The Best Homebrew Power Supply Ever?

 This power supply was originally featured in Practical Wireless (PW) in June 1983.  This is the first ever electronic project that I built after becoming a Radio Amateur.  A month before I wrote the amateur radio examination at the Post Office Head Quarters in Pretoria I joined the then Verwoerdburg Stad Amateur Radio Club today the Centurion Amateur Radio Club.  

One Friday night at the club, power supplies were discussed and this is where I was introduced to the Marchwood Power Supply.  Not long thereafter a club member produced the PCB and the components were bought from the club's electronic parts shop.  I started to build the power supply unit at home and then taking it to the club on Friday evenings when I experienced building issues.  With the kind help of several members at the club I was shown where I made mistakes.  These were then rectified and I would carry on building the next week. 

 About a month later the power supply was completed and it was time for the smoke test.  Several radio amateurs gathered around the table  to see if  my power supply would go up in smoke.  I was told that if it does its not the end of the world and it could be fixed.  Thankfully with the first switch on there was no smoke and the supply worked flawlessly. 

 I build the supply as it provided various protections as described in 1983 PW article. The power supply was further described as a highly reliable unit as it has over voltage protection and over current protection and also Short circuit protection built in.  After 15 years of constant battering in my shack delivering power to HF Radios and  Linear Amplifiers consuming up to 30 Amps I eventually sold the power supply to a new radio amateur.  No I am not sorry as it went to a good shack. 

 Now after 28 years I think it is time to construct another Marchwood Power Supply to be used by the GRHub Network,  if I can find all the parts at a reasonable cost.  Another issue would be to find a suitable transformer.  I will lookout for the parts.  This will not be a quick homebrew project and will require patience and good planning to finish the project.  In the mean time here is a few images of my Marchwood Power Supply Mark I that I constructed.

HERE is a copy of the PW article for those that might be interested to build simply the best homebrew power supply for amateur radio and electronic experimenters. Please excuse the dust and muck in the cabinet but at the time of taking the images I did not want to "scratch" in the supply.  Like they say if it works do not scratch around unless you are looking for work when it goes bang!!

 

Where and how did I obtain the parts:

Cabinet - Jack Sinden ZS6QJ SK
Transformer 19 volts 40 Amps - Tim ZS6TIM
Heat Sinks - Pretoria Flea Market (Hal Lund premises)
Capacitor 45 000 uF 63 volts (ZS6CEN)
Components - Club Component Shop and other electronic shops
PCB - Herman ZS6HVV
Odds and Sods - Computer Scrap Shops

UPDATE: Thermo-Fan to keep your Raspberry PI, Radio, Power Supply and Amplifier Cool

(Click on image for larger view.)

Here is another take on the Thermo-Fan Controller using different component than those mentioned previously.

In many areas of South Africa temperatures soar to 40 degrees celsius during the summer

months. With Global Warming, we might all have the same problem in a few years from now.

New equipment is designed with built in thermo-fans and is fairly well protected against abnormal heat. Older equipment and home brew stuff may appreciate the acquisition of a thermal controller to cool things down. The project described is to ensure that your equipment is never allowed to exceed a preset temperature. It is extremely sensitive, and can easily be set so that a few degrees change is enough to activate the fan/fans.

The controller uses one or more ordinary silicon diodes as a sensor, and uses a cheap op-amp

as the amplifier. The circuit is designed to operate with 12 volt computer fans. These fans typically draw about 200 mA when running, so a small power transistor will be fine as the switch. A BD140 (1A, 6.5W) was used, but almost anything you have to hand will work just as well.

All diodes are 1N4004 or similar, and Q1 must be on a small heat-sink or may be mounted

to the chassis. Make sure it is properly insulated, and use thermal grease. Maximum dissipation will be about 2 watt, but Q1 will overheat very quickly if there is no heat-sink.

The temperature is set with VR1. Operate the piece of equipment to be fitted with the thermo-fan until the normal temperature is reached, then adjust VR1 until the fan starts.

Back off very slowly until the fan stops again. Any increase over the normal temperature will start the fan, and promptly bring the temperature back down again.

It will not matter if the voltage is a little higher than 12V, as the fan will work fine as long as voltage is kept below about 14V. If the voltage is higher than 14V, R5 and R6 will have to be changed.

To calculate the resistor values for R5 and R6 you will need to check the current that your fan draws. Connect the fan to a 12 V supply, and measure the current. Calculate the resistance of R6 with

R6 = (+ve - 12) / I Where +ve is your supply voltage, and I is the measured fan current.

Select the closest resistor value larger than calculated. You will also need to work out the power:

P6 = (+ve - 12)2 / R6

Now you can work out the value for R5 (1/2 will be OK) - here, use the next smaller value if an odd resistor value is calculated.

R5 = (+ve - 10) / 0.01 Where +ve is your supply voltage.

Having worked these out, you can adapt the circuit to any voltage, as long as it is less than

30V and 12V or more. Any other combination is quite acceptable, including the use of fans in series/parallel (current will be double thou) or anything else that you might want to do.

