All posts by G3PKW

Licenced G3PKW in October 1961 - Currently 55 years on the air. Time served Electrical Engineer - Several years developing and testing Military SSB Systems at RACAL - Last 32 years at John Moores University in Physics and Electrical Engineering with Instrumentation and Measurement including researchers with post-graduates. Now I class myself as a professional layabout (i.e.retired) I have written many articles in the RSGB Rad Com and SWM Andy Choraffa D.phys. G3PKW

Newsletter 03/11/2016

The second meeting of the radio amateurs of LARC was very well attended on the 2nd of November last. So many thanks to all those who attended.

Web site address : – http://www.LiverpoolAmateurRadioClub.com

It was an eventful evening with special thanks to Lee G0DBE and his assistants (inc Ron G4DIY) who gave a splendid talk about aerials and his channel island expeditions. They had set up a number
of exhibits including a full 40m vertical aerial system outside in the cold. He gave some excellent and useful tips about aerial erection and their use, with a complete station set up.

A big welcome to all those new members who attended the meeting. We added our first lady operator, Tina M3MUM to the members list who is the station manager of Ian 2E1CYS. Perhaps her presence may entice other YL operators to visit the LARC club.

There were further names added to the prospective members list, including Derek 2E0DEX whose email I do not have, perhaps another member can inform me of his Email and I can send him info.
An old friend Peter 2E0DKO who is the junior of one time splendid 20m CW operator Joe G3IQO sadly now SK. Also a warm welcome to Kevin 2E0XDJ, and Phil G0DOR, Gordon G4VYR, Joey
M3IJD, Jay M3VCV, plus our oldest visitor to date, Don G3OSI still looking very sprightly with his many turns on the coil.
Further news includes the discussion of the intended affiliation with RSGB also some names were suggested as to a possible member to assist in secretarial matters.
A small voluntary donation was levied with the view that it would be prudent to have a small kitty of money which would be used in for instance the RSGB affiliation which would also bring a number of benefits, such as public protection cover and a club copy of Rad Com magazine.
It has also been proposed that the club could extend its meetings to take place every fortnight and to that end the next meeting is scheduled to be on the 16th of November next.

One final thing, someone left their Email address as RonnieHuartu88@Gmail.com and no call sign added on the sheet, but Gmail has sent it back as an error. So if that’s you perhaps you could Email with the correct details ?

I would like to request of any of the members if they have any questions or queries, either in relation to LARC or other matters perhaps of a technical nature or maybe to do with an aerial
problem, they can Email me or grab my attention at the meetings and I will be happy to respond, or they can Email Paul : m6trn@outlook.com.

As the Chair-person designate, I have produced these Liverpool Amateur Radio Club newsletters and notes which I have sent out via Emails and perhaps members may wish to read their newsletter
on the LARC website or I can continue to send them via Email. Perhaps people could indicate which method they prefer ?

Enjoy your radio operating and may you have clear signals, and low aerial SWR

from Andy G3PKW : Andy3pkw@Gmail.com

Newsletter 14/10/2016

As an introduction to launch the new Liverpool Amateur Radio Club, ‘your new club’. I have devoted some time, in an attempt to encourage members to try their hand at making their own
aerial(s) which would not only save a huge amount of ‘spondoolies’ but would also help to enlighten and educate those of the rudiments about an aerial which is often lacking in the knowledge of many.
Particularly if the aerial has a design which allows it to be adjusted and tailored to suit any location where it is to be used. Further more, as we are ‘amateurs’ and not ‘professionals’ I always seek to
find a design which needs very little cost in its construction, and will fit into a small garden.

I am continuously reviewing developments in aerial design and having spent over fifty years in radio both professionally and as a radio amateur I came across the following : –
An adjustable coil loaded dipole aerial by Ken Maxted GM4JMU (Glasgow)
My first attraction was his call sign which reminded me of my old daytime QTH which was JMU.  As I didn’t have a photo copier handy, to copy the original article from the Autumn 2016 Sprat
magazine, I spent an hour or two re-drawing the details and included some of my own comments as I thought
may be helpful.

coil-loaded-dipole

To make up each side of the aerial, the original article suggests using SOTA-Beam green aerial wire which is PVC covered 2.2mm diam but most types of wire will work fine but it needs to be stranded type of wire to enable it to be flexible enough to be adjustable on the coil former.  However it is not essential in order for the design to work.
The lengths used will be affected by the fact that the wire is covered with PVC.  Each side of the aerial uses a total length of wire cut to 10.5 metres.  Then measure from the centre Tee piece about 4 metres and dress the wire around the first peg on the coil former.
Wind twenty three turns over the length of the former, spacing the turns out evenly (in the original article the coil had only 21 turns actively wound in the coil assembly, but by its design the number
of turns can be adjusted easily) Then at the other end of the former dress the wire around the second peg, as shown in the diagram. Use some tie wraps to secure the wire from unravelling from the
pegs, but do not over-tighten them as they may be required to slip off for any adjustments.  This is a slight departure from his original design which he suggested bunching up 21 turns in the
middle of the former, with a single turn to take up the end distances of the coil, but the coil ‘Q’ (Quality) Factor is compromised if this method is used.

One of the problems with any aerial which is loaded by a coil is the losses which the coil endures.  By neatly spacing the turns reduces the losses to a minimum, this is because the capacity which
exists between each winding causes higher currents to exist in the coil causing higher losses. These losses can have a significant effect on an aerials behaviour.  So in any coil loading it is always better to space the turns out as far as possible. After winding the coil continue a further 3 metres to create a total distance from the Tee piece of
about 7 metres. Any surplus wire is doubled back on itself when threaded through the end insulator.  Finally the wire is bound using a tie wrap or similar to hold it over itself and around the insulator.

