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Nzvrs Bulletin NZVRS BULLETIN Vol 32 No 1 February 2011 A Tikker A mechanical “detector” of the continuous wave. NEW ZEALAND VINTAGE RADIO SOCIETY INC. A non-profit organisation devoted to the preservation of early radio equipment and associated historical information. Postal address - PO Box 13 873, Onehunga, Auckland 1643. Web site: - http://www.nzvrs.pl.net Email address: - [email protected] PRESIDENT : Ian Sangster, 75 Anawata AGM is Saturday 9 July 2011 Road, R.D.2, New Lynn, Auckland 0772 Phone: 09-814 9597 or 027 227 0426 A Calendar of Events is listed on our Email: [email protected] website at www.nzvrs.pl.net/aaa/calendar SECRETARY : Paul Woodcock, 2 Levy AUCKLAND MEETINGS are held at Road, Glen Eden, Auckland. the Horticultural Society Hall, 990 Great Phone: 09-818 4740 North Road (opposite Motions Road.) Email: [email protected] Western Springs, on the third Monday of Paul handles general correspondence and the month from 7.30pm. requests for purchase of books and badges. March: Monday 21 Freeview night. TREASURER: David Crozier, P.O. Box April: Monday 18 Auction Nite 13 873, Onehunga, Auckland 1643. May: Monday 16 Freeview – part 2 Phone: 09-636 5954 or 022 698 7978 June: Monday 20 Auction Nite Email: [email protected] July: Saturday 9 A G M 10 ~ 4 pm this David handles editorial, financial and replaces the Monday 18 July meeting. membership matters. A list of members is available on application with a stamped, TARANAKI AREA MEETINGS are self-addressed envelope for the personal use held on the second Sunday in even of members only. Please address all months. Visitors most welcome; contact NZVRS monies to P.O. Box 13 873, either Bill Campbell, Phone 06-753 2475 or Graeme Lea, Phone 06-758 5344 Onehunga, Auckland 1643, N.Z. NZVRS LIBRARY WELLINGTON MEETINGS are held The NZVRS librarian is Ross Paton with typically from 1pm on the second Sunday assistance from Bruce Churcher. Requests of every month at Tireti Hall, Te Pene may be forwarded to the NZVRS PO Box Ave, Titahi Bay. (postal address at the top of this page) or For details contact Bob Hatton, 40 Rose St, Wadestown. Phone: 04-472 8788. Email; [email protected] CHRISTCHURCH MEETINGS are NZVRS BULLETIN is a subscription held on the first Tuesday of odd months at magazine for members only, published the Christchurch West Radio Clubrooms quarterly in the months of February, May, "Auburn Park", 333 Riccarton Road. August and November. Opinions For further details contact Jim Lovell, 41 expressed by writers are not necessarily Yardley St, Avonhead, Christchurch 8004. those of the Society. Phone 03-342 7760 Contributions, letters, etc can be sent to: The subscription year is a calendar year (1 THE EDITORIAL TEAM , January – 31 Dec). Subscription renewal Ian Sangster, 75 Anawhata Rd, R.D.2. slips are sent in the November Bulletin New Lynn 0772 or with final reminders in the February issue. David Crozier, P.O. Box 13873, Onehunga, NZ Rate is $25 for new; $20 early bird Auckland 1643. Email: [email protected] renewal before 15 March, $25 after. NZVRS © COPYRIGHT 2011 2 EDITORIAL CONTENTS Apologies again for the late dispatch of this bulletin – life seems to have a mind of its own Southern Soundings 4 in my neck of the woods. Tikker finding . The 2011 AGM date has been set for Saturday Cover Story – the Tikker 6 9 July. Remember this is also the judging date Some background of this device. for the “One Valve Radio” competition. Some Obituary: Tom Duxbury 12 queries have been received about this and it is A bit of background about Tom. obvious a range of lateral thinking ideas are being entertained. The ‘rules’ are the judging Restoration Project (1) 16 criteria included with the pervious bulletin Albert Smith’s restoration skill. and these are also posted on the website at Restoration Project (2) 18 www.nzvrs.pl.net/aaa/rulesagm2011.pdf Alan Colman tells us how. While the judging criteria may seen very limiting, there are actually quite a wide range The Serviceman Who Tells 22 of circuit ideas that comply, and using a range Murray on rewinding transformers. of valves that are moderately accessible – the The Autograph 26 challenge is to make it all work! Good luck to The ‘unknown’ set from Bryan Marsh all who try. Reunion of 1ZD notice 30 It never ceases to amaze me what members th 1ZD 50 Easter bash in Tauranga manage to drag up – I am first referring to the Christchurch Group where Jim Lovell USUAL ITEMS: presented his “Tikker” – what an interesting Marketplace & Wanted Ads 30 find and something that is worthy of the cover story of this bulletin. Secondly there is the identification of Bryan Marsh’s mystery American FM set mentioned in the last