This circuit is very flexible and I am convinced that there are many other uses for this sensitive thermal controller in amateur radio.

BACAR launched from theTRMC Model Flying Airfield near Secunda

 The Secunda Amateur Radio Club Launched a Balloon Carrying Amateur Radio (known as the BACAR project) on Saturday 30 October at around 07h15 SAST. Several interesting payloads were active, including the new AMSAT-SA AfriCUBE linear transponder, Slow Scan TV, a crossband FM repeater, and an ion thruster scientific experiment. Amateurs from various Amateur Radio Clubs were involved in this project.   Herewith a few APRS images of the flight.

 I want to thank Gert ZS6GC and Cor ZS6CR for providing me with information and operating frequencies used during the BACAR flight.  Unfortunately I am situated right in the Southern part of South Africa and nothing was heard on any frequencies, but APRS-fi provided some data and images.

The GRHub Network is being automated to give the owner of the network more freedom and flexability.

 Automation is not always  a good thing but in this instance it saves time and gives the owner of the GRHub Network more freedom and flexibility.  Several tasks or functions can be automated and I will only discuss those that I already implemented iro the nodes that I am currently running.

Before I continue I would like to make it clear that the GRHub Network is NOT an unmanned device as stated in the post:  

Setting the record straight iro the GRHub Network! Rant??

Now lets continue.  The following functions are currently automated:

• Connection to three Echolink servers from AllStar Node 49355 and control of all Echolink Stations via this AllStar node
  
• Connection to a local Weather Station in Mossel Bay. AllStar Node 49355 obtain WX data and transmit weather conditions every hour to all nodes and the RF Link on 145.550 Mhz Simplex.
• Connection to a local Time Server.  AllStar Node 49355 obtain the local time and transmit the time every hour to all nodes and the RF Link on 145.550 Mhz Simplex.
• The SARL News Bulletins, Pretoria Amateur Radio Club News Bulletin and Amateur Radio Today are automatically relayed to  Echolink ZS1I-L,  Allstar Nodes 49355 + 46765  and RF Link on 145.550 Mhz Simplex every Sunday.
• The Bo Karoo Amateur Radio Klub Bulletin is automatically relayed to  Echolink ZS1I-L,  Allstar Nodes 49355 + 46765  and RF Link on 145.550 Mhz Simplex every Sunday afternoon.
• PEARS ("PE Mobile Net") daily relayed from 06h30 - 07h45 (except on Sunday) on Echolink ZS1I-L,  Allstar Nodes 49355 + 46765  and RF Link on 145.550 Mhz Simplex.
• Pretoria ("Legends") Morning Net. Transmission: Daily relayed from 07:45 - 09:00 except on Sunday on Echolink ZS1I-L,  Allstar Nodes 49355 + 46765  and RF Link on 145.550 Mhz Simplex.
• Auto play the weekly ARRL Audio News Bulletin every Tuesday at 20h00 on Echolink ZS1I-L,  Allstar Nodes 49355 + 46765  and RF Link on 145.550 Mhz Simplex.
• Auto play the weekly Amateur Radio Audio News Bulletin every Wednesday at 20h00 on Echolink ZS1I-L,  Allstar Nodes 49355 + 46765  and RF Link on 145.550 Mhz Simplex.

Please take note of the following:

The GRHub Network will connect automatically to some of the above nodes 15 minutes before the start of the Net or Bulletin.  This does not mean that there is no supervision of the GRHub Network. I get an audio alert every time the network connects to another node or network. In the event that something goes wrong or there is other activity on the guest nodes, I will disconnect the GRHub Network immediately.  I monitor all activity on the GRHub Network at all times.  There might also be times that the mode of operation is in Receive/Monitor Mode Only. 

I will continue to automate the GRHub Network in future if I think it could enhance the capabilities of the network and only if it is to the benefit of listeners and users.

Finally:  I want to thank all the repeater, link, network owners/keepers/administrators/clubs etc. for allowing me to use their facilities and installations.  Highly appreciated.  I again say it is not about me, my image or pride, I do it for amateur radio and as a service to my fellow radio amateurs.  Enjoy!!

Update: The impact of Load-Shedding by Eskom now also "breaks" the GRHub Network

 Just a short update in Afrikaans:   Ek het gou 'n paar toetse gedoen en is die 7 aH battery is tot niet.  n Vinnige soektog op die Internet vir 'n goedkoop vervanging maar ek het die battery soos in gister nodig.  Besoek 'n paar elektroniese plekke vroeg vanoggend en ons kyk na R400 + .  Val my toe by dat ek by die Chinese Winkels gaan kyk.  Nou ja almal praat van kwaliteit?  Die batterye waarna ek by die elektroniese plekke gaan kyk het word almal in China gemaak.  Een van die Chinese winkels het 'n groot verskeidenheid.  R200 later en ek het dieselfde battery wat een van die elektronies winkels vir R424 verkoop.  Nou ja hoekom so groot prys verskil, maar 'n man mag seker maar vra wat jy wil.  Of die battery gaan hou sal tyd wel leer.  Nie alles is goedkoop by die Chinese winkels nie maar moet nie vergeet om daar te gaan kyk nie.  Ek gaan die datum op die battery skryf en kyk hoe lank hy gaan hou.

