1:1 50 Ohm Voltage Balun for HF bands

Here’s my small project of an easy to make 1:1 HF Voltage Balun. I have installed this balun between the input of my HF fan dipoles and the RG213 coaxial cable going down to the transceiver. Below there are photos that show how I’ve constructed this voltage balun. Note that this is not a current balun. The balun presented here has also a DC isolation protection between the input and…

Kenwood TS-590SG Master Oscillator Drift and Warm Up

  A video for informative purposes, measuring the frequency drift of the master oscillator on Kenwood TS-590SG for 30 minutes after a ‘cold’ switch on. FLDigi was used to assess the audio frequency drift of the audible signal. Not shown on the video, is that the master oscillator was eventually settled correctly on the proper frequency after about 45 minutes on the receive mode. Perhaps, if someone was transmitting with…

9 band HF Fan Dipole Antenna System (modification of EAntenna dipoles)

There is a long story behind this project, which took 2 months non-stop to complete. It all started when I decided to install an EAntenna Fan dipole for main HF bands, and later to connect it next to an EAntenna for WARC bands, using only a single coaxial line from the shack. Start of parentheses. As a background information, from the very beginning, the tuning of the EAntenna (Spanish design)…

EAntenna balun (problems..) on the EA1015204080DXS fan dipole

After several weekends on the roof tuning without any success this antenna, I decided to take the choke away. Below is what the interior of the EAntenna balun looks like. It’s effectively a 1:1 current balun (not a voltage balun) also called choke, that is the inductors are in series with the coaxial cable coupled around the magnetic core and exiting at the dipoles’ entry point. After removing the choke,…

Experimental construction of vertical VHF and UHF dipole antennas

  More details to be added soon. See a preliminary construction of my vertical dipoles for VHF and UHF transmission and reception: The UHF (top) and the VHF (bottom) vertical dipoles installed on a 40mm diameter PVC waterpipe The top dipole is for the UHF band. The bottom dipole is for the VHF band. Both antennas are fixed on a vertical plastic PVC boom of 40mm in diameter. The dipole…

Κεραία Inverted V-dipole για HF

Παρουσιάζεται συνοπτικά η ανάλυση και οι υπολογισμοί για μία inverted v-dipole κεραία για τα HF. Η κεραία είναι τοποθετημένη πάνω σε ταράτσα η οποία (ταράτσα) είναι 20μ ψηλά από το έδαφος. Επίσης, τα εξωτερικά άκρα της κεραίας από την επιφάνεια της ταράτσας απέχουν 2μ. Το κέντρο της (το σημείο τροφοδοσίας με το RF σήμα) απέχει περίπου 7μ από την επιφάνεια της ταράτσας). Η κεραία έχει τα εξής τεχνικά και γεωμετρικά…

Review of HF SDR upconverter (design by SV1AFN)

This is simply a very effective and functional SDR upconverter. Since, you’ve reached this post, I presume that you are aware of the purpose of any upconverter: You simply take one RF band and you shift it up in frequency without changing any of the signal characteristics that it carries. Operation in brief: This upconverter collects signals from an antenna, it filters them with a 55MHz LP filter, it amplifies…

Design and testing of an inexpensive HF (up to 30MHz) antenna tuner for reception

Circuits and details to be uploaded soon! For now have a look at my constructed circuit above. The matching network has beed designed for a Pi- orientation: Input and output ports see (each) a capacitor in parallel and between these two is in series a capacitor or an inductor (selectable through a switch). In the middle it’s a single sided copper PCB with the copper removed in some places to…