Return-Path: Received: from rly-dc10.mx.aol.com (rly-dc10.mail.aol.com [172.19.136.39]) by air-dc08.mail.aol.com (v124.15) with ESMTP id MAILINDC081-b474a668f9636f; Wed, 22 Jul 2009 00:03:52 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-dc10.mx.aol.com (v124.15) with ESMTP id MAILRELAYINDC103-b474a668f9636f; Wed, 22 Jul 2009 00:03:36 -0400 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1MTT22-0001Lw-6t for rs_out_1@blacksheep.org; Wed, 22 Jul 2009 05:02:18 +0100 Received: from [83.244.159.144] (helo=relay3.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1MTT21-0001Ln-42 for rsgb_lf_group@blacksheep.org; Wed, 22 Jul 2009 05:02:17 +0100 Received: from blu0-omc1-s26.blu0.hotmail.com ([65.55.116.37]) by relay3.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1MTT1s-0000jG-PU for rsgb_lf_group@blacksheep.org; Wed, 22 Jul 2009 05:02:14 +0100 Received: from BLU146-W19 ([65.55.116.7]) by blu0-omc1-s26.blu0.hotmail.com with Microsoft SMTPSVC(6.0.3790.3959); Tue, 21 Jul 2009 21:02:01 -0700 Message-ID: X-Originating-IP: [138.32.244.2] From: Laurence BY3A-KL1X China To: Date: Tue, 21 Jul 2009 20:02:01 -0800 Importance: Normal In-Reply-To: <57a24ca70907210620v6f208cf2t898ce58cab2e9776@mail.gmail.com> References: <57a24ca70907210620v6f208cf2t898ce58cab2e9776@mail.gmail.com> MIME-Version: 1.0 X-OriginalArrivalTime: 22 Jul 2009 04:02:01.0770 (UTC) FILETIME=[2ABF00A0:01CA0A81] X-Spam-Score: 0.9 (/) X-Spam-Report: autolearn=disabled,HTML_10_20=0.945,HTML_MESSAGE=0.001 Content-Type: multipart/alternative; boundary="_9649a137-2c91-4ff9-b3e8-d1244c0a1c51_" Subject: LF: Warrens Kw's X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.4 required=5.0 tests=FORGED_HOTMAIL_RCVD, HTML_MESSAGE,UP_TO_OR_MORES 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-IP: 193.82.116.20 X-Mailer: Unknown (No Version) --_9649a137-2c91-4ff9-b3e8-d1244c0a1c51_ Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable =20 I agree with John TAG's points on current sharing and keeping the distance= of the conductors apart - my spacing was a lot more than that (feet in pl= aces) but thats due to the ascent stage of the throwing device being non= gyrostabilzed and tended to go off target as it hit a tree (need a bow/sp= ud gun next time!) =20 Voltages wise - with the typical some 350ft circumference loop I had appro= aching 50A of current in the loop, but voltages were were still high enoug= h across the matching components for corona, and as John ann Eric and othe= rs have found out sharp points and conductors/PVC onto branches at high po= wers will arc given a choice.=20 =20 Must still have been over a couple of Kv - I cant afford a forest fire but= verticals just wont work for me and give even more issue. =20 I didnt take a lightweight conductor and insulation solution route - I see= m to remember my total copper and insulation weight being close to 350 pou= nds net - but I adopted a thick insulation, certainly not light or cheap,= but I didnt get burn thru at the +24hr >1Kw level=20 =20 As far as how high you could go - well if you were able to insulate all se= ctions off the tree Im sure You could shove a few Kw round the loop but th= e current capacity of the components is going to be LARGE Warren -=20 =20 - Like John I too used heavy duty insulators with tensioning on the horizo= ntal lower leg - My were marine composite material over 12 inches long -= the rest just sat on the branches. After a year or more I took the loops= down and inspected the insulation and although I had scuffing on the Nylo= n outer sheath it didnt break thru to the PVC jacket and can/will be used= again. =20 There was a load of discussion from my peers and betters on whether multip= le parallel conductors would be stable in the wind as their relative posit= ion to each other "up there" does change - but looking at the phase/amp me= ter during the fierciest Okie storms and my limited experience of single= conductors I would say it was manageable and I had very little tuning iss= ues. =20 I did have heating of my toroids 2T:14T (variable) - more heat from the= two turn side but I think I would change my design to see if I can reduce= the flux/stress a bit more by adding more ferrite and or changing the rat= ios a bit more - though I do remember changing to 3T and varying the turns= accordingly wasnt so good for my "array".=20 =20 Current load sharing on the matching capacitor side was very important and= many smaller value caps versus a couple of large ones was the way to go.= I used a mix of G2 and G3 Sangamos Mica's totallying some 12.5nF and the= G3 7.5nF (thats the biggest) was warm at 24 hr operation - the 1.5nF/3nF= werent... a typical solution would be to use a number of http://cgi.ebay.