What is lately happening on the ZS Link Network in the Southern Cape?

Herewith a short overview of what is lately happening on the ZS Link Network.  

• Repeaters, Links, Hubs, DMR Bridge etc
• "Killing" the use of annoying courtesy tones on the ZS Link Network
• New features to be added to the ZS Link Network 
• Weak Signal Propagation Reporter (WSPR) in the Southern Cape 
• Activity on the ZS Link Network
   

Repeaters, Links, Hubs, DMR Bridge etc: 

All the ZS Link Network repeaters are operational and in a good working condition. For those not familiar, here are the ZS Link Network Group repeaters currently operational over a large part of the Southern Cape.

Aasvoëlkop Repeater:  Albertinia

RF Frequencies = 145.625 Mhz RX, 145.025 Mhz TX 88.5 hz CTCSS

Echolink = ZS1SB-L Node: 123760

Stilbaai Repeater:  Still Bay

RF Frequencies = 145.750 Mhz RX, 145.150 Mhz TX 88.5 hz CTCSS

Echolink = ZS1DRP-R Node: 272595

 

145.725 Mhz Test Repeater: (Currently at Still Bay)

RF Frequencies = 145.725 Mhz RX, 145.125 Mhz TX 88.5 hz CTCSS

 

ZS Link Hub Network:

All the Nodes, Hubs and RF Links are operational and in a good working conditions.

 

Mosselbaai RF Simplex Link:

RF Frequency = 145.550 Mhz RX + TX 88.5 hz CTCSS

Mossel Bay DMR Bridge:

Node: 467652 Talk Group: 65511

 

ZS1I AllStar Hub:

ZS1I AllStar Node: 49355

ZS1I-R Echolink Node: 929614

Mossel Bay Aasvoelkop Direct RF Link:

Radio User (Option 1): Radio Frequencies (Program these frequencies in your HT, Mobile or Base Station radios)

RX = 145.625 Mhz 88.5 Hz CTCSS

TX = 145.025 Mhz 88.5 Hz CTCSS

Radio User (Option 2): Radio Frequencies (Program these frequencies in your HT, Mobile or Base Station radios)

RX = 145.025 Mhz 88.5 Hz CTCSS

TX = 145.625 Mhz 88.5 Hz CTCSS

Note: Option 2 must only be used if you are in reach of the ZS1I QTH / Tower. To setup CTCSS refer to your radio's users manual.

More information about this RF Link available  HERE.

"Killing" the use of annoying courtesy tones on the ZS Link Network

Courtesy tones on any network are short audio signals that indicate the end of a transmission, much like a "roger beep" on a repeater. They serve to let other users know it's their turn to speak, help prevent long-winded transmissions, and allow time for distant nodes to reset timers, making for a more courteous exchange.

Courtesy tones can be a nuisance on the ZS Link / AllStarLink Network. In a small private network courtesy tones seldomly causes problems but in a large network like the ZS Link Network courtesy tones cause all sorts of problems from ping-ponging, irritation, locking up of nodes/bridges etc.

The sentiment that courtesy radio tones are a nuisance is a common one within the amateur radio communities. While they serve certain functions, their implementation and design often lead to user frustration.

Reasons for the Nuisance

• Annoying Sound: The beeps or tones can be simply irritating to the listener, especially if they are loud or high-pitched.

• Disruptive: They break the flow of conversation and can be particularly annoying during long discussions.

• Redundancy: Experienced operators often know when a transmission ends through other means (like the sudden end of the carrier signal), making the tone unnecessary.

• "Roger Beeps": Tones that activate after every transmission, often called "roger beeps" (common on some consumer radios but generally frowned upon in amateur radio), are widely disliked by many users.

• User Error: In some cases, users might not know how to disable them in their radio settings, leading to unintentional use.

The Purpose of Courtesy Tones

Despite the annoyance, courtesy tones are used for several practical reasons, primarily on repeaters:

• Signaling End of Transmission: The primary purpose is to signal that the previous user has finished transmitting (un-keyed the microphone) and the repeater is clear for someone else to use or break in.

• Preventing "Squashing": It provides a brief pause (hang time) before the repeater drops its carrier, which helps prevent users from accidentally talking over each other.

• Emergency Break-ins: The pause allows a window for a station with an emergency to transmit and be heard.

• Confirming Access: For the transmitting user, hearing their tone on the output confirms that they successfully accessed the repeater.

