December 2011
In This Issue
Meeting Program
Club News
Future Meetings & Events
Members News
Computer Corner
Technical Snippetts
Miscellaneous
Noticeboard - Wanted and For Sale
News from other Clubs
A Merry Christmas to all our readers
Meeting and Event Diary:
02 Dec
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M
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Christmas Social
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15 Jan 12
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R
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Eigth Dover Radio Rally
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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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E = External event, M = club meeting, R = Rally, T = Training course
Dear Reader
Recent Event News
4th November 2011- An Evening of Short Talks
The last meeting was an evening of short talks featuring:
Jim Lugsden: Why wood warps and some comments on wood rotColin M0XED: A demonstration of knots used at the most recent garden show e.g. bowline, half hitch, rolling hitch, sheet bend etc
Victor G1PKS gave a short talk on the history of electricity from the first recorded discovery by Thales to the spread of power through out most countries in the world, by the genius of Nicholas Telsa.
Two slides from Victor's presentation:
Nikola Tesla:
Thales of Miletus
Sunday 6th November - Kempton Park
Your scribe attended this event as a visitor and was surprised at the large number of people present by around 10:30. The car park was very busy although space remained for more vehicles.
It appeared that there were a few less traders than the previous event but the main dealers and regular club stands were all in evidence.
As usual there were many interesting items if one was prepared to search carefully.
Robin from Sycom had recovered sufficiently from his recent stroke to attend this event and the CATS Bazaar as a trader.
I managed to find a number of interesting items and components including the following cooling fan, which although insufficient for valves like the 4CX250 is perfectly adequate for more conventional power valves that do not require a high pressure cooling air supply.
Sunday 20th November - CATS Bazaar
Four of our club members manned a table at this event in order to help clear a backlog of items for sale from silent key estates.
I am pleased to advise that the event was very successful and two thirds of the items have now been sold. Thank you to Victor G1PKS, Alan G8NKM and Colin M0XED for their help which was much appreciated.
The following photo shows our Chairman Alan looking very happy with the state of sales and a less laden table by halfway through the event:
The following photo shows Robin G3NFV of Sycom servicng customers at his stand:
Apologies for chopping heads off - the event was very crowded and space to take photos was continually moving. Must do better next time - Ed.
Future Club Meetings and Events
2nd December2011 Christmas Social
Our December meeting has no formal speaker or talks arranged so offers the chance to informally chat with fellow members and visitors, discuss amateur radio projecs and issues etc. Whilst doing this we can enjoy some Christmas fayre. Please bring along a contribution of food, sufficient for your self and any guests so that we can share as usual from a buffet.
The club will provide the usual beverages and there are facilities in the new kitchen for heating food.
This is an ideal opportunity to bring along any friends or colleagues with an interest in our hobby - they would be most welcome.
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 an entry in the construction contest.
Club annual awards should be returned by the AGM please.
Members News
a) We welcomed Jim Lugsden as a member at the November meeting. Jim lives in Beckenham and is interested in electronics in general and currently looking into electronic motor speed control.
b) Your scribe has been busy over the last few months working on the construction of new units for his radio station. The first one is a station console which allows the key, microphone, loudspeaker, station monitor and panadaptor to be switched between a number of different rigs. The digital 24 hour battery powered clock was purchased from a Chinese company on eBay and has a backlight powered from a local supply.
The unit is made and finished in the Heathkit SB-Line style. The remaining task is to attach the fixing brackets which retain the unit in the case.
Miscellaneous
The results of the RSGB EGM held at the Hilton Metropole Hotel, at the Birmingham NEC on Saturday, 19 November can be found on http://www.rsgb.org/EGM/.
Site visitors can download the Powerpoint presentations from the EGM and an audio recording of the event.There is also a feedback facility to leave your own thoughts and ideas on the future of the RSGB.
Technical Snippetts
a) Clansman Radio
Andy G8JAC has written in with some minor corrections to the article on the Clansman Radio System in the last newsletter:
"The only set in the Clansman range to have a valve RF front end is the RT353, so it raises the obvious question: how were the other sets in the range which were all-semiconductor architecture going to survive an EMP?
The answer, (from one of the Marconi design team, Chris Parry G8JFJ) is that at the time of the set's design phase (1965 - 70s), a valve front end was the only method of meeting the specification for dynamic range and blocking performance required by the army's habit of operating that role set in multiple co-located arrangements. In fact, a completely semiconductor version of the RT353 that did meet the specs was produced by 1978 but as production of the partially-valved version was by then in full swing, it was not proceeded with. An unfortunate consequence of this was that the army had to put up with a set that drew over 2A on receive and ran the PA heaters continuously even when only 100mW of RF was required!
