Broadcast - 14 April 2024
Remember last club technical night, we mentioned Colin VK7ZCF’s “find of the decade” at the local “Recycal” agent. A four section commercial telescopic aluminium pole that extended to 5 metres, for a ridiculously low price of $10! This naturally lead to the possibility of portable use, which in turn would require a tow bar hitch for ease of mounting, then the need to be able to tilt it over for ease of antenna placement and finally a rotator controlled top section.
As a quick refresh for the latest update, the rotator section consisted of two aluminium tubes, one sliding easily within the other and turned freely. Colin machined up adaptors and mounted the cylindrical motor and gearbox within the larger diameter of the two tubes. With the application of 12 Volts DC this effectively rotates the inner tube and the attached antenna.
Since then Colin has constructed a hand held remote control unit for the antenna rotator. It provides direction of rotation control of the rotator at the “flick of a switch”.
For an added a touch of finesse into the construction…. He also incorporated a Pulse Width Controller, giving him the ability to adjust the rotational speed of the top section by the “twist of a knob”.
All this from a well spotted find of a telescopic pole, a very well stocked junk box, some hard work and only two minor purchases from e-bay of a motor-gearbox plus a tiny Pulse Width Controller board.
With some excellent engineering by Colin it all came together to make a convenient and portable set up. We will await the field trials.
Peter VK7SP has been trialling a new “SDRplay”, Software Defined Radio and putting it through its paces.
This is a small external enclosure unit as opposed to the usual “dongle” construction, but still plugs in via the USB port. We call it an SDR for short, but the English manufacturer refers to it as a “Radio Spectrum Processing receiver”! Peter has been running it attached to his PC and was using the proprietary SDRuno Software Defined Radio application platform to configure the unit. He was interested in downloading Weather Satellite images so he was also using “GPredict” software to track and predict the orbits of weather satellites. Doppler Correction software, for receive frequency correction and “WXtoImg” software to decode WEFAX signals from weather satellites to produces a viewable image. He has been running it with a temporary V antenna sitting about 600mm above the ground. This may not have had the best horizon to horizon capture window but the sample images Peter brought in to the tech night were successfully decoded and surprisingly good.
One image in particular showed the remnants of the recent Sydney region thunderstorms in stunning colour. Resolution did appear to be high and it will be interesting to compare this unit to a previously purchased “cost effective” Chinese dongle version. Can’t wait to see some comparisons, possibly even with the antenna not quite so close to the ground. hihi
As always, pictures will be available on the NTARC Web site under “Blogs” for this broadcast.
UPCOMING EVENTS
TestNet and TechNet session - Every Wednesday, TestNet/CW course on 3.580MHz from 7pm till 7.30pm…. and a TechNet on 3.567MHz from 7.30pm till about 8.30pm. Your host for the evening will be Nic VK7WW.
Coffee Morning - held every Friday in the NTARC Club rooms. Time is from 10am to noon and we look forward to seeing you all there. So why not pop in and join us for a cuppa, there is endless tea and coffee along with biscuits available for a donation.
Club Room Technical night session - The next session will be on Wednesday the 24th April and will commence at the usual time of 6.30 pm, running through to about 10 pm, at the Club room Archer Street, Rocherlea.
Finally - A reminder to all members that if you have any items of news you would like added to our weekly roundup, no matter how trivial, then please email them to the Secretary at the following address news@ntarc.net all items to be received no later than 5pm on the Friday prior to the Broadcast.
That’s all folks,
73, Stefan VK7ZSB, Secretary NTARC Inc.