Potential Solutions and Workarounds

If you find courtesy tones a nuisance, several approaches may help:

• Disable on your radio: Many radios allow you to disable the transmission or reception of certain tones in the settings.

• Use CTCSS/DCS (Privacy Tones): These sub-audible tones filter out other traffic unless it uses the same specific tone, effectively muting unwanted sounds like courtesy beeps from other groups or random static (squelch tail).

• Simplex Operation: If you are talking to someone nearby and can communicate directly without a repeater, switching to a simplex frequency avoids repeater-specific tones entirely.

• Contact the Repeater Owner: For amateur repeaters, you could contact the owner or group that manages the system to discuss the tone settings. They might adjust the tone or volume if there is enough demand.

The debate highlights a balance between operational efficiency and user preference in radio communication.

The ZS Link Network Administrators has decided to not allow courtesy tones on the ZS Link Network. In the event that a station transmits courtesy tone on the ZS Link Network, the radio amateur will be contacted and referred to the decision taken by the ZS Link Network Administrators. Failure to comply will result in the suspension or ban of the station from the use of the ZS Link Network. Stations connecting to the ZS Link Network and courtesy tones are transmitted over their repeater or links will also be notified and requested to solve the issue. PLEASE lets use great diplomacy in solving the issue amicably. No need to be a "policeman" or even worse ban or chase a station of the air. Rather assist and help such a station. A reasonable time should also be allowed to remove the courtesy tones as some radios need to be re-programmed.

New features to be added to the ZS Link Network 

The ZS Link Network is not a "once off" installation of equipment and software.  Apart from maintenance and upkeep there is also new features that we add to the network on a regular basis.  Experimenting which entails building, modifying, and testing radio equipment and antennas, or using radio signals for scientific and digital communication purposes. Experimentation can range from creating "homebrew" electronics to using the latest and greatest hardware and firmware to enhance the ZS Link Network.

The following experimental projects is currently on the test bench:  

1.  Creating a 5.8 Ghz Backbone Network setup for the ZS Link Network

2.  Testing a SVXLink Node on 70cm to link a specific repeater to the ZS Link Network as and when necessary.

More information  will be provided in future posts regarding these two projects.

Weak Signal Propagation Reporter (WSPR) in the Southern Cape 

Now why would one setup a WSPR Beacon in the Southern Cape?

Read more by clicking HERE and HERE

The beacon is currently running on 40 meters as a test beacon.  The final "VHF Allocation" of the beacon will soon be implemented and work on this is progressing very well.  More information to be published in future postings.  We do have high expectations for this beacon to be spotted in parts of the world and on a frequency never before spotted from the Southern Cape.  Hopefully this beacon will contribute to the WSPR "network and mode" by utilizing a specialized protocol and software for weak-signal radio communication to examine radio wave propagation conditions.

Activity on the ZS Link Network

With three on the air Nets running a day the ZS Link Network is one of the busiest networks in the country.  With an average of  between 10 - 14 stations reporting in during each net the activity on the ZS Link Network is thrive.  Several new radio amateurs that passed the October RAE already participated in the Nets.  All radio amateurs especially the new radio amateurs are most welcome to join the Nets and use the ZS Link Network.  A wide variety of topics are covered during these Nets.  New radio amateurs are encouraged to ask questions or advice from the many experienced participating radio amateurs. 

Finally:  If you have not yet used the ZS Link Network you are most welcome to do so.  The ZS Link Network Adminstrators trust that users will enjoy using this dynamic and busy network.  Enjoy!

“WE WILL REMEMBER THEM” - 11 November 2025

The Armistice was signed at 05:00 on Monday 11 November 1918 and the agreement took effect at 11:00 on that Monday 11 November 1918 – “the eleventh hour of the eleventh day of the eleventh month” and is remembered as a turning point in world history when peace was restored after years of devastating conflict.

Each year this day is commemorated on the Sunday nearest to the 11th or on the 11th of November by the military, military veterans, schools, churches and the community. The focus has changed from the First World War to encompass the fallen of all wars, right up to the present.

Sir Percy FitzPatrick in South Africa suggested the 2-minute silence as a way for people to honour the soldiers who had died in the war. On 7 November 1919, King George V sent a message to the people of the British Empire requesting them to observe the two minutes silence - the first minute is a time of thanksgiving for those who have survived. The second minute is to remember the fallen.

