 m copper schielding tube over the ecoflex feed cable and isolated it with shrinking tube:

IMG_20130801_222027

IMG_20130801_224536

The next part the (first) balun. A 1:1 Voltage balun. 8 Windings per Coil 50mm waste Pipe.

IMG_20130802_211539

IMG_20130802_211539

The whole antenna setup:

IMG_20130803_003955

IMG_20130803_114921

Now to the Problems did start:

I could match the Antenna only with a Manual MFJ T-Match not with the Autotuner I want to use.

  • With 1:1 Voltage Balun Fail 40 Meter
  • With 1:2 Voltage Balun Fail 15 and 80 Meter some bands not optimal
  • With 1:5 Voltage Balun Fail on 80 Meter and some bands not optimal

Then I tried a Current Balun:

From 10-40 Meter best match, 80 Meter is not working. So I tried out to add the Coil of the manual L-Matchbox which I build 1.5 years ago. The SWR indicator is moving, so I need more inductivity. I killed an old CB-SWR Meter (I have lots of them) and found an old Ferrit ring in my shack, and made a coil. I build in a Switch that plugs in the 80m inductivity betwen the inner conductor from the Matchbox and the inner conductor to the antenna.
With that coil and the Matchbox SWR was almost good, so I added more windings and more and more until I had 2 ferrit rings full of cable and still the manual Matchbox in the system. I did't know the \$\mu_r\$ of the ferrit rings but from my calculations I expected something about 90 windings, to much for that ring. Which after several days of experimenting, leads to a more radical solution:

IMG_20130817_094307

Match!!

IMG_20130817_101743

Because ham radio is still experimental I did not add any shielding to that gigantic coil. 80 windings on 11cm waste tube, It seems to work, and it is disabled on the higher bands. I surely will soon find out how bad/good or however this setup performs. ;-)


Chinese monkey escaped from box

| categories: ratbike, rideout

I thought about getting one of those chineese monkeys, for a while. Last thursday the cage from china was delivered, by a german monkey dealer.

IMG_20130726_083756

I freed it from the cage, gave it new schoes, some oil, inspection and a speed sprocket!

IMG_20130727_132243

IMG_20130727_132309

It makes fun riding it. Those Bikes only weight 60 Kg. I did't test the fuel consumption, but the commercials say about 2.8 litres. So it is a good and easy city bike.

to the gallery...


GS Broke down

| categories: ratbike

Also, a few weeks after that missdated post, my Suzuki Cylinder head broke down. It was ill on the left exhaust valve but now also the camshaft bearing is broken.

The valve cover was so rusty, i hat to grind away three screws.



Speaky riser board

| categories: hardware, amateur radio

I soldered the speaky raiser board for the 9 Band modules as I mentioned during an earlier post.

DSCN0986

The following set of pictures may give you an Idea how I made it, and how it fits into the Tranceiver.

DSCN0983

DSCN0984

DSCN0985


Speaky 9 Band Extension

| categories: hardware, amateur radio

Yesterday I did some work on my speaky. I soldered together all the remaining Band modules and put them on a raiser board which fits into the Box.

DSCN0978

DSCN0977

Seriously I do not know how this will work on the HF side, mechaninally this is not a problem because the Box is much bigger than needed due to the frequency counter.

You need to do some cleanups to bring all the modules in.

DSCN0976

The plug for the freq dialer must be grinded down a little bit. The whole Mainboard must go 4 mm lower what you can do by grinding $45^\circ$ angles into the metal cubes what enables you to leave the spacers away.

Test will come in a few weeks.



Got another engine

| categories: dieselbike, ratbike

I got another engine. A friend gave it as a gift.

  • Hatz E75
  • 350cc
  • 6 ps

There is also an old Ural frame available together with some parts for a cool bike! Estimated fuel consumption should be 1-1.5 Liters. I hope.

DSCN0961

DSCN0962

DSCN0963

DSCN0964

The engine is perfectly healthy even if it was lying around for several years.


Just found MathJax

| categories: code, software

during some web research I found MathJaX which is basically a javascript which can format LaTeX Formulas on your website.

Let's test:

$$ U=\sqrt{P \cdot R} $$

all right.




TeXCalc a Calculator for uncertainties and LaTeX

| categories: code, software

Hi there,

during the last year I developed a command line calculator in python which can calculate numbers with uncertainties.

texcalc

The Tool is also capeable to interperate with LaTeX doing python calculations within a

\begin{calc}
...
\end{calc}

environment. Finally you can set your results rounded to two significant digits directly into your LaTeX formulas by using

$\val{foo}}\approx \val[1]{bar}$

You can find out more on the project website: http://www.nawi.at/~zem/texcalc


GIT is cool

| categories: code, misc, software

Most of the time. ;-)
you can easily forward a remote git repo to github by using a send hook:

( 
        PATH=$PATH:/usr/local/bin
        LOG=/dev/null
        unset GIT_DIR
        cd /home/zem/devlocal/phunivie
        git pull origin master
        git push -u github master
)

The hook is placed in a bare repository which is then cloned to a local copy on the server which is then pushed to github
of course you need to add a github origin, first...
git remote add github git@github.com:zem/texcalc.git



first kubota test run

| categories: dieselbike, ratbike

Here a video of the first testrun of my Kubota D950

Unfortunately it burns oil on two cylinders, the water pump does not work and the crankshaft bearing is gone after the run. So it will take a few weeks more to get my second diesel bike on the road.


Easter horrorshow

| categories: dieselbike, ratbike

The first set of pictures shows one of the exclusive Ural dry-enddrives in good shape. Those drives are dry to prevent oil from dripping on the street. Even if you fill in Oil to them, it will last for 20000 km until the bolts of the cover getting lose and the oil will leak out. You can drive another 10000 km when that happens.






The next set shows another end drive which has some serious cracks in its cover, so it ist useless until I figured out a way to get that fixed.


After I found some slightly useable parts I failed to mount a new enddrive ratio, the cover is not closing, I will write more about that when I know whats going on with that transmission:

Finally on the investigation of the Kubota engine I want to show you a short video of the Injection pump:


coming soon... the vertical antenna project

| categories: hardware, amateur radio

One of my current projects is to build a proper antenna system for HF amateur radio bands on the top of my lorry...


After it is almost finished I must admit that this was more complex than I thought. So I will soon write down my Experiences into 3 threads:

  • vertical antenna for 10m - 40m
  • antenna tuner up to 100w
  • DDRR Loop for 80m - 160m

I will also show you what can go wrong, because I constructed almost everything twice.


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