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This is a thorny subject, and I could write a thesis on it. I have already made my position clear to John, but I'll raise a few points here to further the discussion.

Open-source / FOSS is generally a great concept, kids these days like having stuff for free. Music streaming is perhaps one of the best examples. However, the problem is how to make money from it, and many small artists are still arguing about that one.

The principle of collaborative free software is good, as long as everyone contributes, less so when one person does the work, and everyone else sits back and makes use of it. In the workplace, most people know who is actually doing the bulk of the work, and who is just doing the bare minimum, or "clock watching".

John is in a difficult position, where the Opensource software, supports hardware, which he sells to make an income.

When you buy a KiWi you also get for free, a superb level of support from its enthusiastic developer (John), and unfortunately competing products like this, building on his work, but sold at low cost, for short term gain, will impact the long term survival of his business, including the other services he provides, such as TDoA, which run on his servers, at no additional cost to users.

By contrast, most of the previous KiWi clones have fallen by the wayside, despite assurances from the companies producing them, that they would not stop supporting their products. They try to make a quick "buck", then loose interest as sales decline.

The current competitors have used the KiWi code, and introduced some innovations in their own product, but these really only benefit the competing hardware, they do not directly feedback into the KiWi code, product or features. Their software is flaky, and response to significant bugs is usually patchy at best.

I don't think John can compete on the hardware side. Designing, building and selling hardware will always be difficult when competing against certain regions of the world. Low production costs, scale of manufacturing, circumventing import taxes and duties when shipped to other countries, and lack of respect for IPR, all add into the mix.

However, the time and effort he has put into developing the KiWi, since it's original fork from OpenWebRX, needs to be rewarded in some way, and I don't think that in future that can be achieved through the manufacture and sales of the hardware. Some way needs to be found to protect his IPR, provide a source of income, and cover the costs of him providing aftersales support, software updates, and the running costs of the services he provides for free such as TDoA and proxies etc. A subscription for support services, could be one way of achieving this, but in the meantime, protecting the parts of his code that he can, without infringing the Opensource parts, should definitely be considered.

Personally I'd risk doing this, and wait to see what happens, if someone objects then just fix the bit that is problematic, but in many cases it would be "the pot calling the kettle black", so I don't think it would be a major issue.

I'm all for respecting the law, and various formal or informal Open source agreements, however this shouldn't allow an individual to be taken advantage of, especially if they are good-natured and willing to go above and beyond what is required to make a profit, for the benefit of the community as a whole.

That is not fair, and should not be accepted by anyone with a social conscience, or sense of justice.

I could say an awful lot more, but this summarises my position, and I hope it will lead to a more meaningful debate.

Regards,

Martin

"And I think the LT1083/1084/1085 stabilizer is a very good and cheap choice."

The 5A linear regulators do produce LF noise.

But adding a big electrolytic across the regulated output helps a lot.

Regards,

Martin

All the broadband routers I have had provided, have had noisy Switched Mode "Wall Wart" type power supplies as standard.

They produced far more interference than the routers, which generally tended to be of good construction and had been EMC tested as part of the design process.

The power supplies always seemed to be an afterthought, and may have been sourced differently from the actual router, depending on local electrical regulations and requirements.

It is likely that the power supplies have been chosen on the basis of cost, and we all know what happens then.

Because of their small size, it is usually not possible to add extra filtering, and such internal modifications can also result in safety and insurance issues.

I tend to look in Charity (Thift) stores or at Car Boot sales for older, cheap electronics, with separate linear power supplies. As it's difficult and expensive to buy new linear power supplies, especially since the audiophiles are willing to pay silly prices for them. The rest of the electronics are useful for parts too.

On an incidental, but related subject

A friend of mine, who allows me to host a KiWi at the historic Goonhilly satellite earth station in Cornwall UK, was good enough to resite the KiWi to a new location on the site, in an attempt to resolve some long standing interference problems. However, he couldn't get it to connect properly to the network. He could see it acquired a DHCP address, but he couldn't ping it. He then transferred the KiWi back to the original location, and it still didn't work properly.

Thinking that somehow the build had become corrupted, we arranged for him to return the KiWi to me, so that I could fix it, upgrade the OS and take the opportunity to check things like the fan (which as expected was stuck solid).

The actual fault was the Switched Mode Power supply, which seemed to be working correctly, as the output voltage was correct when checked with a multimeter, it would also still happily deliver 5A output.

However, I noticed that the output voltage dipped just a bit more than I would have expected when on load, but only by about 0.2v.

I took the power supply apart and discovered that the main high voltage DC storage capacitor (150uF at 450v) had dried out over time, and was completely open circuit. This is why the DC regulation was so poor, and also why the KiWi was having difficulties.

