January 2012
In this issue:
Recent Event News
Future Meeting and Events
Members News
Miscellaneous Items
Technical Snippetts
Notice Board
News from other Clubs
Happy New Year to all of our members and readers
Subscriptions become due on 1st January 2012 so please send your £12 to our Treasurer as soon as possible or bring it to the next meeting. Cheques should be made out to "Crystal Palace Radio & Electronics Club".
Meeting and Event Diary:
06 Jan 12
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M
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Loops by Colin Butcher M0XED
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03 Feb 12
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M
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AGM and Construction Contest
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15 Jan 12
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R
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Eigth Dover Radio Rally
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02 Mar 12
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M
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TBA
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E = External event, M = club meeting, R = Rally, T = Training course
Dear Reader
Recent Event News
2nd December 2011 Christmas Social
Club members gathered at our annual Christmas Social for some some seasonal fayre and informal discussions. We welcomed two visitors including Jim Lugsden's XYL.
Despite the number of RF engineers present we were all beaten in trying to get the new oven to work. It turns out that the clock must be set before the oven can be switched on. All was well in the end though and thank you to all who contributed to the selection of food.
SCRS Christmas Junk Sale - 15th December 2011
You scribe was one of about 30 members and visitors at this event with a good selection of equipment, cables and components for sale.
Future Club Meetings and Events
25th December 2011 Christmas Day Net
A brief net will take place at 10am on S21 145.525MHz FM. Do try and join in and send seasons greetings.
6th January 2012 Loops by Colin M0XED
The talk will be about small transmitting loops, covering small loop equations, efficiency, radiation pattern, nulls, design considerations, performance comparison, use of the WIMO Baby Loop for 40m - 10m, installation and operation.
Colin has provided the following photos of his installation including a clear view of the tuning capacitor - as you can see below, the plate spacing is very large in order to allow for the very high voltages present with 400W of RF.
Loop Installation with Rotator
View of Tuning Capacitor
The large aluminium tubing is necessary, not only for mechanical stability but to cope with the extremely high circulating currents when the loop is at resonance.
400W in 50ohms is equivalent to 2.828 amps and the current in the loop will be approximately Q times that number where Q is the quality factor of the tuned circuit formed by the loop and its tuning capacitor.
3rd February 2012 - Annual General Meeting
Our AGM and Construction Contest is now on the horizon. It is therefore time to start thinking about your ideas and comments on past and future club activities, what you can do to help the club and offer an entry in the construction contest.
Club annual awards from last year's AGM should be returned by the February 2012 meeting please.
Members News
a) Tevor M0DIA is in the process of changing the mains transformer in his 13.5V PSU to a toroid with a lower secondary voltage. The original transformer delivered 29V DC off load to the regulator which causes considerable overheating of the regulator power device.
b) Earlier this year your scribe upgraded his FT-450 to an Icom IC7400 multimode multiband rig which so far has proved to be very reliable. The receiver performance is considerably improved over the FT-450 and the additional 144MHz band with 100 watts output has helped (to keep the channel free) with the club net.
An external 13.5V 25A supply is required. There are very few sub-menus and most functions are directly accessible from front panel controls.
Ham Radio Deluxe performs well with this rig with the assistance of a USB to serial port adaptor purchased from a UK supplier.
Miscellaneous
Hastings Museum.
If you are in Hastings a visit to the Museum may interest you. It is claimed to be the home of television, and a fascinating display of early broadcasting equipment and history is to be found there. John Logie Baird worked in the town in early 1923 to convalesce, and over 18 months carried out experiments that led in 1925 to the transmission of the first true image, a painted wooden head of Stooky Bill. It was in Hastings that he produced the first shadowy outline of the Maltese Cross.
[Stooky Bill was the name given to the head of a ventriloquist dummy that John Logie Baird used in his early experiments. Thank you Victor - Ed]
Technical Snippetts
a) Many years ago, your scribe worked on the development of an MF/HF lifeboat emergency transceiver which had to be able to function on 500KHz, 2182KHz anmd 8364KHz with a kite aerial or a 15 foot long whip aerial. On 500KHz, the latter aerial looked very much like a 10pF capacitor in series with about 10 milliohms of resistance so the standard test process was to load the 3W transmitter into a 10pF capacitor and measure the resulting RF current which was in the region of 1 - 2 amps. Care was needed during this test because the voltage on the aerial terminal was in the region of 2 - 3KV.
