Re: LF: Re: 137 grabbers

[Stefan Schäfer <Stefan.Schaefer@iup.uni-heidelberg.de>]

This looks like a very good design. Fascinating easy!! Is it completely grown in your head or have you seen it somewhere in the web?
What is the gain, about? I know the BC337 as a low noise NPN transistor.
Your loop is 2m diameter? How many dBs is the background noise abovethe soundcard noise?

Another question: Why are the T37-43 (the 43 types in general) preferred to the 77 types? The 77 types have a higher AL value and should come out with less turns. I tried to wind a band pass coil with but of the types (T50-43 and T50-77) and achieved about the same Q. Is it just a question of an available distributor?

And what is your job? Do you have to design electrical circuits? ;-)

73, Stefan/DK7FC




Am 14.08.2011 18:07, schrieb Minto Witteveen:

Loop antenna: http://www.pa3bca.nl/index.php?option=com_content&view=article&id=10&Itemid=14

From: Minto Witteveen

Sent: Sunday, August 14, 2011 18:03

To: rsgb_lf_group@blacksheep.org

Subject: Re: LF: 137 grabbers

 

Mal, LF,

 

I am now using a single-turn loop in the backyard (hight abt 2 meters) instead of the miniwhip.
One of these days I will test again with the miniwhip. First impression (testing the noise against DCF39) was that they dont differ very much.

 

73’s Minto pa3bca (grabber at http://pa3bca.pa3bca.nl:8181)

 

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Ceterum censeo Carthaginem delendam esse

 

From: mal hamilton

Sent: Sunday, August 14, 2011 17:51

To: rsgb

Subject: LF: 137 grabbers

 

LF

My signal seems consistant on the PA3PCA grabber but varies a lot on the DK7FC grabber, sometimes stronger on this grabber and others like now barely visible. Could it be the type of antenna in use ie one is more prone to noise es qsb than the other?

de

mal/g3kev