vk6flab

You can't wear one leg each from two different pairs of jeans and go about your daily business, like you could for two pairs of shoes or socks, each of which is independent from the other, albeit left and right specific in various cases.

The same is true for a pair of reading glasses.

Whilst it's obvious that both glasses and jeans (and pants in general) are referred to as being a pair, due to the two legs and eyes aspect, we don't refer to a jumper as a pair of jumpers, unless there's physically four sleeves attached to two bodies.

Why is that and where else does this occur?

Death is inevitable but we still seem flummoxed by it happening. We have all kinds of End of Life policies and procedures which do everything possible to make life difficult for those left behind.

Our language is around loss and unexpected, and grief and being bereft.

Why do we make Death so hard to process in our community and what can we do to normalise it across society?

Recently I started an experiment I plan to run for a year. Using a WSPR beacon and a dummy load I'm transmitting 200 mW, 24 hours a day across all bands supported by my hardware, in this case it covers 80m, 40m, 30m, 20m, 17m, 15m, 12m, and 10m. The aim of the experiment is to determine if, and to what extent my dummy load can be heard outside my shack. Why? Because I've not seen anyone do this and because a dummy load is widely believed to not radiate, despite evidence to the contrary.

Together with the transmission side, I've also configured an RTL-SDR dongle, initially with the telescopic antenna it came with, now, since my HF antenna isn't being used by the beacon, I'm using it instead. It's about five metres away from the beacon, outside. It's a helically wound whip resonant on the 40m band built by Walter VK6BCP (SK). It's what I've been using as my main antenna for the past seven years or so.

While I'm telling you this, my beacon has been heard by my dongle 1,182 times across all eight bands. Some of those reports were from inside the shack, some from outside, some while I was monitoring a single band, and for the past week or so, I've been monitoring all the bands supported by "rtlsdr_wsprd", 18 in all. Purposefully, this includes some bands that I'm not transmitting on, because who knows what kinds of harmonics I might discover? The receiver changes band every half hour, so over time when I monitor a band will shift across the day, this is deliberate. I don't know when a stray transmission might suddenly appear and this will give me the best chance of hearing it, short of using 18 different receivers.

At this time, my beacon hasn't been heard by any other station. I'm not expecting it to, but that's why I'm doing this experiment in the first place.

I'm not in any way reaching any sense of "DX on a dummy load", but it got me thinking. My beacon can be heard, albeit by me, from five meters away. So it's radiating to some extent. I've already discussed that this might come from the patch lead between the beacon and the dummy load, or it could be the dummy load itself, or some other aspect of the testing configuration. Regardless of the situation, there is a signal coming from my beacon that's wirelessly being heard by a receiver.

That's the same as what you'd hope to achieve with any antenna.

So, in what way are an antenna and a dummy load different, and in what way are they the same?

Whenever someone asks this, the stock answer is that an antenna radiates and a dummy load doesn't. My experiment, 20 days in, has already proven that this distinction is incomplete, if not outright wrong.

Even so, if we take it on face value, and we say, for argument's sake, that a dummy load doesn't radiate and an antenna does, then how do we materially distinguish between the two? How does an antenna compare to a dipole, Yagi or vertical antenna and where does the isotropic radiator fit in this?

The best I've come up with so far is a spectrum line comparing the various elements. Let's say that at one end of the spectrum is a dummy load, at the other is an isotropic radiator, to refresh your memory, that's the ideal radiator, it radiates all RF energy in all directions equally.

Somewhere between the two ends is a dipole. We might argue if the dipole sits equally between a dummy load and an isotropic radiator, but where does a Yagi or a vertical fit in relation to the dipole?

Also, if you turn a Yagi in the other direction, does it change place?

So, perfect this notion is not, but here's my question.