One of the type approval specification requirements for this equipment was that the entire unit had to survive a 60 foot drop into the sea. The Marketing department then added to that by saying that it should also have enough boyancy to support two people when in the water. The unit could be strapped to the operator who "sat in the water with horizontal and straight legs" to tension the straps", cranked the hand generator with one hand and operated the equipment with the other hand. A very demanding but stimulating design project.
b) Applications (apps) for the Apple iPhone, iPad and iPod series now include decoders for Morse, Packet Radio and RTTY marine weather transmissions.
c) Mini-Circuits are well known in amateur radio circles for their wide range of packaged double balanced mixers like the SBL-1. They also manafacture ranges of packaged amplifiers with up to 100W output power and covering a frequency range of 100KHz to 18GHz together with 90o splitters, filters, voltage variable attenuators and wide band transformers.
d) Freescale have recently developed two new LDMOS high power transistors for use in the 470 - 860MHz TV band. Both devices are pairs of transistors in a single package for push-pull operation capable of 600W CW output at the 1dB compression point and a typical gain of 19dB. They are also capable of tolerating a nearly 100% mismatch (greater than 65:1 VSWR) at all phase angles without any degradation in perofmrance on a 50V supply.
Notice Board - Wanted and For Sale
The Notice Board is for all club members to use so if you have one or more items that you wish to buy or sell then please send in the details. The current list of items may be viewed at: http://www.g3oou.co.uk/ in the "Notice Board - Wanted and For Sale" section.
Wanted:
SWL club member looking for a VHF multimode receiver covering at least 144-146MHz. Contact Victor on 020 8653 2946 or Bob on 01737 552170.
For Sale:
Tronix-1 13V PSU £10
GEC SWR-9 SWR meter (new) £10. Contact Victor G1PKS on 020 8653 2946
Component Suppliers
Barend Hendriksen in Holland carry a wide range of interesting electronic components at reasonable prices and provide a good service with deliveries to the UK taking only a few days. They can be found at http://www.barendh.com/
73
G3OOU
Diary of External Events
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15 Jan - Eigth Dover Radio Rally
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Whitfield Village Hall, Dover CT16 3LY. Talk In via GB3KS, Bring & buy, refreshments and an auction. Website: www.doverradiorally.com
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5 Feb - 27th Canvey Radio & Electronics Rally
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'The Paddocks', Long Road, Canvey Island, Essex SS8 0JA (southern end of A130). Free CP, OT 10.30, C, DF, TS. Dave, G4UVJ, 01268 697 978 (evenings).
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12 Feb - Harwell Radio & Electronics Rally
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Didcot Leisure Centre, Mereland Road, Didcot. Talk In V44 (S22), Opens 10:00/10.30, entry £2.50 (under 12 free). Contact Ann, G8NVI, 01235 816 379, ann.stevens@btinternet.com
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04 Mar - Cambridge & District Amateur Radio Club Rally
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Wood Green Animal Shelter, King's Bush Farm, A1198 London Road, Godmanchester, Cambs PE29 2NH. Opens 10:00, Entry £3, Talk In S22, Contact John, G0GKP, 01954 200 072, j.bonner@ntlworld.com.
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11 Mar - Bournemouth Radio Society 24th Annual Sale.
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Kinson Community Centre, Pelhams Park, Millhams Road, Kinson, Bournemouth BH10 7LH. Opens 09.30, admission £1.50, Contact John, G0HAT, 07719 700 771
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15 Apr - West London Radio & Electronics Fair
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Kempton Park Racecourse, Staines Road East, Sunbury on Thames, Middlesex, TW16 5AQ. Opens 7:30 for traders, 10:00 for visitors.
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15 Apr - Cambridgeshire Repeater Group Rally
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Foxton Village Hall, Hardman Road, Foxton, Cambridge CB22 6RN. Opens 10:00 for visitors, 7am for traders, entry £2, Talk In S22, Contact Lawrence, M0LCM, 01223 711 840, rally2012@cambridgerepeaters.net.
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News from other Clubs
Club Secretaries - please send your meeting programs to Bob G3OOU. Our newsletter is now published during the third week of each month and closes for editorial input at the end of the second week. Due to differing publication dates and short lead times it is sometimes difficult to include other clubs' specific events although we will endeavour to do so if advised in time.
Chelmsford Amateur Rado Society (CARS)
Secretary Martyn Medcalf G1EFL Tel: 01245-469008. First Tuesday of each month at MASC, Beehive Lane, Great Baddow, Chelmsford, CM2 9RX. Essex. UK. Web: www.g0mwt.org.uk
03 Jan 12
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HF Tuners for M3s and M6s by CARS members.
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03 Apr 12
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"Titanic Evening"
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05 Jun 12
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"Marconi - History - Opening of the Worlds first Wireless Factory in New Street, Chelmsford 100 years ago"
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Coulsdon (CATS) 2nd Monday every month, 8pm at St Swithun's Church Hall, Grovelands Road, Purley. Contact: Steve Beal G3WZK on 01883 620730 or secretary(at)catsradio.org
09 Jan 12
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CATS New Year Dinner.
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13 Feb 12
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Contest Logging by G0KZT
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12 Mar 12
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WSPR by Walter Blanchard G3JKV
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Dorking & District Radio Society
Meetings at the Friends' Meeting House, Butterhill, South Street, Dorking RH4 2LE starting at 7.45pm.
24 Jan 12
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- AGM.
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28 Feb 12
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- Early TV Receivers - Stephen Niechcial.
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27 Mar 12
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Valve Audio Amplifiers - aspects of their design and performance - Keith Thrower.
