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Focus on VHF and above 5 April 2020
Audio version
Last week I spoke about monitoring the beacons so that we can get an idea of propagation here inland on the highveld and I requested that beacon reports be sent to vhfnews@sarl.org.za.
Carl ZS6CBQ sent in the following information about the ZS4AFV beacon.
Carl says “The ZS4AFV beacon is not running any more. It is due to continued power problems at the ZS9X site that currently belongs to the military.”
Last year on 1 November 2019, Carl only heard key clicks on 144.415 MHz and Bernie ZS4TX who looks after the beacon reported that 2 phases were off and only 136V on the 3rd Phase resulting in the battery charger not charging the batteries. Bernie then installed a power supply working on 100V and the beacon was back on the air on 6th November.
Carl says “On 26 November Bernie informed me that the voltages on all phases were low and the temporary power supply also went faulty. Bernie said that he would only go back to the site once the AC power is properly restored. The beacon was off since then.”
On 30 March 2020 Carl sent Bernie a WhatsApp and he replied that the we should remove the ZS4AFV beacon from the list because there is no purpose to carry on with this beacon when the AC power at the site is more off than on. Thanks Carl for that information.
This beacon in Bloemfontein was an important beacon to us as it is further south and west that the Bethlehem beacon.
Yes, this is a problem when we put up amateur equipment in good faith on third property and are reliant on resources from the third party. The VHF Work Group which deployed the Bethlehem beacon is currently working on a plan to deploy a beacon in the northern Karoo and we will now explore how we can rescue the Bloemfontein beacon and possibly move it to a more suitable site. We are also strongly exploring the feasibility of a totally self contained beacon for the Karoo that is totally independent of any external power as well the possibility of being mounted on it’s own stand alone tower. What has happened to the Bloemfontein beacon just makes our case so much stronger.
We are please that the ZS6JON beacon is still performing well and I would like to thank Anthony ZS6ARW for his report on the ZS6JON beacon. Anthony mentioned to me as well that he will put up a Yagi to monitor the ZS0BET beacon as well.
If you hear either of the following beacons, send us an email with the beacon heard, your callsign, your grid location, local time and the signal report to vhfnews@sarl.org.za:
ZS6JON on 144.440 MHz
ZS0BET on 144.425 MHz
The Bethlehem beacon’s second antenna is currently point in the direction of Durban. Hopefully the KZN guys can provide us some reports as well.
Now something again for the more technically minded who are looking for a challenge while sitting at home.
Most guys use a single Yagi antenna for VHF and Above work. At some or other stage you are going to decide that you need more gain and let’s face it building antennas are much cheaper than building low noise amplifiers for the VHF and above frequencies. You are left with two choices, build a longer Yagi with more elements to increase the gain of the antenna or build a second matching Yagi and stack the antennas either vertically or horizontally to achieve the desired gain.
A good source of information about stacking of antennas can be found at http://www.grantronics.com.au/docs/StkYagis.pdf
But how do you feed the antennas and match the impedance of the antennas in parallel to your 50 Ohm feedline?
One way to do it is with a coaxial cable. The ARRL handbooks are a good source for information on quarter wave matching devices using coaxial cable or you can use your favourite search engine on the web. One of the challenges with building a matching device with coaxial cable is how do you weatherproof the coax.
Another way to do it is to use a power divider.
Quarterwave_Power_Divider.gif
You can buy a power divider for around R3000 locally or you can build your own. Right now, building your own is the only option as the local suppliers are all closed.
Take a look at the homebrew Hardline Coax RF Power Divider built by Derek on YouTube. Derek discusses how to do the calculations for the material that you may have on hand, to be able to build a RF Power Divider.
Yes, it can be a little challenging, but it is certainly doable.
Danie ZR6AGB built one last year sometime that we tested and it worked really well when tested on the VNA that I have.
What experiments are you going to be trying during this lockdown period?
Take out that project in your bottom drawer and complete it. I’m thinking of a number of fellow Amateurs who have acquired everything to build a noise monitoring system, but have not progressed further with it.
What about a digital interface for weak signal modes on VHF? The interfaces between your radio and computer is not difficult to build on a piece of Veroboard and you can use the same interface for HF as well. Why not build one set of interfaces for each radio that you have. By the way, if you do not have a piece of PC board or Veroboard, why not try building the project using the dead bug or Manhattan method.
While researching some of the material for this week’s program, I came across so many useful projects that one can do. Some of us have the excuse that we are not programmers, or cannot solder. Why not try your hand at it now while you have the time and learn a new skill.
