On Thursday 30^th March members gathered at the club to witness the annual presentation of the Fred Lees Memorial Trophy.

The evening began with a general knowledge quiz created and presented by Steve Crane G0KUY who was last year’s recipient of the Fred Lees Memorial Trophy. The quiz was the usual brain strainer probably more appropriate to mastermind than a radio club but as it was presented in Steve’s usual entertaining and humorous style it turned out to be a pleasure despite the questions.

This year the member who admitted to scoring the highest was our Chairman Geoff Oliver G0BJR. So Steve presented him with the prestigious Quiz Trophy along with a bottle of Chateau Neuf de Royton to cool his little grey cells.

Steve then moved the proceedings along to the main event of the evening. He announced that the member who he and many other club members had whole heartedly voted for as having given exceptional service to our club over the past year was Peter Rushton G7PMZ.

Peter had taken on the role of Treasurer at the last AGM after the retirement of Geoff Ashton M0AUG. Also he was responsible for much of the rally organisation and un-organisation after it could not be held due to lack of trader support. Peter is and always has been throughout his long membership, a great supporter of the club in all it’s outside activities including special events, contests and a more recent role as invigilator for the full set of Amateur Radio Examinations.

The surprised expression on Peter’s face was something to behold when his name was announced. Sadly it could not be captured in a photograph so the one on the front page showing him receiving the trophy from Steve will have to suffice. John Lees G3PD who normally presents the Trophy did attend the ceremony but this year was happy to take a back seat and give Steve the pleasure of making the presentation to Peter.

Later our chairman presented Steve with a certificate which confirms the fact that he has been awarded the Trophy.

Peter was so surprised to have been awarded the trophy that he was moved to put pen to paper and write these few words.

As the day draws near for the presentation of the Fred Lees Memorial Trophy club members are probably thinking about who will receive the award at the next ceremony.

Once the quiz is over everyone waits with bated breath to hear the name announced. This year it was my name that was called out. When I heard it I thought, "Did I hear right?" then suddenly I was urged by those around me to go and receive the trophy from the current holder, Steve Crane G0KUY.

I had been nominated for the award after having accepted the position of Club treasurer following the retirement of Geoff Ashton M0AUG and also for my part in arranging the 2006 rally, with which I was given a great deal of help by other club and committee members to whom I offer my thanks.

I hope to continue to serve the club well in the present year and wish to thank all those who nominated me for the award.

Peter Rushton G7PMZ

NEW LIFE MEMBER

It has become a club tradition that when a club member reaches the age of 80 years he/she will be awarded the status of life membership. This notable anniversary occurred for Arnold Broadbent G3PYH on March 24^th this year.

Just prior to his birthday Arnold suffered a stroke and heart attack but thankfully is now recovering and he has visited us on Thursdays since. In typical laconic humour, Arnold described his illness as being due to his own greed by having both afflictions at once instead of just one or the other.

Arnold first became licensed in 1962 (he thinks). He has been a Tin Basher (Sheet Metal Worker) and an Oldham Taxi Driver. He did not retire until he was 70 years of age. He served with the Army in India as a signals operator during the war.

On 13^th April, our Chairman presented Arnold with a certificate confirming his Life Member status.

In a recent Intermediate tutorial session here at OARC the perennial question of the skin effect in conductors cropped up once again. Some surprise was expressed by course members more used to low frequency AC and DC circuitry when told that the current in a conductor tends to flow more towards the outside of the conductor as the frequency of the signal is increased.

There is a little bit of maths involved with the calculation of the skin effect depth, but the explanation as to why it occurs is fairly simple.

At low frequencies, the effective cross-sectional area is the complete cross-sectional area. At high frequencies, the effective cross-sectional area is only the outer annulus, as shown above. This is because the magnetic field of a current is strongest at its centre and becomes weaker as we move away from the centre of current flow. With an alternating current, a back e.m.f. is developed and because the magnetic field is strongest in the centre of the conductor, the back e.m.f. is also strongest in the centre. This stronger back e.m.f. produces greater opposition to the central current flow of the driving voltage and forces the current to the edges (skin) of the conductor where the back e.m.f. is less. This effect is known as the skin effect. The skin depth is defined as the depth at which the current density has fallen to 0.368 of its value on the conductor surface.

The practical effect of skin depth is that it causes the a.c. resistance of any conductor to increase with frequency. This is because the reduction in effective cross-sectional area causes an increase in resistance; it’s like having a thinner wire.

Skin effect has its practical uses. For example, in selecting printed circuit board material (PCB) a manufacturer often has to decide on the copper thickness associated with a particular type of board. If the circuit is to be used at r.f., then it is pointless to use copper cladding thicker than about 4 skin depths at the lowest operational frequency because extra copper thickness will not help with r.f. current flow. By going to a thinner copper cladding, it may be possible to save money on a cheaper board, minimize etching time, and increase accuracy by minimizing etching under-cut.

Ed da Silva, The Open University, T527, Radio-frequency engineering.

By Mike Crossley M1CVL

The Annual General Meeting of the Oldham Amateur Radio Club for 2006 will take place at Royton ATC, Park Lane, Royton, on Thursday 24^th August 2006 commencing at 20:30. This article is a formal invitation to all members to attend the meeting to elect club members as officers and ordinary committee members who will run our club for the next 12 months.

