12:01am 4/1/09. Bravo, my friend!! 73, Scott, N9AA
Tony Fegan VE3QF wrote: > K3 - Revolutionary Noise Reduction > > It was announced today, by Professor Morsig at the Institute of > Ljubljana, that the K3 has been chosen to test a revolutionary new > approach to combating receiver noise and improving HF reception. > The basic principal behind this approach is the shifting in > frequency of noise by a few mHz (that's milli-hertz) away from the tuned > frequency. This in effect produces a hole in the noise spectrum where > weaker signals may be detected. The residual noise is directly > proportional to the bandwidth of the hole. Therefore, for wider signals, > such as SSB, a modified approach is required. The hole is moved > progressively over the required signals bandwidth and the signal is > sampled at each step and integrated to reproduce the original wideband > signal. > A second feature associated with this algorithm deals with > variations in propagation. We all know that propagation is largely > dependent on the solar flux. Propagation is changed due to the effects > of the solar wind. A little known fact is that the remnants of the solar > wind that reach the receive antenna modulates the noise. When the noise > is detected this modulation can be interpreted to give information about > the condition of the D, E and F layers. This can be used to produce a > real-time table of MUF and critical frequencies for each layer. At night > some kind of remote sensing with suitable location corrections has to be > used. > The third and more revolutionary feature, which depends heavily on > the previous features, involves the generation and use of virtual > transceivers or individual ionosphere layer repeaters. As an example we > will assume a distant CW signal is transmitted on 21.110Mhz and the MUF > is around 15.000Mhz. The signal will not be refracted to our receiving > station and most of it is lost in space. If we transmit a heterodyning > carrier pulse on 14.110MHz, which is below the MUF, then it will mix > with the transmitted signal and produce a weak signal pulse at 7.000MHz > which is reflected back to the receiving station. There is a time delay > between the sending of the pulse and receiving the return pulse. The > transmitted pulse length is made less than this delay so that the > 7.000MHz return pulse may be received between transmit pulses. This > process is repeated and the received signals integrated to reconstitute > the original signal sent. > There are some operating problems to be worked out with the > transmission of multiple heterodyning carriers. Thus only a few K3's are > expected be loaded with the new firmware until these problems are > resolved (spread spectrum has been suggested). > New menu items may be added to include these features in a future > K3 DSP firmware update. MUF OFF/AUTO and 1-10 will vary the effect of > received signals using simulated MUF values. This can improve signals on > all bands. Unfortunately this enhancement is not reciprocal and only > works on receive. Thus K3 to K3 contacts should have a distinct > advantage. The algorithms used are not open source as these features are > expected to have a huge affect on the whole radio communications > industry. It is still in the early beta-test stages. > > The above is a rough summary of the original unwinese language > document submitted by Professor G. E. T. Morsig who is the 1st Associate > Professor of Radio at the Institute of Ljubljana. He will be very > interested in your assessment of this system and may be contacted via > F(zero)OL (qrz.com). > > My apologies if I have made a minor slip or two in the translation. > Unwinese is not an easy language to translate. > > Please do not contact Elecraft for this firmware until there is an > official statement! > > 73 and Enjoy > Tony Fegan VE3QF (anxiously awaiting further developments!) > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
