BARSCOM. January 2018 GX3XG BRAINTREE COLCHESTER G3XG G6BRH. Monthly Communication of the Braintree and District Amateur Radio Society STEBBING DUNMOW

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1 BARSCOM STEBBING GX3XG BRAINTREE RAYNE HALSTEAD COLCHESTER DUNMOW COGGESHALL G3XG G6BRH NOTLEY WITHAM Monthly Communication of the Braintree and District Amateur Radio Society January 2018 Happy 2018

2 Jan 2018 Chairman s Chat John, M5AJB Thought for the month Here we are in the New Year, with an interesting set of evening meetings to look forward to. To be more active this year the committee have looked into putting on more special event days. Things like Churches on the air, museums on the air, Airfields on the air. These all require help and commitment, are you willing to help, please talk to your committee, and tell them what you think. Canvey Rally, as you know the club has booked a table at this rally. If you have something you would like to sell, for a small commission the club will put it on the stall and try to sell it for you. The latest news of Dave Penny, is it is very slow progress, some days better and some not so good. Well that s all for this month. Best 73 s John M5AJB There is no time like the present Don t forget the Club Meeting on 9 th January TX Factor 16 and Light refreshments Contents Chairman s Chat 2 Meeting Report 4 Looking Forward... 5 Looking Back BADARS A G7FEK Aerial 8 Band Plans (part 4)..10 Ham Wordsearch Answers..11 Rallies/Contests.13/14 Committee Info Club Info 15 2

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4 Jan 2018 Meeting Reports Geoff G1WRH Due to a sudden change in the weather which rendered side roads and pavements treacherous, the Christmas social was postponed and an informal evening held in its place. Edwin chaired a group of 7 who really needed to have been wearing crampons to negotiate the few metres from their cars to the hall doors, so quickly had the snow compacted and frozen over. The main items under discussion were a resumé of the events of 2017, details of next year s 4

5 programme, and the GB7HA DMR repeater for which Colin was fortunately present to be able to give us an update. The image of the evening fondly reminded me of a scene from the BBC Christmas special episode of Detectorists complete with serving hatch and all. With best wishes for the new year from your reporter. Looking Forward From the RSGB The recent RSGB Strategic review highlighted a number of priorities including Spectrum and closely related issues of Growth, Research and Participation. The RSGB Spectrum Forum annual meeting generates a large collection of reports the 2017 meeting proceedings have just been published and provide a snapshot on amateur radio activity, emerging trends, band plans, EMC, the recent IARU Jan Region 1 Conference and the forthcoming World Radio Conference in 2019 (WRC-19). Looking ahead, one of our challenges is participation levels (sometimes termed spectrum occupancy) spectrum is a valuable resource and we need to demonstrate that we are using it actively. We keep a close eye on licence numbers and band occupancy data, as do the Regulators. The old adage of use it or lose it applies to the spectrum we have allocated to us and the Spectrum Forum continues to look at ways to increase amateur activity, particularly at VHF, UHF and microwave. The Society s goal for 2022 is to continue to have an active and thriving community. The Spectrum Forum is working hard on a variety of issues throughout the year but we all have a responsibility to our hobby and the next generation. I wish you all the best for 2018 but do please keep an open mind and be prepared to support your hobby it needs you! From the RSGB Affiliated Clubs Newsletter, January 2018

6 Jan 2018 Looking Back BADARS 2017 (in twelve pictures) 6

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8 Jan 2018 A G7FEK Aerial Mike G8DJO While searching for an HF multiband aerial that would fit in my limited space I came across the G7FEK aerial and decided to give it a go. The author of the original design had previously used a half size G5RV as had I. Like me he bemoaned it's lack of 80m capability and general limited performance and his design fits in 46 feet which suits my available space. G7FEK s original, designed in 1988, comprised two quarterwaves in parallel, fed against ground in inverted L. During 2007 the antenna was optimised and tested at sunspot minimum to improve performance and multiband operation. The difference in feed impedance between elements determines which element is coupled to the feeder and which element floats, thus automatic band switching occurs without the need for traps. For the higher bands this antenna utilises the odd harmonic resonance of these elements which are also at low impedance. In each case some radiation is coupled from the driven element into the main antenna, producing a useful radiation pattern and omni directional low angle performance. On 30m, the top horizontal section works as an end fed dipole with ¼ wave transformer feed, giving a dipole radiation pattern while assuring a low impedance feed. Extensive theoretical analysis and practical experimentation with the design is documented on the website of the Royal Signals Amateur Radio Society, RSARS: ( 2013/01/g7fek-antenna-analysisiss-1-31.pdf) The version of the aerial used for this work did not use a counterpoise but a system of radials as the earth. 8

9 I chose to build my G7FEK using radials as opposed to a counterpoise as per the RSARS document. I also added the additional 20m element, again from the same document. Performance G7FEK writes:- My own experiments over the years have shown that, on 80m, this antenna will perform close to a full sized dipole for DX contacts, despite the small size, because of the low angle of radiation (30 degrees) and full size elements. As this is a low angle antenna, NVIS (high angle) short skip contacts are only down by around 10dB compared to a dipole. This does not usually matter, unless the band is in poor shape, because NVIS signals are normally very strong. Remember that a 66 ft Windom or 52ft 1/2 sized G5RV will probably not even work on 80m, and you cannot fit a full sized 80m dipole into a 46ft garden!!. On higher bands, the antenna performs well too. Low angle is dominant on all bands expect 10 MHz, where the antenna is Jan working as a end fed dipole. (There is a variant by OH5RM for low angle on 10MHz. When compared to "straight up" vertical antennas, the combined horizontal and vertical components of the G7FEK antenna still give rise to useful high angle radiation. My own experience, albeit limited to a few months so far is very encouraging. G7FEK s primary aim of achieving decent 80m DX performance is bourne out and it also gives good results on 20m and 17m. I plan to do some analysis using my vector network analyser, as a brief look at measured characteristics show increasing deviations from the RSARS modelling and practical measurements, with increasing frequency. Next Month What items can you contribute??? Plus the usual New Events, Rallies, Contests, etc.

