Troposheric Scatter

Hello possien

The short answer to your Question, is: Both.

Radio Amateur Operators (Radio Hams) have been using that for decades.

Kind Regards....

Yes, you are right :-)

HA5YAR

Tropospheric scattering (also bending, ducting, trapping, etc.) begins to occur noticeably at around 20MHz, and becomes more pronounced at higher frequencies. These effects have been observed by radio amateurs since there has been communication at those frequencies.

The military certainly did not discover these phenomena, although both military and civilian agencies, and private citizens in many countries have taken advantage of them. As yet, no patent has been issued on this use of the layers of the atmosphere.

High,

An area of personal expertise.

I led teams of engineers designing equipments and systems which used this form of communication. The systems were used for military and civilian users, for longhaul low capacity comunication systems; they were used with both analogue and digital modulation methods. I also led teams of engineers working on systems designs and implementation aspects.

Troposcatter employed beyond line of sight communications - long and very long microwave links would be an analogue. The radio beam scattered in the atmosphere - hence the name, and was received many many miles away.

High power transmitter amplifiers were needed for reliable transmission; one needed multiple transmissions of the intelligence to actually obtain the diversity required by the receivers which were generally 4 at a time to obtain quadruple diversity.

A property of the received signal was that it was almost always a heavily fading signal, charaterised by the Rayliegh distribution and multiple (diverse) receivers were employed and their output combined (or selected).

We designed and obtained system reliabilities of 99.9% on a regular basis and interesting systems came forth to handle difficult situations.

Enjoy

Sleepy

I've always heard it referred to as "skip". More common at night, and kinda unreliable, since it's an uncontolled/uncontrollable natural phenomenon. But ham radio operators could CQ from New Zealand to South Africa to New Brunswick (examples used due to distance and remoteness) in either direction from what I was told.

Enviroman,

Skip and skip distance are related to HF skywave communications, not tropospheric scatter. Very different frequency bands.

The Skip distance relate to the distance beyond which Ground Wave operates and before a reflected wave becomes available.

HF is 1 to 30 MHZ approx. It is a narrow band system with a channel capacity up to 1!

Tropospheric scatter operates, broadly, between 450MHz and 4.5 Ghz. Mainly in different approved frequency bands 900Mhz, 2,4 GHZ and 4.4 to 5.0 GHz. It is a relatively broad band technology and analogue systems were built up to around 240 channels.

HF operates on Ground Wave, relatively short distance and Sky Wave through Ionospheric reflections which are capable of running acroos the globe. UK to NZ is possible.

HF communications is very frequency dependent and the MUF or Maximum Useable frequency is a much used parameter.

HF is a very narrow band technology, although there may be newer system technologies that I have not personally experienced.

Have fun guys.

Sleepy

Hello possien:

I am an Amateur Ham Listener, on all wave-bands. But have noticed I can reach have way round the Earth if the weather is good. But, if it is stormy the signal may travel as far but they are not as clear. There furthest I have heard voice transmission from is about 20,000 Kilometres.

I have not done it for a while but when my 'safe cracker fingers' touch a dial (on HF) or buttons on Microwave, I am in heaven.

babybear