What's New - QSL.netApologies Peter VK4COZ, Terry VK4AAT, Renato VK4TNT, Kevin VK4WA, Frank VK4XK Minutes The minutes of the last business meeting were read by the President, Kevin

BARC Newsletter

Volume 34, Issue 8 October 2014

Inside This Issue 1 Diary Dates

1 Inside This Issue

1 Editorial

1 What's New

2 Club Information

3 General Meeting minutes

4 Funnies

5 Funnies

6 History of BARC

7 5/8 2 metre Vertical

8 2 metre antenna continued

9 2 metre antenna continued

11 Roberts 5/8 vertical dimensions

Diary Dates

Next Business Meeting Friday 28th November

Club Net Frequencies

Due to interference to the HF net on 28.450 MHz the following procedure has been adopted. If 28.450 MHz is not available, the first clear frequency in the following list will be used, 28.445, 28.440, 28.455, 28.460 (i.e. down 5, down 10, up 5, up 10) The starting time is 8:00 pm. On Wednesday nights the normal frequency of 439.950 MHz will be used, This is a repeater and an input of 434.950 MHz will be used. The starting time is 8:00 pm. 146.550 MHz simplex may be used if there is a problem with the repeater

Editorial

.

Note The next General Meeting will be held on Friday 28th November

The second and fourth Friday or Saturday of each month will be social time at the Club

house unless otherwise advised.

What's New

The last two social meetings have be held on

a Saturday Afternoon and have been well represented with over 20 members,visitors and friends attending.

Peter VK4PTR brought along a couple of 2 metre and 70cm antennas he had made.

The design was produced by

vk2zoi.com/articles/half-wave-flower-

pot and was called a Flower Pot antenna because it could be disguised and put into a flower pot so that it was not obvious for any person who saw the antenna. It could be covered with some artificial foliage to make it more realistic.

Peter made a simple dual band flower pot antenna which worked very well so he then made a larger version with more gain. This was also a dual band antenna.

Last Saturday we did some experiments on various 70cm antennas and measured the field strength by a remote reading field strength meter

Robert VK4HBD ex VK4FABN brought along a 2 metre antenna he had just constructed and we tried it out. It worked very well so we decided to include this design in this newsletter

CLUB MEETINGS Meetings are held on the 2

nd (social) and 4

th

(business) Fridays of each month at Rochedale Scout Den. 21 Rochedale Road Rochedale No meetings are held on the 2

nd Friday of January

or the 4th Friday of December.

Visitors are most welcome to come along and Sample our hospitality.

MEMBERSHIP SUBSCRIPTIONS

Subs fall due on the last day of August and must Be paid by the 4

th Friday in September

Current Standard Membership fee is $20.00 (Subject to any changes prior to 31

st August)

CORRESPONDENCE

All correspondence (except for items for the Club newsletter) should be addressed to:

The Secretary Brisbane Amateur Radio Club Incorporated P.O. Box 6106 Upper MtGravatt 4122 Qld.

Club Web Site http://www.qsl.net/vk4ba Items for the Newsletter may be sent by mail to:

QSP Editor . P.O. Box 6106 Upper Mt Gravatt, 4122 Qld.. or, by Email to: [email protected]

Deadline is 5pm Monday prior to the 2nd

Friday Each month except January.

CLUB STATION NETS (VK4BA)

28.450 MHz. SSB Mondays 2000 hrs Local 439.950 MHz. FM Wednesdays 2000 hrs Local

COMMITTEE MEMBERS

PRESIDENT Kevin Dibble VK4ZR VICE-PRESIDENT Jim Kelly VK4HJK SECRETARY Ann Forbes VK4FAHR ASSIST-SECRETARY Keith Adams VK4XAK TREASURER Peter Holtham VK4COZ LIBRARIAN Peter Holtham VK4COZ PROVIDOR Bill Scheele VK4TWS REPEATER OFFICER Kevin Dibble VK4ZR STATION MANAGERS (VK4BA) HF Bill Scheele VK4TWS VHF/UHF Les Parker VK4SO PROJECTS CO-ORDINATORS To be announced AWARDS & QSL MANAGER To be selected PUBLICITY and LIASON Berwyn Kelly WICEN REPRESENTATIVES To be selected QSP NEWS EDITOR Kev Dibble VK4ZR CLUB EQUIPMENT OFFICER To be announced W.I.A. ACCREDITED EXAMINERS Les Parker VK4SO BARCFEST COMMITTEE To be announced

