Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=5.0 tests=FREEMAIL_FORGED_FROMDOMAIN, FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS,HTML_MESSAGE,RCVD_IN_DNSWL_MED, SPF_PASS,T_DKIM_INVALID autolearn=ham autolearn_force=no version=3.4.0 X-Spam-DCC: : mailn 1480; Body=2 Fuz1=2 Fuz2=2 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by lipkowski.org (8.14.4/8.14.4/Debian-8+deb8u1) with ESMTP id v3BE6JU9030197 for ; Tue, 11 Apr 2017 16:06:20 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1cxwMf-0007vh-B7 for rs_out_1@blacksheep.org; Tue, 11 Apr 2017 15:01:49 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1cxwMe-0007vY-Tp for rsgb_lf_group@blacksheep.org; Tue, 11 Apr 2017 15:01:48 +0100 Received: from mail-yb0-x22d.google.com ([2607:f8b0:4002:c09::22d]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.89) (envelope-from ) id 1cxwMZ-0004Yj-L7 for rsgb_lf_group@blacksheep.org; Tue, 11 Apr 2017 15:01:47 +0100 Received: by mail-yb0-x22d.google.com with SMTP id l201so43928134ybf.0 for ; Tue, 11 Apr 2017 07:01:43 -0700 (PDT) X-DKIM-Result: Domain=gmail.com Result=Good and Known Domain DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to; bh=+MFfWTORQ8oi2JrOYGN7SuwJidO7ulPgwMFNMuiEEqs=; b=ZG3ssI3BGzO0pPLv7it2rQJ4xMgIpXeDpbc7QcKzwhlqA+fGLKaxJC3XYmBdl5cKjv ks2ar16e76AfSKxlPXSqOOgrNo7s6A+sm9t/hV19rt5SZOGQ+88zzcEN4nSqTAoW0PQY LoqkeMya1TJeyYzBCi2fCsLdKFfGzIelkVIVB1Yyr66qr8KaSZs/FEkmRjybm6PFpKqe 52x63LErBGLicSDR3ZYDY1fbfEPnplZd9a8r9LK2GkzPbM9IeK7S3Swv0LujhXjKbEsd NRfXwzgCfypAdGaZ4mJpNfN5rgqdymhfu5khaKRywBt50UjYW1645qqlthSII0zogT6g Fr1w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to; bh=+MFfWTORQ8oi2JrOYGN7SuwJidO7ulPgwMFNMuiEEqs=; b=rWc3l6xcxRN/zT76fyIyHPvpCNCrjI1duJOGNuaSblZBuC/aF8SpReabeldAJc8099 XdEr9fqYvLgI4k5c/bfmMCbGBlDs2X+An8I1o4MSezQFoSgxH0VtV/u9guNo5xfhzr+t bYBuUg7I3kg2AJEVCc3aC/jHoRU2YHtjqHACx2tykxeBSC0LVjO/6KaaI3b3JxvwjNRD HVMPJSPl1j5SzT9b2qGIOr8Q801N85YtB5te+5N8UbsNcc2pTkrpjw3nL8kV6HVNtux6 Q8d7ACg6jUXbhdta+TmWLQbw8cJlwodQq0joRVw59HYOaD7SEmU1VUUAL0dTwSMbwZMo PTFQ== X-Gm-Message-State: AN3rC/7YozQaKK7fSO6sjvuZSzihArmcjhZFFxHGJZQUbAzsWvy7CvgNhbqOjfl5v+CH1Th7UmWldH6Of+QOvg== X-Received: by 10.37.174.130 with SMTP id b2mr8368804ybj.125.1491919301520; Tue, 11 Apr 2017 07:01:41 -0700 (PDT) MIME-Version: 1.0 Received: by 10.129.173.1 with HTTP; Tue, 11 Apr 2017 07:01:41 -0700 (PDT) In-Reply-To: References: <1294128911.20170408174233@gmail.com> <15b4f9773b2-2fd8-bf55@webprd-a08.mail.aol.com> <1316557940.20170410114729@gmail.com> <948964339.20170411115001@gmail.com> From: Andy Talbot Date: Tue, 11 Apr 2017 15:01:41 +0100 Message-ID: To: rsgb_lf_group@blacksheep.org X-Scan-Signature: 5e4f7dbaa4e67ba4f35166ebb5a870be Subject: Re: LF: Wilkinson combiners - More Content-Type: multipart/alternative; boundary=f403045da834005232054ce488c7 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-Scanned-By: MIMEDefang 2.75 Status: O X-Status: X-Keywords: X-UID: 11229 --f403045da834005232054ce488c7 Content-Type: text/plain; charset=UTF-8 Oops, that should have read V <= 4.44 .F.N.A.B (V RMS) You want to keep B down below some value where it drives teh core into saturation / non-linearity. But not so many turns that copper losses start to dominate 'jnt On 11 April 2017 at 13:01, Andy Talbot wrote: > If your PAs are the push pull type using a transformer, you'll have to > keep those, and take their secondary winding to the combiner. Not ideal > but not a lot you can do if you use that sort of design rather than a > bridge or half-bridge > > I don't use toroids for LF transformers - never have, never would. I use > SMPSU cores - you know where you are with them and are safe in the > assumption they are exactly as advertised . Its