Fotos: Nuwe battery se spanning en die prys van R200 op die pienk plakker.

The impact of Load-Shedding by Eskom now also "breaks" the GRHub Network

  Need I elaborate on the impact of load-shedding on you the consumer.  I do not think it is necessary as we already know what  the cause is and why it is happening. 

For those who would like to find out more on how load shedding can effect electronic equipment, read the following article:

THE IMPACT OF LOAD SHEDDING ON ELECTRICAL EQUIPMENT

The current power backup system run by the GRHub Network now also suffers as a result of phase 4 load shedding. The protection circuitry that I use for the battery power supply shut down the complete GRHub Network this afternoon as the system could not re-charge the battery fully before the next period of load - shedding started.  It would appear that the current battery is either on its way out or the charging unit is at fault.  I will look into this tomorrow morning to see why the protection circuitry was activated.  Sounds like an Eskom statement. Hi hi!!

Another problem that I experience is to connect to certain nodes when there is load - shedding or Internet - shedding.  Ya a new term.  My Fiber Internet outages is even worse than the old copper cable ADSL that I had.  The best system I ever  used was Wireless Internet.  I am ever so sorry that I moved to fiber but this will teach me a lesson not to listen to the advice of others.  Be as it may I do not use my Fiber Internet for the GRHub Network.  I use a 4G LTE connection which so far ("touch wood") works great without any outages.  Rather expensive but VOIP use very little data.

Another problem is the fact that overseas connections will drop at any time when load shedding is implemented.  So to our listeners please understand that outages is beyond my control.  I will do my utmost best to render a good service but as you know by now the GRHub Network is not a one man show and I rely on my fellow radio amateurs, clubs and others to keep the system running.

I hear many shout "We told you if the Internet goes down you will be left in the cold!"  Agree BUT there is always an alternative.  I am currently looking into linking the GRHub Network to AREDN and even more RF equipment and amateur radio systems like WinLink, Digital Modes etc.  This will ensure that when Internet or Power Outages occur, that the GRHub Network will still be in operation.  Yes you will not be able to use Echolink but AllStar will still be working and will keep the GRHub Network up and running with even more features.  Now this is what I enjoy about amateur radio.  There is always an alternative means of communication be it VOIP, RF, HF VHF or UHF.

Experimenting is what it is all about.  I will in the next few days feverishly work on several systems and ideas and hopefully can come up with several solutions for the current glitches being experienced due to load-shedding and Internet Shedding/Outages.

Finally:  I apologize for outages and break in transmissions at times.  I am sure that it is not going to take too long to come up with alternatives. I am looking forward to implement new features and to the challenges ahead.

The beauty of nature in and around Mossel Bay (Part 1)

 Not amateur radio related but the images below reflect the beauty of nature in and around Mossel Bay.  I am sure that you will agree that we live in the most beautiful part of the country.  With all the daily challenges it is great to experience such beauty to "re-charge" the tired mind.  (Click on images for larger view)

 

 

I needed either a UPS or Backup 220v Power Unit for my desktop computer in the Shack ASAP!!

Warning:  Never try to connect any power back-up system to your home electricity distribution box or for that matter to any plug adapter.  You can start a fire and will void your insurance.  I am in the lucky position to have a fully qualified electrician in the house that can perform such tasks and issue the necessary certification certificates that is needed.  Remember electricity is dangerous and can kill you and others!!

The title of this post say it all.  I looked at the price of UPS units but the prices just keeps on going up and up.  Next best solution is to roll my own backup power unit.  Here I had several options.  After some scrounging in my junk boxes I came up with the items shown in the images.  When load-shedding started way back then I bought a small inverter and a few odds and ends but only used the inverter maybe a few times as a stand alone mobile/portable unit, after which it went to the junk box for storage. (plastic ammo case) 

 The cabinet was built maybe 5 years ago for mobile contest work and is fitted with wheels to move it around.  The battery is where the cost comes in, but if you need it you buy it.  I bought this one a few years back and it is still holds a charge well. Never seems to drop down to damaging voltage.  The inverter is a Meanwell 300 Watt Modified Sine Wave unit.  The computer does not complain.  I would have liked it the be a Pure Sine Wave but you cannot always have every thing your way .

After starting the GRHub Network and the latest spate of power outages I was looking to build an ugly style unit as I needed it ASAP due to the implementation of regular load-shedding.

I started getting together every item that I would need and started work on the project this morning.  I plan to add 12v outlets tomorrow in the event that I needed them.

Here is a few photos of today's work.  The unit is not completed but is operational and providing 220v AC for my desktop computer in the Shack.  I will update and add images as the project progress.  The intention is to coat the cabinet with stone chip spray coating and to add a few enhancements at a later stage when the current load-shedding is hopefully suspended.