10 Jan 2018 Band Plans (part 4) VHF 4m 10

11 Ham Wordsearch Jan 2018 How many ham related words did you find? Here are the answers to last month s puzzle. 11

12 Jan 2018 Club Meetings, Activities and Nets Club Net pm local time, 2 Metres (S15) ( MHz) First, third & fifth TUESDAYS Jan 9th 2018 Natter night and TXF16 Jan 23 rd 2018 PAT / PAC Testing / Prep for Canvey Rally Feb 13 th 2018 TX Factor 17 Feb 27 th 2018 Datamodes Demos PSK,SSTV,Logging Mar 13 th 2018 Rig Clinic, club equipment checking for 2018 events Mar 27 th 2018 digital voice Apr 10 th 2018 Talk/presentation from Essex Fire and Rescue Apr 24 th 2018 Sausage and mash supper May 8th QRP Operating Evening/mota update May 11,12,13th Mills on the Air May 22nd The AGM Jun 12th Air Ambulance Talk/ presentation Jun 26th Club BBQ Jul 10th Construction Contest Jul 24th Aerial Clinic Aug 14th Ridgewell Airfield meeting 26 th -28th Summer camp Aug 28th Natter Night TX Factor 18 Sep 11th Railways on the Air Planning Sept 25th Natter Night 21st-23rd Sept ROTA Oct 9th JOTA Planning Oct 23rd TX Factor 19 th -21st JOTA Nov 13th TBA Nov 27th Surplus Equipment sale Dec 11th Christmas social Dec 25th Maybe a natter night 12

13 Jan 2018 Rallies 14 JANUARY 2018 RED ROSE WINTER RALLY The George H Carnall Leisure Centre, Kingsway Park M41 7FJ Venue is easily accessible from Jct 9 of the M60 (opposite the Trafford Centre). This vast hall has superb disabled facilities, being all on one level. It has a huge free car park. There will be our usual bring and buy stall and there is an excellent café on site. Doors open at 11am. There will be trade stands, a Bring & Buy, special interest groups and an RSGB bookstall. Further details from John on JANUARY 2018 HORNCASTLE RADIO RALLY Banovallum School, Mareham Road Entrance LN9 6DA Entry 2. All on one level and all indoors, with all the usual attractions including bacon butties. Free car parking on site. Traders contact for details. Tony, G3ZPU on or tony.nightingale@yahoo.co.uk Jason, G0IZR on th FEBRUARY 2018 The 33rd Canvey Radio & Electronics Rally At the Paddocks Community Centre, Long Road, Canvey Island, Essex. SS8 0JA (The Paddocks is situated at the end of the A130) Doors Open 10:30 am Rally Organizer : Vic Rogers G6BHE Nvr1945@btinternet.com Phone FEBRUARY 2018 HARWELL RADIO AND ELECTRONICS RALLY Didcot Leisure Centre, Mereland Road, Didcot, Oxon OX11 8AY (3 miles from Milton Interchange on A34) Doors open 10am to 3pm admittance 3 (under 12s Free). There is free car parking with disabled parking and facilities. There will be traders, Special Interest Groups and an RSGB book stand. Refreshments available all day. Talk in on MHz (G3PIA). Details Ann (G8NVI) ann.stevens@btinternet.com.:[ww w.g3pia.net/radio-electronics-rally] 13

14 VHF 26 Dec-9 Jan /70/144/432MHz Christmas Cumulative Contest 04 Feb MHz AFS 25 Feb MHz Cumulatives #1 Jan 2018 Contests HF Sat 13 Jan RSGB AFS 80m-40m Contests Phone HF Championship AFS Super League Sat 20 Jan RSGB AFS 80m-40m Contests Datamodes HF Championship AFS Super League Sat 3-Sun 4 Mar March MHz VHF Championship 11 Mar MHz Cumulatives #2 Mon 5 Feb m CC SSB Sat 10 Feb st 1.8MHz Contest HF Championship Committee Chairman: John, M5AJB Ross Cottage, Southey Green Secretary/Membership Secretary: Edwin, GØLPO Panfield Lane, Braintree, Treasurer: Neville, G8CDG Ordinary Members: Geoff, G1WRH Melvin, GØEMK 14

15 Braintree and District Amateur Radio Society The club meets every 2nd and 4th Tuesdays of the month at St Peters Church hall, St Peters Road, off The Causeway Braintree. Doors open at 7.30 pm, meetings run from 8 pm to 10 pm. Membership is 16 annually; Senior members (State Retirement age) and Junior members, under 18, pay 10. A door fee of 1 is also payable at each meeting by members and visitors. BARSCOM is sent to members by on the 7th of the month; paper copies are available at the Jan 2018 first meeting of the month (plus postage if appropriate). Members may sell or exchange equipment etc. before the start of each meeting, during the tea/coffee break and may advertise in BARSCOM free of charge. The Club Net operates on 2 metres only. This should make it easier for all members to remember the frequency, and for non-members to find the net. The net will use V30 (S15) MHz, starting hrs local time on the 1 st, 3 rd, and 5 th Tuesdays of each month. Please send articles for publication to mike.adcock@physics.org The deadline for submissions for the next edition is 1st of the month. Items will be published in the first available edition subject to space availability. For more information and pictures of events and projects see our Web Site at Please contact our Chairman for details about commercial adverts. 15

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