Conductors for HF Antennas

Received from Anne: 

A very interesting article was sent to me by Club member, Johan Sevenster, ZS1A. The article was originally published in the ARRL QEX Magazine back in November / December 2000.  It discusses the merits of various antenna metals with actual measurements such as with stainless steel, aluminum, solid versus stranded wire etc.  [Our chairman] Rob assures me our members will enjoy it.

I haven't been able to get permission to use this article in our Newsletter, so the best way for me to do this is to send you the link to it so you can have a look for yourselves. I am sure you will find it very interesting.

 

Follow this link:    

https://rudys.typepad.com/ant/files/antenna_wire_conductor.pdf

Conductors for HF Antennas

 Putting up an antenna for the low bands? What kind of wire will you use? 

This analysis may change your plans.

By Rudi Stevens, N6NF

CTARC Fox Hunt - 7 Dec '19

Come and join us for our next Fox Hunt this Saturday afternoon, 7 December 2019. Meet at the club house at 12h00 noon for a briefing and get ready to find this elusive critter!

Ideal equipment will be:

• A directional antenna for two metres, 
• A two-meter hand-held radio 
• A simple compass, and possibly 
• Some way to reduce the signal level from your antenna to your radio [i.e. an attenuator].

If you do not have all of this equipment, do come along anyway and bring what you have. It is fun to team up with someone who does have a radio and antenna and together determine where Foxy is hiding.

Great fun to be had by all!

The hunt should take two hours or less to complete.

Always a fun event. See you there!

Rob ZS1SA

_____________________________________

Note: This event has now taken place.

Read the report [here] and in [Ragchew of January 2020]

CTARC Homebrew VHF/UHF Moxon Antenna - Oct '19

Here is a link to what looks like a most interesting VHF/UHF Moxon Satellite beam antenna, described by PY4ZBZ:

https://www.qsl.net/py4zbz/antenas/ms.htm

The web page is not in English, however the dimensions are construction are straightforward and should be easily interpreted.

OM Lem ZS1LEM  built the version with 5 UHF elements and 2 VHF elements.

The components include:

• 3.2 mm aluminum welding rods are available from any welding supplier (Afrox etc).
• A piece of PVC pipe;
• A 3.2mm drill bit,
• A piece of RG-58 coax, and
• A coax plug.

It looks like an easy build.

Many thanks to OM Lem ZS1LEM for passing on the link, and obrigado to PY4ZBZ and PQ2HX for publishing the information online.

Photo copyright Hermes PQ2HX

CTARC Report on Meeting of Saturday 22 Jun '19

On Saturday 22 June 2019, the Cape of Storms strutted its fury across the City with high winds and lots of rain. However, this didn't deter the CTARC from going ahead with the monthly meeting! We had a very well-attended social afternoon with braai fires ablaze under an umbrella where some members chose to keep warm and dry around the fire. Simultaneously, the special Fox Hunt antenna building event took place inside the club house.

28 members and guests attended and socialised while 7 members constructed the portable tape measure fox hunt antenna and will soon join the growing ranks of club fox hunters. These antennas are very portable, being fold-able, which makes them ideal for packing into and taking out of a vehicle. These antennas are highly directional and ideal for finding hidden transmitters in the field. They also function well as transmitting antennas for portable and field operations. The cost to construct these antennas is well under R100 each.

Fox hunting is a growing interest at the CTARC. Perhaps one day we may well do inter-club fox hunting competitions followed by a bring-and-braai. These would be fun social events for everyone, including families.

Photos of the Saturday event will be posted here in due course.

Rob ZS1ZA
CTARC Chairman

CTARC Welcome Bring 'n Braai & Antenna Building Party - 22 Jun '19

REMINDER : TOMORROW - Saturday 22 June 2019:
The RAE Welcome Bring 'n Braai & Antenna Building Party: Read on......

We are aware of the weather situation for Saturday [rain forecast]. However, we have decided to go ahead with the events as planned. We will endeavour to keep the braai fire dry, so we can all have an enjoyable afternoon.

See you all tomorrow!

THIS SATURDAY,  22 JUNE

The Monthly Meeting is a Workshop and Bring ‘n Braai

Hi Everyone

Come along this Saturday for the ‘Fox Hunt’ Antenna Building Party run by Chairman, Rob ZS1SA,

Also come along to meet and congratulate the Candidates that recently wrote the RAE course, and introduce them to our friendly Club.

Bring your own meat and all your preferred accompaniments. Certain refreshments will be available and the fire will be sponsored by the CTARC.

The Antenna Building Workshop will start at 14h00 and braai fires will be lit at 14h30, to be ready by 15h30.

Come along and enjoy an interesting afternoon.


CTARC Fox Hunt Antenna Building Day Requirements

We have stripped it down to the absolute basic requirements.



All you will need to bring:

• Two 20 mm PVC 4-way conduit boxes (about R7 each)
• One 2 0mm PVC conduit Tee (sometimes called an Inspection Tee (about R8)
• One 5 metre long tape measure. 19mm width preferred (about R35)
• Plus whatever coaxial connector which mates with your radio.