I do however predict that we are in for a rough time as far as power generation and supply is concerned in South Africa. No, at my age I am not looking at installing a big solar power system at my house.  There is really no need for this as one can find alternative solutions to easily curb any power outages. 

I am also working on my own solar power unit which I will be able to move around to where ever I need 12v, 24v, and 220 v power.  I call the unit:  "ZS1I Smart Power Trolley". More on this in a future post.

 

This R50.00 Scrap Metal UPS keeps the lights on!

Warning:  Never try to connect any power back-up system to your home electricity distribution box or for that matter to any plug adapter.  You can start a fire and will void your insurance.  I am in the lucky position to have a fully qualified electrician in the house that can perform such tasks and issue the necessary certification certificates that is needed.  Remember electricity is dangerous and can kill you and others!!

Here is my R50 UPS (battery not included in the R50 deal)  that keeps all my lights burning inside and outside my home during load-shedding.  The UPS was scrounged from a scrap metal dealer.  I removed the dead 7aH batteries and connected the shown battery and the unit started up without any problem.  Been running now for the past 3 years without any issues.  As for the plugs and other electrical equipment I use a back-up diesel generator if necessary.  However seeing that the warm water geyser and the stove runs off gas, we never  use the generator.  Just there for a backup should we experience a total blackout.  Not a bad buy for R50 from nogals a scrap metal dealer.

New page called "Down Memory Lane" added to the GRHub Network Blog

 Going through a few of my CD's that I created through the years I discovered some valuable information and photos that could be of benefit to my fellow radio amateurs.   All to often I have seen that when a radio amateur becomes SK his collection of amateur radio photos, QSL Cards  etc. goes to the rubbish heap as there is no interest in the "junk" he or she "collected" as a radio amateur.

I have also discovered that we say that we will remember them, but after a few years we seldom speak about those who went SK. 

I decided to create this page to post information and photos of my collection of amateur memorabilia that I collected through the years.  Now this is not a museum or exhibition  of some sorts as many photos reflect radio amateurs still alive and kicking.  All this is about remembering the "good old days" or maybe "not so old days".  Surely the camaraderie and friendship can never be taken away and we will remember them. 

The above picture was taken in 1998 at a meeting of the then Garden Route Radio Club ZS1GRC.  It was one of  the biggest, if not the biggest amateur radio club gathering in the Garden Route area.  A headcount of 24 of which 8 has since become SK.

The new page will be available HERE.

If you have any photos or information that you would like to add please send it to me.  Hopefully we can preserve amateur radio history and prevent so called "junk" from going to the rubbish bin.

Send info and images to Johan ZS1I by clicking HERE.

What happens to the GRHub Network in the event of a Power- or Internet outage?

Internet outages the past 24 hours in the Mossel Bay area.  Telkom, MTN and Vodacom  experienced several outages in the past 24 hours.  The latest early this morning.

 In short:  Power Outage - No big deal.  The GRHub Network including the RF Links just switch over from mains power to battery power.  Internet Outage -  The only real drawback is that all connections to "outside" nodes are dropped leaving the network operational only in the Southern Cape area.  Current Internet outage is not a train smash and I am working on bringing AREDN and WINLINK back on line should all else fails.  The importance of Repeaters, RF Simplex Links, Cross Band Repeating etc. cannot be underestimated.  The GRHub will in future be linked to more RF links.  The current 145.550 Mhz link works well.   I also have a UHF link radio on 433.400 Mhz coupled to the 49355 node but currently not switched on.  I need to buy another Diamond X50 Antenna for the UHF band.  I hope to have the UHF RF link operational before the December holiday season.

Like they say Rome was not build in one day.  Those who have experience in building RF and AllStar networks will know this all to well.

Finally:  I like a challenge and with Power- and Internet Outages comes new challenges and problems that need to be solved.  Each new installation/alteration brings satisfaction and fulfillment.  No problem is to big to overcome in life. Giving up is NEVER and option or the easy way out!

The GRHub Network activity log for Sunday 24 October 2021 up to 15h30 SAST

 Great to see that activity is on the increase on the GRHub Network especially for the Bo Karoo Amateur Radio Club iro their Sunday afternoon news bulletin at 15h00.  Welcome to all the new call signs.  The GRHub Network is also looking forward to welcome many of the new radio amateurs that wrote the exam on Saturday.   Please feel feel free to use the GRHub Network.  I am currently in the planning phase for new activity on the network.  Watch this space!!

Buy your Raspberry Pi 4 2GB now if it is not already too late!

In response to supply chain issues, particularly around semiconductors, Raspberry Pi is increasing the price of the version of the Raspberry Pi 4 sold with 2GB of RAM. The increase, which CEO Eben Upton says is the company’s first ever, will see the Pi 4 2GB’s price rise by $10 from $35 to $45. To serve the needs of customers on tighter budgets, the company is reintroducing the 1GB Pi 4 for $35, which was discontinued last year.

“These changes in pricing are not here to stay,” Upton writes. “As global supply chain issues moderate, we’ll keep revisiting this issue, and we want to get pricing back to where it was as fast as we can.” Upton said supply chain challenges are likely to continue through next year, echoing the predictions of larger companies like TSMC, Nvidia, and Foxconn, but added that the company sees “early signs that the supply chain situation is starting to ease.”

