Broadcast - 30 Apr 2023
We will start things off this week with a quick look at the latest Club Technical night.
You may recall that a few broadcasts ago Peter VK7KPC, brought in two Pelican look alike padded ABS cases that contained a trial setup for field day operations. Well the next revision has been presented, this time all items have been consolidated into one aluminium brief case. When opened it reveals the original Xiegu clone CS108G HF transceiver and Antenna Matching Unit model ATU-100, which are both mounted on a hinged panel, plus a Yaesu extension speaker with noise filter mounted under the case lid. Beneath the hinged panel there is ample space to store wire antennas, microphone, power and patch cables plus a safe storage area for Peter’s trusty old CW key. Interestingly, access to the underneath CW key is also provided through a strategically placed slot in the hinged panel, this allows limited use without removing the key from the case. I assume this alleviates the need to externally set it up if only needed for a quick message or testing. Anderson Power Pole connectors are used for external DC power and soon there will be an internally mounted antenna socket. To finish the matching outfit there is a soft case holding two 12V batteries to provide both 12 and 24V DC for field operations. A well thought out portable set up that is just waiting for Peter’s next field day excursion.
Peter latest project is a PIXIE 300 milliwatt QRP Transceiver from QSO Labs, designed by W1FB (SK).
The primary design difference is there is no on board crystal but a DB9 socket that accepts a suitable plug containing the crystal. This makes changing the operational frequency as easy as changing a plug. “Plug and Play” might even be a better description. HiHi. Peter was busy looking at circuit drawings and planning improvements to add design features like antenna Band Pass Filter and transmit switching. A work in progress.
Ross VK7ALH delved into his military collection and turned up with a Teleradio transmitter type J6798 which is one part of the 3B set and sports a single venerable 807 vacuum tube final. It was constructed in rugged steel boxes with rounded corners. Clip on front covers could be used for protection when being person-handled. The unit has three selectable operating frequencies and can be used for CW or voice in the 3 to 9 MHz range. It was made by AWA in Australia about 1941 and mainly used by “coast watchers”. It is starting to show its age but nothing Ross can’t handle. Unfortunately Ross doesn’t have the matching C6770 receiver unit to complete the 3B set and would be interested in talking to anybody who may have one.
Just to wake us up, Ross’ other offering was a Stingray 120A SSB and AM Transceiver with accompanying auto aerial tuning unit type 120 in a matching case. They are not your normal white lettering on a black background boring front panels, these two offerings have bright yellow front panels with black contrasting lettering. But in low light levels it sure would help with interpreting the controls! These very attractive units were mainly used for marine, interstate truck drivers, School of the Air and the Royal Flying Doctor Service.
This crystal locked, solid state transceiver hails from last century and was made by Findlay Communications, Sydney which was headed by Maurice Findlay whom in 1948 started work with “Radio and Hobbies” magazine and reported to the great John Moyle. At one stage he had a young Dick Smith working for him and later wrote articles for Silicon Chip, for more information see the link in the text version.
Trevor VK7TB was explaining the nitty gritty of using a Vector Analyser to measure and calculate the equivalent circuit parameters of commercial plug in crystals. To be specific, batches of one hundred individual 6 and 13 MHz crystals were tested for seven parameters. Trevor had the tabulated test results from over 200 crystals, that’s about 1400 individual measurements that he was analysing for parameter spread. The end result is the ability to selectively match groups of “like crystals” that could be used to construct 14 pole crystal ladder filters. Like every aspect of our hobby the ability to test and make measurements of parameters whether they are components, constructed kits or commercial equipment, if you don’t have the comparative information you really are flying blind. Thanks Trevor, hopefully in the near future you will be able to demonstrate for us the art behind testing of some of these parameters.
While we are on the subject of test and measurement, Lionel VK7ZLB, arrived with a piece of test equipment. It was an audio “Output Power Meter” that covered from milliwatts to ten Watts and was manufactured by Radio Corporation Pty Ltd, of South Melbourne. It was a product from their Radio Test Equipment Department and was made about 1950. Externally it was finished in the common crinkly black paint with white lettering, but internal construction employed rotary selector switchers using multi finger wipers for mechanical accuracy and longevity.
The Radio Corporation manufacturing complex was substantial, at about one hectare under one expanse of roof, the facility was organised into the largest works in Australia, devoted exclusively to the production of radio receivers. It generally became known as the Astor factory. The really interesting part is that our very own club member Burnie VK7BR, worked at this actual Astor factory where these units were made! Just for the record his initials weren’t inside this piece of equipment though. HiHi.
Yet another diverse and interesting technical night and as always equipment pictures are available on the NTARC website under “Blogs” for this broadcast.
As this June marks one hundred years of WIA presence in VK7, it has been proposed to have celebrations at clubs in each of the three areas. These may take the form of open days with various displays of the many facets of amateur radio through the years. So if anyone has any ideas for presenting such a display or can assist in the north, please let Peter VK7PD, the NTARC representative know. You can contact Peter directly, via the club Secretary or through the NTARC web site “Contact Us” page.
Hot of the press for competitions, the ZL Sprints results for Autumn 2023 have been published.
Peter VK7KPC, came 3rd in the CW/SSB QRP section. In fact there were only two VKs to receive a place across all sections. This competition was run across the four Tuesdays within the month. Well done Peter.
UPCOMING EVENTS
The Club Technical night - The next session will be on Wednesday 3rd of May and will commence at the usual time of 7.30 pm, running through to about 10.30 pm, at the Club room Archer Street, Rocherlea.
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. Why not pop in and join us for a cuppa there is endless tea and coffee along with biscuits available for a donation.
The TestNet and TechNet session - Wednesday the 10th of May. 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.
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 from Stefan, VK7ZSB, Secretary NTARC.
