Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-mb01.r1000.mx.aol.com (Internet Inbound) with ESMTP id CD2563800009D; Fri, 12 Aug 2011 19:06:23 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Qs0nF-0007Yp-8T for rs_out_1@blacksheep.org; Sat, 13 Aug 2011 00:05:33 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Qs0nE-0007Yg-KY for rsgb_lf_group@blacksheep.org; Sat, 13 Aug 2011 00:05:32 +0100 Received: from relay.uni-heidelberg.de ([129.206.100.212]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1Qs0nC-0003CQ-Vo for rsgb_lf_group@blacksheep.org; Sat, 13 Aug 2011 00:05:32 +0100 Received: from freitag.iup.uni-heidelberg.de (freitag.iup.uni-heidelberg.de [129.206.29.204]) by relay.uni-heidelberg.de (8.14.1/8.14.1) with ESMTP id p7CN5UAj016709 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Sat, 13 Aug 2011 01:05:30 +0200 Received: from [129.206.22.206] (pc206.iup.uni-heidelberg.de [129.206.22.206]) by freitag.iup.uni-heidelberg.de (8.12.11.20060308/8.11.2) with ESMTP id p7CN5TiE011177 for ; Sat, 13 Aug 2011 01:05:29 +0200 Message-ID: <4E45B0F9.1000007@iup.uni-heidelberg.de> Date: Sat, 13 Aug 2011 01:02:17 +0200 From: =?UTF-8?B?U3RlZmFuIFNjaMOkZmVy?= User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; de; rv:1.9.1.8) Gecko/20100227 Thunderbird/3.0.3 MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <4E4527EF.2000304@iup.uni-heidelberg.de> <52970A62D1224CAF9A966D1743DCBF00@PcMinto> <4E456AB7.6090403@iup.uni-heidelberg.de> <4FB899125601413A9077646E2728C784@PcMinto> <4E45A678.5010908@iup.uni-heidelberg.de> In-Reply-To: <4E45A678.5010908@iup.uni-heidelberg.de> X-Spam-Score: 1.4 (+) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001,RATWARE_GECKO_BUILD=1.426 Subject: LF: Faulty FKP-1 Content-Type: multipart/alternative; boundary="------------080607030500000609060702" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.5 required=5.0 tests=HTML_20_30,HTML_MESSAGE 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 x-aol-global-disposition: G X-AOL-SCOLL-SCORE: 0:2:490544384:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d60154e45b1ef12fb X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none This is a multi-part message in MIME format. --------------080607030500000609060702 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable X-MIME-Autoconverted: from 8bit to quoted-printable by relay.uni-heidelberg.de id p7CN5UAj016709 Minto, LF, Maybe interesting for other homebrewers in the QRO region as well... Actually the only thing that caused all the faults was a damaged WIMA=20 FKP-1-2 kV cap. I never have had problems with these caps before. Never=20 expected that. They are even suitable as a shunt cap for a 10 MHz 300W=20 class E PA or as the shunt cap in a 1 kW 137 kHz class E... But now one=20 looks quiet big here. I even heard it dying but thought the sound is=20 coming from the FETs, making some noise when switching, you know. Thus=20 the C was much lower and i didn't come on resonance. Probably the=20 undefined C (sometimes even an inner shortcut?) caused strong mismatch=20 and lastly destroyed the FETs. That was the weakest link of the chain. QRO optimisations... The C was=20 0.33 nF + 1 nF + 2.2 nF in parallel, this in series to the small=20 variometer part in the shack. It allows resonating within the entire band. Now replaced, all works well again... 73, Stefan/DK7FC Am 13.08.2011 00:17, schrieb Stefan Sch=C3=A4fer: > Hi Minto. > > The signal must have been about 6 dB lower than yesterday. Still have=20 > to go back to the old system, unfortunately. Difficult to do good=20 > measurements here in the "shack" where all the stuff is floating=20 > either on mains voltage or on 137 kHz or a mixture of that. Have a=20 > battery supplied oscilloscope but anyway. > > I didn't got more than that what you saw, no higher power was possible=20 > even when running the SMPS at 320 VDC. Unfortunately now i saw what=20 > the reason was/is: Some of the turns of the loading coil moved a bit=20 > and so i was outside the resonance. Since the Q of the TX antenna is=20 > very high, the power goes down quickly when beeing outside the=20 > resonance. I haven't had the tuning-meter (U,I, phase) in line, and=20 > just tuned the shack-internal variometer for a maximum signal. > After the unwanted fault and replacing the FET i had to find other=20 > problems like a non conducting shunt resistor (current sensing). This=20 > wasn't visible. For some reason the current limiting didn't work then.=20 > A second loud BAAAAAAANG caused me to *let it be* for this week! Now=20 > two mains fuses here at QRL are OFF and i don't have the key to put=20 > them in again. > Anyway, i'm in holiday for the next 2 weeks and they will be back in=20 > when i am back and no one will remember that, hopefully, hi. > > Actually all that stuff should be exchanges in a QSO :-) BTW how about=20 > YOUR PA? :-) > > 73, Stefan/DK7FC > > Now trying to bring the coil back to its previous L... > > > Am 12.08.2011 23:07, schrieb Minto Witteveen: >> Hi Stefan. >> I see your CQ on my grabber at this moment. >> How does your ERP now compare with yesterday (during your QSO with Mal= )? >> It looks like S/N is now worse here then yesterday. Reason might be=20 >> the loop versus the miniwhip (with the miniwhip the winner). But on=20 >> the other hand there seems to be a lot of QRN (because of lightning=20 >> at this moment. >> 73=E2=80=99s Minto pa3bca >> ----------------------------------------------------------------------= ---- >> Ceterum censeo Carthaginem delendam esse >> *From:* Stefan Sch=C3=A4fer >> *Sent:* Friday, August 12, 2011 20:02 >> *To:* rsgb_lf_group@blacksheep.org >> *Subject:* Re: LF: PA3BCA >> Hi Minto, >> >> Am 12.08.2011 19:42, schrieb Minto Witteveen: >>> >>> How much power were you generating? >>> >>> 73=E2=80=99s, Minto pa3bca >> >> It changes all the time. Not even sure since i just have an E field=20 >> probe to decouple some power from my TX antenna and feed it to a 50=20 >> uA amperemeter, shunted by a potentiometer. This poti was adjusted to=20 >> show 100% full scale when using 120 W RF before some weeks. Now=20 >> reduced the parallel R on the poti so it shows just 25 uA then. Got=20 >> 50 uA anyway by QRO and more (not sure). So it should be arround=20 >> 500W. This is -6 dBfs :-) >> >> But the antenna, i.e. the coil and its cover is very lossy it seems.=20 >> When there was rain, i have up to twice the losses :-( Need to search=20 >> for an alternative cover (mustn't burn, so a water barrel is no=20 >> alternative...). >> >> >> 73, Stefan/DK7FC --------------080607030500000609060702 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-MIME-Autoconverted: from 8bit to quoted-printable by relay.uni-heidelberg.de id p7CN5UAj016709 Minto, LF,