It’s a significant price increase of over 25 percent for the 2GB Pi 4, a computer prized for its affordability, that could have a big impact on the industrial customers that use Raspberry Pis. Upton says that although the world appears to be slowly emerging from the pandemic, semiconductors continue to be in high demand thanks to companies panic buying components to ensure they have enough to meet their own demands.

The changes effectively revert the price drop Raspberry Pi introduced in February last year in response to falling RAM prices. It came just weeks before the COVID-19 pandemic began to upend demand for, and the supply of, consumer technology. Since then everyone from games console and graphics card manufacturers to automakers has had to grapple with shortages of key components, limiting their ability to produce enough products to meet demand.

Raspberry Pi adds that it’s deprioritizing production of the the Raspberry Pi 3B Plus, and is advising customers who rely on this model to migrate to the 1GB Pi 4 if they want to ensure uninterrupted availability. 

Source: theverge.com

ED. We in South Africa should know by now that this price increase would be substantiate due to the Rand/Dollar/Pound equation. Furthermore everything in South Africa goes up and never comes down. Will this also be the case with the Raspberry Pi?

 

New Telegram Group: Amateur Radio 101

 I created a new Telegram Group named "Amateur Radio 101".  Why and what is it all about?

 “This group is everything Amateur Radio. News, notifications, severe weather, projects, memories, hints and kinks etc. etc. Share anything amateur radio on this group. Stay in touch and in tune and most of all enjoy this wonderful hobby!”

Waarom die Groep?  Hoekom nie? Nie alweer 'n nuwe groep nie en dan hardloop jy weg na 'n paar maande.  Wel julle het seker die reg om dit so te stel maar ek het my redes hoekom ek WhatsApp totaal en al verlaat het.  Kyk maar na die nuutste gebeure rondom Mnr "Sukkelberg" en WhatsApp en dan sal julle sien hoekom ek WhatsApp waarwel toegroep het. 

Language? Op die groep skryf en praat ons Afrikaans en Engels.  Jy kies jou taalgebruik.  You choose your language preference.

Who can join?  Enige iemand selfs nie-radio amateurs is welkom on by die groep aan te sluit. 

Invite/Uitnodiging?  We need your knowledge and expertise in this Group.  Nooi jou amateur radio vriende uit om aan te sluit.  Kom deel jou kosbare kennis met ons.

How do I join? / Hoe sluit ek aan?  Just send me an email (click HERE)  or Telegram message (Johan Terblanche ZS1I) and I will forward the invitation link to you. 

Kom ons maak die groep nog beter as die vorige WhatsApp groep.  Onthou julle maak of breek die groep.  I am looking forward to talk to you on Telegram.

This is not a one man show!!

Important:  The invite link expire after 24 hours and you will have to ask for a new link.
Belangrik:  Die uitnodiging skakel verval na 24 uur en dan moet jy vra vir ‘n nuwe skakel.

QSX (PEARS) Power Supply now powers the GRHub Network 145.550Mhz RF Link Radio.

Recognition :  Al Akers ZS2U,  Andre Botes ZS2ACP and Bryan Haefele ZS2BH (SK)

An article by Al Akers ZS2U describing a power supply appeared in the June 1993 issue of Radio ZS.  The circuit, to which a fourth 2N3055 has been added to enhance the current handling capability.

In addition to this ZS2CP has produced a circuit board which incorporates an over voltage protection circuit adapted from n article by the late Brian Haefele ZS2BH in QSX Newsletter of April 2000.

The original article, schematic diagram, PCB outlay and component outlay can be downloaded by clicking HERE.

I constructed this power supply in early 2001 and it has run flawlessly for the past 20 years.  This power supply is now connected to the GRHub 145.550 Mhz RF Link Radio and also powers 2 x Fan Controllers discussed on this Blog.

I opened the power supply this past Friday to clean the inside and to fit a auto fan controller to run the fan. (Not shown in the images.)  I have tested the fan controller installed to the power supply.  It works great and even reduced some of the fan noise considerably.  

With both the radio and power supply now fitted with a automatic fan controller, it is really an "assurance of mind" that I do not have to manually switch fans on and off.  As the temperature rise it switches on automatically and once the temperature falls below a set level it switches off automatically.  Fingers crossed that the fan controllers do not fail which could destroy the radio or the power supply if they overheat. I however do have a plan in mind to inform me should they fail.

Here is a few diagram images of the power supply.  Images of the fan controller is also available on this Blog. Just click on Fan Controller in the Labels column.

 Click on images for larger view.

 

 

Repeater born out of a dream by two radio amateurs - The then Aliwal North Repeater on Kramberg.

Image Tower with 4 stacked J-Pole Antennas

(Note:  This article is written in Afrikaans and English.  Please use Google Translate if you do not understand Afrikaans or English.)

