Date: Mon, 10 Oct 2011 22:41:00 -0230 (NDT)
From: jcraig@mun.ca
To: rsgb_lf_group@blacksheep.org
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Subject: Re: LF: VX9MRC QRV 507.77 kHz/ Arcing relays &c.
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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
>>>
>>
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>
>

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