Message-ID: <20080824233353.muhlmpin3r34kggk@webmail4.kuleuven.be>
Date: Sun, 24 Aug 2008 23:33:53 +0200
From: Rik Strobbe <Rik.Strobbe@fys.kuleuven.be>
To: rsgb_lf_group@blacksheep.org
References: 	<000d01c9052d$6f142c30$0301a8c0@mal769a60aa920><C6D17EC6BC594EC7A5CAAF551968B84E@AGB><003e01c90543$b12bb870$0301a8c0@mal769a60aa920>
	<20080823193946.20d4b66b@sighthound.demon.co.uk>
	<005701c90555$0018bcb0$0301a8c0@mal769a60aa920>
	<9256A09B44B94949B34506B5E7260A84@AGB>
In-Reply-To: <9256A09B44B94949B34506B5E7260A84@AGB>
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Subject: Re: LF: 500khz rtty
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Based on the antenna description given by Mal ("1/4 wave inv L for 500 =20
khz, 100 ft vertical and rest horizontal") simulation reveals a =20
radiation resistance of 5 Ohm and a directivity of 1.5 dBd. This means =20
that only 375 mA antenna current is needed to radiate 1 W ERP.
It is hard to tell from here, but such a big antenna should have a =20
loss resistance of 20 Ohm or less. So in the worst case 2.8 Watt TX =20
power is needed to get 1 Watt ERP.

I can only dream of such a situation ;-)

73, Rik  ON7YD - OR7T

> From: "mal hamilton" <g3kevmal@talktalk.net>
> Sent: Saturday, August 23, 2008 8:18 PM
> To: <rsgb_lf_group@blacksheep.org>
> Subject: Re: LF: 500khz rtty
>
>>
>> ANYTIME . If you saw the fet in my PA you would'nt bother.
>> G3KEV
>>
>> ----- Original Message ----- From: "John Pumford-Green GM4SLV"  =20
>> <gm4slv@sighthound.demon.co.uk>
>> To: <rsgb_lf_group@blacksheep.org>
>> Sent: Saturday, August 23, 2008 7:39 PM
>> Subject: Re: LF: 500khz rtty
>>
>>
>>> On Sat, 23 Aug 2008 18:14:23 +0100
>>> "mal hamilton" <g3kevmal@talktalk.net> wrote:
>>>
>>>> I thought that would be the response from you. Why no ID?
>>>> I will let OFCOM decide if necessary
>>>> G3KEV
>>>
>>> Perhaps we could ask them to check your ERP at the same time?
>>>
>>>
>>>
>>> No virus found in this incoming message.
>>> Checked by AVG - http://www.avg.com
>>> Version: 8.0.138 / Virus Database: 270.6.6/1626 - Release Date:  =20
>>> 8/21/2008 6:54 PM
>>>
>>>
>>>
>>
>>
>>
>>
>> No virus found in this incoming message.
>> Checked by AVG - http://www.avg.com Version: 8.0.138 / Virus  =20
>> Database: 270.6.7/1628 - Release Date: 8/22/2008 18:32
>>
>>
>>



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