This repeater was born out of a dream by two radio amateurs who had a conversation on the 40 meter band one morning and teamwork by many others to fulfill the dream. Nico ZS2N and Johan ZS1I discussed the need for a repeater in the North Eastern Cape area when the Late Colin Robinson ZS2CR joined their discussion and indicated that this idea must be taken further and that he would lend a helping hand to Nico in getting the necessary equipment to bring a repeater to life in that area.

This “idol” chat set the ball rolling and with in a week or two Colin came back on air to inform Nico and Johan that he managed to get a fairly old but solid repeater from one of his friends in East London. The excitement and enthusiasm was noticeably hearable in the voice tones of these three radio amateurs. In the meantime Nico secured a near perfect site on Kramberg a mountain in the Aliwal North district about 20 km from town.

Nico and Colin started the painstaking process to gather all the necessary bits and pieces needed at the site. The repeater was transported from East London to Aliwal North by Colin. A 9m tower and 4 x 2m folded dipoles were “homebrewed” by Nico as time permitted. Parts and odds and ends started rolling in when other radio amateurs heard of the project.

There was no turning back now. The repeater was now taking priority over many other chores and family matters and Nico worked hours at end to fulfill this “dream”. Within a couple of weeks the antenna’s were ready and a test with the MFJ Antenna Analizer revealed that the four dipoles resonates and is ready for the work of receiving and repeating. Nico tested the repeater at home one evening and found that their was something wrong with the power supply unit.

This is were real amateur radio spirit came to light. Hennie ZS2HG from Bloemfontein Amateur Radio Klub got involved and the repeater was transported to Bloemfontein for a good old re-alignment and thorough checking. Hennie fixed and aligned what had to be fixed and be aligned. The only problem now was to find a decent couple of cavity filters for the repeater.

Die filters is deur die Bloemfontein Amateur Radio Klub goedgunstiglik aan Nico geleen. Hennie ZS4HG was verantwoordelik vir die nodige verstellings aan die herhaler sowel as die filters. Intussen het Nico die toring en staal kas gemaak vir die veilige bewaring van die toerusting. Stadig maar seker is al die toerusting gereed gemaak totdat die groot dag uiteindelik aangebreek het. Nico en twee helpers is een Saterdag middag na Kramberg waar die toring opgerig is en die herhaler geinstalleer is.

Die tyd het hulle egter gou ingehaal, maar wou hulle nie weer die volgende dag terugkeer nie. So in die skemer, donker het hulle die finale afrondingswerk gedoen en is die herhaler aangeskakel. Die adrenalien het hoog geloop en is die nodige toetse gedoen in samewerking met Johan ZS2Z vanaf INDWE wat ongeveer 100km soos die kraai vlieg geleë is vanaf die Kramberg. Johan kon die herhaler met gemak sneller en het die manne die aand behoorlik die herhaler se gal gewerk. Self stasies sover as Bloemfontein het gedeel in die opgewondenheid. Verskeie kontakte is die aand bewerkstellig.

‘n Droom deur drie radio amateurs het waar geword, danksy wyle Colin ZS2CR wat die aanvoerwerk gedoen het vir die daarstelling van ‘n herhaler in die Aliwal Noord gebied. Natuurlik was die installering van die herhaler ‘n ware span-projek deur talle radio amateurs en is ek dus bang om elkeen by die naam te noem, maar gaan ek tog ‘n uitsondering maak om die volgende persone wat ‘n waardevolle bydae gelewer het tot die projek , te bedank. Die Robinson familie, Chris ZS2S,

Jim ZS2JM, Border Radio Club, Bloemfontein Amateur Radio Club, Hennie ZS4HG, Dennis ZS4BS, Port Elizabeth Amateur Radio Society, Chris ZS2AAW, Trevor ZS2AE, Nico ZS4N, Kenny Moolman (privaat indiwidu) Johan ZS2Z , Rodger ZS1J, DRIES ZS4AJ en laaste maar nie die minste nie almal wat bygedra het om die herhaler ‘n werklikheid te maak.

 

 Repeater Technical Details:

 

Call Sign: ZU9LKE

Frequency.: 145.750 Mhz RX and 145.150 TX

Repeater Make: Motorola Micor

Power Output: 15 WATT

Mountain Site: Kramberg, Aliwal North

H.A.S.L.: 1958 Meters

Distance from Aliwal North: 15Km

Tower Height: 12 Meter

CO-AX Cable: RG213

Connectors: N-TYPE

Antenna: 4 X Homebrewed Folded Dipoles

Cavity Filters: 2 X RX AND 2X TX. 

Repeater Coverage: Radius of 100—120 Km.

 

Foto:  Die herhaler, holteresoneerders and ander toerusting.

Foto:  Tuisgeboude gevoude Di-Pool Antennas

Image:   Repeater, Timer, Speaker and UHF Radio Link installed in the cabinet.

 Image:  View from Kramberg, Aliwal North towards Bloemfonein.

Setting the record straight iro the GRHub Network! Rant??

 

Time to set the record straight; further automation; information iro the GRHub Network; get your facts and information correct! 