Tomorrow, 9 November 2025 the Annual Remembrance Day Service on Amateur Radio Today will be led by Hannes Enslin, ZS6JDE. The SARL transmitted the first Remembrance Day service in 1961 when the Service was broadcast simultaneously on the amateur bands and by the Afrikaans and English services of the South African Broadcasting Corporation. As a mark of respect radio amateurs are requested to observe radio silence during the Service.  The Service will be broadcast at approximately 10:30 CAT.

Where can I monitor WSPR Beacon information, data, spots etc?

The acronym

WPSR in the context of "spotting" most commonly refers to the Weak Signal Propagation Reporter (WSPR) protocol used by amateur radio operators, not a traditional spotting community site for aircraft, trains, or ships. 

WSPR is a specialized protocol and software used for weak-signal radio communication to examine radio wave propagation conditions. It involves low-power beacons and receiving stations ("spotters") that upload data to a central database. 

The primary site for this activity is WSPRnet: 

• WSPRnet.org: This is the centralized database that collects and displays real-time propagation reports (spots) from WSPR stations worldwide. Users can view maps, tables, and statistics related to WSPR activities.

This technology has also been used in experimental ways for other types of "spotting," such as detecting and tracking aircraft over long distances, which gained some prominence during the search for MH370. However, this is a technical application of the radio data, not a general public spotting site in the traditional sense. 

WSPR Viewing, Mapping, and Analysis Tools Available at:

1.  WSPR NET =  http://www.wsprnet.org/drupal/wsprnet/spotquery

2.  WSPR LIVE = https://wspr.live/?s=35

3.  WSPR NET CHARTING VK6YSF = https://vk6ysf.com/wsprnet_data_charting_V2.htm

4.  LU7AA WSPR PROPAGATION =  http://lu7aa.org/dx.asp

5.  WSPR STATS = https://wspr.live/gui/d/o_qTGcqik/home?orgId=1&from=now-6h&to=now&timezone=utc

6.  WSPR APRS = http://wspr.aprsinfo.com/

7.  WSPR ROCKS = https://wspr.rocks/

8.  WATT WSPR Analysis tool = https://www.gm4eau.com/home-page/wspr/

9.  WSPR SPOT = https://wspr.spot/

10.  PSK REPORTER  = https://pskreporter.info/pskmap.html

 

And there you have some WSPR Tools for Analysis, Mapping, Timeline Animation and Reporting.  

Enjoy!!

Constructing a WSPR Beacon to monitor propagation conditions from the Southern Cape (Part 2)

In Part 1 available HERE we looked at the construction of a WSPR Beacon to monitor propagation conditions from the Southern Cape.

In Part 2 we will be looking at the functioning and operating of the beacon as well as reports received and stations that spotted the beacon.

The ZS1I WSPR 40M Beacon is currently on air since the 7 October 2025 @ 10h00 SAST.  The first station to spot the beacon was Fred ZS5SAM (Div 1) from Barrydale. (Distance 134 km)

 Image:  Barrydale.  Take note of the mountains surrounding the town.  Photo:  Viv ZS1VIV on a mountain site.

 

 

Images (Click on images for larger view.)

I hear many of you say but that is no big deal receiving the beacon.  Well after I constructed a project it is important for me to know that the project is working and that it is working well.  Thanks, Fred for taking the time to spot the beacon.  Highly appreciated.  Now Fred is not the only one that spotted the beacon. 

More on this later as here is another interesting occurrence once again involving Fred.

Fred also run a Ultimate 3S beacon from Barrydale.  On the 9 October 2025 I was busy monitoring the beacon in my Shack using my RTL-SDR V4 Dongle and the included portable V antenna.  (See photo of antenna.)

Images (Click on images for larger view.)

The equipment that I used to monitor the ZS1I Beacon on the 9 + 10 October 2025 can be seen from the above images.  The third image reflect my setup on the two days.  The antennas were not extended as I concentrated on the ZS1I Beacon that was running in the Shack.  I used SDR Console and WXJT-X to decode my beacon's signal.  Well I nearly fell on my back when the WSPR Beacon of Fred ZS5SAM was decoded  using the test setup inside the Shack on the 9th and 10th.  Look at the images below for more information.  Remarkable that this setup decoded the signal of Fred's beacon from Barrydale especially using this simple antenna.

Images (Click on images for larger view.)

This is proof that WSPR is living up to it's name!

