Re: LF: VX9MRC QRV 507.77 kHz/ Arcing relays &c.

["Graham" <g8fzk@g8fzk.fsnet.co.uk>]

Joe..

There  are  some  'good'   rf relays  at  :-

http://www.surplussales.com/Relays/rfopen.html

Ive  used the  small  open  frame  one's  for  some time  on the  HF bands
may  be a couple of the  6 Kv   open  frame  in series  would  work ?

G..



--------------------------------------------------
From: <jcraig@mun.ca>
Sent: Tuesday, October 11, 2011 2:11 AM
To: <rsgb_lf_group@blacksheep.org>
Subject: Re: LF: VX9MRC QRV 507.77 kHz/ Arcing relays &c.

> Hi Alan, Group.
>
> Thank-you for the reply. Multiple contacts in series were considered... 
> but the gap has to
> increase by orders magnitude!  How much gap will I need for 50 kV?
>
> Your spiral pie story was most enlightening.  My pies are ~35 turns of
> 4mm litz about 37 cm diameter with L=0.24 mH. A stack of 4 yields
> 3mH.  Each pie has ~23 metres of litz.  Do you think this is will give
> the most L for the least length of litz?
>
> VX9MRC is still sending the 8 WPM beacon as yours truly looks at a fried
> relay...
>
> Cheers
> Joe
>
> On Tue, 11 Oct 2011, Alan Melia wrote:
>
> > Hi Joe, why not stick two sets of normal contacts in series....doubles 
> > the
> > gap :-))
> >
> > Alan
> >
> > ----- Original Message -----
> > From: <jcraig@mun.ca>
> > To: <rsgb_lf_group@blacksheep.org>
> > Sent: Monday, October 10, 2011 11:54 PM
> > Subject: Re: LF: VX9MRC QRV 507.77 kHz/ Arcing relays &c.
> >
> >
> > > Hello Hartmut, Group.
> > >
> > > Good to hear from you again, Hartmut.  Thank-you for  the report.
> > >
> > > The beacon is on again, but there was some trouble: to use the tower
> > > on 160m the 500 kHz tuning coil (0.2 mH) is shorted by a relay. The
> > > N.O. contacts on this relay arced over.  Perhaps a high voltage (vacuum)
> > > relay would help?
> > >
> > > This  problem will be much worse on 137.777 kHz with the higher voltage.
> > > I have some spiral wound 4mm (Decca) litz to make up the 3 mH for that
> > > project.  (The spiral winding was inspired by G3NYK's experiments with
> > > tuning coils on his web page.)
> > >
> > > 73
> > > Joe
> > >
> > > On Mon, 10 Oct 2011, Hartmut Wolff wrote:
> > >
> > > > Am 2011-10-09 23:50, wrote jcraig@mun.ca:
> > > > > Dear Group,
> > > > > Reports on the 8 WPM CW beacon will be appreciated!
> > > > > 73
> > > > > Joe VO1NA
> > > > Attached a screenshot of the 8wpm signal. The signal came up at about
> > 23:20
> > > > and faded out at about 7:35. The strongest part was between 04:00-06:00
> > UTC
> > > > --
> > > > 73
> > > > Hartmut
> > > > www.h-wolff.de
> > > > Locator: JO52hp
> > > This electronic communication is governed by the terms and conditions at
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> > >
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