External MIC/PTT/PF interface for Kenwood TS-590SG

      . Circuit design was based on information provided within the following official Kenwood TS-590SG manuals: 1) Instruction Manual, p.3 and p.70. 2) In Depth Manual, p.43. The 4-button membrane keypad is this: http://grobotronics.com/membrane-keypad-1×4.html For my MIC, the approximate values of POTs were set as follows: 5k POT set to ~2.15kOhm (typical, keep this close to 2k) 50k POT (upper) set tp ~3.66kOhm 50k POT (lower towards MIC)…

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…

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)…

'Ugly' balun for the HF bands

This small project wasn’t meant to happen until I faced serious side problems with the coaxial cable connected with my EAntenna HF fan dipoles. The problem can be summarized like this: Movement of the coaxial cable near the antenna input was severely influencing the SWR across all dipoles, despite the presence of the EAntenna choke balun. So much, that sometimes I was questioning whether tuning could ever be predicted or…

How to make an aluminium tube (used in antennas) tunable in fast and easy way

The photos below are self explanatory. They give you an idea of how to construct quickly and easily a tunable element to be installed n various types of antennas, such as dipoles, yagis, log-periodic, verticals, etc. On these photos, the 2 different tube diameters were considered: One with 12mm and the other with 14mm. Of course the choice depends on the application and priorities such as durability, etc. The tubes…

Installation of X50 VHF/UHF dual-band antenna

This is NOT the original Diamond X50 antenna, rather a replica of it. Nevertheless, the appearance of this X50 is indistinguishable from the Diamond X50. Specifications are also identical, according to both manufacturers. The antenna was installed on about 4m height. It shows SWR~1.2 at VHF and SWR~1.3-1.4 at UHF from one end of the bands to the other. It has an N-connector at its base.      

'Smart' VHF tripod antenna for mobile missions

HF tripod antenna

[DESIGN DIMENSIONS AND MORE PHOTOS TO BE ADDED SHORTLY. MY APOLOGIES FOR THE DELAY, BUT WE ALSO HAVE A FULL TIME JOB TO KEEP OURSELVES GOING…] This article demonstrates the construction of a VHF monopole over a tripod-like ground plane, based on the concept introduced on this post: “Special Tripod Antena…” As stated in previous post this antenna possesses several attractive characteristics:   Only 3 drill holes are required! (one…

Ultra-light super-portable VHF/UHF antenna for critical missions!

This a very simple design of a VHF/UHF antenna for super portable missions! It’s also very quick to construct this antenna, it took me around 30min or so to put all pieces in place. The dipole elements are tunable, the classic adjustable rods used in old FM/AM radios. The blue cables, are copper solid-type core cables. These are used to tight the antenna in rods, etc, wherever you like to…

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…

Prototype tripod ground plane antenna for rapid installation and portability!

┬áThe tripods play the role of the ground for the vertical antenna (short vertical fixed with red tape on a plastic PVC tube) located at the tip . This geometry is not tuned for any frequency, it is presented here for illustration purposes. Vertical and tripod elements are from aluminium. For now, see a preliminary construction of my prototype tripod antenna above. Some of the properties of my design include:…

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…