Other spotting stations:

I would like to thank all the many other stations that spotted the ZS1I 40M WSPR Beacon since the 7 October 2025.  Many stations taking the time to listen out for the beacon.

Here is a lists of stations listed by LU7AA:

Images (Click on images for larger view.)

Thank you to all the stations that assisted me in getting the beacon "fine-tuned" for its ultimate use in the next few weeks.  Yes the 40M band beacon will be changed to something more exiting and challenging.  I can confirm that the beacon has been running flawlessly after making the necessary small set-up adjustments.  Lookout for Part 3 relating to more information as to the ultimate use of the beacon.

End of Part 2

Opdatering van Verjaarsdag- en Huweliks Herdenking lys / Updating Birthday and Wedding Anniversary List:

Opdatering van Verjaarsdag- en Huweliks Herdenking lys:  Die ZS Link Netwerk Groep is besig om die verjaarsdag en huweliks herdenkings lys op te dateer.  As jy nuut is op die WhatsApp groep of die ZS Link Netwerk Groep word jy versoek om asb jou verjaardag en huweliks besonderhede te verskaf op die WhatsApp Groep  vir inligting Danie ZS1DJ.  Die lyste sal dienooreenkomstig bygewerk word.  Kan ons asb die besonderhede ontvang voor die 15 November 2025, asseblief.


Updating Birthday and Wedding Anniversary List: The ZS Link Network Group is busy updating the birthday and wedding anniversary list. If you are new to the WhatsApp group or the ZS Link Network Group, you are requested to please provide your birthday and wedding details on the WhatsApp Group for information Danie ZS1DJ. The lists will be updated accordingly. Can we please receive the details before November 15, 2025, please.

Let's build a 100 and 20 watt Dummy Load!

Above Image: Large RF dummy load for shortwave transmitter at the Moosbrunn transmitting station of the Austrian Broadcasting Service, Moosbrunn, Austria. It uses a sodium hydroxide solution to absorb the radio energy, which is circulated through the radiator (center) to cool it. It has a capacity of 100 kW.  - Source:  Wikipedia

At some stage of your amateur radio "career" you will need a Dummy Load.  Now what is a dummy load and what is it used for?

A dummy load is a device used to simulate an electrical load, usually for testing purposes. In radio a dummy antenna is connected to the output of a radio transmitter and electrically simulates an antenna, to allow the transmitter to be adjusted and tested without radiating radio waves. A dummy load is connected to the output of an audio power amplifier to electrically simulate a loudspeaker, allowing the amplifier to be tested without producing sound. Load banks are connected to electrical power supplies to simulate the supply's intended electrical load for testing purposes. 

Above Image: Small RF dummy load with capacity of 1 kW at frequencies up to 450 MHz. It consists of a 50Ω resistor immersed in oil to absorb the heat.  Source:  Wikipedia

In radio this device is also known as a dummy antenna or a radio frequency termination. It is a device, usually a resistor or many resistors, used in place of an antenna to aid in testing a radio transmitter. It is substituted for the antenna while one adjusts the transmitter, so that no radio waves are radiated so that the transmitter does not interfere with other radio transmitters during the adjustments. (As no dummy load is ideal, however, some radiation does occur). If a transmitter is tested without a load attached to its output terminals such as an antenna or a dummy load, the power will be reflected back into the transmitter, often overheating and damaging it. Also, if a transmitter is adjusted without a load, it will operate differently as compared with a load, and the adjustments may be incorrect.

The dummy load ordinarily should be a pure resistance; the amount of resistance should be the same as the impedance of the antenna or transmission line that is used with the transmitter (usually 50 Ω or 75 Ω). The radio energy that is absorbed by the dummy load is converted to heat. A dummy load must be chosen or designed to tolerate the amount of power that can be delivered by the transmitter. 

The ideal dummy load provides a standing wave ratio (SWR) of 1:1 at the given impedance.

Veterinarian-grade mineral oil, an inexpensive form of mineral oil, is frequently used by amateur radio operators as coolant in RF dummy loads. 

Above Image:  ZS1I external 100 watt Dummy Load.  Built many moons ago and never bothered to put it in a container of project box.  Still working as it should though!

Now that we know what a dummy load is it is time to put one together.  The dummy load we are going to construct can tolerate 100 watts of RF Power for one minute.  More than enough time to test a transmitter etc. The load uses carbon non-conductive resistors  mounted between two PCB's.

