Software defined radio, RF preamplifier's and mixers. Adventures into RF antennas and proof that theory <> practice ;).

Jeroen Steeman - Telecommunication projects


Software defined radio, RF preamplifier's and mixers. Adventures into RF receivers, transmitters and antennas. Showing that when theory states that theory and practice are the same, practice shows this is not always true when working with UHF (Ultra High Frequencies).

I'll be working mostly in the UHF band (Ultra High Frequency) and irrespective of what you read on Internet about the length of antennas...yes! length is critical, so do not be fooled by antenna parameters unless you are sure they apply to the frequency you require. The alternative is to use a coat hanger or even a pencil, the results will be about the same.

ADS-B (Automatic dependent surveillance – broadcast) Digital Aircraft Spotting.

Phase I: Antennas for 1090.000 MHz. Goal: Construct, test and compare various antenna designs against a 'tried and trusted' 1/4 wave dipole. Check the results...each have their pros and cons.

More information about the SDR virtual radar setup can be found at ADS-B project and a live view of the virtual radar in operation is avaiable at Vitual Radar Live.

Endurance tests

ADSB Antenna Comparison Tests

Simultaneous trial testing with different antenna designs. Using the Raspberry PI as software defined radio receiver and data decoder. Initial tests show the PI B+ and PI 2 to be acceptably stable for lengthy trial runs while collecting data.


ADSB Quaterwave vs ADSB J-Pole

Antenna types 1/4 wave and J-pole construction explained. The first trial tests between two types of antenna designs includes explanation about basic antenna design. A good place start if you want to know how antennas work.

Abstract Constructs

Colinear construction testing

'What if I tried this' collinear antenna abstraction and other 'oh well there goes the theory' antenna constructions. Some still have me baffled at present. Everything UHF and above is partially 'black science'. PS: Wave guides are out of scope.

Fragments of a Whole

ADSB 1/4 Wave

The 'trusty' 1/4 wave antenna. Easy to make, the most basic in theory and works perfectly in practice to. It has no gain, but is the perfect control subject for what is to follow. Find out how to construct a 1/4 wave antenna guaranteed to function well.

Antenna Design Measurements Calculator

Frequency to wavelength antenna design calculators for several popular (tried and tested) antenna designs.

See the Antenna Design Calculator for more details.

PVC Pipe Antennas

PVC Pipe Antennas

Antenna designs ideally suited for weatherproofing by their slim design so they can easily be mounted in PCV tubing and placed outdoors preventing corrosion and damage from the elements.

Antenna Prototyping

Antenna Prototyping

Tips and tricks invented to help in testing prototype antenna constructions. From easy variable matching stub connection specifications to the effects of foreign housings, casings and mounts.

Antenna Tweaking

Prototype Antenna Construction

Getting the antenna from the state of working prototype to a fully functional industrial design. Confirming the functionality by building the first operational version and the subtle tweaking.

Antenna Preparation

collinear mast mount

Preparing the antennas for being mounted on masts. Weather proofing and fixture construction so that ic can operate in all weather conditions.