Message-ID: <4DF0AAEE.90208@iup.uni-heidelberg.de>
Date: Thu, 09 Jun 2011 13:13:50 +0200
From: =?ISO-8859-1?Q?Stefan_Sch=E4fer?= <schaefer@iup.uni-heidelberg.de>
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Subject: Re: LF: antenna for 137kHz.
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Hi Martin,

Am 09.06.2011 13:00, schrieb Martin Evans.:
>
> Hi Stephan.
>
> Well, the plan is to get my aerial working properly on receive first, 
> then use it to transmit as well.  I am only interested in LF - 137kHz 
> and  160m, no higher.
Sounds good! ;-)
I think mostly the TX antenna is rather noisy compared to a separate RX 
antenna, at least if you are not outside in the landscape.
>
> It would be most convenient if I could just use the one aerial for 
> both because I have the usual problems with the Estates Manager (the 
> XYL!!).
Oh, i know about that problem ;-) Maybe you can build a single turn loop 
(out of copper tube) and cover it with some flowers like roses? This 
should not affect the resonance too much ;-) Or build a loop disguised 
as an archway, like 
http://ecx.images-amazon.com/images/I/51YGxLs6YZL.jpg :-)
>
> I do intend to get an E probe working as well - it could go on the 
> pole on the house, on a smaller pole on top, and be maybe 15 meters 
> above ground,  but this comes later.
OK. But maybe the "earth" of this pole is "contaminated" with QRN. 
You'll see!

Good luck and fun. The season comes! :-)

73, Stefan
>
> Martin  GW3UCJ.
>
> #######################
>
>
>> I assume you're talking about RX antennas?
>> If you want to use a loop, maybe you want to build an own loop for 
>> 137 kHz that is placed as far as possible from the house. The size 
>> (enclosed area) may be smaller. You may use a coax cable going to the 
>> shack (maybe RG174) that is grounded in the garden, with an own LF 
>> earth rod. Then you can use a transformer to couple the signal to 
>> your RX.
>> There are several ways to do it and the best SNR that can be achieved 
>> depends on the local noise situation.
>> I am rather a fan of small E probe antennas since they are easy to 
>> build and can easily be lifted to 10 m above GND, e.g. with a small 
>> plastic rod. But my experience with loops is small, maybe i become a 
>> fan of them too soon :-)
>>
>> 73, Stefan/DK7FC
>
>
>