The dummy load we going to construct can be used internal or externally. Here I am talking about a project cabinet.  Your choice.  Mine has been used externally with no cabinet. The dummy load can be made up of  54 x 2k7 2 watt or 48 x 2400 Ohm carbon non-inductive resistors that are sandwiched together, with air spacing of 5 mm, between two identically drilled circuit boards.  The resistor ends are mounted flush with the non-clad side of each circuit board.  Then the leads are soldered to the foil side and cut.  Keep wiring including coax cable as short as possible.  This keeps the ground connection short, which eliminates stray reactances at the higher R.F. frequencies. The finished dummy load, shown in Fig. 1 is capable of dissipating at least 100 watts. 

I also constructed a 20 watt dummy load using 11 x 560 Ohm 2 watt carbon non-inductive resistors.  See images.

Calculation Results:

100 Watt Dummy Load

54 x 2K7 Resistors in Parallel = 50 Ohm

48 x 2K4 Resistors in Parallel = 50 Ohm

20 Watt Dummy Load

11 x 560 Ohm Resistors in Parallel = 50.91 Ohm 

Congratulations to all the candidates who passed the October 2025 RAE Examination!!

 As per the above title the Southern Cape Link Network Group would like to congratulate all the RAE candidates on passing the RAE. They wrote the examination last Saturday (18 October 2025).  A special word of welcome to every new radio amateur and we trust that every single one that passed will be and active radio amateur for the rest of his lifetime on this planet.  We as "older" radio amateurs would like to take this opportunity to share our knowledge that we gathered throughout the years. Let's be realistic there will by experienced radio amateurs that might not share their knowledge but they are definitely far and in between. There are also a few "soar plums" around.  Please ignore them and find a friendly helpful radio amateur.  The only thing that you must do is to ask questions on the airwaves, and NOT social media as we would like others to also learn from you questions.  After all we talk about amateur radio here and NOT social media!  If you do not ask questions you will not gain the knowledge of experienced radio amateurs. Yes, there is Google, YouTube etc. but they do not always explain the "nitty gritty" and definitely not the way experience radio amateurs will personally assist you with any problems you might experience in your amateur radio career.  The worst thing you can do is to "disappear" after you wrote the RAE.  Please get into the swing of things as soon as possible!! 

The following candidates passed the RAE in the Southern Cape Area:

1.  Ingrid ZS1ILL

2.  Juah ZS1JUA

3.  Divan ZS1DZA

4.  Vladimir ZS1VR

Finally:  Many thanks to all those who are/were involved in the RAE, PR and the recruiting process.

                                                           ************************

Soos uiteengesit in die bogenoemde titel wil die Suid-Kaap ZS Link Netwerk Groep al die RAE-kandidate gelukwens met die slaag van die RAE. Hulle het die eksamen verlede Saterdag (18 Oktober 2025) afgelê. 'n Spesiale woord van welkom aan elke nuwe radio amateur en ons vertrou dat elkeen wat geslaag het, vir die res van sy leeftyd 'n aktiewe radio amateur op hierdie planeet sal wees. Ons as "ouer" radio amateurs wil graag van hierdie geleentheid gebruik maak om ons kennis wat ons deur die jare versamel het, te deel. Kom ons wees realisties, daar sal ervare radio amateurs wees wat dalk nie hul kennis deel nie, maar hulle is beslis in die minderheid. Daar is ook 'n paar "suur pruime" in die rondte. Ignoreer hulle asseblief en vind 'n vriendelike en behulpsame radio amateur. Die enigste ding wat jy moet doen, is om vrae op die luggolwe te vra, en NIE sosiale media nie, aangesien ons wil hê dat ander ook uit jou vrae moet leer. Ons praat immers hier oor amateur radio en NIE sosiale media nie! As jy nie vrae vra nie, sal jy nie die kennis van ervare radio amateurs opdoen nie. Ja, daar is Google, YouTube ens., maar hulle verduidelik nie altyd die "nitty gritty" nie en beslis nie die manier waarop ervare radio amateurs jou persoonlik sal help met enige probleme wat jy in jou amateur radio loopbaan mag ondervind nie. Die ergste ding wat jy kan doen, is om te "verdwyn" nadat jy die RAE geskryf het. Kom asseblief so gou as moontlik aan die gang!!

Die volgende kandidate het die RAE in die Suid-Kaap gebied geslaag:

1. Ingrid ZS1ILL

2. Juah ZS1JUA

3. Divan ZS1DZA

4. Vladimir ZS1VR

Ten slotte: Baie dankie aan almal wat betrokke is/was by die RAE, PR en die werwings proses.