Replacing the capacitor fixed the problem, and the KiWi was back to working as normal.

Most of my past KiWi problems have been power supply related in one way or another, so my rule of thumb now is:-

If your KiWi is misbehaving in any way, check the power supply first, and pay close attention whilst you do it.

Regards,

Martin

I'd also suggest emphasising the "works straight out of the box" aspect of the KiWi.

One competitor is making an attempt at this, so far unsuccessfully, but the majority of previous competitors have not been able to achieve this. Other options, such as OpenWebRX (moderate pain) or PhantomSDR/Plus software (really painful), are still in their infancy, and require a fairly extensive knowledge of Linux to get running initially, and then update and maintain.

Regards,

Martin

Those are valid, and he has identified himself.

It's a member of the UDXF list logging ALE networks, which requires long periods of continuous monitoring to capture stations that may only sound once an hour.

I have given him passwords for my KiWi's so that he doesn't time out.

Regards,

Martin

When using an MLA-30, I don't think you can have too much gain :-)

Auto waterfall settings can have you chasing your tail. So I tend to set the KiWi waterfall & Spectrum display to manual, zoom fully out to see the whole spectrum, then set the maximum waterfall level to -20dB and the minimum to -110dB. This gives a good baseline for comparison with other KiWi's when the same settings are used on them too.

Don't worry about the noise increasing, you should see some, especially in an urban environment.

Just aim for a 6dB increase in the noise floor on the upper HF bands 20-30MHz, when the MLA-30 is powered up.

As I said before, turn the bias tee control to maximum gain, and then just use the amplifier gain control to achieve the best overall performance.

Regards,

Martin

"Seems the interface is a bit slicker."

Not really, it's just different, and has as many "quirks and foibles" as the KiWi (sorry John).

OpenWebRX + is more orientated to the VHF / UHF bands, and is good at the modes that can be found there, and I operate both.

However, the developers are not as responsive as John, and the admin interfaces and configuration processes require a good degree of skill to set them up and make them function correctly.

By contrast, the KiWi works pretty much straight out of the box and is generally stable, OWR+ is more of a work in progress.

This may suit folks proficient in Linux, who enjoy spending many hours resolving problems, but some of us just want something that works, with minimal hassle.

Regards,

Martin

For transmit purposes, it's all about antenna efficiency, and radiating as much of the applied RF power in the direction you want it to go.

For reception purposes, it's all about the Signal to Noise Ratio, and a good transmit antenna may not always be a good receive antenna.

The natural noise floor on the LF bands is relatively high, especially in urban areas, and even quite small antennas can still be performance limited by the surrounding noise floor.

Rather than concentrating on large antennas, you may get better results with a smaller antenna in an electrically quieter location. Some experimentation is required, to get the best results.

Balanced antennas are generally better than unbalanced ones, and end fed wires have a reputation as being noise magnets.

If you do wish to install one, this diagram may provide some suggestions about minimising unwanted noise.

Regards,

Martin

I should have clarified the way it works a bit better.

Pushing the mouse wheel down whilst rotating it enables the opposite mode to the default that has been chosen. in OpenWebRX.

Having the possibility to tune using the mouse opens up other possibilities such as making your own VFO knob, using the optical encoder recovered from a scrap mouse, or buying one of the more expensive ready-made commercial items.

If it could be implemented in a way similar to that of OpenWebRX , then it would still retain the mouse wheel zoom option for those who prefer it, but offer an alternative for folks who would like to use mouse wheel tuning.

Try it and see for yourself.

http://wessex.hopto.org:8060

If you open up the settings pane in the control panel, you should see the "Hold mouse wheel down to tune" tick box. Also set the tuning step size in the controls section, 500Hz or 1kHz is useful for SSB, as most folks use 'rounded up' frequencies.

I'm not specifically requesting this feature, as I don't wish to add to John's already massive workload of much more important issues, but I can understand the appeal of it.

Regards,

Martin

My experience of building filters like this, is that the values provided by the various on-line calculators for self-supporting air spaced inductors wound from wire, is that they are not that accurate.

Even when you have wound them, and tweaked than so that their measured values are correct, you will need to adjust them again once they are installed in the circuit, in order to achieve the required response curve.

To do this you ideally you need a VNA, or Spectrum Analyser and noise source, so that you can bend the coils in real time and observe the effect.

SMD components can produce reasonably repeatable filters, as their construction and tolerances are much less affected by external factors.

However, if you don't have access to the test gear required to set it up, then there are plenty of cheap kits, or ready built, FM Band Stop filters being sold on AliExpress, starting at less than $5 USD, which is pretty much just the component cost if you were to buy the parts alone.

https://www.aliexpress.com/item/1005007644615468.html

Regards,

Martin