G8JNJ

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

Hi Andy,

I understand the points you are making, but having previously discussed this with Philippe, I think there are some valid concerns, that may discourage other people, in other countries, from operating a KiWi.

If a simple fix, which John has already implemented, can help remove some of these barriers, then surely it is a good thing ?

Some countries are extremely sensitive about some aspects of the radio hobby, and to be honest, if I was living in one, I wouldn't be running a KiWi. It's easy to forget this when living somewhere that is more "relaxed" about such things.

Callsign piracy has always been an issue, and using an alpha-numeric string (or emojis) to identify an individual doesn't mean that they are who they say they are. However, I can understand the problem for the KiWi admin, if someone else decides to use your callsign, and you, the legitimate owner, find out, and then blame the admin for something that he has no control over. This may sound unlikely, but I have experienced similar problems when we had the "Chat" facility enabled on one of our websdr's, which caused so many issues we, (like most other websdr admins) removed it. Any public site, that has the ability for folks to anonymously post comments, no matter how brief in content, will unfortunately be abused.

Andy - "they" already know, who you are and where you are :-)

Regards,

Martin - G8JNJ ( or am I )

Sometimes, when used inside a Switched Mode Power supply, the additional choke inductor in the ground (L3 in the circuit) can sometimes be more problematic than useful.

I tend to wire the DC 0v / -ve directly to the mains earth, but depending upon the local configuration, this can also make things worse.

Unfortunately, it's one of those cases where, although it may be good practice to do certain things, you generally have to experiment, in order to find the best solution for your own setup.

Regards,

Martin

Fldigi has a decoder, but I note that there are a number of Linux based parsers and decoders too.

Just a quick selection.

Regards,

Martin

Hi Philippe,

I'd agree with John that it doesn't make sense to list KiWi's that folks can't openly use.

But I do understand your reservations, and some countries are definitely more restrictive than others.

Short range local VHF / UHF communications are certainly more problematic from a legal perspective than HF communications, which generally tend to completely ignore geopolitical boundaries

Maybe it would be worthwhile emailing some of the other KiWi admin / operators in France, to see if they have the same concerns as yourself ?

Regards,

Martin