Message-ID: <001201c05fc2$5eef2940$c80c883e@default>
From: "MAL HAMILTON" <MAL@g3kev.freeserve.co.uk>
To: rsgb_lf_group@blacksheep.org
Subject: LF: Re: Re: LF keep cool
Date: Wed, 6 Dec 2000 18:47:04 -0000
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-----Original Message-----
From: Talbot Andrew <ACTALBOT@dera.gov.uk>
To: 'rsgb_lf_group@blacksheep.org' <rsgb_lf_group@blacksheep.org>
Date: 06 December 2000 12:39
Subject: LF: Re: LF keep cool


>Some of us don't have such large antennas as you, Peter.  For 1 Watt ERP
>I would need approx 4kW RF.
>Anyone got any cheap 3 phase 500V bridge rectifiers ?
>
>The Litz wire around surplus now will do a better job at keeping cool
>than copper tube at these frequencies.
Not as good as 25mm water cooled but the pump pressure must be adequate,
otherwise at the 3 - 5 kw power you will get MELTDOWN.
>
>Andy  G4JNT
>
>> With a transmitter running 900watts I can get 1watt erp even with my
>> 'bit of wet string' so there is no need to run more power. To get
>> 1watt erp I have to obtain 4.5amps antenna current with my antenna.
>> The coil is wound with 1.5mm Litz wire (2.5mm including plastic
>> insulation) with an RF resistance of approximately 5ohms and will
>> dissipate around 100 watts during key-down periods.
>
>
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