G5RV Measurements

After replacement of my 80/40 m trap dipole with the G5RV antenna, I made some measurements. The antenna has a height of 12 m at the center, and is hanging as an inverted V with both ends still 4 to 5 meter above ground. The symmetric feeder line is connected via a 1:1 balun to 12.9 m 50 Ohm coaxial cable.

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Fiberglass Balcony Stealth Antenna for 40 m

In Singapore space is limited, and in our appartment it is difficult to setup any HF antenna. Our balcony is the only place where I have a space to mount something. Even there, officially nothing is allowed to extend out from the building.

I decided to setup a simple vertical, using a telescopic fiberglass pole, which I can pull out temporarly, when it is getting dark.  The pole has a total length of 10 m, approx. 1 m (the lowest segment) safely mounted to the balcony railing and sidewall.

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Weak Signal Digital Modes on HF-Bands

Many open source programs are available for Windows, OS-X and Linux, if you want to become active on the amateur radio HF bands using digital modes. Modern coding and modulation schemes allow for long distance contacts with low power.

Below you can  download my presentation about PSK 31 (Phase shift keying) and JT-65/JT9 modes as presented in our monthly SARTS meeting August 2016 in Singapore.

Presentation (pdf): WeakSignalModes


ICOM IC-7300 – SDR radio in a box

Finally the new IC-7300 arrived, and I am still in the process to get familiar with it. I could not resist, as my IC-718, though reliable, is quite “outdated” in its technology, developed more than a decade ago.

Unfortunately, the first IC-7300 unit I picked up from the retailer in Singapore, had a DOA (defect on arrival): the CW keyer always sending dashes. Luckily, there was a second unit available, and it was exchanged without any problems.

Now the new unit is in operation for a week and doing its job without any problems. Size and weight are the same as my IC-718, but the features are not comparable, and it is a real advance in technology. The menus are intuitive and signal reception is excellent, as I can adjust all parameters – gain, filter bandwidth and response, audio processing etc. – according to the actual band conditions.


Two days ago, I setup the configuration for digital modes, connecting my Apple MacBook via USB, using fldigi and the IC-7300 built-in USB sound interface and serial control. So there is no need for any additional interface box, just one USB connection between computer and radio. It works fine, and I was able to make my first contacts in PSK-31.