bulletin. Gerry Billman managed to get breed identification and the model – the rest is just a NEW MEMBERS: snip from Riders, but what detective skills! S Stiplovits Wellington J Dodgshun Christchurch Sadly we have an obituary to Tom Duxbury – S Read Christchurch one of the grand old men of the NZVRS. An abbreviated version of Tom’s story is included and we hope to post a larger version on our NZVRS Bulletin website when permissions are granted. P.O. Box 13 873, Onehunga, Finally as I write this (late as I am) Auckland 1643 Christchurch has had another serious Email: [email protected] earthquake and begins to pick up the pieces. This looks like a mammoth recovery effort and one that is sure to have a wider impact than just Canterbury. Any support requests The Cover Picture: and of course offers (or ideas of) will be seriously entertained by the committee and I This ‘Tikker’ was a surprise am sure all members wish those affected discovery presented at the November speedy recovery. Christchurch Group meeting. Best of luck to all. See the item on page 6. Cheers, David Crozier 3 Southern Soundings from David Chapple (from Nov 2010 Meeting) Word from Christchurch will be somewhat less melodious this time. You see I had an email from our man, Pete Ingram, and the subject heading gave me cause for concern. It said, “Feeling a Bit Crook” and went on to ask if I could handle the notes for our next meeting. What a hard act to follow as Pete has a way with words. I’ll do my level best while Pete sets his mind, body and soul to getting back on deck. Sixteen Christchurch members met for the last time this year and as is usual at our meetings there were some interesting exhibits to talk about. Jim Lovell pulled out the latest in radio technology (for its day that is) - a ‘tikker’ [also called the ‘slipping contact detector’. Ed] ; a device that allowed early crystal radio circuits to detect continuous-wave telegraphy by breaking up high frequency undamped waves into audio frequency. It was a beautifully engineered piece consisting of a disc (terminal 1) spinning very close to, and just touching, a small block of brass (terminal 2). Fascinating to say the least – see the following item Ed. A note from Wikipedia: “A tikker was a device that allowed early crystal radio circuits to detect continuous-wave telegraphy. Ordinary crystal detectors cannot demodulate continuous waves as the direct current (DC) signal is inaudible in headphones. The tikker consisted of a fine wire just resting on a rotating drum, which interrupted the DC voltage to produce an audible tone. It was invented by Valdemar Poulsen, who is perhaps best known for developments in magnetic recording.” [Perhaps the name derives from the clockwork that may have provided the driving force for the drum or disk. There is also a “tikker” used for timed measurements. Ed.] See following item on Tikkers. Exhibit two was John Dodgshun’s Pacemaker Type 6151 belonging to his late grandmother. It was in absolute mint condition though John reckons it is probably all of 60 years old. John Dodgshun’s Grandmother’s Pacemaker Type 6151 4 It’s amazing what one can pick up from auctions. Paul Burt was lucky enough to blow the dust off a pile to expose a very tidy Super Trans-Oceanic Portable, Model H500, Chassis 5H40. Clipped snugly inside the back cover is a complete set of spare valves plus it was complete with a circuit diagram and a manual. But portable? Not in today’s terms! To conclude the evening David Chapple and David Fahy had prepared a fiendish trivial pursuits quiz with a radio twist to it of course. In teams of three or four we tackled the twenty-five questions given to us. Half an hour later and after much laughter and debate a winning team emerged. And who was in the winning team? None other than Mr. Lovell, helped of course by Murray Clark and John Dodgshun. All three were presented with a bottle of wine each while the rest of us mere mortals had to do with a chocolate fish. It was judged as a fun night with some learning taking place along the way. That’s it from Christchurch for 2010. We all look forward to Pete’s return when we meet next in March 2011. PS: If other Clubs would like our quiz complete with answers to run a similar night contact David Chapple at [email protected] 5 The Tikker – cover story The presentation of the delightful eccentric hardware of a “Tikker” at the Christchurch group’s November meeting was a radio technology surprise to me. At the time – roughly about the early 1900’s Morse (or telephony) transmissions were generated by spark transmitters rich in spectrum harmonic components easily receivable by the crudest of crystal detectors.
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