Don’t forget to tell us about it at vhfnews@sarl.org.za.
All the links mentioned are in the text version of Focus on VHF and Above that is available on the SARL home page as well as this audio file.
Focus on VHF and above is compiled, edited and presented for Amateur Radio Today by Brian Jacobs ZS6YZ.
Focus on VHF and Above 29 March 2020
Audio file
On Friday morning 27 March 2020 there was again good VHF propagation inland and the 46 Group made good use of the opportunity.
Dries ZS4AJ in Bloemfontein was heard by Carl ZS6CBQ S9 +10 in Krugersdorp. Carl was also hear S9+20 by Pierre ZS4PF in Welkom.
ZS6CBQ_Recordedby_ZS4PF.jpeg
Similar reports were also given to Koos ZS6KSG by Pierre and Rickus ZS4A was reported 57 by Kobus ZS6BOS in Randfontein.
The forecast for Pretoria for Saturday 28 March was fog and I had a look at the sounding forecasts on Windy.com for the area Pretoria to Hopetown and Kimberley to Secunda and it seems that the whole of the highveld was experiencing temperature inversion. The humidity at 500 hPA (5500 m/asl) was below 30% with the humidity increasing at lower levels to above 80%. The synoptic chart from the Weather Service showed a high pressure cell SE of the country with a low pressure cell to the NW over Namibia.
Synoptic_Chart2020032800:00Z.gif
The Hepburn chart for Saturday morning 06:00 UTC looked good as well.
Hepburn_Chart_0600UTC.png
Possibly good conditions for Tropoducting?
The conditions reported on the ground around 08:00 local time (06:00 UTC) showed weaker conditions than the previous day with Carl ZS6CBQ only giving Dries ZS4AJ a S5 report.
This raises a number of questions, like:
What were the conditions like earlier in the morning? Looking at the Hepburn Charts the conditions look good early in the morning that then disappear later in the day. What about later in the day? Most of the radio amateurs are active in the early morning, but not too early, for a couple of hours.
Was anyone monitoring the beacons, especially the ZS6JON beacon in Tarlton, the ZS4AFV in Bloemfontein and ZS0BET beacon in Bethlehem?
Monitoring the beacons are an excellent way to be able determine how the conditions change over a period of time.
We have not yet progressed to an automated beacon monitoring and reporting system, and we are still not quite there yet with the beacon reporting Bot on Telegram.
In the meantime you can assist us by listening out for the beacons and sending us your reports to vhfnews@sarl.org.za.
The beacons that we are interested in are:
ZS6JON on 144.440 MHz
ZS4AFV on 144.415 MHz
ZS0BET on 144.425 MHz
We require the following information: Beacon heard, your callsign, your grid location, local time and the signal report.
This will help us to get a better idea of the propagation, especially here on the highveld.
Going further up in the bands.
There is now an official QO-100 International Emergency Frequency.
In order to coordinate potential emergency communications, a frequency has been assigned as the international emergency frequency on the QO-100 geostationary satellite narrow band transponder
QO-100 International Emergency Frequency
Downlink: 10489.860 MHz
Uplink: 2400.360 MHz
SSB channel: max. 2.7kHz bandwidth
All users on QO-100 are encouraged to monitor this frequency, but keep it clear for emergency traffic!
How many QO-100 ground stations are there in South Africa? Write to us at vhfnews@sarl.org.za and tell us a little about your QO-100 station setup.
The UK Microwave Group has made available a PDF of their trifold printed leaflet 'Amateur Radio in the GHz Bands' which aims to inform the public who may ask what you are doing when outside with a portable microwave setup or for publicising amateur microwaves. You can find a copy of the leaflet at https://microwavers.org/files/UkuG_Leaflet.pdf. What activity is there in South Africa on the microwave bands?
Again, write to us and let us know about your experiments in the microwave bands.
This information is very important for us as we need to motivate and protect our bands. We may have made some gains or maintained the status quo at WRC-19, but there is a constant threat to our bands, especially the higher bands where we are secondary users. The more information we have available to us that proves that we are active on the bands the easier it is to fight to protect the bands that we have access to.
Radio amateurs are always on the lookout for a freebie.
On 19 March, CQ Magazine announced that in view of the "stay at home and flatten the curve" recommendations from the health experts during this worldwide pandemic, CQ would like to give everyone the opportunity to escape the news alerts for a brief period and enjoy the hobby they love through the pages of CQ! View the March and April issues of CQ magazine at no charge! It's easy, simply send an E-mail to FreeIssues@cq-amateur-radio.com and we'll send you the March issue now and the April issue on April 1st!