Maybe interesting for other homebrewers in the QRO region as well...

Actually the only thing that caused all the faults was a damaged WIMA FKP-1-2 kV cap. I never have had problems with these caps before. Never expected that. They are even suitable as a shunt cap for a 10 MHz 300W class E PA or as the shunt cap in a 1 kW 137 kHz class E... But now one looks quiet big here. I even heard it dying but thought the sound is coming from the FETs, making some noise when switching, you know. Thus the C was much lower and i didn't come on resonance. Probably the undefined C (sometimes even an inner shortcut?) caused strong mismatch and lastly destroyed the FETs.

That was the weakest link of the chain. QRO optimisations... The C was 0.33 nF + 1 nF + 2.2 nF in parallel, this in series to the small variometer part in the shack. It allows resonating within the entire band.

Now replaced, all works well again...

73, Stefan/DK7FC


Am 13.08.2011 00:17, schrieb Stefan Sch=C3=A4fer:
Hi Minto.

The signal must have been about 6 dB lower than yesterday. Still have to go back to the old system, unfortunately. Difficult to do good measurements here in the "shack" where all the stuff is floating either on mains voltage or on 137 kHz or a mixture of that. Have a battery supplied oscilloscope but anyway.

I didn't got more than that what you saw, no higher power was possible even when running the SMPS at 320 VDC. Unfortunately now i saw what the reason was/is: Some of the turns of the loading coil moved a bit and so i was outside the resonance. Since=C2=A0 the Q of the TX antenna is very high, the power goes down quickly when beeing outside the resonance. I haven't had the tuning-meter (U,I, phase) in line, and just tuned the shack-internal variometer for a maximum signal.
After the unwanted fault and replacing the FET i had to find other problems like a non conducting shunt resistor (current sensing). This wasn't visible. For some reason the current limiting didn't work then. A second loud BAAAAAAANG caused me to let it be for this week! Now two mains fuses here at QRL are OFF and i don't have the key to put them in again.
Anyway, i'm in holiday for the next 2 weeks and they will be back in when i am back and no one will remember that, hopefully, hi.

Actually all that stuff should be exchanges in a QSO :-) BTW how about YOUR PA? :-)

73, Stefan/DK7FC

Now trying to bring the coil back to its previous L...


Am 12.08.2011 23:07, schrieb Minto Witteveen:
Hi Stefan.
=C2=A0
I see your CQ on my grabber at this moment.
How does your ERP now compare with yesterday (during your QSO with Mal)?<= /div>
It looks like S/N is now worse here then yesterday. Reason might be the loop versus the miniwhip (with the miniwhip the winner). But on the other hand there seems to be a lot of QRN (because of lightning at this moment.
=C2=A0
73=E2=80=99s Minto pa3bca
=C2=A0
=C2=A0
--= ------------------------------------------------------------------------<= br> Ceterum censeo Carthaginem delendam esse
=C2=A0
Sent: Friday, August 12, 2011 20:02
Subject: Re: LF: PA3BCA
=C2=A0
Hi Minto,

Am 12.08.2011 19:42, schrieb Minto Witteveen:

How mu= ch power were you generating?

73=E2=80=99s, Minto pa3bca
=C2=A0
=C2=A0

It changes all the time. Not even sure since i just have an E field probe to decouple some power from my TX antenna and feed it to a 50 uA amperemeter, shunted by a potentiometer. This poti was adjusted to show 100% full scale when using 120 W RF before some weeks. Now reduced the parallel R on the poti so it shows just 25 uA then. Got 50 uA anyway by QRO and more (not sure). So it should be arround 500W. This is -6 dBfs :-)

But the antenna, i.e. the coil and its cover is very lossy it seems. When there was rain, i have up to twice the losses :-( Need to search for an alternative cover (mustn't burn, so a water barrel is no alternative...).


73, Stefan/DK7FC
--------------080607030500000609060702--