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Re: LF: DK7FC in North Italy

To: <[email protected]>
Subject: Re: LF: DK7FC in North Italy
From: "Graham" <[email protected]>
Date: Thu, 23 Feb 2012 15:07:02 -0000
Importance: Normal
In-reply-to: <[email protected]>
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two beer cans spaced abt 1.5m  ..... more intermodulation
 
Q was that  prediction  made when the  cans  where full  ..or  slightly  afterwards  ?
 
G..

Sent: Thursday, February 23, 2012 2:40 PM
Subject: Re: LF: DK7FC in North Italy

Hi Alberto,

Interesting. Keep us informed about your results with the short active dipole. I've never tried such an antenna so far. But maybe it could be an idea, if the ground is QRM-contaminated...

73, Stefan/DK7FC

Am 23.02.2012 15:10, schrieb Alberto di Bene:
On 2/23/2012 2:30 PM, Stefan Schäfer wrote:
Hi Alberto,

That looks fine. I'm glad to get a report from you, thank you.
How long was that wire and was it in the house or outside? :-)
Hi Stefan,

   oh, that wire was just a dipole for the 40m band, directly connected to the receiver, without any form of tuning for the 137kHz band.
Signals are low, but so also is the noise...  :-)    
Often is advantageous to have a not so high gain antenna... the S/N ratio can improve... not always, but sometimes yes.

That dipole is low in height. Actually it is an inverted V, with the apex at 10m from the ground.
For the LF band I have also a mini whip, temporarily out of service, as I used the coax feeding it for some tests of a differential active antenna,
with two beer cans spaced abt 1.5m connected to the differential inputs of a high impedance amplifier.  It works quite well, as it  does
not need to be referred to a ground potential, but maybe I have to change the schematic of that transimpedance amplifier, as it
exhibits more intermodulation that I thought it should have....

73  Alberto  I2PHD

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