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Friday, 20 October 2017

The Ultimate 3

Well,

Quite some time ago, I built myself an Ultimate 3 QRSS/WSPR beacon kit from QRP Labs.

Now this is a fab and groovy kit from the infamous Mr Hans Summers.

The completed kit is currently sat atop of my FT-817 and is configured to send WSPR beacon and a QRSS beacon both on the 30M band.

The output of the unit looks like this:


and is 13.12V peak to peak.

That's a power output of 420.2 mW or 26.3 dBm.


So, I've left this running for 24 hours connected to a simple 30M dipole in the garden, and here's the WSPR map of the resultant reception of my signal:


Never fails to amaze.

And here is my very beautiful Bonnie Dog:


Local conditions.

Thursday, 19 October 2017

Three holes in the ground (well, well, well)

Well,

I just found out, very much by accident, that one of my 'scopes has a built in "Easter Egg" in that you can play Tetris on it!


After power on, press Print/Utility and then hold down function keys 2&3 - voila!

Bonkers.

Friday, 8 September 2017

The Art of Rotator Control

Well,

I decided that there had to be an easy way to computer control my antenna rotators. I already have this on the Satellite antennas in Azimuth and Elevation, but not the "normal" antennas I have here for HF & VHF.

I looked on the big bad internet and found that Yaesu make a rotator interface for the G-1000 rotators that I have, but they are a simply staggering price.

So, there had to be a way....

The first thing I did was connect to the interface socket on the back of the rotator and figure out which pin did what. We have a voltage output that represents the heading, which plotted like this:


Using simple bit of maths we can then create an equation to calculate the voltage at any heading (to save me having to keep moving the antennas back and forth):


There are also two pins on the interface connector that you ground to turn the rotor left and right. There's also a fourth pin you can use to set the rotator speed.

I then figured that Arduino was certainly the way to go, but then I found this:

https://blog.radioartisan.com/yaesu-rotator-computer-serial-interface/

Now, this interface does all I want and a million things more, it's been written in a way that allows you to configure the bits you want and exclude the bits you don't.

To get this to work with my G-1000 series rotator, I configured the following:

#define AZIMUTH_STARTING_POINT_DEFAULT 0

in the rotator_settings.h file; that's about it!

That setting defines the rotator as one that turns around 0 degrees (rather than 180 being the end stop).

Once I had done that and defined the pins (I just used the defaults) and also defined Digital pin 10 as the speed output:

#define azimuth_speed_voltage 10

in the rotator_pins.h file

I compiled the code for a Arduino Nano with an ATMega328 processor (because that is what I had lying around).

I then built the simple interface needed:


Now, the next step was to calibrate the software. Instead of turning the rotator from fully CCW to fully CW (including the 90 degree overlap), I just used the equation I established above to calculate the voltage and set the bench PSU to deliver same.


Then once that was complete, I connected the Arduino board to my Radio Control PC, fought with COM port settings (a favorite hobby of mine) and then configured my logging software to use a rotator controller emulating the Yaesu GS-232B command set.


So now I have this display above, it shows where the antennas are pointing and allows me to click on a heading to send the antennas there. I can also configure the system to auto turn the rotator based on selection of DX spot if I like too.

Neat, egh?

Sunday, 3 September 2017

I'm forever blowing bubbles? No! bulbs!

Well,

I have a couple of Yaesu Rotators here, and the controllers were stacked one on top of the other with a small cardboard box propping up the top controller. The cases are kind of slanty topped and the whole arrangement meant that they both fell to the desk regularly. This in turn ensured that the bulbs illuminating the front scale blew farily soon after purchase.

My local friendly emporium LAM Communications sent me some replacement bulbs some time ago, I just never got round to replacing them - mainly because I couldn't find any instruction on how to do so.

So, here's how to replace the bulbs in a Yaesu Rotatorbamob (or certainly the 1000DXC variety).

Firstly we remove the main external case:



Now, the bulb is clearly part of the main dial thingy on the front, so that had to be removed also (there are 4 screws):



The bulb is under the silver paper I've highlighted below:


So it's just a case of peeling back the tape carefully, and soldering in a new bulb.