The 5 Band Inverted L-Antenna of Len Paget GM0ONX (Part 1)

Click on image for larger view.

Very few of us these days have gardens that will allow the “traditional” 40m long dipole (for the 80 Meter band) to be erected.  Fewer still have space for the double sized dipole for “Top Band”.  So, essentially, this means for many of us that 80 Meters is totally out of the question.  Or such a full sized antenna has to be bent into various contortions to get it to fit into the available space.

The antenna I am describing here was intended to allow operation on both 80 Meters and 40 Meters in less than half the space of the traditional dipole.  However, it will, in most instances, give a performance equal to, or greater than its full size cousin.  The antenna will also give a good account of itself on 14, 21 and 28 Mhz being electrically similar to the W3DZZ dipole.  

The antenna system will almost certainly require some impedance matching to suit rigs with solid state power amplifiers – again, this is just like the W3DZZ antenna.  Antenna purists will often tell you that  an antenna of this type requires radials, or a sophisticated earth system for optimum performance.  But in practice the antenna works very well with a modest earth system, although this is dependent on soil conditions.

The prototype antenna was constructed from heavy copper earth wire.  There is a single 7 Mhz resonant trap to make it more efficient on that band. The general layout of the antenna and the theoretical lengths of the antenna are shown in Fig. 1.  The antenna is fed with 50 ohm coaxial cable, with the coaxial screen connected to the earth rod.  This connection is secured using an earth clamp intended for earthing water pipes.  The center core of the coaxial cable is connected to the antenna via a single 15A “chocolate block” connector. Cover all connections with a waterproof tape.   No balun or other matching network is needed for 80 Meters and 40 Meters as the antenna’s feed point impedance is close to 50 Ohm.  The 7 Mhz trap is constructed from 11 turns of RG58 coaxial cable wound on a 100 mm piece of 40mm PVC pipe as shown in Fig. 2.  In this type of trap the coaxial cable acts as both capacitor and inductor and is capable of working at power levels in excess of 400 watts.

It is imperative that screen and center cores of the coaxial cable are parted as close to the point the cable passes through the hole in the pipe as possible.  This is to ensure the correct value of capacitance and inductance.  The center core of one end of the coaxial cable is soldered to the screen at the other end.
As with the feed-point, the ends of the coaxial trap and other joints must be weather proofed. The capillary effects of coaxial cable are legendary and water ingress will total ruin your trap.  The height at which the antenna folds over from vertical to horizontal is not critical but generally the higher it is the better.  Extra height, not only aids the DX performance of the antenna but also significantly reduces the amount of horizontal space required.  Tuning the antenna is quite simple but it is imperative that it is done in the correct order.  

Firstly cut both sections of the antenna about a half a metre longer than the dimensions shown in Fig. 1.  To start the tuning operation, begin on 7 Mhz and trim the wire length at the end nearest the earth connection 50 mm at a time until he lowest s.w.r. is achieved.  I managed an indicated s.w.r. of less than 1.2 : 1 over the whole of 40 Meter.  Then move to 80 meters and repeat the process, but this time trimming the side of the antenna furthest away from the earth i.e the side nearest the shack in Fig. 1.  The S.W.R. on the 3.5 Mhz band should be less than 2:1 over the whole of the band falling to about 1.2 to 1 at the point of resonance.  So it is worth setting the lowest S.W.R. at the section of the band you normally use, if you have a preference.

ED: I have had a lot of fun using the antenna and thoroughly recommend it to anybody not having enough garden room to erect a full size dipole in the optimum direction. 

Images:  (Click on images for larger view.)

What to do when your antenna rotator needs a new "starting" capacitor?

 

Image:  Antenna Rotator Control Unit.. Click on image for larger view.

I overheard a conversation recently between two radio amateurs in the Western Cape trying to scrounge a 130 mf 50-volt capacitor for a dead rotator.  The rotator suddenly died after several decades of faithful service.  The control unit of his Ham IV Rotator ceased to function.  A postmortem examination revealed a dead alternating current motor starting capacitor.

These capacitors are hard to come by in South Africa and if you can find one, it will be very expensive.  Ask me how I know that.  To solve the problem, two 150 mf, 50 volt electrolytic capacitors and two 100-volt, 3 ampere silicon rectifier diodes were used in the circuit shown.  The control unit was resuscitated.