BRISBANE AMATEUR RADIO CLUB Business Meeting 22nd August, 2014

The meeting was opened at 7.30pm by the President VK4ZR. Twenty members and four visitors were present as listed in the attendance book. Apologies Peter VK4COZ, Terry VK4AAT, Renato VK4TNT, Kevin VK4WA, Frank VK4XK Minutes The minutes of the last business meeting were read by the President, Kevin VK4ZR, who moved they be accepted, seconded by Norm VK4ANB. Business Arising $6,000 in term deposit is due for renewal and it was recommended that this be rolled over at best rate. Kev VK4ZR proposed this be accepted and Greg VKFPGM seconded. No correspondence received. Financial Report Les VK4SO tabled Treasurer’s report (please see attached). The opening balance as at 22nd August was $xxxxxxxx Petty cash was $xxx.00. Asset total was $xxxxxxx. The total income was $1xxxxx0, made up of memberships, callbooks, Foundation Books, yagis, Coax and BARCfest takings. Expenditure was $xxxxxxxx, made up of coax cable, WLD Dept Fair Trade, hall hire, BARCfest expenditure and Bank fees. This left a net income of -$xxxxxxx The balance sheet as at 22nd August, 2014 showed a total of $xxxxxxxx Les VK4SO moved the Treasurer’s report be accepted and seconded by Jim VK4HJK, and approved. Correspondence The usual magazines have been received. Reports 10m Net. Bill VK4TWS reported everything going well. They have been experimenting with FM with little interference. 2m/70cm Net. Les VK4SO reported usually 6-8 attendees with up to 12. Problems that have developed with repeater with occasional ‘noise’ has stopped the 70cm net, and they are currently communicating on 2m net. A new repeater is being worked on. General Business Repeater Kev VK4ZR reported 70cm repeater has been donated to the club and needs reprogramming. This replaces the current club repeater that has intermittent static. Programming new repeater is being worked on with discussion as to whether this should include an additional input of 2m or 10m. Consensus of opinion was that 2m would be of more benefit. BARC Kev VK4ZR said that start and finish times for BARC next year needed to be clearly stated by the Club. This year this wasn’t told to all exhibitors and there was some confusion. Everyone agreed. Foundation Course The course was completed and five students enrolled. Four passed exams. Congratulations to all. Membership Numbers Last year the club had 25 members, and this year there are now 60. Norm VK4ANB gave feedback that he appreciated the presentations that had been given and found them well worthwhile. This was agreed. Radio Mobile Software Kev VK4ZR had been working on getting club production data on Radio Mobile Software. In particular, he spoke about the contour map from Googlemaps and interference in communications across Brisbane. This highlighted areas blocking communications (eg Mt Cotton). Kev received a spontaneous round of applause at his powerpoint showing a green contour map of Brisbane region overlaid with BARC member communications as red lines. It looked remarkably like a six pointed red star over Brisbane. Meeting closed at 8.15 pm.

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Above is the answer to the item in last months newsletter correctly answered by Chris VK4YE

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Thanks to Chris VK4YE and Les VK4SO for the cartoons

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History of the Brisbane Amateur Radio Club

The Brisbane Amateur Radio Club was formed in 1977 and met at a church hall in

Springwood street Mt Gravatt.The first President was Brian Beamish(now SK) Vice

President was Doug Hunter ZVK4ADC.

Treasurer was John Wilson VK4NCH and 2 committee members Don Thompson

and Dave Prince VK4NAK. The cub newsletter QSP was started and still being

produced.

In 1978 the club moved from Mt Gravatt to Holland Park West High School

Bapaume road Holland Park. The club net was held on Sunday mornings after the

WIA broadcast on 21.175mhz and Monday evening at 1930hrs.

In 1979 to raise funds a disposal system was set up. This was run by Col Gladstone

and Dave Prince and a lot of work went into this which raised a lot of money for

the club.

Friday 27th June 1980 saw the club meet at the Yeronga SES

In July 1981 the club net frequencies were changed to Monday evenings

28.450mhz 7.30pm and 3.570mhz 8.30pm.

On Friday 26th July 1991 the club moved to new premises at St John’s Presbyterian

church hall in King Street Annerley.The club met there for a considerable time. A

new meeting place was found at the Queensland Maritime museum. This venue

was not an ideal place for meetings and so a new meeting place had to be found.

That is our present meeting venue at Rochedale. This is the best meeting place we

have had as It allows us to have our 70cm repeater at the site and have recently

held the first course for foundation license. Membership is increasing at almost

every meeting and is now over 60 members. The club also has a transmitting

console and a 3 element beam and long wire antenna for hf. I trust this resume of

the Brisbane Amateur Radio Club’s history will give newer members an idea of

what the club has done over the last 37 years

Les Parker VK4SO

QSP Page 6

A simple VHF vertical aerial for the home station.