What's the measurement along the axis between the dummy load and the isotropic radiator? It's not SWR, since the ideal antenna and a dummy load share the same SWR, unless this line is a circle that I don't know about. It might be Total Radiated Power expressed in Watts, but that seems counter intuitive. It would mean that in order to determine the effectiveness of an antenna we'd need to set-up in an anechoic chamber, basically a warehouse sized room where incoming radiation is shielded to some predetermined standard.

Do we measure gain using a VNA and call it a day, or is there something else going on? Remember, we're attempting to quantify the difference between a dummy load and an antenna.

In case you're wondering, I'm asking the question.

In the 15 years I've been part of this community, I've never seen any coherent response. The Internet seems to return a variation on the radiation vs. not-radiation pattern, but so far I've not seen anyone quantify this, or perhaps I haven't understood it while it was staring me in the face. I even checked the syllabus for the three license classes in Australia. The single reference that the regulator appears to specify is that at the introductory level you are required to, wait for it, recall that when testing a transmitter, a non-radiating load, or dummy load, is commonly used to prevent a signal from being radiated.

Very illuminating. Obviously my dummy load is of the wrong type, the radiating variety. Which begs the question, if there's an ideal radiator, is there a theoretical ideal dummy load that doesn't radiate in any way, and if so, how far away on this line is it from my actual dummy load?

Over to you. What are your thoughts on this? Better yet, got any references?

I'm Onno VK6FLAB

Recently Glynn VK6PAW and I had the opportunity to play radio. This isn't something that happens often so we try to make the most of it. For our efforts we had plenty of frustrations, to the point where we were joking that I should rename this to "Frustrations of Amateur Radio".

That was until we heard something weird on-air. All setup shenanigans forgotten, we marvelled at the experience.

I was playing around on the 10m band, trying to hear people making noise and potentially our first contact for the field day we were participating in, when I heard something odd. Two stations talking to each other, but the audio was strange. It was like they were doubling up, the same audio played a fraction of a second later, until that moment, something I've only ever heard in a radio studio whilst editing using a reel-to-reel tape machine with separate recording and playback heads.

Having just started using a digital only radio, at first I thought this was an artefact of the radio. I took note of the frequency, 28.460 MHz and told Glynn about it. After we moved the telescopic vertical antenna to the analogue radio, we discovered that this was in fact real, not caused by the radios, no doubt a relief to the proud owner of both radios, Glynn, who was thinking more clearly than I. He took note of the callsigns, Dom VK2HJ and Yukiharu JE1CSW. Looking back now, an audio recording would have been helpful.

At the time I suggested that this might be a case of long path and short path signals arriving at our station and being able to hear both. If you're not sure what that means, when you transmit, an antenna essentially radiates in all directions and signals travel all over the globe. Some head directly towards your destination, the short path, others head in exactly the opposite direction, taking the long way around Earth, the long path.

You might think that the majority of contacts are made using the short path, but it regularly happens the other way around, where the long path is heard and the short path is not. As you might know, radio waves essentially bounce up and down between the ionosphere and Earth and it might happen that the signal arrives at the destination antenna, or it might happen that it bounces right over the top, making either short path or long path heard, or not.

In this case, both arrived clearly audible.

It wasn't until I sat down on the couch afterwards with a calculator that I was able to at least prove to my own satisfaction that this is what we heard.

So, what were those calculations and what was the delay?

The circumference of Earth is roughly 40,000 km. RF propagation travels at the speed of light, or about 300,000 km/s. It takes about 0.13 seconds or 130 milliseconds for a radio signal to travel around Earth.

At this point you might realise that 40,000 km is measured at the surface, but ionospheric propagation happens in the ionosphere, making the circumference at the very top of the ionosphere about 45,000 km, which would take 150 ms.

There are several things that need to line up for this all to work.

Propagation aside, the distance between all three stations needs to be such that the number of hops between each combination is a whole number so we can all hear each other.

As it happens, the distance between Perth in Western Australia and Maebashi City in Japan is pretty close to the distance between Goulburn in New South Wales and Japan, and the distance between Goulburn and Perth is roughly half that.

