Return to KLUBNL.PL main page

rsgb_lf_group
[Top] [All Lists]

ULF: 44 mA into my antenna on 2970 Hz

To: [email protected]
Subject: ULF: 44 mA into my antenna on 2970 Hz
From: DK7FC <[email protected]>
Date: Sat, 06 Aug 2016 18:48:08 +0200
In-reply-to: <[email protected]>
References: <[email protected]> <[email protected]om> <[email protected]> <[email protected]> <[email protected]> <[email protected]> <[email protected]> <[email protected]> <[email protected]> <[email protected]>
Reply-to: [email protected]
Sender: [email protected]
User-agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; de; rv:1.9.1.8) Gecko/20100227 Thunderbird/3.0.3
Hi all,

Since a few hours i'm running a higher power on 2970 Hz. My own grabber shows an increase of 5 dB. The measured antenna current is now 44 mA, see https://dl.dropboxusercontent.com/u/19882028/ULF/44.4mA%402970Hz.jpg (with the Heidelberg castle in the background ;-) ). This should mean 5 kV on the antenna and 250 nW ERP.
A suitable capacitor is now in parallel to the antenna. It seems to have a high temperature coefficient. I'm trying to stabilize the working point of the system to keep the current constant...
270 mA is now running though the yoghurt cup coil which was used on 6.47 kHz in the past. Maybe the internal iron powder cores begin to saturate slightly at this current and frequency? This could explain the higher losses and the lower resulting voltage or antenna current. Actually i did expect 57 mA...

73, Stefan
<Prev in Thread] Current Thread [Next in Thread>