This type of aerial has the current maximised at the feed point so this is where it couples its energy into space, so that needs to be at a high point above ground. If only one support is available then the
so called ‘Inverted Vee’ arrangement can be used.
The original aerial uses 50 ohm co-ax as a feeder and not even using any balun. It will work that way and should present a low VSWR but it will be slightly quieter on receive if a current balun is
used at the Tee piece. This is because the aerial will be better balanced and therefore it will give better ‘common mode’ rejection to any local noise from TV’s or heating systems etc. A current balun
can be easily made by winding half a dozen turns of the co-ax through a ferrite ring.
The aerial as it stands will work well on 40 metres and also 15 metres and should provide a good match on most of the higher bands. The ability to be able to adjust the number of turns on the coil
and its position on the aerial length makes it very flexible to experiment for each band and even optimise it for your favourite bands. There are many coil loaded aerials out there but this makes it
easier to set up and adjust at any location. As stated it can be seen that a wire which will allow being flexed is desirable to avoid the wire from fracturing, if it is to be moved often.  I haven’t yet made one myself as I am able to erect a bigger doublette aerial but I am contemplating making one of these aerials to use portable.

Another point worth mentioning is that the centre Tee feed could be fed using ribbon, either 300 ohm or 450 ohm type, or even ‘figure of eight’ twin lead. These are all truly balanced types of feeder
as opposed to co-axial feeder, but in the ribbon case would need a suitable matching network in the shack to make the aerial work efficiently. The twin lead being of a lower ohmic value (75?) may be
fed directly from the rig with a one to one balun. This method of feed would reduce the weight which a ferrite balun would add to the Tee piece if it is unsupported.

Enjoy the satisfaction of home brewing your own aerial and spend the money you save wisely.

Andy G3PKW

Newsletter 10/10/2016

Here is a first written newsletter – Emailed to circulate membership with an official opening communication of your newly formed Liverpool Amateur Radio Club.  I and others would initially thank everybody who attended the first meeting which took place at the Bootle Cricket club (L20.2DD) venue on 5th October 2016.  It will have the initials LARC (which perhaps could be pronounced as ‘Lark’).

A Web site address has been established at : -http://www.LiverpoolAmateurRadioClub.com As a newly formed club, it is a blank canvas and therefore a number of questions go begging, to be answered.  Feedback is needed from members as to what they want from their radio club ?  Also by the same premise what can they as members contribute to their radio club ?
We, as a fraternity, have a common interest in radio matters or electronics and radio communicating, thus we need to establish a number of details to exemplify those aspirations.  Perhaps there is behaviour of members which needs to be discouraged or conversely
any behaviour which needs to be encouraged. These things need to be established early on to formulate a solid constitution which all members can recognise.  This will start the draft for a written constitution which in an ideal world is not really necessary but our world today needs such details documented.  Further to that, some sort of guiding group (commitee) needs to be established to
proceed with any responsibility.

That process was started at the meeting and Paul M6TRN was nominated as a club secretary but he pointed out that he is heavily occupied with other activities. So another will need to be proposed.
A second candidate for secretarial matters, I would nominate is, Reg 2E0REG but it is open for you the general membership to make these decisions.  So please reply via email or at the next meeting with any ideas of whom you would like to see in the various posts to steer your club.
I have been tentatively nominated for the chairman position which I have agreed to as a starting point, but it is up to all members (you) to elect whoever you think is the right person. As you can see I have assisted Paul by producing this.  My skills are of a technical nature so I hope my efforts here are understandable and as I tried to point out at the meeting any member with radio questions is welcome
to email me as appropriate.

We also need a treasury member to be able to handle any monies which may become required subsequently.
At present we are very fortunate that the venue which Paul TRN has kindly availed to the club has not currently required a rental charge but this may not always be the case.
A treasurer needs to be a person with integrity and skills to be trusted with finance which entails producing an account of money flow on a regular basis.  Such a position needs a small and set amount of time to be devoted to that.  Therefore a guiding group needs to be established – so please email your thoughts.

To either : –
Paul 2E0TRN [M6TRN@Outlook.com] or
Andy G3PKW [Andy3PKW@Gmail.com]

The following is a complete list of names / call signs as registered at the meeting (5th.Oct)

Ian G1DFT
Denny M6XBJ
Dave 2E0FGN – NO EMAIL
Alan M3XYY –
Jimmy 2E0VWL –
Vince M6BFB –
Lee M6OAU –
Paul G1LOV –
Ian 2E1CYS –
Gary can’t read – NO EMAIL
Phil 2E0PRO –
Reggie Davis 2E0REG – NO EMAIL
Lee Kelley –
Andy G3PKW –
Ron G4DIY –
Lee G0DBE –
Alan G4NXG –
17 members names left on attendance sheet – 14 valid email addresses – much more than 17 attended – so many names missing
Finally I hope all members or even prospective or new members ensure that their email details are lodged with Paul 2E0TRN who is temporarily our secretary as and when , or to me Andy G3PKW. So if your name is not listed here, email it.
You may also note that I have kept email details in a BCC on the email. The only live address on the header being my own
I have done this in order to maintain email details security. This is a useful way to maintain security for anyone who emails multiple recipients.
May I welcome everybody to the Liverpool Amateur Radio Club and please send your thoughts and ideas etc. OR bring them along to the next club meeting which is scheduled for the 2nd November 2016 (details on web site)
from Andy G3PKW