In fact, the only official EMP protection worked out for the field radios as far as I am aware was an instruction to signallers to remove the antenna if an attack was likely!
The coverage of the PRC351/352 and the 353 is actually 30 - 75.975MHz in 25kHz channels."
Thanks for the update Andy - Ed.
b) Unusual Valves
In a previous newsletter I briefly mentioned that I had purchased some Russian missile valves at a very reasonable price. These are wire ended with a 1.2V/2.4V heater and are extremely rugged with a hardened glass envelope.
A photo of a 1P24B follows:
This valve has a slope of 1.7mA/V, a maximum anode dissipation of 2.5W and a minimum output of 1.3W at 45MHz with a 150V supply - users have suggested that considerably more output power is possible. Other valves in the series are specified up to 100MHz for use in both receivers and transmitters.
An unusual feature of some of these valves is the absence of a conventional grid structure which is replaced by a series of rods to focus and control the electron stream as shown in the following diagram (the dot in the centre represents the directly heated filament):
This is claimed to result in a much lower amount of partitioning noise and a better VHF performance.
These and other valves in the series including the 1J17, 1J18, 1J24, 1J29 and 1J37 are still available on eBay for reasonable prices. Data sheets are available on the Internet although not all have been translated into English.
c) High Speed Amplifier
An interesting current feedback amplifier is the National LM6181 which is available in 8 pin DIL or 16 pin SSOP packages. It has a -3db frequency response of 100MHz as a unity gain inverter and 60MHz as an inverting amplifier with a gain of 10 and will provide ±10V pk-pk into a 100ohm load.
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:
a) Heavy duty Radio Mast, (Clark Mast DAF 30) which stands at 7ft 6in tall when collapsed and 30feet fully extended. There is a fitting at the top for many different aerials to be fitted to this mast, 6 guy lines and 3 heavy duty iron angle ground pegs to assist when using in windy conditions and a bag with a hammer to hold the guy lines and pegs when transporting them. £500.00 ono. Delivery within a reasonable distance may be possible otherwise buyer must collect as it is far too heavy to post or ship. Photos available on request. Contact Norman Norris M0NTN on: 020 8299 0242 or 07817 338 255.
b) 20W Valve audio amplifier £20
Tronix-1 13V PSU 10
GEC SWR-9 SWR meter (new) £10
YC 3550 Yeasu freqency counter £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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4 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 Dec
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CARS Christmas Christmas Lunch", 12 for 12.30pm at the Lodge Inn near Battlesbridge
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06 Dec
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"Radio Control Modelling" by Chelmsford Model Flying Association Member, Chris Collins.
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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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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
12 Dec
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AGM
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09 Jan 12
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CATS Annual 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.
09 Dec
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Christmas Dinner at The Stepping Stones, West Humble
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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).
14 Dec
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Christmas Social and Radio Night
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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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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
05 Dec
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Club Talk
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19 Dec
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Pre-Xmas Get-together
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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/
15 Dec
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Christmas Junk Sale - note change of date just for this month
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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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`Military Radio' by Denis Noe MØNDJ
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15 Mar 12
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TBC
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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
09 Dec
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Christmas Social
(final meeting for 2011)
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Please replace the (at) with @ in all email addresses shown in this newsletter.
Items For Sale
Sensible bids 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:
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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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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b) The following items are from the shack of Ron G8OTG:
Description
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Price
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Description
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Price
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Advance Signal Generator SG62B
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£30
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Complete 230V Soldering Iron station
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£25
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FT290 + manual
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£50
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ARRL Handbooks - 1976 and 1988 editions
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£5 each
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2 gang 500pF standard varable capacitor
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£4
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Mains Bench PSU with 12V output
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£10
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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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Icom IC-240
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£30
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Heathkit RF Probe
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£5
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Nova mobile radio
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£10
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RSGB VHF Manual
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£5
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AM Radio Techniques by G3VA
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£5
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1 Daymart HF bands Wavemeter
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£4
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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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Avo Universal Multimeter - Model 7
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£5
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Commercial Loudspeaker in black case with lead and 3.5mm plug
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£5
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All items are bought as seen and sold on a first come first served basis.