= com/SANGAMO-Mica-Capacitor-.0012-MFD-10,000-Volts-11-Amps_W0QQitemZ4000625= 64002QQcmdZViewItemQQimsxZ20090719?IMSfp=3DTL090719159005r24905 or similar= in parallel - I do prefer the heftier G3's though. =20 Differing tree, types, rough/smooth, varying incident branch angles may ch= ange your choice on conductor and insulation type - Id love to use a load= of u/g RG6 in parallel but I think my Silver Birch in AK will wear it dow= n - I cant shove hose pipe up to protect the insulation as everything has= to be invisible (invisible in a forest/!) I used Black 4 or 6 AWG TFFN -= pvc insulation with a nylon sheath - that slippery 6 mils of nylon really= helps. =20 As john indicated the proof was in the smell and thermal temperatures of= the components - Keeping a weather sealed box, critters out without getti= ng thermal stress was difficult in my case. Going to +2Kw with what Ive go= t wouldnt work and I would have to redesign everything again - =20 =20 My Ceramic feed thrus using brass knurled nuts some 1/4inch diameter were= getting noticably warm and probably needed uprating - and it was more lik= e high voltage/high current battery telephone exchange wiring techniques= than radio. =20 What was interesting was looking at the efficiency of loops at 137kHz and= some of the modelling tools - 350ft was considered by one program (too sm= all <1%) but as you went up to 400-500 ft or more the efficiency really do= es zoom up - its going to be one of those copper RF losses versus total lo= op size variable but I can shove up a 500 footer loop but not with the wan= ted vertical section height - so again it would probably prove not so effi= cient. =20 My water table is only 11ft beneath the array so Im not expecting as good= as results on the rocky ground of Okie - but Ill proably be wrong again= - Empirical measurement rools... =20 good luck with the combiner Warren -=20 =20 Off topic but just had a solar eclipse here - just taken on my Blackberry http://kl1x.com/eclipsejuly2209teda.jpg - didnt have the LF radio on this= time. =20 Laurence Kl1X China =20 > Date: Tue, 21 Jul 2009 09:20:43 -0400 > From: wd2xgj@gmail.com > To: rsgb_lf_group@blacksheep.org > Subject: LF: Loop (was Re: IGBT in 136 KHz TX?) >=20 > Laurence, >=20 > What do you think is the upper power limit for a loop using > coaxial cable as a conductor? > I've run about 1.3 kW into my loop made up of one turn RG-11 and one > turn RG-214 (both turns parallel as in your case). > Once one of the coax conductors came into contact with wet leaves near > the feed point and began to burn through the insulation and the leaves > - the first indication was erratic aerial currrent. >=20 > I'm thinking of running two Deccas into a combiner but not sure > if the loop insulation is sufficient. >=20 > --=20 > 73 Warren K2ORS > WD2XGJ > WD2XSH/23 > WE2XEB/2 > WE2XGR/ >=20 > On Tue, Jul 21, 2009 at 1:47 AM, Laurence BY3A-KL1X > China wrote: > > Jeff - The "turns" of the mains WD2XDW loop were just distanced parall= el > > loops running in roughly the same plane to reduce the RF copper losses= and > > open up the bandwidth a bit - . I did try a couple of "turns" but neve= r > > managed to get the ommppff field. Interesting given the fact that some > > people use 2 turns on their K9AY's successfully - > > > > All the loops ends up welded together on lugs and attached to the tun= er. > > Ive just overhauled the tuner ready to put on line for WE2XPQ but it= will be > > running lower power for a while as I dont want to start a forest fire= in > > Alaska! > > > > Back home in KL7 on August 14th again...just need time... > > > > laurence > > BY3A-KL1X Tanggu China 34degC > > We2XPQ/ x Wd2XDW Wasilla AK > > > > > > Subject: Re: LF: Re: IGBT in 136 KHz TX? > > > > > > Hello Markus and Rick! > > > > I have only just acquainted myself with your messages. > > (Just going out from hospital, big blood pressure problem...) > > Thanks a lot for precious information, of what make fun still! > > I recovered some ferrites N87 types which should work in 137 KHZ. > > Another subject interests me, it is the possibility of transmitting wi= th a > > big spool of several turns (a bit as WD2XDW). But EIRP is much weaker= than > > with a vertical aerial, then it is necessary to "push more" in power! > > > > Thanks in advance! > > > > 73: Jeff / F6CWN > > > > > > > > ________________________________ > > Windows Live=99 SkyDrive=99: Store, access, and share your photos. See= how. >=20 >=20 >=20 > 1 >=20 _________________________________________________________________ Windows Live=99 Hotmail=AE: Celebrate the moment with your favorite sports= pics. Check it out. http://www.windowslive.com/Online/Hotmail/Campaign/QuickAdd?ocid=3DTXT_TAG= LM_WL_QA_HM_sports_photos_072009&cat=3Dsports=3D --_9649a137-2c91-4ff9-b3e8-d1244c0a1c51_ Content-Type: text/html; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable  
I agree with John TAG's points on current sharing and keeping the dis= tance of the conductors apart - my spacing was a lot more than that (feet= in places) but thats due to the  ascent stage of the throwing= device being non gyrostabilzed and tended to go off target as it hit a tr= ee (need a bow/spud gun next time!)
 