Take advantage of this opportunity to read CQ - free of charge - and keep connected with the latest trends and activities in amateur radio!
Thank you CQ Magazine.
Here are two items for the more technically minded amateurs.
I found an article titled “Efficient 2 meter Disguise Antenna Made From a TV Satellite Dish”. In the article John Portune W6NBC describes how he used a 2m satellite TV dish to make a horizontal slot antenna which is totally unobtrusive to the casual viewer. Ideal for putting up in your housing complex where only DSTV dishes are allowed and no other antennas. You can find the interesting article at https://w6nbc.com/articles/20xx-dishslot.pdf
I previously mentioned an article where a fellow ham in Europe was experimenting with APRS on LoRa frequencies.
Here is another article, this time of an experiment in the US to use troposcatter to receive a LoRa signal bounced off the troposhere. You can read the article at https://inductivetwig.com/blogs/news/1500-watts-of-lora-on-the-440mhz-band
What experiments are you going to be trying during this lockdown period?
Scratch in that bottom drawer where all the projects are lying which you plan to do later. Now is the ideal time to relieve that boredom by trying something new. Something different. Something out of the box, or that bottom drawer.
Don’t forget to tell us about it at vhfnews@sarl.org.za.
All the links mentioned are in the text version of Focus on VHF and Above that is available on the SARL home page as well as this audio file. Focus on VHF and above is compiled, edited and presented for Amateur Radio Today by Brian Jacobs ZS6YZ.
Focus on VHF and Above8 March 2020
AUDIO VERSION
Firstly some news about Koos ZS3JPY from Kleinzee.
Koos is still in hospital fighting infection in his leg. Earlier there was a report that they may need to again amputate a portion of Koos’ leg, but the good news passed on yesterday by Charles ZS1CF is that this has not been done and they are seriously trying to stop the spread of the infection. Charles says that Koos is experiencing pain, but remains positive. Koos and Michelle ZS3TO, you remain in our prayers and we pray for a speedy recovery.
Have you recently experienced or are currently experiencing intruders and /or interference on the amateur bands, especially the 2m and 70cm bands?
The flood of cheap Chinese two way radios that can easily be purchased in the local corner store that sells all sorts of electronic gadgets and so forth is a problem. Yes, the root of the problem is the uncontrolled import of these radios. This has been addressed with the relevant authorities and is primarily out of our hands as a radio amateur and spectrum user. If you know of these radios being sold in a shop near you then you can report this to the ICASA Regional Manager in your area who will take action.
Further more we can also assist and report intruders on our bands to the local ICASA Regional Manager. In the case of interference, whether intruders or other forms of interference that prevents you from using a particular frequency, try and get as much information such as a recording of the interference, date, time and frequency as well as any other information that may be relevant. Some guys have been successful in applying their fox hunting skills and being able to identify an address from where the interference is coming from. Send all this information to the ICASA Regional Manager in your area and they will follow up.
A complete list of ICASA Regional Managers can be found on the SARL website http://www.sarl.org.za/public/licences/licences.asp
We request that you also copy artoday@sarl.org.za to allow the SARL to monitor how wide spread the problem is.
There have been some recent successes in interference cases so if you experience interference, report it and help us protect the future of our amateur radio spectrum which is continuously under threat.
The latest issue of the IARU VHF, UHF and Microwave Newsletter is available at https://www.iaru-r1.org/wp-content/uploads/2020/03/Newsletter85.pdf
Please take some time to read through it.
Now something for the technology junkies amongst us.
Have you heard about LoRa? What is LoRa? LoRa is a Wireless RF Technology. LoRa, which is short for Long Range, is a spread spectrum modulation technique derived from chirp spread spectrum technology. LoRa devices and wireless radio frequency technology is a long range, low power wireless platform that has become the de facto technology for Internet of Things (IoT) networks worldwide. LoRa works on the license free portion of 868 MHz.
During the BACAR balloon flight held last year a LoRa payload was built by Henry ZS6IIX and the signal transmitted was heard over a very long range.
Now here is an interesting article about mobile LoRa-APRS via QO-100.