Reprint from Geelong Amateur Radio Club

as built by Robert VK4HBD

Contributions from Michael VK3FMIC, Shane VF3FSRG, Lou VK3ALB, and Peter VK3ZAV.A simple aerial can be constructed from 10mm aluminium tubing fixed to a mobile aerial base. This makes it easy to change bands, just jump up on the roof & unscrew the radiator, change it over, screw on the new one! A genuine multi-band version is under development. To reduce corrosion, seal the top with non-acid silicon, and grease the thread in the tube.

Make sure that the coaxial cable is absolutely water tight at the mounting base; best way is to use an inverted die-cast box on the underside to keep driving rain out. The coax is protected against damage on the ridge cap edge by threading a short piece of garden hose over it, and it protects from the next hazard too.

Another hazard to coax cables is shown here, link thanks to http://graemechapman.com.au. Do not mount several aerials close together without checking by simulation with MMANA-GAL or similar, as the longer (lower frequency) ones can interfere with the others, giving a lumpy pattern, ie. poor results in some directions (try multiples of half wavelength spacing at highest frequency).

Mounting bases and ground-planes.

This type of base gives a very simple mounting to the ridge cap of a galvanized iron roof. It is a small piece of flat sheet galvanized iron, bent in the home vice. In the centre, mount a standard vehicle mobile type base. There are two thread standards in Australia for this, the 5/16” 26tpi brass thread (BSB), and the 8mm metric. They look much the same size, but don't swap them over. The metric thread has a much coarser pitch. Peter VK3ZAV has both taps.If you have a tiled or other non-metal roof, then four radials will be required, each one quarter wavelength long at your lowest intended frequency. One of the textbooks suggests 0.28 to 0.3 wavelengths long. The actual aerial length is not very critical, but is affected by the sum of, the mounting base capacity, the roof shape (slope), and your mobile mounting base shape.

Mounting arrangements

Roof mount of Shane VK3FSRG, held in place by six 3mm pop rivets. QSP Page 7

An alternate mounting method which includes ground plane radials.

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A close up of the mounting arrangement of the two ground radials bolted to a

piece of 75mm aluminium angle.

QSP Page 8

A Quarter wave vertical

The simplest of all verticals is a quarter-wave long at the operating frequency of interest. The aerial is made of 10mm diameter aluminium tube, with a thread cut to fit the base. The vertical radiator should be about 95% of a quarter wavelengths long, for the following bands:

10m 2586mm You will need guy ropes

6m 1415mm May get away with this for 2m also, for test anyway.

2m 489mm will also work @ 70cm

70cm 173mm

Not much point, as the 2m one works just as well.A higher gain 5/8 wavelength 2m aerial.

A very simple way to more than double your effective transmitter power, as well as the transmitter power of those you're listening to, and costing about $10, is to use a longer aerial, and tune it (as many of the AM Broadcasting stations do). A 5/8 wavelength aerial will exhibit around 4dB (6dBi) of gain. A 5/8 wavelength at 147Mhz, the middle of the 2m FM band, calculates at 1275mm. With careful adjustment you will find that this aerial works quite well on 70cm too. Note: This is not a J-Pole, which is an end fed half-wave dipole, having the same gain as a quarter-wave ground-plane, and has 4db less than this 5/8 wave radiator.

If you run the simulation program MMANA GAL (see the links list, Design Software), you will see that the 5/8 wavelength gives a nice 50 ohm resistance, requiring a series inductor to give a good match, with best pattern & gain). Although the simulation program MMANA-GAL suggests more, don't bank on greater than 4dbd gain (6dbi). Download the simulation file for this aerial from here

A clever way to add the tuning inductance, as suggested by one of the RSGB books of the 1960's, is the use of a coaxial stub, but the linear stub shown here seems to work just as well, and is easier to make. Although the clamp in the picture is made from a solid block of aluminium it is best made from either round or square aluminium tubing, as it positions the actual short circuit point more accurately than with the solid clamp shown.

To make a clamp like this, two 10mm holes must be drilled with high precision through a piece of about 20mm tube, either round or square, and a drill stand and drill vice are recommended to get the two tubes accurately parallel. After the 10mm holes are drilled, drill a bolt hole for about a 4mm stainless steel screw, then cut the clamp in half with a hack saw, so that tightening the screw makes good firm contact with the two vertical tubes. Trim the SWR by moving the clamp up and down a little. The simulation shows that adjusting the total height mostly adjusts the R component, and the stub length the X component. As shown, height 1275mm, stub 375mm, spacing 25mm (centres), base 325 x 200mm.

As a club project, we would expect to find a club member that can make up several of these clamps.Finished product at VK3FSRG

Close-up of stub arrangement

QSP Page9

Finished product by VK3FSRG

Close up Stub arrangement

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