Broadcast - 7 August 2022
Saturday morning rolled around and a good number of hardy club members turned up in the cold for the working bee at the club rooms. Peter VK7KPC, turned up first and had the urn and hot water on in plenty of time for the arrival of the troops. We certainly did need the first drink to get warmed and motivated. It was good to see VK7s Peter KPC, Andre’ ZAB, Ian IG, Brendan VIP, Idris ZIR, Stuart FEAT, Lewis IT, Kevin KJL, Tony ZTT and Stefan ZSB all raring to go.
The “Hope to be able to do” job for the day was the installation of a Folded Multi Band HF Dipole, which is on long term loan from Peter. Made by Marshal and covering 80 to 10 metres of HF bands. This is to replace the old G5RV which succumbed to storm damage. As this was external to the building, completion was in the lap of weather gods. It was a case of all hands on deck and under the guidance of Peter all went well. The fixings on the chimney and a convenient tree were installed and the antenna hoisted sky ward. No doubt this will be tested out by Peter during next Wednesday night’s TestNet session held on HF, hosted by Nic VK7WW, fingers crossed.
The security alarm system upgrade was started with some new field cables being run in and the preparation of the wall space for the main control equipment. A work in progress for Kevin and helpers.
A pile of wood was split and stacked in anticipation of Luke Sky Warmer’s appetite and what he will consume while keeping us all warm and cosy for the rest of the winter chills. Stuart sure is handy with an axe.
The hall fire place finally has its “Crowning Glory” or should I say its “Mantelpiece Glory”. It now looks complete. One of those “non-radio” type jobs that has niggled away for years but gets forgotten about. Thought to be an easy job, but like most mature buildings, it’s never as easy as it looks. Thank you Brendon for persevering with this one.
We eventually stopped for some refreshments and lunch as it was getting well into the afternoon. You know how it is, when you are on a roll and you can see progress you just want to keep going!
Luckily the rain held off for the remainder of the day. This allowed some of the guttering and down pipes to be repaired and replaced by Lewis and hampered by the many supervisors. The last of the outside jobs being, removal of broken bottles and pruning of some dangerous looking tree limbs.
Finally a well-earned finish, final drinks and a warmup next to Luke Sky Warmer. All in all it ended up being a very productive day. Great job by all who ventured out.
Pictures from the day are available on the NTARC website under “Blogs”.
The "mystery item" that turned up in one of the donated boxes of equipment and parts mentioned last month has been formally identified by Lionel, VK7ZLB.
This item took the form of what looked like a vacuum tube with a valve type base at one end, the other end has a ceramic insulated electrode. Its casing is a lathed stainless steel cylinder about 100mm long and 38mm diameter with quite a hefty weight to go with it. The only visible marking was the word "Vibron" printed on the steel sleeve.
Well, it turns out not to have been a vacuum tube, but a "Vibrating Capacitor".
Internally, the top electrode is fixed to a 19mm diameter highly polished gold plated disc 1.5mm thick. There is an identical plate in the bottom of the cavity, and when assembled, there is a spacing of approximately 2mm between the plates. The lower plate is mechanically attached to a shaft which passes through the centre of a non-polarised solenoid coil assembly in the base. The entire unit is also filled with an inert gas to prevent any contamination of the capacitive plate surface.
Depending on the polarity of the applied current to the solenoid coil, the plates move closer together or further apart. Variation of the gap produces variations in capacitance which generate a sinusoidal alternating voltage of magnitude proportional to the input voltage.
This provides the Vibron with an extremely high input impedance, and the ability to measure resistances as high as 10 to the power of 9, Meg Ohms. Yes you did hear correctly! The solenoid can be energised from a normal valve AC heater supply.
A most unusual and I would say pretty rare device to find nowadays. Thanks to Lionel for his perseverance in solving this one.
A much more comprehensive description of this amazing device and a link to pictures is available on the NTARC Web site under “Blogs” Link included in text version.
Mystery Object - Vibron — NTARC Inc.
SSTV - Thursday night was once again an enthusiastic night, no interference in either direction was experienced. This resulted in very clear images compared to last week. We had the added advantage of a new web site by Phil, VK7ZPD, for the automatic decoding and displaying of the last twelve received SSTV images.
The site is in the construction phase and more information will be passed on after Phil is happy with the testing. Between Phil in the North and Ken VK7KRJ in the South, amateurs will soon have the ability to see how their images are being received in various areas of the state.
The link to Phil’s SSTV Web site is available in the email edition of the broadcast. vk7zpd.freeddns.org
UPCOMING EVENTS
Club Technical night – Wednesday 10th August. Held at the NTARC Club rooms, 7.30pm until late.
SSTV Net - held every Thursday night on the 70cm repeater, VK7RJG and linked to the South via repeater VK7RAF. Conducted from 7.30pm till about 9.30pm, at the moment. These SSTV images will be available on the NTARC website under ‘Blogs’.
Club General Meeting – Saturday 13th August. Held at the NTARC Club Room, Rocherlea Scout Hall, Archer Street, Rocherlea. Meeting commences at 2pm.
TestNet and TechNet – Wednesday 17th August. 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 again be Nic VK7WW.
Club Social Night - Wednesday evening the 14th of September. To be held at the family friendly Mowbray Hotel. Those who wish to attend please register the number of places required to the Secretary or on the registration sheet at the club rooms.
Coffee Morning – held every Friday in the NTARC Club rooms. Get warm while you catch up, time is from 10am to noon and we look forward to seeing you all there. These coffee events represent a good opportunity to collect your QSL cards. We currently have cards awaiting collection, so why not pop in and check the QSL box and join us for a cuppa and chat.
The club is follow the Covid 19 recommendation to continue wearing face masks when gathering.
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.
