Checking My Inverted L Antenna

I have two antennas at home, an off centre dipole and an Inverted L. The Inverted  L has been up since the year 1999 when I first received the M5LMY licence and could operate on HF.

This antenna is fed at the base of the vertical section by an SGC auto tuner. The vertical section is about 5m tall and the horizontal section about 7m long with both sections strung within some oak trees.

Had the opportunity today to check the Inverted L, the first time in a year. In the 14 years that this antenna has been in use, the insulator at the bend from vertical to horizontal has become almost fully embedded within the supporting tree branch. This insulator was free when installed, held to the tree by some Kevlar rope wrapped around the branch. In the 14 years, the branch has grown and almost taken the full insulator. See the following photo:

A bit difficult to see as the photo was taken into the sun, however only the hole for the wire and a small bit of the insulator body is still free. The main part of the body and the hole at the opposite end for the supporting rope has fully disappeared into the branch.

The following photo shows the horizontal section running to the tree at the end of the garden.

The wire almost rubs against the branch in the foreground, I wanted to check that the insulation has not been worn through, however it was in good condition. As can be seen, the wire is fully within the trees.

The following photo shows the auto tuner at the base of the vertical section.

This is an SGC model SG-230. This is the second one I have had since 1999. the first failed around 2002. The replacement has worked perfectly since.

The two yellow/green wires at the base of the tuner connect to a copper earth rod, from this a single wire runs under the earth beneath the horizontal section in the air.

This set-up was originally used by my TS2000 and now supports the FT2000. It supports operation on all bands between 80m and 10m which is very good for such a small system. Obviously performance is a very big compromise, however for a simple antenna that does not stand out in the garden it work really well.

Computer Operating Temperatures

As I have a number of computers always running I built an outside shed to host these so they would not have to be in the Radio Room. These computers are receiving Eumetcast Weather Satellite data, running my Weather Station, acting as a Media Server, monitoring WSPR and APRS for good propagation conditions, running an NTP server etc.

The problem with the shed is a confined space with no ventilation or cooling unless I open the door, which I usually do on hot days but often do not remember until later in the day.

The computers in the shed have been running, with the exception of a couple of very small breaks, continuously for 5 years.

The temperature inside and outside the shed is monitored and it has been very interesting to monitor the inside temperature which can exceed 40 degrees centigrade at times.

The following graph shows a typical day from this August with the internal and external temperatures.



The external temperature always reads a couple of degrees too high as the sensor is located on the side of the shed between the shed and a fence with very little free air flow.

The graph shows very well the difference between the internal and external temperatures.

In the 5 years of continuous operation, the only failure I have had is one of the computer power supplies, no other problems despite continuous operation (and with very heavy disk usage with the Eumetcast satellite receiver), all with standard, consumer, off the shelf computer components.

I suspect being always on helps, but it is interesting how robust computer components really are.

Decoding now working - But problems remain

Following on from my last post and my JT65 problems after installing a new sound card, it is sort of fixed but I cannot find the root cause.

I tried removing the new sound card and doing a system restore to get the system back to the same state as it was prior to installation of the new card. The problem with JT65 remained, it would not switch to decode.

I also tried HRD DM780 to decode PSK, however this also was not working and could not decode, so not specifically a JT65 problem.

My next step was to switch the radio interface from the original motherboard sound to the new sound card and it worked. JT65 would switch to decode and was decoding stations as usual.

So whilst I have not fixed the problem, decoding applications do not work on the original, motherboard soundcard, they are working with the new soundcard.

What I do not understand is why JT65 would not switch to decode and why this is soundcard dependent. I assumed it was a timing function with JT65 switching to record after 49 seconds (hence the need for accurate PC timing).

The new Soundcard is an ASUS Xonar DS and the motherboard is the usual Realtek. Operating System is Windows 8.

Why Are Computers So Unpredicatble ?

Why does what seems like a simple change cause what seems like unconnected problems on computers.

I installed a new sound card today to provide a second sound device in addition to the one on the motherboard. 

Installation went well but when I started JT65, signals were displayed on the waterfall but it would not decode. The program stayed in Receiving mode all the time and would not attempt to decode. 

Tried a new installation but exactly the same. Checked all the configuration parameters but nothing that would impact decoding. 

Not sure where to go now, have done the usual Google searches but nothing similar to this problem. Have put a question on the JT65 group, hopefully someone has seen this before and can suggest a fix.