I've also made a wooden stand thingy so the controllers stack without the need for cardboard wedges and other jiggery-pokery and hopefully the wont fall over any more:


Local conditions.

Thursday, 20 July 2017

First On-Air Test Complete

Well,

Thanks to the help of Col, G4OHV I have tonight tested my Portsdown transmitter on air.


Here's the video Col captured of my TX - Thanks!

Good, egh?

Tuesday, 11 July 2017

More InnovAntennas Fun

Well,

You may remember my sharing an instruction sheet from an InovAntennas purchase back here and basically explaining how poor I though the instructions were. Well, here's another excellent example:


So, credit where credit is due - this time I didn't actually have any missing parts for the antenna itself; however I did have some spare bits for the antenna (some extra end caps and element clamps) and unfortunately the antenna to boom mounting plate and associated u-bolts are missing completely.

But lets take a look at the instructions:

  1. The title tells me it's a 1.4m antenna; I assume that's the boom length, but, oh no, the boom is 1.7m long.
  2. The bottom of the page tells me the boom is 1.7m long - so which is it? Let's get a tape measure and check.
  3. The bottom of the page also also tells me that "guy and supports are supplied" - I don't think so.
  4. So let's look at the shortest element - there are three numbers 1705mm, 1405mm and 903mm. So I think one of these (the 1705) is the distance from the boom end, the 903 is the element dimension - no idea what the 1405mm is - perhaps this is for the 1.4m antenna mentioned in the title that I haven't got? If that 1703 is the distance from the boom end then the first element is nearly a foot from the boom start - that can't be right either.
  5. Then we have the added information "X-POL SIZES"; you have to assume this is for a cross polarized variant perhaps?
But once again, no actual information on which bolts or other bits to use where. One of the driven element clamps is metal - now I assume that's not at the end the feedpoint is and it seems the feed is at the back. I assume I need a coax balun near the feedpoint but that's clearly guesswork as there is no information on that aspect at all.

Local conditions.

Saturday, 1 July 2017

EMC 'n' all that Jazz

Well,

I've been having some issues when I TX on 6M CW. Very strange in that my Radio PC (the one sending the CW) shuts down - it doesn't crash - it performs an orderly shutdown.

This is definitely an RF issue as it only happens when the TX power is above a certain value.

So, by using a process of elimination, i.e. removing cables from the back of the PC one at a time and seeing if the problem goes away, I concluded that it's probably the HDMI cable to the monitor (well, one of the monitors) that's causing the problem.

This has lead me to question the effectiveness of ferrite suppression and other such gubbins.

Now, all of us hams will have purchased a bunch of clip on ferrites at a rally; these are supposed to be made of type 31 material which is rated up to 500MHz.

I mean something like this:


Now, these are designed to clip on a cable, effectively providing one turn through the ferrite. How well does that work then? So here's the spectrum analyser showing 0 to 100 MHz and a simple loop back from the generator to the input - no ferrite here:


So, lets now add a single turn of the clip on ferrite and see what difference it makes:



So the answer is, quite expectedly, not a great deal. So, let's increase that to 5 turns:



So, thats much more like it.

We have to conclude that clipping these ferrites onto cables around the shack is next to useless at HF - we need at least 6 turns through the material before we see any significant attenuation.

There are a number of larger ferrites available, using the same material, but bigger:


These will allow you to get multiple turns of coax or mains cable, or in my case a HDMI lead through the core, and most importantly they are also clip on.

I've tried a few combinations of different cores on my HDMI cable to see what works best; there are all sorts of other issues creeping in now though, like the resonant frequency of the cable itself:




The bottom picture above effectively gives me 6 turns by using 6 cores; the image above uses much more expensive cores and passes the wire through multiple times. They both have much the same impact.

So, I plan to add the cable above as an extension to my existing HDMI cable and see if the problem is solved.

Here's our very beautiful Elmo enjoying the fact that summer has finally arrived:


Local conditions.