Using back of napkin trigonometry, it appears that 27 hops around the planet are required to make this happen. That's five hops between Perth and Japan, and between Goulburn and Japan, and two hops between Goulburn and Perth, and 27 hops between Perth and Japan the long way around.

Given that the F2 layer where the 10m signal is refracted exists between about 220 km and 800 km, we can estimate that the total delay for the long path is at least 144 ms.

That doesn't really translate into anything you might relate to, but at 8 wpm a Morse code dit takes 150 milliseconds, which gives you a sense of how long the echo delay is. In other words, it's something that you can absolutely hear without needing to measure it.

There are other implications.

WSPR signals are used to test weak signal propagation. Stations around the globe report on what they can hear and when. For this to work, the signal need to be synchronised, something which is commonly implemented using something called NTP, or Network Time Protocol. It can achieve a time accuracy of 10 ms. GPS locked WSPR beacons can achieve an accuracy of 40 nanoseconds.

In other words, if we know that the beacon and the receiver are time synchronised, we can probably detect if the signal arrived using a short path or a long path. The WSPR decoder tracks the time between when the signal arrived and 2 seconds past an even minute as perceived by the receiver. Gwyn G3ZIL wrote an interesting document called "Timescale wsprdaemon database queries V2" on the subject of the data format used by wsprdaemon, a tool used to analyse WSPR beacon transmissions. If this is something you want to play with, check out wsprdaemon.org

From our adventures there was plenty to take away. Stay curious, go portable, take notes, practice putting up an antenna, keep a log, laugh and have fun, and last but not least, get on air and make noise.

Before I forget, make sure your mate brings a pen for logging when your own trusty scribble stick suddenly gives up the ghost for no apparent reason. I knew there was a reason I prefer pencils.

I'm Onno VK6FLAB

cross-posted from: https://infosec.pub/post/25342439

cross-posted from: https://lemmy.radio/post/6473282

One of our fellow amateurs needs help to recover their Google account. They have the credentials, but no longer have access to their recovery phone number.

Does anyone have any suggestions on how to proceed? My Google-fu is only unearthing unhelpful forum posts without any firm process described by Google.

Anyone have any links or contacts?

One of our fellow amateurs needs help to recover their Google account. They have the credentials, but no longer have access to their recovery phone number.

Does anyone have any suggestions on how to proceed? My Google-fu is only unearthing unhelpful forum posts without any firm process described by Google.

Anyone have any links or contacts?

Recently I received a question in relation to the Bald Yak project. If you're not familiar, "The Bald Yak project aims to create a modular, bidirectional and distributed signal processing and control system that leverages GNU Radio."

I know that I've said that several times now and I suspect I'm going to say it several more times before we're done. I was asked about a specific radio and if this project could make it use a frequency that the supplied software didn't cover.

The answer is deceptively simple and if you know me at all, you know what's coming: "It depends". As with many things, what it depends on is not fixed. I'll come back to the question, but I'm making a diversion past a magical place, the local hardware store. You can buy everything you need to build a house with the caveat that some assembly is required. GNU Radio is similar for building a signal processing system, but, wait for it, some assembly is required.

In the context of GNU Radio this means that you'll need to collect all the bits and wire them together, fortunately you're unlikely to need Personal Protective Equipment or access to a First Aid Kit, unless of course the idea of playing with computers gives you palpitations, in which case I'd recommend that you go see your doctor.

One of the less obvious things you'll come across with GNU Radio is how to bring signal processing into the physical realm, in other words, how do you get a signal into your computer, known as a "source", and get it out, called a "sink".

The ability to talk to physical hardware arrives in roughly three different ways. Let's call them, "native", "library", and "abstraction". Native access requires that GNU Radio already knows about the hardware out of the box. Library access requires that the hardware manufacturer has provided software libraries, also known as drivers, allowing GNU Radio to communicate, and finally, abstraction is where a third party has written a library that knows how to talk to hardware from different manufacturers.