a long time since I > bought any, but the last ones I used were 3C90 material IIRC, but there's > better stuff out there now. > > I might use iron dust toroids as inductive elements for filters and DC > chokes, but gapped ferrites work as well, and rather more precise in their > calculations > > As for determining core size and number of turns Just use the equation V > >= 4.44 .F.N.A.B (all in Si units) , keeping B below around 0.1 or even > below 0.07 Tesla and you're there. Look at SMPSUs to get a feel for the > size of core for a given power. > > If your individual modules are designed for 50 ohm load, then your > secondary on the combiner needs to deliver the summed power to 50 ohms. I > only ever saw the idea used on the Deccas with their own individual tanks. > You'll just have to try it and see > > Just noticed you sent this message off-list ? > > > Andy > > > > > On 11 April 2017 at 11:50, Chris Wilson wrote: > >> Hello Andy, >> >> >> OK, I can see the elegance in that, but pardon the probably daft >> question, but at the combining output transformer, is its input taken >> from my existing output transformers' secondary windings, or do I >> remove both of those and the combining transformer takes their place? >> How would I work out what toroid and winding wire to use as a single >> amp already causes some warming, albeit I believe it is derived from >> the primary wire, rather than the ferrite itself being heated. Thanks. >> >> Monday, April 10, 2017, 7:49:36 PM, you wrote: >> >> > Why not keep it simple, and do it like the Decca transmitters? >> > Forget complicated splitters/combiners with messy deliberate >> > isolation. You are combining identical signals so that sort of design >> is not required. >> >> >> > BEFORE any low pass filters, take each output of each transmitter >> > module to separate identical primary windings on one, normal ferrite >> > transformer core. Use a single secondary to take the combined power >> > off through a low pass filter to your antenna. (But do size the >> > core and turns for the TOTAL power to be generated) >> >> >> > As both transmitter modules will be delivering identical outputs, >> > the voltage induced in primary 2 coil from Tx module 1 will be >> > exactly equal to the that delivered to it from Tx module 2 (and >> > vice versa) so with both transmitters operating correctly, the >> > outputs will sum in the secondary. you are adding teh currents >> > delivered by each stage, from an equal voltage delivered by both. >> > You are, to all intents and purposes, connecting the transmitters in >> > parallel to multiply the current delivered in total >> >> >> > You can use the combining transformer for impedance matching if >> > wanted - for example the Decca ones have direct drive to the >> > primary windings via a tank circuit and each of the ( In their case >> > three) primary to single-secondary turns ration ratio sets the >> impedance transformation. >> >> >> > Isolating combiners like Wilkinsons only come into their own >> > properly when non-identical signals need to be summed while keeping >> > the two sources isolated. Intermod testing in receivers is a >> > particular case in point, where the two test signals have to be >> > summed without generating their own intermod products caused by the >> > output of one source leaking into the (probably non-linear) output >> > of the other. If that happened, self-generated IMPS that could swamp >> those being tested-for. >> >> >> >> > Andy G4JNT >> >> >> >> >> >> >> -- >> Best regards, >> Chris mailto:dead_fets@gmail.com >> >> >> > --f403045da834005232054ce488c7 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Oops, that should have read=C2=A0

