Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by klubnl.pl (8.14.4/8.14.4/Debian-8+deb8u2) with ESMTP id w38AmhAC016585 for ; Sun, 8 Apr 2018 12:48:45 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1f57m3-0004c5-H4 for rs_out_1@blacksheep.org; Sun, 08 Apr 2018 11:42:15 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1f57m2-0004bw-T6 for rsgb_lf_group@blacksheep.org; Sun, 08 Apr 2018 11:42:14 +0100 Received: from resqmta-ch2-01v.sys.comcast.net ([69.252.207.33]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.89) (envelope-from ) id 1f57ly-0003CW-55 for rsgb_lf_group@blacksheep.org; Sun, 08 Apr 2018 11:42:13 +0100 Received: from resomta-ch2-05v.sys.comcast.net ([69.252.207.101]) by resqmta-ch2-01v.sys.comcast.net with ESMTP id 57jufrQWO6JVp57jufQJui; Sun, 08 Apr 2018 10:40:02 +0000 X-DKIM-Result: Domain=comcast.net Result=Signature OK DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=comcast.net; s=q20161114; t=1523184002; bh=JlM96kIT1werQ/sv8F7O/bpHJ59E9i4saF+HGCrQBms=; h=Received:Received:From:Subject:To:Content-Type:MIME-Version:Date: Message-ID; b=SLyOHb6+m5PyoxTlCO1WszmueUPUzNcydNkDFAlkKzGlF1kSD3XgpMUDDRp+FeQkg kG6HAOlVXb1EYeQx2w/4PYUWAGFkRQmephAG8jF+oLik/u6bvkzZzZvQIbXNEu0vcs 4rYnsmYeVyJY/6l+iiTGcLrRkzUwvQ6LFExWlXU2t5u8YjAUBnQJx+bQzCo2wD68Py dbXwNNjB8Tj3Xa2yw0jPiLZ4MFAiNYfKCGlAAVNoVNiZZhNaBGCkKi4DyHwbN4FgS3 V0pNZbeCTseX6jvfKrdRb2qTEx2YnzRG6D6NUe21fktJSKG8ZJ0AEVBsHAjr/C+J11 eBIbCOugcA4eQ== Received: from Optiplex980-PC ([73.4.253.141]) by resomta-ch2-05v.sys.comcast.net with SMTP id 57jsfgJ2bYwe657jtfldLA; Sun, 08 Apr 2018 10:40:01 +0000 From: "jrusgrove@comcast.net" To: "rsgb_lf_group@blacksheep.org" MIME-Version: 1.0 References: <162a4797468-1db9-bdf2@webjas-vae168.srv.aolmail.net> Date: Sun, 8 Apr 2018 06:40:00 -0400 Message-ID: <1UQROqZht1.1c1VdzC0S69@optiplex980-pc> In-Reply-To: <162a4797468-1db9-bdf2@webjas-vae168.srv.aolmail.net> User-Agent: OEClassic/2.7 (Win7; P; 2017-02-12) X-Mailer: OEClassic/2.7 (Win7; P; 2017-02-12) X-CMAE-Envelope: MS4wfP8clgiPVdKxo4Qo0hIkEp3imEOeYjHMEPJhAMSRPOMglj87SN4nR3Dg2OLSeD0trpfAgyAU6c9HNkgqiWmKJUk9laCjRi0631o7gXrQkmkao5uM9dS0 uIygWQB8CNZp6GE60rNg5PTBk/XyW1SL8tHbuS8oZR/L1+QPnrQWDAbqWeIrzePHDzLNwSKsY7aZYg== X-Spam-Score: 0.0 (/) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has NOT identified this incoming email as spam. The original message has been attached to this so you can view it or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Paul In addition to Ward's comments ... To be more consistent with the original design (to avoid the "I built it just like ... except" syndrome) move the driver board close to the FETs to shorten the gate twisted pairs. Resistors / diodes should be right at the gates. [...] Content analysis details: (0.0 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 T_RP_MATCHES_RCVD Envelope sender domain matches handover relay domain 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (jrusgrove[at]comcast.net) 0.0 HTML_MESSAGE BODY: HTML included in message 0.0 T_DKIM_INVALID DKIM-Signature header exists but is not valid X-Scan-Signature: e3d323418d60e0f7f0af176deb9f3e2b Subject: Re: LF: W1VD amp help Content-Type: multipart/alternative; boundary="BXv1kvMJlORK5et3kbu=_VuWv8ASU1Li9Y" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.1 required=5.0 tests=HTML_FONTCOLOR_UNKNOWN, HTML_MESSAGE,TO_ADDRESS_EQ_REAL autolearn=no version=2.63 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 This is a multi-part message in MIME format --BXv1kvMJlORK5et3kbu=_VuWv8ASU1Li9Y Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Paul In addition to=20 Ward's comments ... To be more consistent with the original design (to avoid the "I built = it just like ... except" syndrome) move the driver board close to the = FETs to shorten the gate twisted pairs. Resistors / diodes should be r= ight at the gates. HP3325A ... set frequency x2, square wave, amplitude 5 volts, dc offse= t 2.5 volts. Have used the HP3325A here for countless numbers of years= =2E=20 51 ohm resistor is there to properly terminate the end of the coaxial = cable connecting the HP3325A (or other exciter) to the amplifier. On the gate waveforms, what's=20 going on above the FET turn on / off voltage (several volts) is of lit= tle=20 concern unless there's significant 'anomalous=20 action'. Some rounding above the turn on voltage is normal. On the drain waveforms, what's=20 going on above zero volts on the waveform is of less concern than what= the=20 waveform is doing when at zero volts (FET conducting). During conducti= on (zero=20 volts) the waveform should go to zero and stay there for the duration.= During=20 the non conduction period (voltage higher than zero) the peak of the r= inging=20 should be well below the FET breakdown voltage.=20 Chris's waveforms look pretty normal. =20 The prototypes of the doubler and amplifier were all run with no shiel= ding for years. In fact, even after building the packaged amplifier I = continued to run the 'out=20 in the=20 open' prototypes rather than reconfigure the station.=20 Always start out on the dummy load. Test in stages. Test the driver in= to the FETs with the FET drain supply off. Verify the waveforms with a= dual trace scope to see that there's=20 a small 'dead zone' between the two phases. This prevents the possibil= ity of=20 cross conduction. Once the gate waveforms are confirmed to be correct,= turn on=20 the FET drain supply. Once the amplifier is verified to be working pro= perly add=20 the doubler. Gotta run ... more later if necessary. Jay W1VD =20 =20 ----- Original Message ----- From: Ward K7PO Reply-To: To: Sent: 4/8/2018 4:57:26 AM Subject: Re: LF: W1VD amp help Paul, I may have missed some of the previous posts, but=20 here's my $0.02 worth. When I built my first version of the amp, I set= the X2 option on the U3S and drove the amp directly from the CLK outp= ut on the U3S synth. Everything worked fine. On the next one, I had al= l sorts of weirdness until I removed the 50 ohm resistor on the input.= I assumed the U3S at 3.3v couldn't=20 provide enough drive across the resistor. Since then, I have left the = resistor=20 out of every amp driven by the U3S, with no issues. A level translator= would=20 probably be better, but I have thousands of hours on a couple of these= amps=20 with no problems. Ward K7PO=20 -----Original Message----- From: JD To: rsgb_lf_group Sent: Sat, Apr 7, 2018 10:37 pm Subject: Re: LF: W1VD amp help The 74F74 is an edge-triggered flip-flop. so the correct input for the= main=20 board is a square wave at TTL voltage levels, with fast rise and fall = times,=20 but with a current requirement greater than TTL because of the 51 ohm = load=20 resistor. As for the oscillation when the doubler is used, the issue may be whet= her there's enough shielding. The phase detector input of the 74HCT404= 6 that provides signal conditioning is very sensitive...maybe not enou= gh to break into oscillation spontaneously, but perhaps enough to sust= ain it once a feedback path has been established with actual RF throug= h the power stage. 73 John --BXv1kvMJlORK5et3kbu=_VuWv8ASU1Li9Y Content-Type: text/html; charset="utf-8" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline
Paul
 