Andreas Malek, OE3DMB has been active on QO-100 since the satellite went live and has built up his own transverter. Andreas says “Parallel to the development and construction of the transverter I was asking myself if it would be possible to do mobile operation via QO-100 with just 20 Watts of RF power. I was especially interested in the question, if it would be possible to use LoRa-APRS via satellite to get whole European coverage (and of course much more than that) in addition to the terrestrial LoRa-APRS network. “
In the article Andreas describes his experiment to transmit a mobile LoRa-APRS signal via the transponder on the QO-100 geostationary satellite. Andreas generated a 20 watt 125 kHz bandwidth LoRa signal on 2.4 GHz which was fed into a small omni-directional antenna mounted on the roof of a car.
Read the article at http://aprs.org/LoRa_Documentation.pdf
The curiosity and willingness to try something is what amateur radio is all about. What else can we radio amateurs use LoRa technology for?
What interesting projects are you playing with? Why not tell us about it at vhfnews@sarl.org.za.
Just over a year after QO-100 has gone live, the custodians of the satellite have published updated band plans.The QO-100 Narrow Band transponder band plan can be found at
https://amsat-dl.org/en/p4-a-nb-transponder-bandplan-and-operating-guidelines/
and the Wide Band transponder band plan at
https://amsat-dl.org/en/p4-a-wb-transponder-bandplan-and-operating-guidelines/
The SARL National Convention will be taking place at the Wanderers Conference facility in Illovo, Johannesburg with the SARL Unlocking Amateur Radio Technology Symposium on Friday afternoon 3 April.
Be sure not to miss this afternoon of interesting topics that will get you thinking and who knows what new things you will discover in this exciting world of amateur radio. I hope to see you there.
Well that’s all for this week. Don’t forget to send us details of your club or group’s activity on VHF and above or any other news snippets to vhfnews@sarl.org.za.
All the links mentioned are in the text version of Focus on VHF and Above that is available on the SARL home page as well as this audio file. Focus on VHF and above is compiled, edited and presented for Amateur Radio Today by Brian Jacobs ZS6YZ.
Focus on VHF and Above 9 February 2020
Audio version
You will recall during the build up to WRC-19 that one of the issues that was proposed to be put on the agenda for WRC-23 was interference caused to the Galileo GNSS constellation by activity on the 23cm band.
Bob Atkins KA1GT has documented his recent observations of interference to 1296 EME from the Galileo navigation satellites' E6 mode.Go and take a look at Bob’s observations on his website https://bobatkins.com/radio/galileo-1296.html.
Previously Peter Blair G3LTF also wrote an article about the potential interference to Galileo from 23cm band operations. Although the article was written in 2006, Peter explains the whole history of the Galileo project, what it is where it stemmed from as well as describing possible interference scenarios. Peter’s article can be found at http://www.southgatearc.org/articles/galileo.htm. Be sure to click on “Continued” link at the bottom of the page to go to the next page.
After reading both these pieces of information, I now also have a better understanding what the potential issues are and why this item was on the agenda during WRC-19.
Work will shortly begin with the first preparatory meetings for WRC-23 and we will again need to make sure that we are fully informed and take part in the various meetings and forums to ensure that the interests of the Amateur Service is protected.
Now on to something more technical.
I have previously spoken about hand held radios and their rubber duck antennas that are fundamentally dummy loads. I have a requirement next weekend where I will need to use my hand held radio while away from my vehicle when we are busy assisting with a cycle event on the East Rand.
I have also previously spoken about a simple modification that you can build that will give you a significant improvement on the signal that you transmit from your hand held radio. I’m going to revisit this as I’m now in the process of building another antenna for 70cm as we will be working on 70cm for this event.
You can go and look at a commercial product called a RatTail Antenna which basically adds a counterpoise to your existing rubber duck antenna. The problem with this design is that it inductively couples to your radio and while transmitting you need to determine where the best place is to attach the device to your radio. This device will set you back 32 USD plus shipping.
A little research on the internet will bring you to the webpage of Mike KM4FMK. Mike has written an article titled "Tiger tails" - Are they really worth using? The Tiger tail is nothing other than a counterpoise that you add to the radio’s antenna. Based on the measurements that Mike has done on various radios and antennas you can see that there are definitely gains that can be achieved. We are talking in the region of 6db gain over the standard antenna. Of course the gains will vary depending on the radio and antenna that you have.
There is another article on Hamuniverse.com titled HT Antenna Modification For Increased Performance! written by Edward Harris, KE4SKY. Again interesting reading and you will see the amount of attenuation provided by a rubber duck antenna which varies greatly depending whether the radio is in your hand level with your face or you have it clipped to your belt and use a speaker mic.
