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Message-ID: <00e601c7d5c2$e0d29fa0$a17d383e@Tom>
From: "Tom Boucher" <tom@telemetry.demon.co.uk>
To: <rsgb_lf_group@blacksheep.org>
References: <005001c7d3fe$e4786d80$6400a8c0@oem17oeylz9on8>  <001901c7d42b$e6fbeaa0$86048351@w4o8m9>  <00a001c7d43c$f4180690$0a7ee150@o>  <Pine.LNX.4.64.0708011456010.10082@lurcher.twatt.local> <1IGMYh-02648G0@fwd31.t-online.de> <003001c7d4d1$fcaf0390$db3a383e@Tom> <000101c7d5a4$5f527220$4e69e150@o> <008901c7d5b0$eea7c040$a17d383e@Tom> <003801c7d5ba$56f3cc80$6401a8c0@JAYTERMINAL>
Date: Fri, 3 Aug 2007 12:38:56 +0100
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Subject: LF: Re: Re: Re: 500 / OLB test-sig...
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Status: O

Most interesting Jay. Your 136 installation looks extremely well engineered. 
The loading coil/variometer looks almost identical to the one I made for 
136, without the gears and motor. I used an 1100' end fed wire when active 
on that band!

73, Tom G3OLB

----- Original Message ----- 
From: "Jay Rusgrove" <JRusgrove@comcast.net>
To: <rsgb_lf_group@blacksheep.org>
Sent: Friday, August 03, 2007 11:37 AM
Subject: LF: Re: Re: 500 / OLB test-sig...


> Tom
>
> That's a lot of wire in the air...congratulations! Usually the more the 
> better but in this case it
> sounds like too much. One approach would be to trim the horizontal top 
> wire of the L to get the +j18
> close to 0. Then it would be a matter of matching the R to 50 ohms. You 
> could use a smaller version
> of the tapped transformer shown near the bottom of this page:
>
> http://www.w1vd.com/XNStxantenna.html
>
> If a low SWR is important to you across the band you may want to shorten 
> the antenna beyond the j0
> point and add a variable inductor in series with the vertical wire.
>
> Jay W1VD / WD2XNS
>
>
>
> ----- Original Message ----- 
> From: "Tom Boucher" <tom@telemetry.demon.co.uk>
> To: <rsgb_lf_group@blacksheep.org>
> Cc: "Finbar" <beachwood@eircom.net>
> Sent: Friday, August 03, 2007 5:30 AM
> Subject: LF: Re: 500 / OLB test-sig...
>
>
> Rog (and others) - thank you for this. You may, or may not, be interested 
> in the matching
> arrangement for my antenna.
>
> The antenna is an extension of my 160 metre inverted 'L' which has an 80' 
> vertical section to a tree
> on a 20' bank - the effective height may therefore not be as much as 80'. 
> This antenna sits on 19
> radials which are 60 - 100' long and are either buried or lying on the 
> ground, in order to act as
> trip wires for my XYL when she trespasses on my antenna area.
>
> An additional 358' has been added to this antenna to make the total 
> quarter wave length of 492'.
> This added wire zig-zags for 50' or so then is largely in a straight line 
> held up by 3 further tree
> halyards and ends up about 30' above ground.
>
> This antenna with no matching showed a minimum VSWR at 506KHz of 2.5:1 and 
> impedance of 22 + j18. By
> empirical means (!) I established that a parallel capacitance of some 6000 
> pF brought the SWR to a
> low figure but, not unexpectedly, took the resonant frequency up to 
> 521KHz; an L-section using part
> of the antenna's self-inductance. To bring the antenna back down to 
> 502KHz, I added a small
> inductance between capacitor/coax and the base of the antenna.
>
> The final values were 9 micro-Henrys (22 turns on 1'' dia) and 6,600pF (3 
> x 2,200 pf 1000v
> polypropylene) giving 1.1:1 @ 503 KHz, 50 + j10.
>
> I was surprised at the high value of capacitance needed to resonate this 
> antenna and am not sure how
> you go about calculating the necessary values as these were established by 
> trial and error. Perhaps
> there is an academic out there who can tell me!
>
> 73, Tom
> G3OLB
>  ----- Original Message ----- 
>  From: GW3UEP
>  To: rsgb_lf_group@blacksheep.org
>  Sent: Friday, August 03, 2007 8:55 AM
>  Subject: LF: 500 / OLB test-sig...
>
>
>  Tom,
>  Hrd your test-loop ydy - steady S7 on meter - ur tidying up has wrkd!
>  Ur closing the gap on Mike [S9/40mls via Preseli mountain] over the 
> ~90mls part sea-path bn us.
>  Hope to improve ant nxt wk, jobs permitting.
>  Rog.
>
>  ----- Original Message ----- 
>  From: Gw3UEP
>  To: Tom Boucher
>  Sent: Monday, July 30, 2007 2:18 PM
>  Subject: Re:
>
>  Tom - what hve u done?  Fantastic sig nw - on meter S5/6...
>
>