Image:  Capacitor circled in red in the Control Unit  (Click on image for large view.)

For those interested in the theory of the functioning of the circuit, the explanation is simple. During any half cycle one capacitor is shorted by its associated diode. It might be presumed that having two capacitors in series, the resultant capacitance would be halved. This, however, is not the case because the diode acts as a bypass for the capacitor during every half cycle.

It is NOT a motor starting capacitor!!!

The purpose of the cap is to cause a 90-degree phase shift across the windings of the motor, which determines which direction the motor will turn. Some old capacitors dry out and the value changes.  This does result in the motor not starting to turn.  Replacing the cap (if you can find the correct value) will make the motor work again.

Note:  A larger value cap will allow more current to flow, but will also effect the phase angle, which will actually decrease the starting torque.  An infinitely big cap would be a short!  So don’t damage your motor!  A non-polarized cap if obtainable would also do the trick. If it is impossible to find the correct cap, well then back to our schematic.

Image:  Schematic Diagram of the Diodes and Capacitors (Click on image to enlarge.(

Use two back-to-back electrolytics as indicated in the above schematic.  Connect the negative sides of the electrolytics together, and connect the diodes so that the “bar” is at the positive end of each cap.  You want no current to flow through the diode when the voltage at the positive end of the cap is positive.

Another idea is to move the cap/s directly to the rotator, properly weatherproofed of course.  This eliminates the cable resistance in series with the cap.  Now use the two wires in the cable which went to the cap, and double up on the motor wires, cutting the resistance down there to.

Image:  ZS1I successful test setup. Click on image for larger view.

Hopefully this article will resuscitate those dead rotator control units.

-  Compiled many years ago by ZS1I for QSX, the monthly newsletter of PEARS. 

- Source 73 Amateur Radio

Southern Cape Repeater History - Period 1966 tot 2025 (Part 2)

History of the first 145.600 Mhz Danabay Repeater in Mossel Bay.

First some background relating to repeaters in the Garden Route Area. Circa 1980's there was only one repeater in the area and that was the 145.700 Mhz George Mountain Repeater.  This repeater was a free standing repeater and the only repeater in the Garden Route Area.  The repeater belonged to Eskom but through their kindness radio amateurs could use the repeater.  The repeater worked great but the coverage area excluded large parts of the Mossel Bay district. 

There was definitely a  need for another repeater in the Garden Route Area.  OM Stan Jones ZS1T took it upon himself to obtain and install the first ever 145.600 Mhz repeater in Mossel Bay.  Stan a then member of the Boland Amateur Radio Banch resided in George and was for many years the Head of the Radio Technical Division of the South African Police Force in George.  In April 1996 he contacted Rassie ZS11YT of the then Boland Amateur Radio Branch and it was not long afterwards that he informed me that he picked up the then Groenberg Repeater on loan to him to install as the 145.600 Mhz repeater in Mossel Bay.  Stan re-tuned the old Storno CQM 600/662 Mobile Radiophone/Professional land mobile transceiver that was converted to a amateur radio repeater. 

 

 

It originally was a 9-12 Channel Radiophone. By the early 1970's this was state of the art equipment, very well manufactured. In this time period there were only three authorized suppliers of equipment, Storno, Pye and Marconi. The installation typically consisted of a control head, handset and loudspeaker fitted in the front of the vehicle, connected to a transceiver unit usually mounted in the boot connected to a whip antenna. Storno also produced a transportable battery operated version for pedestrian use.The CQM600 with it's stylish remote control head and 'cornet' microphone won a design award in Denmark when introduced. The rugged, waterproof mobile unit was adaptable to a wide variety of applications and included marine and duplex versions. 

Specifications of the Storno Radio courtesy RigPix:

Type:	Professional land mobile transceiver
Frequency range depending on version:	68-88 MHz 132-156 MHz 146-174 MHz 420-470 MHz
Mode:	FM
RF Power output:	6-25 W
Receiver system:	N/A
Sensitivity:	N/A
Selectivity:	N/A
Image rejection:	N/A
Voltage:	6, 12 or 24 VDC
Current drain:	RX: ? mA TX: Max ? A
Impedance:	50 ohms
Dimensions (W*H*D):	? mm
Weight:	? Kg
Manufactured:	1968-197x (Discontinued)
Other:	9 -12 channels, XTAL

The repeater was tested on the test bench by Stan ZS1T after adding a Low Loss Helical Band Pass Filter on the receive side and a Cavity Filter on the transmit side.  After a few weeks of testing the 145.600 Mhz repeater was ready to be installed on site. The only problem was that there was no site available at short notice to install the repeater on.   Yours truly offered to host the repeater for the interim up high in Heiderand, Mossel Bay at my QTH.  My QTH was situated quite high up on the ridge in Heiderand and would have to suffice until a permanent site could be found.  It was an ideal high interim site,  situated in a quiet area (free of interference then but not today), line of sight to George and in a safe area.

