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Date: Mon, 11 Apr 2016 12:46:39 -0400
Message-ID: <CAMFjj71mz43WMxbTrUgUf3rvoHPCL9CVhWF5wxJisGw0Re5Nag@mail.gmail.com>
From: Warren Ziegler <wd2xgj@gmail.com>
To: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Subject: Re: LF: Re: Screening an LF Loading Coil
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Status: O

Hugh,

   You have opened up a profitable new area of research with your use
of a beer keg:-)
May I suggest a moonshine (hard liquor) distillery for your next project?
 The condenser features a large copper vessel with coils of copper
tubing attached.
Should be very high Q :-)

73 W

On Mon, Apr 11, 2016 at 12:31 PM, LineOne <dhchurch@lineone.net> wrote:
> It just sits on a corrugated steel roof which is grounded so a strap from
> keg to roof would also prevent any "diode" action when transmitting. I have
> just made s field strength device which will be installed if it ever stops
> raining so that may help.
>
> Hugh, M0DSZ
>
>
> On 11/04/2016 11:10, Alan Melia wrote:
>>
>> Hi Hugh,mmm that is quite a lot. Thinking of the copper lined tuning huts
>> Decca and Orfordness I guess the keg should be grounded. ??
>>
>> Alan
>> G3NYK
>> ----- Original Message ----- From: "LineOne" <dhchurch@lineone.net>
>> To: <rsgb_lf_group@blacksheep.org>
>> Sent: Monday, April 11, 2016 10:32 AM
>> Subject: Re: LF: Re: Screening an LF Loading Coil
>>
>>
>>> Thank you Alan, the location inside makes your suggested spacing,
>>> suspended and spaced on fibreglass rods. It needs more Tx testing as a
>>> few
>>> brief reception reports were about 5dB down but that was probably
>>> "propagation" conditions.
>>>
>>> Hugh.
>>>
>>> On 10/04/2016 17:04, Alan Melia wrote:
>>>>
>>>> Hi Hugh I think the rule of thumb (or at least the one I use) is that
>>>> the
>>>> lowest turn should be at least half the coil diamter from the screen
>>>> base
>>>> (which if too close will exhibit the properties of a shorted turn) and
>>>> the diameter of the screen should be at least twice the diameter of the
>>>> coil....more is better, but.......
>>>>
>>>> I think that should be OK with your coil size supported in the middle of
>>>> the keg, Hope you had the pleasure of emptying it :-))
>>>>
>>>> Alan
>>>> G3NYK
>>>>
>>>> ----- Original Message ----- From: "LineOne" <dhchurch@lineone.net>
>>>> To: <rsgb_lf_group@blacksheep.org>
>>>> Sent: Sunday, April 10, 2016 4:50 PM
>>>> Subject: LF: Screening an LF Loading Coil
>>>>
>>>>
>>>>> A few years ago I found an aluminium beer keg which had been used for
>>>>> mixing cement. As it was damaged it was no good returning it to the
>>>>> brewery so I have just moved my LF loading coil into it and placed the
>>>>> assembly outside on a corrugated steel roof. (Having the coil suspended
>>>>> from the shack ceiling was not a good idea for the long term).
>>>>>
>>>>> I took the end off the keg, which is 370mm internal diameter, and the
>>>>> coil is on a 130 mm former, likely to be no more than 160mm diameter
>>>>> wound. The antenna is predominantly current fed so no voltage larger
>>>>> than about 3kV is present.
>>>>>
>>>>> Has anyone tried this and am I likely to lose radiated power by
>>>>> reducing
>>>>> the Q of the coil, the Tx output voltage and current are just the same?
>>>>>
>>>>> Hugh, M0DSZ
>>>>>
>>>>
>>>>
>>>>
>>>
>>>
>>
>>
>>
>
>


-- 
73 Warren K2ORS
                WD2XGJ
                WD2XSH/23
                WE2XEB/2
                WE2XGR/1