Broadcast - 28 May 2023
NTARC News for Sunday Broadcast – 28th May 2023
Back in April 2017 there was a presentation after the NTARC General Meeting, by two of our members Bill VK7MX and Kevin VK7HKN. It was a very interesting introduction to the BITX HF transceiver building block, a phenomenon which was sweeping the homebrew and QRP worlds. Pronounced as “Bye-tex” as this came from the bi-directional amplifier that is the heart of the original modules.
This was designed by Arshar Farhan VU2ESE who was based in far off Hyderabad in India.
After a local TV manufacturing plant folded he was able to take it over and re-employ workers to hand-assemble his BITX boards. This philanthropic move provided the collective of women an alternative livelihood to help support their families.
Kevin demonstrated his new BITX40 HF transceiver with Bill demonstrating the slightly later version that sported an Arduino for better VCO control. As a result of this presentation Bernie VK7BR also built one.
Move forward six years to our latest Club Technical night, show and tell. Bill now has Arshar’s latest model HF Transceiver, the SBITX, with the S now standing for SDR or Software Defined Radio. Bill brought in his Version 1 and his recently arrived Version 2. The main difference between them is the Version 2 case depth has been halved and the unit now comes in at a slim 250 x 150 x 50mm size and weighs in at less than 2 kg. They both sport a very impressive and large 180mm, capacitive touch colour liquid crystal screen and now use a Raspberry Pi microcomputer in conjunction with the SDR. Power Output is 40 watts on 80 to 20 Metres and 30 watts on higher bands. Both are capable of running a larger external secondary HDMI display.
According to the manufacturer, “The sBitx is an open source, high performance Hybrid SDR for the 21st century radio amateurs. Powered by an internal Raspberry Pi 4, it has CW/RTTY/PSK31/SSB and FT8 with logging software, macros, spotting in-built.” That’s quite a lot for a small self-contained rig especially without the need to connect it to your desk top PC or laptop computer.
The company that Arshar founded called HF Signals is now based in Illinois America, but they still get parts like toroids hand wound by the women in India.
The concept is great and the implementation looks good, we all will be interested in seeing the finished unit put through its paces at a future Club Technical Night, good luck with the remainder of the build Bill.
The web link to the Transceiver page at HF Signals is in the text version. sBitx v2 – HF SIGNALS
On the same night Ross VK7ALH brought in a WeldSkill 185 Cig welder capable of up to 185 Amps and suitable for domestic power use. That’s a lot of welder from a single phase 10 Amp power point! It is a solid unit at just under 14 kg, but still a huge decrease in weight from a couple of decades ago.
We took a look at the quality of build and yes it was made “you know where”, but in this case well-constructed. All high voltage tracks and parts were coated or covered in a solidified insulating gunk for protection, Ross probably finds it much like working on a valve radio, but safer Hi-Hi. They certainly went to good lengths to stop, well try and minimise the RF rubbish from getting out on the mains lead. Needless to say because Ross was working on it, it had a fault, in this case an intermittent one.
Ross did manage to bring the intermittent fault on a couple of times during the night and even isolated it to a continuous trigger locking wire feed mode that seemed to stop working for some reason.
It’s an excellent start for fault location but as soon as it is back on his test bench it will not be playing up again. Have fun Ross….
Stuart VK7FEAT had with him a pocket sized hard cover book, it appeared to have been well used but was still in excellent condition. It first went to press in 1937, Stuart had the fifth edition published in 1941. The title is “Wireless Coils, Chokes and Transformers and is by F.J Camm.” Does this ring any bells?
The preface of the book is interesting and it states in part, “The only information formerly available for constructors who wished to make their own coils existed in the form of articles which have appeared in Practical Wireless. This book presents all of the necessary practical information in a form suitable for easy reference. There is no other book on the market which deals with coil construction with particular reference to the needs of the amateur.” Its sister book in 1955 was titled “A Beginners Guide To Radio”. Does this one ring any bells? Concentrating on the author, Frederick James Camm was born on the 6th of October 1895. He was an English technical author and magazine editor. He founded and edited several radio and electronics periodicals, including Practical Mechanics, Practical Television and the one that should be familiar to all of us, Practical Wireless. The hobby of amateur radio certainly has come a long way since Practical Wireless (PW) was launched in 1932. I wonder if Frederick Camm would have believed his magazine would still be in publication and evolving or even that his books were still being consulted and relevant over ninety years later!
Now a quick stop press, it is nice to see Peter VK7KPC finally receiving his certificate of participation in the Oceania DX Contest from 2022, in the Single Operator QRP All Band – CW category, well done Peter and to the volunteers that process the myriad of log sheets.
Equipment pictures are available on the NTARC website under “Blogs” for this broadcast. Now back to the house keeping.
UPCOMING EVENTS
The Club Technical night - The next session will be on Wednesday the 31st 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 7th of June. 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.
Club General Meeting - Saturday the 10th of June at 2.00pm. Held at the NTARC Club Room, Rocherlea Scout Hall, Archer Street, Rocherlea. If you have items you would like added to the agenda please email the secretary at: secretary@ntarc.net no later than Friday the 9th of June.
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.