V <= ;=3D 4.44 .F.N.A.B =C2=A0 =C2=A0 (V RMS)

You want = to keep B down below some value where it drives teh core into saturation / = non-linearity. =C2=A0 =C2=A0But not so many turns that copper losses start = to dominate


'jnt

On 11 April 2017 at 13:01, Andy Talbo= t <andy.g4jnt@gmail.com> wrote:
If your PAs are the push pull type using a transformer, you'= ;ll have to keep those, and take their secondary winding to the combiner. = =C2=A0 Not ideal but not a lot you can do if you use that sort of design ra= ther than a bridge or half-bridge

I don't use toroid= s for LF transformers - never have, never would.=C2=A0 I use SMPSU cores - = you know where you are with them and are safe in the assumption they are ex= actly as advertised . =C2=A0 Its a long time since I bought any, but the la= st ones I used were 3C90 material IIRC, but there's better stuff out th= ere now.

I might use iron dust toroids as inductiv= e elements for filters and DC chokes, but gapped ferrites work as well, and= rather more precise in their calculations

As for = determining core size and number of turns Just use the equation V >=3D 4= .44 .F.N.A.B (all in Si units) , =C2=A0 =C2=A0 keeping B below around 0.1 o= r even below 0.07 Tesla and you're there. =C2=A0 Look at SMPSUs to get = a feel for the size of core for a given power.

If = your individual modules are designed for 50 ohm load, then =C2=A0your secon= dary on the combiner needs to deliver the summed power to 50 ohms.=C2=A0 I = only ever saw the idea used on the Deccas with their own individual tanks.= =C2=A0 You'll just have to try it and see

Just= noticed you sent this message off-list ?


Andy




On 11 April 2017 at 11:5= 0, Chris Wilson <dead.fets@gmail.com> wrote:
Hello Andy,


OK, I can see the elegance in that, but pardon the probably daft
question, but at the combining output transformer, is its input taken
from my existing output transformers' secondary windings, or do I
remove both of those and the combining transformer takes their place?
How would I work out what toroid and winding wire to use as a single
amp already causes some warming, albeit I believe it is derived from
the primary wire, rather than the ferrite itself being heated. Thanks.

Monday, April 10, 2017, 7:49:36 PM, you wrote:

> Why not keep it simple, and do it like the Decca transmitters? =C2=A0<= br> > Forget complicated splitters/combiners with messy deliberate
> isolation.=C2=A0 You are combining identical signals so that sort of d= esign is not required.


> BEFORE any low pass filters, take each output of each transmitter
> module to separate identical primary windings on one, normal ferrite > transformer core.=C2=A0 Use a single secondary to take the combined po= wer
> off through a low pass filter to your antenna. =C2=A0 (But do size the=
> core and turns for the TOTAL power to be generated)


> As both transmitter modules will be delivering identical outputs,
> the voltage induced in primary 2 coil from Tx module 1 will be
> exactly equal to the that delivered to it from Tx =C2=A0module 2 (and<= br> > vice versa) =C2=A0so with both transmitters operating correctly, the > outputs will sum in the secondary. =C2=A0 =C2=A0you are adding teh cur= rents
> delivered by each stage, from an equal voltage delivered by both. =C2= =A0
> You are, to all intents and purposes, connecting the transmitters in > parallel to multiply the current delivered in total


> You can use the combining transformer for impedance matching if
> wanted - for example the Decca ones =C2=A0have direct drive to the
> primary windings via a tank circuit and each of the ( In their case > three) primary to single-secondary turns ration ratio sets the impedan= ce transformation.


> Isolating combiners like Wilkinsons only come into their own
> properly when non-identical signals need to be summed while keeping > the two sources isolated. =C2=A0 =C2=A0Intermod testing in receivers i= s a
> particular case in point, where the two test signals have to be
> summed without generating their own intermod products caused by =C2=A0= the
> output of one source leaking into the (probably non-linear) output
> of the other.=C2=A0 If that happened, self-generated IMPS that could s= wamp those being tested-for.



> Andy =C2=A0G4JNT
=





--
Best regards,
=C2=A0Chris=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 mailto:dead_fets@gmail.com




--f403045da834005232054ce488c7--