Return-Path: Received: from mtain-ma04.r1000.mx.aol.com (mtain-ma04.r1000.mx.aol.com [172.29.96.12]) by air-me08.mail.aol.com (v129.4) with ESMTP id MAILINME083-8bbe4d55ce7b1b5; Fri, 11 Feb 2011 19:04:11 -0500 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-ma04.r1000.mx.aol.com (Internet Inbound) with ESMTP id 03D82380000A4; Fri, 11 Feb 2011 19:04:08 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Po2wz-0005pB-2x for rs_out_1@blacksheep.org; Sat, 12 Feb 2011 00:02:57 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Po2wy-0005p2-AO for rsgb_lf_group@blacksheep.org; Sat, 12 Feb 2011 00:02:56 +0000 Received: from out1.ip05ir2.opaltelecom.net ([62.24.128.241]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1Po2ww-0004Fn-6A for rsgb_lf_group@blacksheep.org; Sat, 12 Feb 2011 00:02:56 +0000 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AjUBAD5dVU1cHY6K/2dsb2JhbACCS5Bwg2WOXnO8AIVdBIFjjWWCcg X-IronPort-AV: E=Sophos;i="4.60,459,1291593600"; d="scan'208,217";a="331838893" Received: from unknown (HELO xphd97xgq27nyf) ([92.29.142.138]) by out1.ip05ir2.opaltelecom.net with SMTP; 12 Feb 2011 00:02:45 +0000 Message-ID: <002801cbca48$2c87bb60$0401a8c0@xphd97xgq27nyf> From: "mal hamilton" To: References: <988315.45122.qm@web28515.mail.ukl.yahoo.com> <4D5436DE.3040602@iup.uni-heidelberg.de> <673772.16865.qm@web28515.mail.ukl.yahoo.com> <004c01cbca06$f1b88f50$0401a8c0@xphd97xgq27nyf> <690897.31788.qm@web28511.mail.ukl.yahoo.com> Date: Sat, 12 Feb 2011 00:00:52 -0000 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2600.0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 DomainKey-Status: bad format X-Spam-Score: 0.1 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001,HTML_TAG_EXIST_TBODY=0.126 Subject: Re: LF: VLF Transmissions - G3XIZ - 12th / 13th February Content-Type: multipart/alternative; boundary="----=_NextPart_000_0024_01CBCA47.EB4F4280" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.2 required=5.0 tests=HTML_60_70,HTML_MESSAGE, HTML_TAG_EXISTS_TBODY 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-sid: 3039ac1d600c4d55ce781ac8 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none ------=_NextPart_000_0024_01CBCA47.EB4F4280 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Tnx Chris for info, sounds interesting=20 de mal/g3kev ----- Original Message -----=20 From: Chris Osborn=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Friday, February 11, 2011 10:39 PM Subject: Re: LF: VLF Transmissions - G3XIZ - 12th / 13th February Mal,=20 I calculate the PA including the mains transformer is about 70% effi= cient. The push-pull FET's are wired to the 10 - 0 - 10V windings and the= output tappings are at 0 and 240 volts. It has a laminated iron core. The measured secondary voltage is about 350 volts rms so I dare not= push the output power any higher. I'm hoping that with a more efficient loading coil the secondary vol= tage will reduce and I can then push more power, hence current into th= e aerial. I initially tried a LOPT but found the power output very limited. Maybe I was doing something wrong ! 73 Chris G3XIZ ----------------------------------------------------------------------= -------- From: mal hamilton To: rsgb_lf_group@blacksheep.org Sent: Fri, 11 February, 2011 16:15:43 Subject: Re: LF: VLF Transmissions - G3XIZ - 12th / 13th February Chris How efficient is ur mains transformer at 9 Khz, what sort of core,= ferrite or laminated iron I assume from what u say you couple your 5 ohm impedence PA to this= transformer PRIM and output from the SEC to the antenna loading coil.