The distinction between these is almost arbitrary, for example abstraction might require a driver from a hardware manufacturer. Similarly, because all this software is open source, native can include software from other projects, like the RTL-SDR blocks from Osmocom, Open Source Mobile Communications, and UHD blocks written by Ettus Research, which in turn can be seen as an abstraction.

As I said, some assembly required.

I will point out that this provides a great deal of flexibility, albeit at the cost of complexity, there's still no such thing as a free lunch.

At this point you might shake your head and run away. I get that, it can be daunting. Before you do, consider the scenario where you have a working system and you upgrade your hardware. In a GNU Radio world you'll need to figure out how to configure the new hardware and then all your other stuff will continue to work.

The alternative is upgrading each of your applications to connect to your new radio and in doing so, run the risk of making your old radio obsolete, even if you are collecting them .. let's say for posterity rather than hoarding .. because radio amateurs never hoard anything .. right?

Back to the original question. Can GNU Radio make a radio use frequencies that the software that came with the radio cannot? As I said, "it depends".

First of all, the hardware needs to actually be able to support the frequency. Then someone needs to have written a library to use that frequency, then GNU Radio needs to be able to use that library.

That said, the chances of that happening are much higher than the chance of the hardware manufacturer rolling out this feature within your lifetime. Before you start yelling at me, yes, this is manufacturer dependent, some provide open source tools, many still don't.

There are alternative ways to access different frequencies.

The PlutoSDR is a computer and radio in a box. You can connect to it, change some settings and have it access a whole lot more frequencies. In some ways it's like adding or removing jumpers on a traditional circuit-board.

Another approach is to use an up- or down-converter. Essentially a piece of hardware connected between antenna and radio that translates frequencies to different bands. A down-converter allows you to use the 23cm band on a radio that's only capable of 70cm. Similarly, an up-converter allows your 70cm radio to hear HF signals. If you see a symmetry here, you didn't imagine it. You need both to transmit and receive, sold together in the same box as a transverter.

Just so we're clear, the radio is still using the 70cm band, but the RF coming in and out of the antenna connected to the transverter is on a different band entirely. It's why my Yaesu FT-857d has three menu options, 89, 90 and 91, to adjust the display to show the actual RF frequency. As an aside, you could use this functionality if your radio is off frequency by a known amount.

As I've said before, GNU Radio is a powerful tool. It contains many different moving parts, the system is complex and unwieldy, but with it comes the promise of doing some amazing stuff.

The whole point of the Bald Yak project is to make this all accessible to the wider amateur community, not just computer geeks and software radio nerds.

If you have questions, feel free to drop me a line.

I'm Onno VK6FLAB

Update:

https://darkmentor.com/blog/esp32_non-backdoor/

Update: https://darkmentor.com/blog/esp32_non-backdoor/

Recently I made a joke about operating your station with a dummy load in response to John VA3KOT operating their station with the craziest antenna they ever used.

It got me thinking about the ubiquitous "dummy load" as an antenna.

Since becoming licensed I've spoken with several amateurs who tell a similar story, one comes to mind immediately, Lance VK6LR, now SK, who told me that they managed an unexpected 2m contact with another station using a dummy load, across the city. There's various versions of this doing the rounds, incandescent light bulbs used as both dummy load and antenna, coiled up roll of coax, everyone has a story to tell.

Having spent several years proving that you can in fact use 10 mW and be heard on the other side of the planet, 13,945 km away, it tickled my fancy to think about what would happen if I replaced my antenna with a dummy load on purpose, as a test.

For the past two or so months my WSPR beacon has been transmitting every ten minutes on the 15m band. It was heard 3,493 km away. Interestingly, even in that short amount of time, the radiation pattern of my antenna as seen on the "wspr.live" website shows a similar outline to the 10m transmissions I've been doing since late 2021.