In addition to Ward's comments ...
 
To be more consistent with the original design (to avoid the "I b= uilt it just like ... except" syndrome) move the driver board close to= the FETs to shorten the gate twisted pairs. Resistors / diodes should= be right at the gates.
 
HP3325A ... set frequency x2, square wave, amplitude 5 volts, dc = offset 2.5 volts. Have used the HP3325A here for countless n= umbers of years.
 
51 ohm resistor is there to properly terminate the end of the coa= xial cable connecting the HP3325A (or other exciter) to the ampli= fier.
 
On the gate waveforms, what's going on above the FET turn on / of= f voltage (several volts) is of little concern unless t= here's significant 'anomalous action'. Some rounding above the tu= rn on voltage is normal.
 
On the drain waveforms, what's going on above zero volts on = the waveform is of less concern than what the waveform is doing w= hen at zero volts (FET conducting). During conduction (zero volts= ) the waveform should go to zero and stay there for the duration.= During the non conduction period (voltage higher than zero) the = peak of the ringing should be well below the FET breakdown voltage. Ch= ris's waveforms look pretty normal.     
 
The prototypes of the doubler and amplifier were all run with no = shielding for years. In fact, even after building the packaged am= plifier I continued to run the 'out in the open' prototypes rather tha= n reconfigure the station.
 
Always start out on the dummy load. Test in stages. Test the= driver into the FETs with the FET drain supply off. Verify the wavefo= rms with a dual trace scope to see that there's a small 'dea= d zone' between the two phases. This prevents the possibility of = cross conduction. Once the gate waveforms are confirmed to b= e correct, turn on the FET drain supply. Once the amplifier is verifie= d to be working properly add the doubler.
 
Gotta run ... more later if necessary.
 
Jay W1VD     
 
  
 
 
----- Original Message -----
From: Ward K7PO <w= mwheaton@aim.com>
Sent: 4/8/2018 4:57:26 AM
Subject: Re: LF: W1VD amp help
Paul,

I may have missed some of the previous posts, bu= t here's my $0.02 worth. When I built my first version of the amp, I s= et the X2 option on the U3S and drove the amp directly from the CLK ou= tput on the U3S synth. Everything worked fine. On the next one, I had = all sorts of weirdness until I removed the 50 ohm resistor on the inpu= t. I assumed the U3S at 3.3v couldn't provide enough drive across the = resistor. Since then, I have left the resistor out of every amp driven= by the U3S, with no issues. A level translator would probably be bett= er, but I have thousands of hours on a couple of these amps with no pr= oblems.

Ward K7PO



-----Original Message-----
From: JD <us66soft@aol.com>To: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Sent: Sat,= Apr 7, 2018 10:37 pm
Subject: Re: LF: W1VD amp help

The 74F= 74 is an edge-triggered flip-flop. so the correct input for the main b= oard is a square wave at TTL voltage levels, with fast rise and fall t= imes, but with a current requirement greater than TTL because of the 5= 1 ohm load resistor.

As for the oscillation when the doubler is= used, the issue may be whether there's enough shielding. The phase de= tector input of the 74HCT4046 that provides signal conditioning is ver= y sensitive...maybe not enough to break into oscillation spontaneously= , but perhaps enough to sustain it once a feedback path has been estab= lished with actual RF through the power stage.

73
John
--BXv1kvMJlORK5et3kbu=_VuWv8ASU1Li9Y--