= Is the PRIM normal 250v and what is the sec voltage. or do u use a 6v= winding. etc=20 I have a selection of mains transformers which I could ck out. Have u tried instead a LOPT=20 de mal/g3kev ----- Original Message -----=20 From: Chris Osborn=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Thursday, February 10, 2011 7:23 PM Subject: Re: LF: VLF Transmissions - G3XIZ - 12th / 13th February Mal, Roger, Stefan and group Thanks for the good wishes. It will all depend on weather conditions as to whether I can fly= the balloons but I shall keep you posted via the reflector. I can try longer QRSS periods but begrudge the long wasted 'off'= times especially if I'm having trouble keeping the balloons aloft. A compromise would be for me to manually cut the carrier for 5-10= minute periods. The transmitter feeds the loading coil and aerial via a large step= up (mains) transformer. The TX/ transformer will push its RF power into 2000 - 3000 ohms= which is an approximation of the aerial circuit resistance when reson= ant.. I tried using a 50 ohms TX output and link coupling to the loading= coil but without success. The aerial current should be as before about 0.15 - 0.2 A 73 Chris G3XIZ ----------------------------------------------------------------------= ------ From: Stefan Sch=E4fer To: rsgb_lf_group@blacksheep.org Sent: Thu, 10 February, 2011 19:05:02 Subject: Re: LF: VLF Transmissions - G3XIZ - 12th / 13th February Hi Chris,=20 I think DFCW-600 or even 2400 is a good compromise between a const= ant carrier and some ID but 60 is probably to fast. Jim received you= in less than 2 mHz if i remember correctly. QRSS60 is to fast for tha= t. Looking forward to your results :-) 73, Stefan Am 10.02.2011 18:52, schrieb Roger Lapthorn:=20 Hi Chris, Very good luck. I'll be looking for you and hoping for success= this time.=20 An email direct and to this group saying when TX starts/ends wou= ld be helpful. Don't suppose you can send QRSS60 or similar to help wi= th ID? Have passed the word on to Nick G4IKZ as he is closer to you th= an me and not sure he subscribes to this list. 73s Roger G3XBM On 10 February 2011 14:42, Chris Osborn wrot= e: LF, I have had permission to transmit on VLF this coming weekend:= 12th and 13th February. Weather permitting I shall try again with my balloon-launched= aerial, hopefully about 50m vertical. The frequency will be=20 8.976 66 kHz (i.e. 10.000 MHz / 1114) and is derived from an= oven controlled xtal oscillator. Hopefully the frequency will be more stable than last time. If this frequency proves unsuitable I can transmit on 10.000= MHZ / 1112 . .10.000 MHz / 1116 etc. I shall send a continuous carrier as and when conditions permi= t. My newly built VLF TX is working well and can deliver about 15= 0 watts of RF. On this occasion I shall be using the original (fairly lossy)= loading coil but am presently making a more efficient one. All reports will be most welcome. 73 Chris G3XIZ --=20 g3xbm-qrp.blogspot.com/ www.g3xbm.co.uk www.youtube.com/user/g3xbm G3XBM GQRP 1678 ISWL G11088 =20 =20 =20 =20 =20 =20 =20 =20 =20 =20 =20 =20 =20 =20 =20 =20 =20 =20 =20 =20 =20 =20 =20 =20 =20 =20 =20 =20 =20 =20 =20 ------=_NextPart_000_0024_01CBCA47.EB4F4280 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Tnx Chris for info, sounds interesting =
de mal/g3kev
 
