Return to KLUBNL.PL main page
| To: | <[email protected]> |
|---|---|
| Subject: | Re: LF: Opera continuous changes |
| From: | "James Moritz" <[email protected]> |
| Date: | Wed, 18 Jan 2012 01:32:55 -0000 |
| Dkim-signature: | v=1; a=rsa-sha256; c=relaxed/relaxed; d=btopenworld.com; s=s1024; t=1326850372; bh=awhswiagVBhMs8fwEhgIANzcZcxy30lUJvcME2RSguk=; h=X-Yahoo-Newman-Property:X-YMail-OSG:X-Yahoo-SMTP:Received:Message-ID:From:To:References:In-Reply-To:Subject:Date:MIME-Version:Content-Type:Content-Transfer-Encoding:X-Priority:X-MSMail-Priority:X-Mailer:X-MimeOLE; b=EmwEwTmQjf0OfjAPy/z+cDr6/5AQeDAVwggwUSAxTU6pkRXnGUP7Cv5pgOtjdRF9SyFc7n0plyomPbZjc3jkwk39aAoe5fxllJtWCodmXduAu3YuGDZT0kKJ4Y8MTGjqOSmxFpHqp7vo6TVVnu+FyCqwv3Kb8wBQHDACQGZ7rE0= |
| Domainkey-signature: | a=rsa-sha1; q=dns; c=nofws; s=s1024; d=btopenworld.com; h=DKIM-Signature:X-Yahoo-Newman-Property:X-YMail-OSG:X-Yahoo-SMTP:Received:Message-ID:From:To:References:In-Reply-To:Subject:Date:MIME-Version:Content-Type:Content-Transfer-Encoding:X-Priority:X-MSMail-Priority:X-Mailer:X-MimeOLE; b=a3tw67W2d1A8F+CrEXCoNGqUL32WP5ffoe4sTrmT91CVTuCYJAJFwDrYpwuwt+pTtNz8XOzmY00Qbu11RHEIjIWVHEPufmycPr8iVQebExKKKQ/+qyZH5aq/yu7sbneYGwgO8wlO+77w8pX2Fun3tZ0/9tGgxw1esIHmf66K394= ; |
| Domainkey-status: | good (testing) |
| In-reply-to: | <FB2C78B23F9943B8B7A52E40B3F0ABC2@AGB> |
| References: | <CAA8k23STzh0z0=AqAXBhz-AEpcT67y-5CSazZny-QT=wuDPhoQ@mail.gmail.com> <2BB40A231A1A4EF8B2DB14786249FA35@AGB> <B52B4B55DF224E24956CAAAF049C6E1A@JimPC> <FB2C78B23F9943B8B7A52E40B3F0ABC2@AGB> |
| Reply-to: | [email protected] |
| Sender: | [email protected] |
Dear Graham, LF Group, Looking at the spec-plots for long haul DX on 136 , the peak signal levels do not appear to support the full call sign when using the very long qrss periods , the ref is often pinged with post asking as to who xx is or zyz etc I think partly this is due to the habit of only transmitting partial callsigns - I am not sure why this is preferred to complete callsigns for beacon transmissions. But it is also true for, e.g. QRSS60 on 136kHz, that there will very often be one or more fades during the time it takes to transmit a full callsign, leading to loss of some of the symbols. So, for an effective low-speed mode where the duration of the message is likely to be longer than the period between fades, the encoding scheme really has to include redundancy in order be able to cope with the loss of some of the data during fades. Over a much shorter period WSPR does this rather well; more than half the transmitted signal can be completely missing and the original message can still be fully recovered. WOLF also achieves this in a different way by integrating several repeated transmissions over a long period. You can do this "visually" with QRSS, etc, by looking at the received fragments of a repeated ID. From what you say, I guess Opera must already include this sort of redundancy in some way, although it is obviously hard to comment without knowing anything about the encoding scheme... Cheers, Jim Moritz 73 de M0BMU |
| <Prev in Thread] | Current Thread | [Next in Thread> |
|---|---|---|
| ||
| Previous by Date: | Re: LF: BIG EARS Grabber, jcraig |
|---|---|
| Next by Date: | LF: 80m qrg, David Michael Gaytko // WD4KPD |
| Previous by Thread: | Re: LF: Opera continuous changes, Graham |
| Next by Thread: | LF: Opera reception, Mike Dennison |
| Indexes: | [Date] [Thread] [Top] [All Lists] |