(from page 4)
SWR and the modern transceiver
Where the SWR does play an important in proper station operation concerns the match between the antenna system and the transmitter. Back in the 'good old days' most transceivers had 'tubes' in their final amplifier and an adjustable pi-network output circuit. (Remember the 'Tune' and 'Load' controls?) Many of those rigs could accommodate SWR values as high as 4:1 or even 5:1, depending upon the transmitting frequency. The modern solid state rig, on the other hand has a fixed-tuned broadband output network designed to work into a 50 ohm load. As the SWR on the feedline rises, and the load departs from 50 ohms, the transceiver compensates by shutting itself down in order to protect the output transistors. The higher the SWR, the less the power output!
For example in a modern transceiver at 7.0 MHz at an SWR of 2:1 power output drops from 150 to 120 watts. An SWR of 2.5:1reduces the output to about 60 watts and at 3:1 the output is a meagre 35 watts.
Now look at a frequency of 28.6 MHz. This is more complicated. The power output versus SWR ratio varies depending upon line reactance. With a mismatch having positive reactance, the power output follows a similar curve as at 7 MHz. With a mismatch having negative reactance, the shutdown curve is much more sensitive. At 2:1 the power has already dropped down to 70 watts, at 2.5:1 the power is 40 watts, and at 3:1 the power output is less than 20 watts,
These results are for a single test of one transceiver. How does your transceiver respond to a reactive value of SWR? The results probable will be different from this examination, but you get the idea. As far as the tube-type rig does, high SWR is not an important factor. However for the solid-state rig, a high value SWR may mean the difference between full output and almost no output!

From 8.00 PM the doors will be open for a natter night. Currently a lot of space is taken by building material for the lining of the walls and ceiling, and to be erected dividing walls. Come along and discuss the building plans with your fellow club members. Unlike last month were we had to run a generator, we now have mains power (one GPO so far), so we can at least serve a hot coup of coffee or  tea.  Also, in case the temperature is low, bring a jumper, as walls and ceilings have not yet been insulated. And, if it rains, do not park on the grass!

My name is Tomas Alva Edison (1847 - 1931). Over the period of my lifetime I accumulated some 1.093 patents, far to numerous to list. The salient being, the incandescent electric light bulb, electrical generating system, sound-recording device and motion picture projector, electric-power station, the kinetoscope, (the first machine to produce motion pictures by a rapid succession of individual views). The Edison storage battery (an alkaline, nickel-iron storage battery), the electric pen, the mimeograph, the microtasimeter (used for detection of minute changes in temperature), and a wireless telegraphic method for communicating with moving trains.

Apart from the monthly newsletter which is now available via our home page, we need more information to add to the club's Home page. If you wish to add any information or links to the club's home page you may forward it to Paul VK3GPS. His e-mail address is as follows: sleep@mpx.com.au  Or you can e-mail peter VK3TE as follows: pbrennan@telstat.com.au.