----- Original Message -----
From:=20 Chris= Osborn=20
Sent: Friday, February 11, 20= 11 10:39=20 PM
Subject: Re: LF: VLF Transmis= sions -=20 G3XIZ - 12th / 13th February

Mal,

I calculate the PA including the mains transformer= is about=20 70% efficient.

The push-pull FET's are wired to the 10 - 0 -= 10V=20 windings and the output tappings are at 0 and 240 volts.
It has= a laminated=20 iron core.
The measured secondary voltage is about 350 volts rms= so I dare=20 not push the output power any higher.
I'm hoping that with a more= efficient=20 loading coil the secondary voltage will reduce and I can then push= more power,=20 hence current into the aerial.

I initially tried a LOPT but= found the=20 power output very limited.
Maybe I was doing something wrong !
73=20 Chris G3XIZ

From: mal hamilton= =20 <g3kevmal@talktalk.net>
To:=20 rsgb_lf_group@blacksheep.org
Sent: Fri, 11 February, 2011=20 16:15:43
Subject:= Re: LF: VLF=20 Transmissions - G3XIZ - 12th / 13th February

Chris
How efficient is ur mains transformer at 9= Khz, what=20 sort of core, ferrite or laminated iron
I assume from what u say you couple your 5= ohm impedence=20 PA to this transformer PRIM and output from the SEC to the antenna= loading=20 coil. Is the PRIM normal 250v and what is the sec voltage. or do u= use a 6v=20 winding. etc
I have a selection of mains transformers whi= ch I could=20 ck out.
Have u tried instead a LOPT
de mal/g3kev
 
----- Original Message -----
F= rom: Chris Osborn
Sent: Thursday, February 10= , 2011 7:23=20 PM
Subject: Re: LF: VLF Transm= issions -=20 G3XIZ - 12th / 13th February

Mal,=20 Roger, Stefan and group

Thanks for the good wishes.
It= will all=20 depend on weather conditions as to whether I can fly the balloons= but I=20 shall keep you posted via the reflector.

I can try longer= QRSS=20 periods but begrudge the long wasted 'off' times especially if I'm= having=20 trouble keeping the balloons aloft.
A compromise would be for= me to=20 manually cut the carrier for 5-10 minute periods.

The trans= mitter=20 feeds the loading coil and aerial via a large step up (mains)=20 transformer.
The TX/ transformer will push its RF power into 20= 00 - 3000=20 ohms which is an approximation of the aerial circuit resistance wh= en=20 resonant..
I tried using a 50 ohms TX output and link coupling= to the=20 loading coil but without success.

The aerial current should= be as=20 before about 0.15 - 0.2 A

73
Chris G3XIZ


From: Stefan Sch= =E4fer=20 <schaefer@iup.uni-heidelberg.de>
To:=20 rsgb_lf_group@blacksheep.org
Sent: Thu, 10 February, 2011=20 19:05:02
Subject: Re: LF:=20 VLF Transmissions - G3XIZ - 12th / 13th February

Hi= Chris,=20

I think DFCW-600 or even 2400 is a good compromise between= a=20 constant carrier and some ID but 60 is probably to fast. Jim recei= ved you in=20 less than 2 mHz if i remember correctly. QRSS60 is to fast for tha= t. Looking=20 forward to your results :-)

73, Stefan

Am 10.02.2011= 18:52,=20 schrieb Roger Lapthorn:=20
Hi Chris,

Very good luck. I'll be= looking=20 for you and hoping for success this time.

An email direc= t and to=20 this group saying when TX starts/ends would be helpful. Don't su= ppose you=20 can send QRSS60 or similar to help with ID? Have passed the word= on to=20 Nick G4IKZ as he is closer to you than me and not sure he subscr= ibes to=20 this list.

73s
Roger G3XBM


On 10 February 2011 14:42, Chris Osborn= <g3xiz@yahoo.co.uk>=20 wrote:
LF,
 
I have had permission to transmit on VLF this coming week= end: 12th=20 and 13th February.
Weather permitting I shall try again with my balloon-laun= ched=20 aerial, hopefully about 50m vertical.
 
The frequency will be
 
8.976 66 kHz  (i.e. 10.000 MHz / 1114) and is= derived=20 from an oven controlled xtal oscillator.
Hopefully the frequency will be more stable than last tim= e.
If this frequency proves unsuitable I can transmit on 10.= 000 MHZ /=20 1112 . .10.000 MHz / 1116  etc.
 
I shall send a continuous carrier as and when conditions= =20 permit.
 
My newly built VLF TX is working well and can deliver abo= ut 150=20 watts of RF.
On this occasion I shall be using the original (fairly lo= ssy)=20 loading coil but am presently making a more efficient one= .
 
All reports will be most welcome.
 
73
Chris G3XIZ
 
 




--
g3xbm-qrp.blogspot.com/=
www.g3xbm.co.uk
www.yo= utube.com/user/g3xbm
G3XBM   GQRP=20 1678    ISWL G11088
3D""
&= nbsp;  
=

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&= nbsp;=20



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