Voltages wise - with the typical some 350ft circumference loop I had appro= aching 50A of current in the loop, but voltages were were still high= enough across the matching components for corona, and as John ann Er= ic and others have found out sharp points and conductors/PVC&nbs= p;onto branches at high powers will arc given a choice.
 
Must still have been over a couple of Kv - I cant afford a forest fire but= verticals just wont work for me and give even more issue.
 
I didnt take a lightweight conductor and insulation solution route - I see= m to remember my total copper and insulation weight being close to 350 pou= nds net - but I adopted a thick insulation, certainly not light or cheap,= but I didnt get burn thru at the +24hr  >1Kw level
 
As far as how high you could go - well if you were able to insulate all se= ctions off the tree Im sure You could shove a few Kw round the loop= but the current capacity of the components is going to be LARGE Warren -=
 
- Like John I too used heavy duty insulators with tensioning on the horizo= ntal lower leg - My were marine composite material over 12 inches long -= the rest just sat on the branches. After a year or more I took the loops= down and inspected the insulation and although I had scuffing on the Nylo= n outer sheath it didnt break thru to the PVC jacket and can/will be= used again.
 
There was a load of discussion from my peers and betters on whether multip= le parallel conductors would be stable in the wind as their relative posit= ion to each other "up there" does change - but looking at the phase/amp me= ter during the fierciest Okie storms and my limited experience of single= conductors I would say it was manageable and I had very little tuning iss= ues.
 
I did have heating of my toroids 2T:14T (variable)  - more heat from= the two turn side but I think I would change my design to see if I can re= duce the flux/stress a bit more by adding more ferrite and or changing the= ratios a bit more - though I do remember changing to 3T and varying the= turns accordingly wasnt so good for my "array".
 
Current load sharing on the matching capacitor side was very imp= ortant and many smaller value caps versus a couple of large ones was the= way to go. I used a mix of  G2 and G3 Sangamos Mica's totallyin= g some 12.5nF and the G3 7.5nF (thats the biggest) was warm at 24 hr= operation - the 1.5nF/3nF werent... a typical solution would be to use a= number of http://cgi.ebay.com/SANGAMO-Mica-Capacitor-.0= 012-MFD-10,000-Volts-11-Amps_W0QQitemZ400062564002QQcmdZViewItemQQimsxZ200= 90719?IMSfp=3DTL090719159005r24905 or similar in parallel - I do= prefer the heftier G3's though.
 
Differing tree, types, rough/smooth, varying incident branch angles may ch= ange your choice on conductor and insulation type - Id love to use a load= of u/g RG6 in parallel but I think my Silver Birch in AK will wear it dow= n - I cant shove hose pipe up to protect the insulation as everything has= to be invisible (invisible in a forest/!) I used Black 4 or 6 AWG TFFN -= pvc insulation with a nylon sheath - that slippery 6 mils of nylon really= helps.
 
