Message-ID: <002001cac175$33623910$0301a8c0@your91hoehfy9g>
From: "mal hamilton" <g3kevmal@talktalk.net>
To: <rsgb_lf_group@blacksheep.org>
References: <000a01cac139$b9d5e5a0$0401a8c0@xphd97xgq27nyf> <9D7C2F9B306347BEA848AC1560D1162B@JimPC>
Date: Thu, 11 Mar 2010 23:47:24 -0000
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Subject: LF: Re: Re: DREAM 9 ANTENNA
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Jim & Co
This is a band that really requires a large TX antenna to be realistic about
covering a few hundred miles otherwise all the work could be in vain with no
one to communicate with. No point having several stations active that only
radiate a few miles when in fact they are all hundreds of miles apart.
When I fired up on 73 most had moved to 137 at the time but I put in a few
appearances on CW. All the action was on 137 CW and I worked over 30
countries at the last count. I cannot say I have heard you much over the
years, just once in a while.
I suggested 50 ohms for my own convenience, equipment availability etc but
it could be anything.
g3kev

----- Original Message -----
From: "James Moritz" <james.moritz@btopenworld.com>
To: <rsgb_lf_group@blacksheep.org>
Sent: Thursday, March 11, 2010 8:34 PM
Subject: LF: Re: DREAM 9 ANTENNA


> Dear Mal, LF Group,
>
> G3KEV wrote:
> ... Base load the antenna with the necessary inductance for resonance and
if
> necessary add another small inductor in series to ground and adjust with
> taps up from ground to get a 1 : 1 match with the coax feed from the TX,
> readjust the main inductor to maintain resonance if necessary.
> This system has never failed me on 73, 137 and 500 kcs and this would be
my
> approach on 9 kcs.
> ...
>
> - However it would fail at 9kHz, or on any other band, if the total loss
> resistance of the antenna and main loading coil is >50ohms. This is often
> the case with smaller antennas than those at G3KEV, especially at lower
> frequencies. At 9kHz, it seems to be quite hard to make the loading coil
> resistance by itself as low as 50 ohms. If the total loss resistance IS
> greater than 50ohms, then a different configuration of matching network is
> required.
>
> BTW, Mal, I don't ever remember hearing you on 73kHz...
>
> Cheers, Jim Moritz
> 73 de M0BMU
>
>
>
>
>
>
>