Leif: Forgive me if I'm not aware of everything that is inside Linradio and you already have something like the below.
I'd like to see you expand the scope of #4 to include splatter from any source. For those of us that mostly DX the AM broadcasters, splatter is the huge enemy. A solution that I'd like to see is a sort of Costas loop where: (1) the signal is split into two paths where one is demodulated with an in-phase carrier and the second with a 90 degree shifted carrier, (2) the "Q" output is shifted an additional 90 degrees, and (3) the two demodulated outputs are selectably added or substracted. Chuck WD4ELO -----Original Message----- From: Linrad mailinglist [mailto:[EMAIL PROTECTED] On Behalf Of Leif Asbrink Sent: Sunday, October 28, 2007 10:31 AM To: Linrad mailinglist Subject: [linrad] Challenges!! Hi All, Any interference that is not random can in principle be modelled and subtracted. In real life it might be too difficult, but I guess there are man-made interferences that could be significantly reduced. Improvements are also possible with random interference in some cases. I think the interference fighting in Linrad can be significantly improved, but I do not want to work on artificial signals where I try to simulate various forms of QRM - mistakes are easily done so I look for real life recordings of signals that are at the detection limit or slightly below. Is there really nobody reading this who has problems in copying "the other station" occasionally? I have asked before, but still I have no recordings to work with. Currently I am only interested in the traditional modes CW, SSB, AM or NBFM. Here are a few examples: 1) SSB in white noise but with inadequate S/N. Rather than using a rectangular filter Linrad could use a filter that is shaped as the power spectrum of the signal. 2) Interference from TV transmitters on 50 MHz. 3) Lightening crashes on (low?) HF bands. 4) Splatter from local amateurs. On Nov 05 I will leave for one month spending my time in a more pleasent climate than what Sweden can offer this time of the year. I will have plenty of time to work on any challenges you might give me. The Tx side of Linrad is now producing 10mW on 144 MHz, but I can not work on it when away from home because the next step will be to arrange for the Rx/Tx switching for QSK in CW and SSB. It is possible to listen while talking, one can "cut holes" in the transmitted signal occasionally to generate perhaps 1% of silence without affecting intelligibility. Will allow monitoring of what happens in a pileup etc. The next version, Linrad-02.40 will work under Windows Vista, but only with 16 bit audio. Please report all bugs you have noted in 02-39, I will upload 02-40 before leaving. 73 Leif / SM5BSZ ############################################################# This message is sent to you because you are subscribed to the mailing list <linrad@antennspecialisten.se>. To unsubscribe, E-mail to: <[EMAIL PROTECTED]> To switch to the DIGEST mode, E-mail to <[EMAIL PROTECTED]> To switch to the INDEX mode, E-mail to <[EMAIL PROTECTED]> Send administrative queries to <[EMAIL PROTECTED]> ############################################################# This message is sent to you because you are subscribed to the mailing list <linrad@antennspecialisten.se>. To unsubscribe, E-mail to: <[EMAIL PROTECTED]> To switch to the DIGEST mode, E-mail to <[EMAIL PROTECTED]> To switch to the INDEX mode, E-mail to <[EMAIL PROTECTED]> Send administrative queries to <[EMAIL PROTECTED]>