Myself and Stan arranged for the installation of the repeater on a Saturday morning at my QTH.  When Stan arrived I already installed the 5/8 vertical antenna for the receive side.  Stan brought a folded dipole which was installed underneath the 5/8 vertical antenna with enough space between the two to prevent de-sensing. The Band Pass filter was installed on the RX side and a cavity filter was installed on the TX side. The power supply was installed and the repeater was switched on. The necessary final checks and tuning were done.  It was not long before contact was made with Isak ZS2I (Now SK) in Klein Brak River which confirmed great signal strength and audio.  The output of the repeater was tuned down to 10 watt as we did not have a full set of cavity filters for RX and TX.  For the newer generation of radio amateurs this is how repeaters worked in years gone by as cavity filters were scarce as hen's teeth and very expensive if you can find one.

Now to find a suitable high site for the repeater.  Thanks must go to Chris ZS1M who at the time was working for the Mossel Bay Municipality.  He was able to obtain the current site on a water tower at the entrance to Danabay.  This site gave great coverage and it was decided to use the site for the 145.600 Mhz repeater.

The time arrived for the repeater to be moved from my QTH in Heiderand to the DanaBay water tower.  In the mean time Stan ZS1T again came to the rescue with a full set of cavity filters on loan from the Boland Amateur Radio Club.  This would solve the use of two antennas.  We now only have to install one antenna.  We still used the small band pass filter on RX as an extra filter.  The repeater was installed in December 1996 inside the water tower pump room with the folded dipole high up on the top of the tower.  Standing on top of this water tower revealed a clear 360 Deg take off with no obstacles in the way.  To secure the repeater, filters, power supply etc. the repeater was housed in a old computer main frame cabinet that I donated.  This cabinet was ideal as it came with great cooling fans to keep things cool. 

This repeater functioned great for several years and I had the privilege of maintaining this repeater on behalf of Stan ZS1T who could not always visit the site. As these Storno Radios are build like tanks, it was not necessary to re-tune them at regular intervals.  From time to time the cavity filters were re-tuned to ensure optimal functioning.

The repeater was enjoyed by many local and visiting radio amateurs from all over.   This was the first 145.600 repeater installed on the Danabay Water Tower in the Mossel Bay area.  A few years before the year 2000 the repeater and cavity filters was returned to the Boland Amateur Radio Club as Chris Scarr ZS2AAW and his late father Trevor ZS2AE installed a new 2m repeater, antennas and 70cm link on the Danabay Water Tower which was a great upgrade.  This upgrade amongst others allowed for the 600 and 700 repeater to be linked via DTMF.  This setup functioned  well for many years and was maintained by Chris ZS2AAW and Trevor ZS2AE (Now SK).

I would like to thank every single radio amateur that was involved in making the first 145.600 Mhz Repeater in Mossel Bay a reality and bringing it to life.  I do not like to mention names as indicated in many of my posts as I might leave somebody out in the cold but I must mention the following radio amateurs, clubs and organizations:

1.  Stanley Jones ZS1T, George

2.  Boland Amateur Radio Club (Members and Committee)

3.  The then repeater keeper of the  Boland Amateur Radio Club (???)

4.  Chris ZS1M, Danabay

5.  Mossel Bay Municipality

6.  All those who assisted and not mentioned in the article

7.  Garden Route Radio Club

8.  Rassie Erasmus ZS1YT, Strand

Finally:  I would like to plea to the younger and older generation radio amateurs.  Please if you have any information, images and articles on local (SA) amateur radio history make it available for publication and preservation.  You can forward the info to Johan ZS1I by clicking HERE.

Images:  (Click on images for larger view.)

           Coverage of the then 145.600 Mhz Danabay Repeater - Mike Hanslow then ZS1RMS

Satellite and Street Maps Courtesy -  Satellites Pro / Apple Map

- End