Date: Fri, 23 Nov 2018 21:29:31 +0000 (UTC)
From: Markus Vester <markusvester@aol.com>
To: rsgb_lf_group@blacksheep.org
Message-ID: <1050898420.5270936.1543008571489@mail.yahoo.com>
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Subject: Re: LF: No 2200m TX tonight
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Hi Paul,

sorry to read that. Have pity on the poor FETs!

You mentioned that the antenna resistance is gradually decreasing (i.e. imp=
roving) during longer transmissions. I often see that effect here, with the=
 current rising by say 20 % during the first few minutes. I've put it down =
to moisture or dew around the coil and insulators=C2=A0(tiny little polycar=
bomnnate=C2=A0pencil tubes), which evaporates as things warm up. It is more=
 prominent during cold damp weather, and much more so=C2=A0with the very hi=
gh antenna impedance at VLF than at LF.

Good luck,
Markus=C2=A0


-----Urspr=C3=BCngliche Mitteilung-----
Von: N1BUG <paul@n1bug.com>
An: rsgb_lf_group@blacksheep.org <rsgb_lf_group@blacksheep.org>
Verschickt: Fr, 23. Nov. 2018 22:12
Betreff: LF: No 2200m TX tonight

No transmissions from me this night. The little amplifier has died.
I think it may be related to this resistance change in the antenna
which is getting worse and worse.

I'm going back to MF for this night, sorry!

73,
Paul


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<div style=3D"font-size:10pt;font-family:arial,helvetica,sans-serif;color:b=
lack;"><div style=3D"color: black; font-family: arial,helvetica,sans-serif;=
 font-size: 10pt;">Hi Paul,<br><br>sorry to read that. Have pity on the poo=
r FETs!<br><br>You mentioned that the antenna resistance is gradually decre=
asing (i.e. improving) during longer transmissions. I often see that effect=
 here, with the current rising by say 20 % during the first few minutes. I'=
ve put it down to moisture or dew around the coil and insulators&nbsp;(tiny=
 little polycarbomnnate&nbsp;pencil tubes), which evaporates as things warm=
 up. It is more prominent during cold damp weather, and much more so&nbsp;w=
ith the very high antenna impedance at VLF than at LF.<br><br>Good luck,<br=
>Markus&nbsp;<br><br><br>-----Urspr=C3=BCngliche Mitteilung-----<br>Von: N1=
BUG &lt;paul@n1bug.com&gt;<br>An: rsgb_lf_group@blacksheep.org &lt;rsgb_lf_=
group@blacksheep.org&gt;<br>Verschickt: Fr, 23. Nov. 2018 22:12<br>Betreff:=
 LF: No 2200m TX tonight<br><br></div><div dir=3D"ltr">No transmissions fro=
m me this night. The little amplifier has died.<br></div><div dir=3D"ltr">I=
 think it may be related to this resistance change in the antenna<br></div>=
<div dir=3D"ltr">which is getting worse and worse.<br></div><div dir=3D"ltr=
"><br></div><div dir=3D"ltr">I'm going back to MF for this night, sorry!<br=
></div><div dir=3D"ltr"><br></div><div dir=3D"ltr">73,<br></div><div dir=3D=
"ltr">Paul<br></div><div dir=3D"ltr"><br></div></div>
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