The number of total spots wasn't nearly as significant. I added a local receiver to my shack, just to prove that I was in fact transmitting, but there were plenty of days without a single external report, this in contrast with my 10m experiment where most days I had at least one or more reports from outside my shack, most of them outside my state.

In other words, not every band gets the same kind of report. My license restricts me to the 80m, 40m, 15m, 10m, 2m and 70cm bands. The two antennas I've used so far are essentially limited to a single band, unless I start tuning it every time I change bands.

As you might recall, I purchased a Hustler 6BTV antenna several years ago. Unfortunately, it's still sitting in the box. Climbing on my roof has not been an option for several years, but its time will come. The purpose of getting that antenna was specifically so I could use WSPR across multiple bands and see how propagation was in my shack in real-time without needing to rely on external forecasts or predictions.

Switching to a dummy load has several benefits and impacts.

First of all, it's not something I've seen anyone do. Then there's the idea of band hopping without needing to re-tune. The idea of radiating into something that's not supposed to radiate, is something that makes me smile.

Given that each band has a different level of propagation, which ones should I choose? I could pick all the ones I'm licensed for, but that would leave out the WARC bands and the ever popular 20m band.

What if I ignored convention and transmitted on all bands supported by my WSPR transmitter? Remember, I'm transmitting into a dummy load. By all accounts this should not radiate. It's taken as gospel by the amateur community that it doesn't.

So, using a dummy load, one that's rated at 15 Watts between DC and 150 MHz, feeding it with 200 mW, or 23 dBm, my WSPR transmitter is currently merrily pinging away across 80m, 40m, 30m, 20m, 17m, 15m, 12m and 10m.

If all goes to plan, nobody will ever hear this.

That said, I can hear the uproar from here.

What's the point? You're illegally transmitting on bands you're not licensed for. I'll report you to the regulator.

Here's the point.

The community and the regulator both state that the dummy load is the approved method for testing equipment. It's implied that the equipment will be happy and there will be no radiation. I'm testing and monitoring that assumption.

I'm using all bands because if conventional wisdom is right, nobody will hear this. On the other hand, if conventional wisdom is wrong, there will be reports from bands where there are many people monitoring.

I'll note a couple of other things.

There's a patch lead between the WSPR transmitter and the dummy load. It's about 200 mm long. It's the shortest one I have. It was terminated at the factory and connects the SMA output of the WSPR transmitter to the SO-239 on the dummy load. Theoretically it might radiate. Perhaps this is where other transmissions into a dummy load emanate from, perhaps not.

I discussed the idea of measuring the emissions from a dummy load with a fellow amateur versed in testing much more sensitive equipment. We were not able to come up with a way that would be simple to do by any amateur. If you have ideas, feel free to share.

I'm likely going to cop flack from those who think I'm doing something illegal. You cannot have it both ways. Either I'm transmitting legally or a dummy load isn't a suitable testing tool. Unless instructed by the regulator to cease, I'm confident that I'm operating precisely within the obligations and requirements of my license which encourages me to test and monitor interference, which is literally what I'm doing.

One other point. Until now my WSPR transmitter has paused for eight minutes between transmissions, transmitting once every ten minutes, or six times per hour. It was the default as I recall. I've changed that to transmitting every cycle on a different band. This means that every 16 minutes, the same band will get activated. It also means that because 16 minutes doesn't fit neatly into an hour, the band will move over time, which I think is a good thing. The frequency hopping appears to be round robin, so no grey-line changes, but feel free to correct me.

I don't know what this will do to the transmitter and if it will sustain this. I haven't asked Harry SM7PNV, but if it cooks itself, I'm sure that I can order a new one and mark it down as a lesson learnt.

So, have at it. Point your receiver at VK6 and see what you can hear. I expect to keep this running for a year and see what we learn.

I'm Onno VK6FLAB

What kind of world are the Orange and his puppet master billionaires building?

Are we headed for slavery, extinction, the matrix or some other post apocalyptic future?

How do these despots think that food arrives?

At the moment it seems they're hell bent on global destruction.