Return to KLUBNL.PL main page
| To: | [email protected] |
|---|---|
| Subject: | Re: LF: F5WK EbNaut |
| From: | Markus Vester <[email protected]> |
| Date: | Wed, 28 Sep 2016 17:21:50 -0400 |
| Dkim-signature: | v=1; a=rsa-sha256; c=relaxed/relaxed; d=mx.aol.com; s=20150623; t=1475097711; bh=6YnJX3HWNlhxPx9MkFKOWNRKDeysNZ1+E10qKkjhZ9I=; h=From:To:Subject:Message-Id:Date:MIME-Version:Content-Type; b=X4LkM0PNJtuoQ/6AD3kEeMoHjxekewmGJy+H1TJWkLjCtIyyd2N7Di7FmOm0fwRg+ lNPREvwThZkkZH8WVcIVL0NBl+Rq+8PGDFJpc7cGRpri1Kgrk3yPIdiJz1o4VRQNgb O480zy3LfM8KiknEIhinhtNHtKGF7zTrcJr0CMeQ= |
| In-reply-to: | <[email protected]> |
| Reply-to: | [email protected] |
| Sender: | [email protected] |
|
Hi Michel,
your signal is not weak at all, surely good enough for comfortable QRSS3 reading here. Regarding overcurrent trip: I found that for safest operation of a class-D PA, the antenna impedance should be presented as a series resonant circuit to the transistors, because that will have high impedance for any out-of-resonance spectral components. Then during phase reversals, the current will experience a dip rather than a peak. The impedance condition depends on the total phase shift of the matching circuits and low pass filters, which should ideally be 0 or 180°. However feeding into a 50-ohm loading coil tap (or through certain PI- or T-filters) tends to have around 90°, transforming series resonance into parallel resonance, and presenting a short-circuit to the PA for out-of-band exciation. Tonight there seems to be a (somewhat weaker) trace on your QRG again, are you still sending EbNaut? Best 73, Markus (DF6NM) -----Ursprüngliche Mitteilung----- Von: Michel Brunel <[email protected]> An: Domenico IZ7SLZ <[email protected]> Verschickt: Mi, 28 Sept 2016 7:13 pm Betreff: Re: LF: F5WK EbNaut
Hi,
Big thanks to Domenico, Markus and Stefan for their successful decoding of my EbNaut transmissions. Ebnaut decoding is not an easy task especially with weak signal. I fear my GPSDO frequency was not as accurate than expected. I had the bad idea to use a low cost GPS antenna wich performed not as good as the professional grade antenna I used for tests at home. Thus some jitter and phase jumps depending on GPS constellation position. As a "proof of concept" I made Loran-C records during the day using the ebnaut setup and results are sometime good sometime not so good. The transmitter overcurrent was randomly triggered by the phase reversal. Bpsk modulation is performed synchronously by exclusive OR gates, between the D flip-flop and the MOS drivers. Phase reversal is like changing the frequency for a very short time, which leads to a current pike due to the high Q of the LF antenna. Decision was taken to bypass the overcurrent detection. The good way to do bpsk modulation is with a suitable DDS such as AD9852. I found the antenna performs poorly at LF since the radials are burried in a sandy soil, as time goes on. No big deal for ebnaut though. A lot of things to improve for my next LF campaign, 73, Michel - f5wk/P -----Ursprüngliche Mitteilung----- Von: DK7FC <[email protected]> An: rsgb_lf_group <[email protected]> Verschickt: Mi, 28 Sept 2016 2:42 pm Betreff: Re: LF: F5WK EbNaut Hi LF, I tried the 20 UTC transmission (didn't thry the others) and got a nice decode, see attachment. Congrats to the successful transmission. I will join in too in some time :-) 73, Stefan Von: Markus Vester <[email protected]> An: rsgb_lf_group <[email protected]> Verschickt: Mi, 28 Sept 2016 12:33 pm Betreff: Re: LF: F5WK EbNaut Also very nice decodes here: 2016-09-27 "F5WK IN99EF" start Eb/N0 (db) UT symbol carrier 16:15:01 8.5 17.4 (aborted after 9 min) 16:45:01 71.1 22.2 17:00:01 17.7 20.3 17:30:01 17.7 21.3 18:00:01 nil (aborted after 2 min) 18:30:01 17.7 21.7 19:00:01 71.1 21.4 19:30:01 17.7 23.1 20:00:01 17.7 23 20:30:02 71.1 23.9 (1 sec later) 21:00:01 10.4 14.1 21:30:01 16.7 20.7 22:00:01 14.7 15.8 Michel's transmissions are also well visible as blue dashes in the daily grabber archive: http://df6nm.bplaced.net/LF/archive/2016/20160927.jpg http://df6nm.bplaced.net/LF/archive/2016/20160926.jpg Best 73, Markus (DF6NM) Le mercredi 28 septembre 2016 à 11:08:55, Domenico écrivait :
-- |
| <Prev in Thread] | Current Thread | [Next in Thread> |
|---|---|---|
| ||
| Previous by Date: | R: Re: LF: IK1HSS 27th Sept, [email protected] |
|---|---|
| Next by Date: | Re: LF: F5WK EbNaut, Michel Brunel |
| Previous by Thread: | Re: LF: F5WK EbNaut, Michel Brunel |
| Next by Thread: | Re: LF: F5WK EbNaut, Michel Brunel |
| Indexes: | [Date] [Thread] [Top] [All Lists] |