As john indicated the proof was in the smell and thermal temperatures of= the components - Keeping a weather sealed box, critters out without getti= ng thermal stress was difficult in my case. Going to +2Kw with what Ive go= t wouldnt work and I would have to redesign everything again -
 
 
My Ceramic feed thrus using brass knurled nuts some 1/4inch diameter were= getting noticably warm and probably needed uprating - and it was more lik= e high voltage/high current battery telephone exchange wiring techniques= than radio.
 
What was interesting was looking at the efficiency of loops at 137kHz and= some of the modelling tools - 350ft was considered by one program (too sm= all <1%) but as you went up to 400-500 ft or more the efficiency really= does zoom up - its going to be one of those copper RF losses versus total= loop size variable but I can shove up a 500 footer loop but not with the= wanted vertical section height - so again it would probably prove not so= efficient.
 
My water table is only 11ft beneath the array so Im not expecting as good= as results on the rocky ground of Okie - but Ill proably be wrong again= - Empirical measurement rools...
 
good luck with the combiner Warren -
 
Off topic but just had a solar eclipse here - just taken on my Blackberry<= BR> http://kl1x.com/eclips= ejuly2209teda.jpg - didnt have the LF radio on this time.
 
Laurence
Kl1X China

 
> Date: Tue, 21 Jul 2009 09:20:43 -0400
> From: wd2= xgj@gmail.com
> To: rsgb_lf_group@blacksheep.org
> Subject: LF= : Loop (was Re: IGBT in 136 KHz TX?)
>
> Laurence,
> > What do you think is the upper power limit for a loop using
>= coaxial cable as a conductor?
> I've run about 1.3 kW into my loop= made up of one turn RG-11 and one
> turn RG-214 (both turns paralle= l as in your case).
> Once one of the coax conductors came into cont= act with wet leaves near
> the feed point and began to burn through= the insulation and the leaves
> - the first indication was erratic= aerial currrent.
>
> I'm thinking of running two Deccas into= a combiner but not sure
> if the loop insulation is sufficient.
= >
> --
> 73 Warren K2ORS
> WD2XGJ
> WD2XSH/23=
> WE2XEB/2
> WE2XGR/
>
> On Tue, Jul 21, 2009 at= 1:47 AM, Laurence BY3A-KL1X
> China<hellozerohellozero@hotmail.c= om> wrote:
> > Jeff - The "turns" of the mains WD2XDW loo= p were just distanced parallel
> > loops running in roughly the= same plane to reduce the RF copper losses and
> > open up the ba= ndwidth a bit - . I did try a couple of "turns" but never
> >= ; managed to get the ommppff field. Interesting given the fact that some> > people use 2 turns on their K9AY's successfully -
>= >
> > All the loops ends up welded together  on lugs and= attached to the tuner.
> > Ive just overhauled the tuner ready= to put on line for WE2XPQ but it will be
> > running lower power= for a while as I dont want to start a forest fire in
> > Alaska!=
> >
> > Back home in KL7 on August 14th again...just ne= ed time...
> >
> > laurence
> > BY3A-KL1X Tangg= u China 34degC
> > We2XPQ/ x Wd2XDW Wasilla AK
> >
&g= t; >
> >  Subject: Re: LF: Re: IGBT in 136 KHz TX?
>= ; >
> >
> > Hello Markus and Rick!
> >
&g= t; > I have only just acquainted myself with your messages.
> >= ; (Just going out from hospital, big blood pressure problem...)
> &g= t; Thanks a lot for precious information, of what make fun still!
>= > I recovered some ferrites N87 types which should work in 137 KHZ.> > Another subject interests me, it is the possibility of transmit= ting with a
> > big spool of several turns (a bit as WD2XDW). But=  EIRP is much weaker than
> > with a vertical aerial, then= it is necessary to "push more"  in power!
> >
> >= Thanks in advance!
> >
> > 73: Jeff / F6CWN
> >= ;
> >
> >
> > ________________________________<= BR>> > Windows Live=99 SkyDrive=99: Store, access, and share your ph= otos. See how.
>
>
>
> 1
>

Windows Live=99 Hotmail=AE: Celebrate the moment with your favorite spo= rts pics. Check it out. =3D --_9649a137-2c91-4ff9-b3e8-d1244c0a1c51_--