On that same page there is another article written by Dale Kubichek N6JSX which gives a simple method of building a counterpoise and how to attach it to your handheld. There is also a link to a PDF document where Dale provides info on building a brass quarter wave whip antenna.
This is what I have previously built for 2m, and the tests that I have done on my Icom IC-T70 hand held showed that the whip and counterpoise gave me a signal gain of 6dB over the standard rubber duck antenna.
I hope to get good results from my new 70cm antenna on the hand held that will allow me to at least get better reception, never mind the significantly improved transmission which may even allow me to use my hand held outside of my vehicle without having to run back to the vehicle every time I am called on the radio. The length of the 70cm antenna will also be smaller and much easier to handle in and out of the vehicle.
I also need to ensure that the radio is not clipped to my belt, but sitting high up on my body in some form of a harness to ensure that I actually get maximum signal out of the radio.
Remember, being able to kerchunk the repeater with your hand held, does not mean that you are putting out a sufficiently good signal to be able to have a proper QSO or pass that urgent message that may save a person’s life.
Well that’s all for this week. Don’t forget to send us details of your club or group’s activity on VHF and above or any other news snippets to vhfnews@sarl.org.za.
Focus on VHF and Above 2 February 2020
Audio version
This week, we again report on activity along the West Coast.
Charles ZS1CF says “The West Coast Radio Group have their net on Mondays at 19h30 on 145.500 FM simplex.
The Tropo ducting forecast for Monday 27 January looked fair again, but not as strong as it was the previous Monday. Charles received Cobus, ZS3CVB with a S9+10dB signal compared to a full scale reception the previous Monday.
On Monday 27 January, a total of 9 stations called into the net and everyone enjoyed it thoroughly.
1. Cobus ZS3CVB in Port Nolloth
2. Michelle ZS3TO in Kleinzee
3. Koos ZS3JPY in Kleinzee
4. Marco ZS6NEU mobile in Saldanha Harbour
5. Thys ZS1TBP mobile in Saldanha Harbour
6. Chris ZS1FC in Jacobsbaai
7. Tienie ZS1HO in Vredenburg
8. Andre V51LZ in Oranjemund
9. Charles ZS1CF in Langebaan
The tropo ducting lasted well for about an hour, after which it faded quite rapidly
Thank you to all for calling in and participating in the discussions!
West Coast greetings from Charles, ZS1CF in Langebaan.”
Charles thank you very much for this report.
We encourage other clubs and groups to also send us information regarding their activities on VHF and above.
The VHF Workgroup met again on 29 January 2020 for the first time since the installation of the Bethlehem beacon in early December 2019.
The Bethlehem beacon is operating very well and reports continue to come in, some from unexpected areas such as Charl ZS3K reporting that he heard the beacon at his QTH at grid KG10wa, which is in the Northern Karoo near Strydenburg. This is an interesting report as it appears that Charl heard the beacon off a side lobe as the antennas are pointing North and East.
This report prompted Carl ZS6CBQ and Charl to do some tests on 2m CW and Charl could hear Carl’s beacon in and out of the noise.
There is now a renewed enthusiasm to get the next beacon up and running in the Northern Karoo.
The hunt is now on to find a suitable location for the beacon. There are also discussions around building a totally self contained beacon that does not require any third party tower or access to electricity to be able to operate. So the beacon will be solar powered with battery backup and on it’s own 6m tower. This idea will allow for a lot more possible sites upon which to locate the beacon.
Carl ZS6CBQ and Rickus ZS4A have been experimenting with JS8Call on 2m and their findings prompted the question whether the next beacon should be a CW beacon or should the beacon be a digital beacon being able to send and receive a digital signal on 2m SSB.
Unfortunately load shedding cut the meeting short, however, there are a lot of ideas that need to be explored before the next meeting. A draft budget also needs to be prepared so that funds can be acquired.
The next meeting of the VHF workgroup will be on Skype at 20:00 on 27 February 2020. If you would like to join the VHF Workgroup, please send your Skype name to vhfnews@sarl.org.za.
Two amateurs in Germany have achieved a new IARU R1 record on 134 GHz. Michael Kuhne DB6NT and Roland Becker DK4RC exchanged reports on both SSB and CW over a distance of 65 km on 29 December 2019. You can see some photos of Michael’s equipment on his website http://www.db6nt.de.
Well that’s all for this week. Don’t forget to send us details of your club or group’s activity on VHF and above or any other news snippets to vhfnews@sarl.org.za.
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