Sunday, 30 September 2018

Discone Antenna

This weekend I installed the Albrecht disconne antenna '"Allband'".
It is an omnidirectional discone antenne capable of receiving 25 - 1300 MHz signals.
Transmitting is possible from 50 - 1300 MHz (VHF till 300 Watts, UHF till 200 Watts).
Antenneheigth is appr. 6 m. above sealevel. In the north, east and west direction I have a clear view. 
I used Aircell7 coaxial cable to limit the losses on the higher frequencies.
I was able to receive various 2 m. repeaters in the neighbourhood ( Goes, Rotterdam, Bergen op Zoom) using a Boafeng BJ-218 VHF/UHF transceiver. First contact with this antenna was with PA0RPA via the repeater of Goes (145.775 MHz, 88.5 Hz CTCSS).



                                                         Discone antenna 



Coming period I will do various trials on various frequencies (50 MHz, 70 MHz, 430 MHz) to get an impression how the antenna performs.


Boafeng BJ-218 VHF/UHF transceiver 

Thursday, 20 September 2018

QSL from the past

In the eQSL inbox of my former callsign PH0RF, I found a QSL from Vlad YL2GC from Latvia. The QSO was from 2004 in SSB (20 meter band);



Off topic:


Steam locomotive over the Lek bridge in Culemborg, 28 Sept. 2018



70 cm FM transmitter

Last months I am not very active in radio homebrew activities. Luckily other radio amateurs are. I visited Hans, PE1DWA, last week and he realized a nice DIY 70 cm Wide Band FM  transmitter with an RF output of 5 Watts.


430 MHz ATV transmitter combi; the Local Oscillator is on top

Local Oscillator, inside

Friday, 7 September 2018

David Edward Hughes

I always thought that either Heinrich Hertz, Marconi or Faraday realized the first radio transmission. But someone was ahead of them;

David Edward Hughes (16 May 1831 – 22 January 1900), was a British-American inventor, practical experimenter, and professor of music known for his work on the printing telegraph and the microphone. His family moved to the U.S. while he was a child and he became a professor of music in Kentucky. In 1855 he patented a printing telegraph. He moved back to London in 1857 and further pursued experimentation and invention, coming up with an improved carbon microphone in 1878. In 1879 he identified what seemed to be a new phenomenon during his experiments: sparking in one device could be heard in a separate portable microphone apparatus he had set up. It was most probably radio transmissions but this was nine years before electromagnetic radiation was a proven concept and Hughes was convinced by others that his discovery was simply electromagnetic induction.


Hughes seems to have come across the phenomenon of radio waves nine years before they were proven to exist by Heinrich Hertz in 1888. In 1879 while working in London, Hughes discovered that a bad contact in a Bell telephone he was using in his experiments seemed to be sparking when he worked on a nearby induction balance. He developed an improved detector to pick up this unknown 'extra current' based on his new microphone design and developed a way to interrupt his induction balance via a clockwork mechanism to produce a series of sparks. By trial and error experiments he eventually found he could pick up these 'aerial waves' as he carried his telephone device down the street out to a range of almost 500 meters.

Hughes wireless apparatus, a clockwork driven spark transmitter and battery (right) and a modified version of his carbon block microphone (left) which he used in his 1879 experiments.