Return to KLUBNL.PL main page
| To: | <[email protected]> |
|---|---|
| Subject: | Re: LF: Re: Ferrite wideband antennas? |
| From: | "James Moritz" <[email protected]> |
| Date: | Thu, 1 Sep 2011 23:08:35 +0100 |
| Dkim-signature: | v=1; a=rsa-sha256; c=relaxed/relaxed; d=btopenworld.com; s=s1024; t=1314914853; bh=24N8ehYPIsKg9x2+XcvDb5IFOjqeCSgU1CzYugmniE0=; 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=xYi9ZM3lweDzyej0+4aIOIS1s3jDTdeOYbDxR97nmkwQm/xIQoRL2SbdrOccCSZK6WeetFZqQmPp7vBJyVYLmpYQaTZOjBPo43xqhmspHwLway6mcJ3QSiH+ZYBVyKZvQaccX+4RCuhVGoshQD+G2uxvQbDdp9M/uno4lcSNSUw= |
| 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=2XfSGbsSiucL9mpLUpJ3WwS9PEKwwwmFj/BXRXlVFdDCx4cJlZxUrGmVM3HR4uPB87taiBOUcAF/cFqVbgpbpuY07YQiw4OKrAy8+UF7Fyk921Bvjb6d8RNSDPMo75iCnIcWoJ7gyF6wLdEMpcQXYlrwjlXZrXbPBOYMIlCvqMM= ; |
| Domainkey-status: | good (testing) |
| In-reply-to: | <[email protected]> |
| References: | <[email protected]> <[email protected]> |
| Reply-to: | [email protected] |
| Sender: | [email protected] |
Dear Peter, Victor, LF Group,Thanks for the info... unfortunately the wide-band type of loop is not really viable at my QTH due to the 10s of volts/metre from the nearby broadcast stations. try a BFP640,rBB 1ohm.Noise as low as 300pV/sqrt(Hz) is possible.Verycheap,but one drawback,Ft is about 40GHz,not easy to get stable.For topbandI use BD139 (yes a lf driver),rbb 1,2 Ohm,very easy to use.. For my 136k and 500k "bandpass loops" preamps, I have used the ZTX690B. The complete preamp circuit with the input shorted gives an equivalent input voltage noise of about 600pV/sqrt Hz. The feedback and bias resistors must contribute significantly to this, so the transistor itself is certainly lower noise still. It is characterised as a small power switch, with high current rating, low saturation voltage and minimum hFE of 500 - transistors of this general type seem to be good choices for LF/MF low-impedance preamps. The fT is "150MHz minimum", so UHF instability is not a problem. Cheers, Jim Moritz73 de M0BMU |
| <Prev in Thread] | Current Thread | [Next in Thread> |
|---|---|---|
| ||
| Previous by Date: | RE: LF: ros, Laurence KL7UK |
|---|---|
| Next by Date: | LF: test, Markus Vester |
| Previous by Thread: | Re: LF: Re: Ferrite wideband antennas?, pws |
| Next by Thread: | Re: LF: Re: Ferrite wideband antennas?, pws |
| Indexes: | [Date] [Thread] [Top] [All Lists] |