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Date: Mon, 29 Feb 2016 22:26:40 +0000
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From: Andy Talbot <andy.g4jnt@gmail.com>
To: rsgb_lf_group@blacksheep.org, rsgb_lf_group@yahoogroups.co.uk
Subject: Re: LF: Wolf Test transmission again
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Its still running, and the old design is holding-up .  I found a circuit
diagram in the archives and realise there is yet another bit of bodgery
that needs to be sorted if this is to be used for long duration unattended
transmissions.

The 12V supply used for the fan and other bits of control circuitry is
derived from the input supply by a single LM317 regulator.  That device is
specified for 40V maximum across it, so at 50V input gives
just a 2V margin.   Nowadays, when I want a regulator from 50V to something
low, I use an auxiliary emitter follower to coarsely pre-regulate the input
to the main regulator to some lower intermediate and safe value.

Will inform here when it finally goes off tonight

'jnt


On 29 February 2016 at 20:03, John Andrews <w1tag@charter.net> wrote:

> Andy,
>
> Will be watching!
>
> John, W1TAG
>
> On 2/29/2016 2:16 PM, Andy Talbot wrote:
>
>> I've put the signal back on, this time using the new (actually very old)
>> transmitter.   Running a little over 200 Watts so about 90 - 100mW EIRP
>>
>> Not entirely sure how long I'll run it for - certainly not overnight.  I
>> don't think that PA has ever been used in anger - until now
>>
>> 137630Hz   Wolf-10
>>
>> Andy  G4JNT
>>
>
>

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<div dir=3D"ltr"><div>Its still running, and the old design is=C2=A0holding=
-up .=C2=A0 I found a circuit diagram in the archives and realise there is =
yet another bit of bodgery that needs to be sorted if this is to be used fo=
r long duration unattended transmissions.</div><div><br></div><div>The 12V =
supply used for the fan and other bits of control circuitry is derived from=
 the input supply by a single LM317 regulator.=C2=A0 That device=C2=A0is sp=
ecified for 40V maximum across it, so at 50V input=C2=A0gives just=C2=A0a=
=C2=A02V=C2=A0margin.=C2=A0=C2=A0=C2=A0Nowadays, when I want a regulator fr=
om 50V to something low, I use an auxiliary emitter follower to coarsely pr=
e-regulate the input to the=C2=A0main regulator=C2=A0to some lower intermed=
iate and safe value.</div><div><br></div><div>Will inform here when it fina=
lly goes off tonight</div><div><br></div><div>&#39;jnt</div><div><br></div>=
<div><br></div><div><br></div></div><div class=3D"gmail_extra"><br><div cla=
ss=3D"gmail_quote">On 29 February 2016 at 20:03, John Andrews <span dir=3D"=
ltr">&lt;<a href=3D"mailto:w1tag@charter.net" target=3D"_blank">w1tag@chart=
er.net</a>&gt;</span> wrote:<br><blockquote class=3D"gmail_quote" style=3D"=
margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Andy,<br>
<br>
Will be watching!<br>
<br>
John, W1TAG<br>
<br>
On 2/29/2016 2:16 PM, Andy Talbot wrote:<br>
<blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;padding=
-left:1ex;border-left-color:rgb(204,204,204);border-left-width:1px;border-l=
eft-style:solid">
I&#39;ve put the signal back on, this time using the new (actually very old=
)<br>
transmitter.=C2=A0 =C2=A0Running a little over 200 Watts so about 90 - 100m=
W EIRP<br>
<br>
Not entirely sure how long I&#39;ll run it for - certainly not overnight.=
=C2=A0 I<br>
don&#39;t think that PA has ever been used in anger - until now<br>
<br>
137630Hz=C2=A0 =C2=A0Wolf-10<br>
<br>
Andy=C2=A0 G4JNT<br>
</blockquote>
<br>
</blockquote></div><br></div>

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