2019-07-11

Building My Own Website.

I do have an extremely simple page on https://qsl.net/oz9qv/
This may grow a bit, but I have just got the domain where the main (detailed) parts should be.
It should also host the contents of this blog.
When it becomes active, it will be at http://oz9qv.dk When I find out how to set it up it will be at
https://oz9qv.dk https://oz9qv.dk

It will take time to get everything in there, but I should get there along the way.

Next post will be #100, so I will see if I can make a good one ...
(A good opportunity to launch the new website/blog.)

2019-07-09

10GHz Horn Antennas and Update on the LNB RX Experiment.

I have a number of horn antennas.
I am well aware that horn antennas of these sizes for 10GHz are a compromise. Small size is used, sacrificing gain, as compared to dish antennas.
Today I found a horn antenna calculator , so I can see what I should expect of the different sizes.
The calculations are like this:

- The largest horn (145x115mm): 20dBi
- Two slightly smaller horns (120x115mm) 19dBi
- Two metallised plastic horns purchased new: 17dBi. Same as specified by manufacturer
- a tiny horn with a (Gunn or detector?) diode in an integrated waveguide: 10dBi

I should be able to find more horn antennas when I get access to the rest of the storage - if I have brought them home when I moved, that is.
The three larger horns were painted when I got them, so I hope the paint is not too lossy.
For the 3 larger horn antennas I need to make a coax to WR75 transition. The 2 standard 17dBi horns need WR90. It should be possible to use the WG transition from some ancient single polarization LNBs I have, or, in the first instance, maybe use the preamplifier in the LNB as a 10GHz preamplifier. Still, a modification is needed, and the noise figure is expected to be about 1.5dB. Not as good as it could be, but still in the acceptable range.

It looks like I may have to create a 10GHz antenna "test range" in my garden, so I can check the gain figures. It is a good thing that I now have a set of 17dBi reference horn antennas, so I can get some relatively reliable gain indications. I know, a test field is not ideal in a garden, due to reflections etc, but it is better than nothing. Yes, coax to WG transitions needed there, too.
Initially I expect to use a HB100 as the signal generator, and test, if I can find log detector covering 10GHz. I am trying to make it simple. It may be possible to use an old (low gain) LNB for converting 10GHz and use log detector for a lower frequency. More tests to do.

Finally, a small update of the LNB receive experiment:
I looked up today to see that the direction of the horn is about 60deg. off the heading to the local beacon. Impressive that I still get a signal at 36km.

2019-07-06

A Bit of Work to Get a Workshop Up and Running.

The last few days I have worked a bit more in my "out-house" (40 sqm), to get a better organized space. The plan is getting to one section for storage with a small desk, one section with mechanical tools, and a section for other activities.

It is slow work, because there is a lot of stuff to move around, but right now I have done the beginning of the storage space, not yet with the desk space. A lot of stuff has been discarded, and more will come.

There is a fair bit of good quality tools that I inherited from my father when he passed and I took over the house, but it has been out of use for a while. Some of it probably needs maintenance. I will get there eventually.

Right now the corner section with shelves (and space for the desktop plate) is partly done. Some old stuff needs to be moved, so that more of the shelf space can be made ready and orderly. Next should be the workshop getting ready. A slow process, but it is progressing, along with all the other projects.

6m JA "Heard" - and a bit of rain scatter on 10GHz.

I got up late this morning and I could see on the PSK Reporter that I had received several JA stations on 50MHz this morning (50.313). The best signal was about -10dB, so quite good. I might have been able to work that station.
On top of this, I had received a few South Korean stations.
Interesting propagation at the bottom of the solar cycle. Who knows if the same propagation is seen at solar maximum. I am not sure.

In the afternoon some showers passed across the island of Zealand (Sjælland), and two beacon signals were audible. In addition to OZ9GHZ that I seem to hear at all times, OZ7IGY came through with the characteristic rain scatter sound.


2019-07-05

Update: Local 10GHz Beacon Monitoring.

Here is a quick update on the LNB receiving experiment.

The LNB is just mounted to the mast with duct tape with no dish reflector, and just in a fixed direction.
Here are the reception results after some tropo days and days with more or less flat conditions:
The beacon OZ9GHZ can always be found when tuning around for the drifting. It varies in strength from a solid S5-7 sometimes with short fade-outs of less than a second.
OZ7IGY is still out of reach for this setup.
I suspect that the part sea path for OZ9GHZ with few obstructions, and the landscape being against my signal, is the reason for the difference, in spite of the OZ7IGY being located closer to me.

At least, it looks like I have a stable 10GHz signal source to test basic reception on the band.

2019-07-04

Antennas: The Right Tool for the Purpose. Part 1.

Over the past few years I have been working a bit of everything on every band I could.
Just over 4 years ago I returned to my native Denmark after 25 years working abroad.
I moved back to my childhood home and started re-building my antenna system which had deteriorated a lot over time. That process is far from finished, and I suspect it will never be, due to new projects and interests in the ham radio field.

#1: Getting some local VHF FM system working. I chose the Diamond V-2000 antenna, because it had 3 bands available: 6m, 2m and 70cm. 6m has been a great interest of mine ever since I the band started becoming available in Europe.
So, why use a simple vertical omnidirectional antenna for a band like 6m? You can work so much more with a beam. The simple answer is that I wanted to get started quickly, because the Sporadic E season had just started, and getting a beam and rotator would take too long.
I had been working a fair amount of DX on 2m, 70cm and 23cm before, so that was not high priority, and I wanted to have some antenna for local FM traffic.
The V-2000 simply fits the bill very nicely, and easy to mount on my mast going up through an apple tree. the 6m capability was a great bonus, though.

#2: In my years since I got licensed in 1973, I have worked very little HF, but I would like to try out more. The exception was 10m, I have worked a lot on that band, especially in the summer Sporadic E seasons. The choice was a 5 band dipole for 10-15-20-40-80m. I tuned the antenna for the low parts of the bands, because I worked mostly CW and later digital modes. I managed to work DX on 80m, like the US and Japan, in the deep of winter, so the antenna was working, at least.
10m was OK-ish, but not too good for my taste hence:

#3: 10m vertical. I purchased a low-cost 27MHz end-fed half wave antenna and got it mounted about 6m above ground. Even in the rapidly deteriorating solar activity I was able to work some DX on 10 most of the year. This has, of course not been quite as good right now, as we are in the deepest low of solar activity. Only the sporadic E season is really any good on 10m, but I know things will improve when the sun gets going again. The 10/11m vertical does work on some lower bands, using the built-in antenna tuner of the radio. Suddenly I was able to work on 30m, even if that was bot the best antenna in the world.

This is what happened with my antennas the first year or so after I returned home. More happened later, but this is sufficient for now.
At the least this got me going on most of the bands from 80m to 70cm.