Tuesday, 18 July 2017

CTARC Committee Meeting - 14 August 2017

CTARC Committee Members are reminded of the earlier-than-usual committee meeting that will take place on Monday 14 August 2017, at 19h00 at the CTARC Clubhouse.

The main purpose of this meeting will be the planning and logistics of the forthcoming International Lighthouse/ Lightship Weekend set to take place at Green Point Lighthouse on the weekend of 19 / 20 August 2017.

Thanking you in advance.

Monday, 17 July 2017

CTARC Antenna Work Party - 29 July '17

Following a decision made at the CTARC Committee Members meeting of 17 July 2017, a very necessary Antenna Work Party will be held at the CTARC Clubhouse on Saturday, 29 July 2017, starting at 09h00 sharp.

We request all club members who are free that day to come and assist. We will be assembling and raising a new beam antenna for the clubs station.

Tuesday, 4 July 2017

CTARC Forthcoming AGM - 22 Jul '17

The Cape Town Amateur Radio Centre's July meeting will be our Annual General Meeting.
It will take place, as always, at the CTARC clubhouse at 14h00 on Saturday 22 July 2017.

All members are encouraged to attend this important club meeting for the election of CTARC office bearers and committee, reading of club financial statements, reception of club awards and a good get-together in general.

Soup and sherry (served in separate vessels!) will be available for the delectation of the members.

We look forward to seeing you there.

Further details will be announced here, on the bulletins and in Ragchew.

Last year's AGM in 2016

Monday, 3 July 2017

CTARC Ragchew July 2017

The July 2017 edition of the Cape Town Amateur Radio Centre's bi-monthly newsletter "Ragchew" is now published. Grateful thanks once again to Anne for another fine edition!

Download the PDF file [here].

Ragchew is also on our Newsletters page


Sunday, 25 June 2017

CTARC Photos of June 2017 Meeting - 25 Jun '17

The written report of this meeting is [here].

Rob / ZS1SA opens the meeting and reports on the recent Committee Meeting
 
Stephen Paine of the UCT Radar Remote Sensing Group started the lecture


Skippy Burger / ZS1SKP, who is involved with HF Surface Wave Radar


Form follows function: Some examples of different Radar antenna applications

Congested international aircraft flight paths require radar for ATC

The airways congestion in Europe is even more severe!


A basic block diagram of a Radar installation

The RCS (Radar Cross Section) determines how much energy is reflected from the target

An illustration (on right) of how Stealth Radar deflection reduces and redirects
reflected Radar energy. The civilian aircraft (on left) produces a far greater
Radar echo

The Doppler effect plays a huge role in Radar sensing technology

The difference in the phase of the received signal can determine its incoming angle

NeXtRAD, a netted coastal Radar system being used to detect
small vessels in rough seas.
Sydney Harbour Bridge. This image could have been obtained
at midnight, because it is a Synthetic Aperture Radar image.

Surface Wave Radar can be used to detect the direction of ocean currents
and their responses to changing weather conditions  in real time.
The SA Navy would also like to see what is going on off our shore line.

A three-node Surface Wave Radar system
Block diagram of a single Surface Wave Radar node.
The formidable Red Pitaya digital back-end; the core of the Surface Wave Radar node.
The Biconic radar antenna. You too can have one in your back yard!
A BiStatic Passive Radar Receiver uses two antennae: One for the reference signal and
the other for the actual tracked echo from the target. The more Surveillance antennae used,
the greater the accuracy of the system.
Front of the multi-tiered Passive Radar Receiver.
The symmetrical signal paths of the Reference and Surveillance channels

The two antennae of the Passive Radar Receiver on top of the RRSG building at UCT

Input signal of the received signal before filtering

All the clutter removed after filtering and amplification, leaving the pure signal

The formidable Ettus USRP N210 Software Defined Radio,
the core of the Passive Radar Receiver

Approaching and departing aircraft can be tracked as they enter the
Cape Peninsula region
Various radar plot maps show the position of an aircraft

Another plot map with an aircraft position (highlighted)

After the meeting begins the bunfight!
Skippy / ZS1SKP and John / ZS1AGH
Barry / ZS1FJ peruses some radio swops brought by Ian / ZS1SX
Among the swops are some battery charger units from Mike / ZS1FP

Frank / ZS1CM and Stephen. In the background is Justin, also involved at UCT's RRSG
More swops! This fine dual dipole galvanised SWL antenna is available
from Mike / ZS1PE, for a very reasonable price!