Pick up these four items at any Buco or hardware store for well under R75 and come and build your own three-element Fox Hunt Yagi antenna at CTARC this Saturday afternoon. We will supply the remaining pieces and help you to put it all together. This directional antenna is also suitable for transmitting on and ideal for field operations in addition to fox hunts.

The only other item you will need to purchase is a suitable coax connector which fits your hand held radio. Alternatively we will have a few BNC connectors available for sale at the club for R30 each or you can purchase a suitable connector at a later time and install it on the coax cable yourself at home. In order to save some time, if you already have a connector for your radio and about 1.5 metres of RG-58 cable you can fit the connector to one end of your coax cable and bring it along on the day to attach to your new Yagi.

Regards,

Rob, ZS1SA.
(CTARC Chairman)

Anne
(CTARC Secretary and Editor)
Cell: 072 268 1207

_________________________________________________________

NB: This event has now taken place. Read the report [here]

CTARC Antenna Work Party - 23 Mar '19

Before the main meeting on Saturday 23 March 2019, CTARC members were at work fixing the antennas at the clubhouse.

I would like to thank everyone who assisted with the repair of our tower rotator system on 23 March, and a special thank you to James ZS1ZKZ. While we were all enjoying Tom Ambrose’s talk about satellites James was busing working and welding outside repairing the club’s tower and had been working on it since much earlier in the morning. He refurbished the winding winch and cabling system for the mast and completed the coupling to the rotator. James bought the new pulley, the new pillow block bearings and supplied the welding rods and tools in addition to getting his brother in law to help. He insists that all of that is a donation to the club and he won’t take no for an answer. A big thank you from all of us James.

Rob ZS1SA

Report-back on Repeater Work Party of 21 Mar '19

On the public holiday of  Thursday 21 March 2019 several CTARC members gathered at the club’s repeater site to form a work party to repair the UHF repeater and mount the UHF antenna onto I.R. Pope’s new tower. The UHF antenna has been mounted on the wall of the repeater building below roof level since the previous tower had blown down in the major storm of June 2016.

The back-up batteries were cleaned and a spare cable was identified and readied to be installed up the tower leg to mount the UHF antenna underneath our existing VHF antenna. Upon inspection, Paul ZS1S discovered that the cable connecting our VHF antenna to its antenna had never been waterproofed! Paul checked the connection and installed the waterproofing. Unfortunately, before he could install the UHF antenna, the wind picked up making further tower work unsafe and he had to come down.

While we were there we also checked the SWR on the VHF antenna and found it to be extremely high. Using his antenna analyser, Peter ZS1PGC discovered there was a very bad connection within the repeater building. Upon inspection we found a badly corroded connection and repaired it. The SWR was now excellent and the repeater works much better than before.

I would like to thank Lem ZS1LEM, Paul ZS1S, Dave ZS1SG, Peter ZS1PGC and Keverne ZS1ABU for coming up the hill and assisting that day. We still need to get our UHF antenna up on the tower and planning is in progress for that.

Addendum:

Following on from this work party, this yesterday Mike ZS1TAF, Peter ZS1PGC and Paul ZS1F put our UHF antenna back on the repeater tower and it is now working fantastically. Now that our Force 12 beam, the new rotatable 40-metre dipole and the tower at the club have all be repaired, all of our equipment is back in perfect working order. What a relief! No more freak June storms please...

Rob ZS1SA



 

 

CTARC Report-Back on Antenna Work Party - 26 Jan '19

On Saturday, 26 January 2019, the first meeting of the year for the Cape Town Amateur Radio Centre started earlier than normal. At 11h00, we assembled at the clubhouse to tackle the next phase of our main antenna refurbishment. Under a cloudless sky with a mild south-easter blowing, the coaxial mast was cranked down and then folded over on its main hinge to rest on a conveniently positioned ladder. The next stage was to replace the main feedlines with fresh RG-8X coax cable, generously donated to the club by Barry ZS1FJ. Thanks to ZS1BL, ZS1BOK, ZS1EQ, ZS1FJ, ZS1FW, ZS1PGC ZS1S, ZS1TK, ZS1ZD, ZS1ZKZ and others who attended the work party.

There was a minor set-back when the stainless steel cable snapped while being winched [fortunately with the mast still lying horizontal!], but we still had the old steel cable that was now redeployed as a temporary measure. The mast was winched back into vertical position just as the other club members arrived for the main meeting.

The purpose of the work party was to replace the main feedline to the antennas with some RG-8X coax [kindly donated by Barry ZS1FJ] , and to do some work on the baluns and attachments for the new 40m beam that was recently mounted on the tower. This was achieved in time for our main meeting which followed on at 14h20.

Thanks to all those who attended and assisted with the Work Party!

CTARC Antenna Work Party - 26 Jan '19

Hello Everyone

On Saturday, 26 January 2019, before the Monthly meeting, the club is going to have a work party to replace the two co-axial cables on our tower.

