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I'd be tempted to have a chat with your neighbour, mine have always been interested in finding out what could be causing such interference, but perhaps I'm lucky that many of them seem to be ex-engineers.

As previously mentioned, it's most likely a Chinese battery charger or similar, that hasn't got the mains filter components fitted.

Also, don't discount your own property, try and drop the main breaker if you can, whilst monitoring using batteries. It's surprising what can be overlooked.

Regards,

Martin

In addition.

If you have more than the specified number of users trying to connect, the additional ones can "queue" to wait for the next free slot, or "camp" where they can "piggyback" onto an existing user and hear just the audio.

This is useful when you have a lot of users all wanting to listen to the same thing, such as a popular amateur radio net.

The maximum number of campers can be defined in the "Control" admin page.

Regards,

Martin

Ideally, you should place attenuators between the LNA and receiver, this ensures the best overall Noise Figure.

However, there is a trade in LNA design between strong signal handling and Noise Figure.

Most cheap LNA's don't have a sufficiently good enough strong signal handling performance, and they produce Intermodulation products, which typically show up around the MW broadcast band and either side of the 160m Amateur band.

The Intermodulation performance of an amplifier is usually specified by the second and third order intercept points that are typically measured at the amplifier output. This is a theoretical value where the Intermodulation products rise at a faster rate than the original signals, and if you plot all these levels against each other, you will find points at which they intersect. Once you have such a graph, you can then work backwards, to see what maximum level the input signals can be, before the Intermodulation products start to rise above the receiver noise floor.

I use a copy of the DXE-RPA1 pre-amplifier and have measured the IOP2 at +92dBm, and the IOP3 at +45dBm, and this is just about acceptable when connected to a decent antenna.

For comparison, a single PGA-103+ amplifier (still decent, and better than most) measured an IOP2 at +48dBm, and the IOP3 at +36dBm, but this does produce noticeable IMD products.

The Kiwi typically has a Noise Figure of 14dB at 30MHz, which is just about adequate. If you add an LNA with a better noise figure, that will improve the sensitivity on the upper HF bands. But every dB of attenuation, you place before the LNA, will degrade its Noise Figure by the same amount. Placing attenuation after the LNA, does not degrade the system NF to the same extent. There are various cascade Noise Figure calculators on the web, if you wish to investigate this for yourself.

Pre-amplifiers should ideally only have enough gain to overcome any system losses. As a simple test, if you connect a 50 ohm load in place of the antenna, and note the level of the noise floor at 30MHz, then connect the antenna back up, you should aim for a 6dB increase in the level of the noise floor. Any less than this and you are missing some signals, and any more than this, you are using up the KiWi's valuable dynamic range, which is not desirable.

Regards,

Martin

Personally, I think the internal attenuator is more trouble than it is worth.

An external attenuator controlled by the KiWi, as a separate accessory, may be a better option for those that need to handle day / night propagation changes.

However, in most cases, an amplitude / frequency slope equaliser and / or Broadcast band notch filters can fix most problems, without having to dynamically change the overall gain distribution once it has been initially set. Having a fixed system gain, makes it easier to observe changes in propagation and noise levels.

Regards,

Martin

You have pressed something by mistake.

Bring up the right click menu, and change the default setting back to zoom.

Regards,

Martin