I received an email from a local radio amateur that wanted to know how do I connect and disconnect nodes and stations to the GRHub Network.  He indicate that he observed that while listening on the RF Link and Echolink that an announcement was made that a node connects or disconnects at certain time intervals.  He also wanted to know whether  I sit in front of the computer throughout the day monitoring and connect or disconnect nodes.  He further stated that I must not see the questions as "pfishing" about the system.  He fully support me in operating the GRHub Network as I currently do.  He just found it interesting that there is such a lot of activity and wanted to know how I operate the system.

Others might not agree with how the GRHub Network is operated with an RF Link connected to AllStar and Echolink. I was recently told that I operate a repeater on a simplex frequency.  I am not even going to try and explain the general operating procedures  other than to say that those who complain must please get their facts/information correct.  I advise them to use Google Search to gain more knowledge about VOIP and RF Links before making bold statements and accusations.  The complainant clearly illustrate his lack of knowledge in this regard.  I am currently considering whether I should release any operating information in future however I believe in transparency.  Enough  lets continue.

Let me make it clear that the  GRHub Network is NOT a unmanned device and that I need not apply for a special license or callsign.  The GRHub Network is monitored continuously by me except when I am asleep but then the  145.550 Mhz RF Link is disconnected and not in operation.  I have several means to monitor the GRHub Network.  For those non-believers here is a list of monitoring devices including software I use:

• Web Browser - PC/Laptop
• Cellphone
• 2m/70cm HT Radio
• 2m/70cm Mobile Radio
• 2m/70cm Base Station Radio
  
• Mozilla Firefox
• MobaXterm
• WinSCP
• iaxRpt
• Zoiper
• Opera
• ConnectBot
• Connection and other Log Files
  

I can monitor virtually from any location locally, countrywide or worldwide and should there be any problem I can disconnect any station, node or even shutdown the GRHub Network.  This can be done via the Web Browser, Cellphone, 145.550 Mhz RF Link or via an Emergency Halt Button.  I have the options to use Supermon to normally connect/disconnect or via DTMF.  On the RF Link I have DTMF to effect different functions and commands.

 From the above can be seen that the GRHub Network can be monitored and controlled by various means and firmware.  With this out of the way lets go to how do I connect/disconnect stations/nodes.  I would advise readers to read more about this on the various web-sites relating to AllStar/Echolink/Voip.

I will only elaborate on how I connect and disconnect stations/nodes to the GRHub Network.  I use the following methods:

• Manually connect/disconnect using a PC /Laptop (DTMF or Normal Function)
  
• Manually connect/disconnect using a Cellphone   (DTMF or Normal Function)
  
• Manually connect/disconnect using a HT/Mobile or Base Station Radio (DTMF)
• Automatic connect/disconnect using a Cron Job  (Setting up cron jobs for various nodes and options)

Please note that when using DTMF I will make an  announcement to the effect.  In the event of manual or automatic connect/disconnect the node/s will make an announcement to the effect.  There might also be times on certain hubs that connect/disconnect announcements will be heard.  Apart from the announcements a ZS1I call-sign beacon is transmitted over all GRHub Nodes and the RF Link.  Please note I only touch here and there iro connect/disconnect.

I also have the option to connect to any node in monitor mode.  Monitor mode is self explanatory.  You will not be able to make contact via any station on this node if in monitor mode.  This is quite useful listening to bulletins to prevent any "hogs/pigs" from causing interference to the bulletins or repeaters.  Any activity on the GRHub Network is logged and audio recorded in the event of interference/problems of any type.

You might say that I hog the 145.550 Mhz Simplex Frequency in the Southern Cape to such an effect that others cannot use the frequency.  Now this is a lot of hog-wash.  The 145.550 Mhz frequency is open for use to any radio amateur as is the case with any other simplex frequency when it is not in use. Local amateurs can use the 145.550 Mhz Simplex Frequency any time if it is not occupied as is the case with other simplex frequencies.  I studied local activity on 2m simplex frequencies for a month. Apart from the 145.500 and 145.525 frequencies which were used occasionally no other simplex frequency were used on two meters during the month of study.  Update: 23/10/2021 10h00  I just heard a local station calling on the 145.550 Mhz link. "Is this frequency in use?" .... and then he called,  Great operating procedure!!

To summarize:

• The GRHub RF Link/Network is not a repeater or unattended/unmanned system
• The GRHub Network is monitored extensively locally or from anywhere in the country
  
• The GRHub Network can be shutdown at any time should a problem occur
  
• Connect or Disconnect nodes via DTMF, manually or automatically. 
• A ZS1I call-sign identity beacon is transmitted over all GRHub Nodes and the RF Link as required by the radio regulations.
• Any activity on the GRHub Network is logged and audio recorded in the event of interference/problems of any type.
• The 145.550 Mhz frequency is open for use to any radio amateur as is the case with any other simplex frequency when it is not in use.

Finally:  Thank you to those who support and use the GRHub Network regularly. I hope the above information gave some radio amateurs more insight to how the GRHub Network is operated.  I only touched on a few functions and issues here. 

