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Which KiWi is your own KiWi, where is it located, and is it public ?

Thinking about this, as this forum only allows limited information to be included in our profiles, it would probably be a good idea for folks to include their KiWi URL(s) in relevant posts.

Regards,

Martin

http://wessex.zapto.org:8074

http://websdr.uk:8060

Two or three times an actual MW broadcast frequency is often observed when very strong local transmitting stations are present.

In this case 3 x 1278kHz = 3834kHz

Sometimes these are actual harmonics being radiated by the transmitter, sometimes they are externally generated by objects such rusty wire fencing, that is rectifying and re-radiating signals, and sometimes they are produced somewhere in the reception chain.

Many times it can be a combination of all of the above.

Placing some attenuation, or better still an amplitude / frequency slope equaliser ahead of the affected KiWi can often help to minimise such problems.

Regards,

Martin

I use 75 ohm, foam filled, all copper satellite TV coax, with braid and foil for my active antennas.

Low loss and effective screening, don't worry about the slight impedance mismatch to 50 ohms.

Something like WF100 costs around £30 for 50m.

Don't use stuff with air spacing, or aluminium foil, or copper clad steel.

Regards,

Martin

They are most likely pirates, probably fishermen.

They often like to find "private" frequencies in order to conduct their "private" conversations, and these tend to be on frequencies with number sequences that are easily remembered.

There tend to be lots of them speaking all sorts of Asian languages, and frequently performing lots of chanting.

5 to 12MHz seems to be the most used frequency ranges, but they can pop up almost anywhere.

Regards,

Martin

As I said previously, the majority of Bias Tees have very poor filtering between the DC line and the RF path.

Nearly all the circuits you find on the internet tend to be outlining theoretical designs, that concentrate on providing the least attenuation and impedance "bumps" in the direct RF path, but don't worry about what happens with RF entering via the DC path.

The better designs for our reception purposes, incorporate additional filtering components in the DC path, in order to reduce this problem. But very large values of L and C are required in order to be effective at the low frequencies, especially at less than 100kHz.

Regards,

Martin