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24 Apr 12
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Radio from VP8 - Roger Eeles - G0SWC / VP8DBR
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Echelford Amateur Radio Society
Meets on 2nd and 4th Thursday of each month.
Phone for details.
Mitcham & District Amateur Radio Society
Secretary: Mike Knott G0WCR, 76 New Barnes Avenue, Mitcham, Surrey, CR4 1LF.
Tel: 020 8764 4716
Phone for details
Reigate Amateur Transmitting Society
Secretary: Tim Trew G8JXV
Tel: 01293 775278. Email:
Meeting on 3rd Thursday of each month, 7:30pm at RNIB Redhill College, Philanthrophic Road, Redhill.
South East Essex Amateur Radio Society (SEARS) ContactDave G4UVJ on: 01268 697978,
Meetings: 8pm 2nd Weds each month at: 31 Feeches Road,Southend on Sea SS2 6TE (temporary location which may change for each meeting - please see web site).
11 Jan 12
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Canvey Radio Rally preparation evening
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05 Feb 12
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Canvey Radio Rally .Paddocks, Canvey Island, SS8 0JA
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14 Mar 12
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Talk by Dave G4AJY "Frequency, Wavelength and Waveform."
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11 Apr 12
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Radio Practical operating and Rally report
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09 May 12
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Talk by Mike M6KEB on Aircraft servicing
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13 Jun 12
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Club Station on the air.
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24 Jun 12
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Museums on the Air GB2BM Bay Museum
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Surrey Radio Contact Club (SRCC)
1st. and 3rd. Mondays every Month (unless Bank Holidays) 7.30 for 7.45pm at Trinity School, Shirley Park, Croydon, CR9 7AT. Contact John Kennedy G3MCX on 020 8688 3322 or
23 Jan 12
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Croydon Airport by John King
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06 Feb 12
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TBA
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05 Mar 12
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Spring surplus equipment sale
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02 Apr 12
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SRCC AGM
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14 May 12
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Construction Evening
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11 Jun 12
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Construction Contest
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02 Jul 12
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Club Barbecue
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03 Sep 12
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Autumn Surplus Sale
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Sutton & Cheam RS. 3rd Thursday every month, 8pm at Sutton United FC, The Borough Sports Ground, Gander Green Lane, Sutton. Contact John Puttock G0BWV on 020 8644 9945 or email info(at)scrs.org.uk Web: http://scrs.org.uk/
19 Jan 12
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'Ham Radio Olympics' by Roger Western G3SXW
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16 Feb 12
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`'Limited Space Dipoles' by Dave Jefferies G6GPR
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24 May 12
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AGM
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Wimbledon. 2nd and last Friday every month, 8pm at Martin Way Methodist Church, Buckleigh Avenue, Merton Park, SW19 9JZ
Contact Jim Bell, M0CON on 020 8874 7456
13 Jan 12
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Members Christmas Activities Roundup by Eric G0KRT
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27 Jan 12
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Demonstration and Talk by Andrew G4ADM
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10 Feb 12
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Update on Bletchley Park and the Computer Museum by Len
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24 Feb 12
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On the Air
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Please replace the (at) with @ in all email addresses shown in this newsletter.
Items For Sale
Sensible offers are invited to Bob G3OOU for the following items that are for sale from three radio shacks:
a) A few remaining items from the shack of Eddie G4KBY (SK):
Description
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Price
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Description
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Price
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2 two-way data transfer switch box - useful painted project box
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£2
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1 bag of pre-packed ICs, 1 bag of RS Components prepacked, 1 bag of identified ICs and transistors
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£5
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3 way data transfer switch box - useful painted project box
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£2
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Original HRO receiver printed manual with an S Meter conversion article.
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£5
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2 x 15W soldering iron, mains powered
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£1
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A Future Electronics transistor tester FTC 401
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£5 the lot
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1 Box of various coax and general purpose sockets & plugs
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50p per connector
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b) The following items are from the shack of Ron G8OTG (SK):
Description
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Price
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Description
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Price
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Nova mobile radio
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£10
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Mains Bench PSU with 12V output
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£10
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Icom IC-240, 144-146MHz, 1 & 10W FM, synthesised transceiver. Internal diode matrix channel programming panel.
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£30
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Crystal calibrator on a PCB with 1MHz HC6/U crystal and some TTL ICs
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£2
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Bosch mobile radio with fist mic - amateur band frequencies not yet established
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£20
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Daymart HF bands Wavemeter
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£4
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FT290 + manual. 144MHz, 0.5W/2.5W, multimode transceiver
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£50
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c) The following items are from Trevor's shack:
Description
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Price
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Description
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Price
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Marconi TF2437 100MHz counter timer
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£50
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Box of assorted valves including one 6SA7
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£1 each
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Datong D70 battery powered Morse tutor
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£25
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Box of assorted variable capacitors
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£3 each
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Ex Army Morse key
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£5
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All items are bought as seen and sold on a first come first served basis.
FT-290 IC-240 TF-2437
