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Date: Sat, 28 Nov 2015 16:26:54 +0000
Message-ID: <CAA8k23QsB+NEdkYwnMtX3Kn1KgF6y=OGGkNdP-1=1v3_y6yJqQ@mail.gmail.com>
From: Andy Talbot <andy.g4jnt@gmail.com>
To: rsgb_lf_group@blacksheep.org
Subject: Re: 3 phase (was LF: G3KEV)
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What's wrong with that ?
Sounds an excellent idea for a QRO transmitter.   300Hz ripple - much
easier to filter out.

My 137kHz Tx runs from rectified (single phase) mains - the isolation is
provided in the ferrite output transformer and FET drive pot-core

A school we once went around with long leads and an AVO  identifying
sockets to be found on all three of the phases.  That was so that, using
extension leads, we could bring them all into the lab to get a three phase
motor running.   Such interesting things could be done in schools in the
1970's

Andy G4JNT


On 28 November 2015 at 15:52, John Rabson <john.rabson07@gmail.com> wrote:

>
> In the early days of 73 kHz I believe a Luxembourg station built a
> transmitter which was powered off full-wave rectified three-phase mains
> without an isolating transformer. NOT the best way of doing things!
>
> John F5VLF
>

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<div dir=3D"ltr">What&#39;s wrong with that ?<div>Sounds an excellent idea =
for a QRO transmitter. =C2=A0 300Hz ripple - much easier to filter out.</di=
v><div><br><div>My 137kHz Tx runs from rectified (single phase) mains - the=
 isolation is provided in the ferrite output transformer and FET drive pot-=
core</div></div><div><br></div><div>A school we once went around with long =
leads and an AVO =C2=A0identifying sockets to be found on all three of the =
phases.=C2=A0 That was so that, using extension leads, we could bring them =
all into the lab to get a three phase motor running. =C2=A0 Such interestin=
g things could be done in schools in the 1970&#39;s</div><div><br></div><di=
v>Andy G4JNT</div><div><br></div><div class=3D"gmail_extra"><br><div class=
=3D"gmail_quote">On 28 November 2015 at 15:52, John Rabson <span dir=3D"ltr=
">&lt;<a href=3D"mailto:john.rabson07@gmail.com" target=3D"_blank">john.rab=
son07@gmail.com</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"><br=
>
In the early days of 73 kHz I believe a Luxembourg station built a transmit=
ter which was powered off full-wave rectified three-phase mains without an =
isolating transformer. NOT the best way of doing things!<br>
<br>
John F5VLF<br></blockquote></div></div></div>

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