Please use the GRHub Network.  Transmit - let radio amateurs know you are there.  Start or answer a QSO and make new friends.

NEVER FEAR THAT YOU ARE "TYING UP THE NETWORK SYSTEM" - IT IS THERE TO BE USED.

I cannot get into a local Repeater or the Garden Route Hub Network RF Link

  I have heard this many times before especially with regards to the 145.600 Mhz local repeater. No I do not down-run the repeater, custodian or club in any way.  I only use it as a general example as I experienced this first hand.   This is/was a real problem for several radio amateurs living in Wilderness, George and also in the Hartenbos Heuwels area.  As we all know this is not only related to one repeater in South Africa but many repeaters do not cover all areas especially if you behind a ridge or in a valley.  In the days gone by a good friend stayed in the Hartenbos Heuwels area and he could not access the 145.600 Mhz repeater and this was not due to a repeater issue.  Well like they say in afrikaans  "n boer maak 'n plan".  Thanks to PEARS and the Scarr family the 145.700 Mhz and 145.600 Mhz repeater was linked together and could be switched in with DTMF.  Now this resulted in many more radio amateurs being able to use either the 700 or the 600   repeater and even the linked repeater network reaching from Cape Town to Welkom/Umtata etc.  

I am not familiar with the current repeater setup and can therefor not comment on the accessibility of repeaters in the Southern Cape Area.  Now why would I mention the above?   Well I have a simple solution should there be radio amateurs that cannot access a repeater in their area.  You can easily access such a repeater by simply install/build the following:

• Install/build an AllStar Node/Hotspot and add a 2m RF Link to the node for your Shack if you would like to use your HT, mobile or base station in and around the house/town.  This setup is ideal and you do not have to rely on other means of accessing the repeater.  The node option is an all in one package.  A small Baofeng 888 radio, raspberry pi, sound-card fob, power supply is needed.  You control "your link" to the repeater and can chat away at any time of day even World Wide if you choose to do so.  This setup also allows for other stations in your area to link to your system to get into the repeater.  Flexibility and accessibility rules!!
  
• Cross-band Repeater:  You can through the help of another amateur radio station use his cross-band repeater facility should he have the capabilities.  This might work but has drawbacks.  You will have to rely on this radio amateur to allow you access to his system. If he is not available you cannot use his radio. Overheating can be a problem as many radios with this capability is  used for short overs and emergency situations.   This is not the ideal option and cross band repeating require careful frequency selection.
• Ask the repeater custodian/club to install a permanent link between two repeaters in close proximity to your station.  One must however be accessible to you.  This way you can switch in/out the repeaters with DTMF.  This will allow you to access the repeater via another repeater.   This could however be problematic if the majority of repeater users are against linking of one local repeater to another as some do not approve this action.
• Echolink:  You can ask your repeater custodian/club to connect Echolink to the repeater which is not accessible to you.  Unfortunately many custodians/clubs do not want to link Echolink to their repeater/s.  Many radio amateurs see Echolink as the Internet and not radio.  Be as it may Echolink is used world wide by millions of radio amateurs.
• Setup a Remote 2m Station:  You can setup a remote 2m station on a hill or high site.  Have a look at operating a remote station on HF.  It should not be difficult to use this setup on 2 meters.  This might not be a feasible option for many as you need a high site, tower, power, security etc.
• Construct a 2m Yagi Antenna:  Now this will depend on your topography and propagation conditions.  In the past a radio amateur living in Glentana used a yagi antenna to access the 145.700 Mhz repeater.  For those that do not know Glentana it is situated behind a hill right at sea level.  You will definitely struggle to access the 700 repeater with a vertical antenna.  The Yagi antenna also posed several challenges in such a setup.  This radio amateur however used a reflected signal to get into the 700 repeater.

Now I know that there are many radio amateurs that cannot access repeaters from their QTH.  However if you want to access a "difficult to reach"  repeater then the above could assist you in getting into a repeater.   You will have to choose an option but some options rely on clubs and a repeater custodian to make changes to their repeater systems.  Some are however reluctant to make changes for a few that cannot access their repeater.

Which option above is the best.  I will try not to be biased, but my first choice would be the AllStar Node/Hotspot option if your repeater is already equipped with Echolink or AllStar, period. Use this option also if you cannot get into the Garden Route Hub Network.  Second would be the repeater RF/hardware linking option if you have the cooperation of your club/repeater custodian.  Thirdly Echolink (must be installed on repeater and at your QTH station).  It works but then your fellow radio amateurs must leave large enough gaps between overs for you to get in.  Fourthly the Remote 2m Station.  Fithly: Cross Band Repeating and finally to construct a 2m Yagi Antenna depending on your topography.  (Not effective when behind hills or in valleys but works great if you just need extra gain where terrain is not an issue.)

Finally:  My motto - I am of the opinion that "if a door is closed in your face, then just open another door".  The same with accessing a repeater, just "open another door".  Make a plan, build, ask, read, research etc to assist you in this regard.  I trust that the above will assist you in getting full quieting  into a repeater to have a chat with your club members or other radio amateurs.