In response to a request by Flt. Lt. Mark Hamilton of the ATC we ran a special Radio Amateurs Foundation Training Course and Examination throughout the weekend of 3^rd/4^th June.

There were just 9 candidates in all. There should have been more but there were 2 ‘no shows’ and the anticipated number of ATC cadets did not request the training. The ATC interest is due to the fact that Cadets can claim the ATC Radio Communications Badge after gaining our Foundation Licence and doing a little more study purely related to ATC radio comms. So the final numbers taking the course were 5 ATC cadets and 4 club members.

The course was organised by Mike Crossley M1CVL who is registered with the RSGB as a "Lead Instructor".

Although we have run many Foundation Courses in the past, this was the first that we had undertaken at a weekend. Because of our lack of experience in this matter we had first consulted Dave Wilson G7OBW who runs the very successful weekend courses in Frodsham for the 3 Counties Training Group. Dave came to visit us on a Thursday evening prior to the course and gave a fascinating and very informative talk on how they do it. He also supplied us with the PowerPoint displays that they use along with their timetable of subjects. We modified some of his displays to suit our situation. Having now some experience of running a weekend course we decided to make some changes to the timetable to give what we feel would be a slightly better flow through the various topics.

It was hard work cramming all the information into the one weekend and it required great concentration and dedication not only by the candidates but also by the tutors. But in the end it all paid off because everyone passed the exam and made their way home both weary and relieved but very satisfied.

Many thanks go to the following members who helped out during the weekend as tutors, invigilators or general helpers.

Congratulations are due to the following members who successfully passed the weekend Foundation Radio Amateurs Course.

Club Members

Their new callsigns are included where known.

ATC Cadets

Ian Moth formerly M0IJM has taken advantage of the ruling that allows callsign changes under certain circumstances. This rule makes it possible to adopt the callsign of a relative. In Ian’s case he has adopted his late father’s callsign G8ZHC who was originally licensed in 1962.

The following items are in the club’s diary for the next 3 months.

22^nd/23^rd July – Special Event Station GB4RL (Royton Lives)
Location – Site of the former Royton Hall, Hall St. Royton.
The second year of the 2 year project to uncover the ruins of Royton Hall.
All members are invited to take part in this event.

24^th August – Oldham Amateur Radio Club Annual General Meeting
Location – The ATC - commencing 20:30 hours
Paid up members only.
Please do not forget to send you nominations for Officers and Committee Members posts to club secretary Mike Crossley M1CVL

For some time now we have been encountering problems with the winches on our antenna tower. This was brought to a head when Paul Eckersley M3PDA was trying to lower the tower to its parked position late one Thursday evening. The holding clutches failed completely and the handle was wrenched from Paul’s grip and went spinning round, clobbering Paul in the process. Fortunately only Paul’s pride was hurt and the insertion of the safety bar prevented the tower from coming down at considerable speed and no damage was done.

The following weekend the winches were stripped down by Ian Firby G7VCG and examined. It was found that the clutch discs on both the vertical and tilt over winches were extremely worn and no more adjustment could be made.

Mike Crossley M1CVL made inquiries at the supplier and was able to order new discs. These duly arrived in time for the next club meeting when Ian spent the whole evening stripping down the winches and installing the new clutch discs.

Thanks to Ian’s efforts the tower is now fully operational once again and is safe to use.

The editor would like to thank all contributors to this edition of Old Hams News. The next edition is due to be issued in October 2006. Any contributions for this edition should be forwarded to the editor, Geoff Oliver G0BJR on or before Thursday 21^st September 2006 to ensure inclusion.

Articles will be accepted on many formats, by email to "news@oarc.org.uk", by word of mouth, hand or type written notes, or as a .txt file on a CD ROM or 3½-inch floppy disc. Photographs, drawings, circuit diagrams and other graphics to enhance your article will also be most welcome.

An edited version of Old Hams News is available on the Internet at the following URL
www.oarc.org.uk
then click on the "Club Journal" hyperlink.

If you submit an article for inclusion in Old Hams News and you do not wish it to be included in the Internet edition you must state your wishes at the time of submission. Otherwise the editor reserves the right to include/exclude your article as he sees fit.

Chairman – Geoff Oliver G0BJR
Secretary – Mike Crossley M1CVL     Treasurer – Peter Rushton G7PMZ

Craig Taylor G7MCT     Chris Cunliffe G7OOD
Stuart Wilson G7MFK     Jeff Hollowood G7LMI
Sue Burgess G0RKE     Keith Graham M0KGM

N.B. Old Hams News is the official journal of the Oldham Amateur Radio Club. It is distributed free of charge to all fully paid up members of the club. Articles appearing herein do not necessarily reflect the views of the editor, the Officers and Committee, or the membership of Oldham Amateur Radio Club. Whilst every effort is made to ensure the accuracy of articles included, the editor is not responsible for any inaccuracy that may occur.

Written, edited and produced by Geoff Oliver G0BJR
© Oldham Amateur Radio Club 2006