The Committee asks if members are able to help, please come to the clubhouse about 11h00 .

With appreciation,

Rob ZS1SA
CTARC Chairman

--------------------------------------------------------------------------------

This event has now taken place

The report-back and photos are [here].

CTARC Antenna Work Party - 8 Dec '18

Hello Everyone

We have decided to have an Antenna Work Party on Saturday 8 December.
Paul, ZS1S, will be ‘Commander in Chief’ for the day!

We will be lowering the tower and repairing the Yagi antenna, and also installing the new Dipole antenna that Barry ZS1FJ kindly purchased for us from the USA.

All members are welcome if you can please spare an hour or two to have some fun whilst helping your club maintain the equipment. Do bring your own lunch.

If you’re able to help, see you at 09h30 on Saturday 8th December 2018.

With appreciation,

Rob ZS1SA
CTARC Chairman

CTARC Huge e-Book on Antennae - 14 Oct '18

Below is a link to a website with a PDF e-book that contains an enormous amount of info on antennas and associated theory and practise.

Access the website via the link below; you will find the link to the PDF file (a compact 855kB) halfway down the page.

Thanks to Lem ZS1LEM for letting us know about this:

Understanding Antennas For The Non-Technical Ham
 

A Book By Jim Abercrombie, N4JA
(Jim Abercrombie n4ja@prtcnet.com)

Illustrations by Frank Wamsley, K4EFW
Edited by Judy Haynes, KC4NOR
Copyright July 2005. Second Edition
Edited for the web, N4UJW

Editors Note: This is a book length web article provided by the author FREE for all hams.
It is to be used only for personal non-profit educational use.
It is HUGE!
Bookmark this page for future reading or see more options for saving at bottom of page!
The original book contained 60 pages and illustrations.
They are all here!
Many of the antennas described here are in project form on this web site.

http://www.hamuniverse.com/n4jaantennabook.html

CTARC Work Party Cancelled - 29 June '18

Owing to inclement weather, we regret to announce that the scheduled Antenna Work Party at the CTARC clubhouse for tomorrow, Saturday, 30 June 2018 has been CANCELLED until further notice.

With apologies

CTARC Solar Noon Calculator - 4 April '18

John / ZS1AGH kindly sent us this useful link:

It is an online calculator for Solar Noon at your QTH.

Solar Noon is when the sun is at its highest and the shadow cast is at its shortest; the shadow should then be pointing directly North - South. Useful for aligning antennas accurately, if you don't have a GPS.

First obtain the Latitude and Longitude coordinates of your antenna's location (which you can acquire from Google Maps - just click on the exact point with your mouse and a label will appear with the selected location's decimal coordinates).

Then go to the Solar Noon web page [here]

Then plug in the Latitude and Longitude coordinates into the fields provided. Remember to set your time zone (as GMT +2 hours for local time).

Then the web page prints out a year's table with the exact Solar Noon times for each of the 365 days.

Below is an example of the process done for the CTARC clubhouse's (approximate) location:

CTARC Report on Antenna Work Party - 28 Mar '18

The CTARC Antenna Work Party of 21 March 2018 was a great success. At 09h00 the team assembled and set to work.

Present were:
ZS1S - Paul
ZS1SA - Rob
ZS1ZKZ - James
ZS1EQ - John
ZS1TK - Tony
ZS1RIC - Richard
ZS1FW - Noel
ZS1BL - Danny
ZS1FJ - Barry
ZS1PGC - Peter 

The vertical mast for the main beam antenna was finally fixed and the club's beam antenna mounted on top. The vertical antenna was also mounted in position on the western wall of the clubhouse.

At the end of the work party, Danny / ZS1BL tested the antenna on 20m and made a contact with the USA using 100W, so the antenna is getting a signal out. Well done, guys!

Here are some photos and captions, kindly provided by Peter / ZS1PGC.

The guys examine the snagged cable on the mast

Rob / ZS1SA makes up an adaptor pipe
to mount the vertical antenna

James / ZS1ZKZ uses a bit of gentle persuasion to remove a pulley
to release the snagged cable.

Tony / ZS1TK attaches the vertical antenna to the mast
using Rob's adaptor pipe.

Examining the mast to determine catch points. It turns out that
the screws were a bit long and had to be shortened.

The vertical antenna in position.

Noel and then Richard and Tony assemble the beam.

Rob and Paul make an adaptor pipe to mount the bean antenna
to the mast.

The pause that refreshes! Danny / ZS1BL has a quick cup of coffee.

Paul mounts the adaptor pipe to the vertical mast.

Assembling and checking the beam antenna.

The beam antenna now assembled and attached to the mast,
ready to be hoisted up.

Noel enjoys some pizza, kindly provided by one of the team. Tony / ZS1TK provided
some samoosas that were enjoyed. John / ZS1EQ and others also provided
cold drink and water for the team.

The beam antenna up and in position at the top of the mast,
with the two vertical antennas also in the picture.

John / ZS1EQ cranks up the mast to its full height.