View Single Post
Old 24th Nov 2020, 5:10 pm   #22
Bazz4CQJ
Dekatron
 
Bazz4CQJ's Avatar
 
Join Date: Apr 2009
Location: Oxfordshire, UK.
Posts: 4,924
Default Re: How effective is an earth for reducing noise on AM?

Quote:
Originally Posted by stevehertz View Post
Quote:
Originally Posted by Bazz4CQJ View Post
Well, if a passive loop seems interesting, you have to wonder what an active loop might be like, which brings us back to posts 2&3.

B
Indeed, I think I'm going that way. They are expensive though.
Not if you build one. I think the Wellbrook clone is do-able for ~£20; the main components are two transistors and two ferrite beads. The construction of a Wellbrook clone has been described in detail in a BVWS bulletin by a member of this forum who decided not to use the tiny PCB which can be bought. The one challenge about the Wellbroke clone is making the multi-winding transformer using a binocular ferrite core, but that's a question of time/effort rather than expense.

There are other designs. David (EBT) is using a design by Paul Tempest (also in BVWS). There's an amateur in Bulgaria who started building magloops as a hobby but now runs a business doing it. His older designs are around.

I suspect that the big difference between the various designs is how they perform at higher frequencies, but as you seem to be mainly interested in MW/LW, they might all do a good job. My Wellbrook clone does a reasonable job on the 80m amateur band and stands a good comparison against my inverted V.

Cannot comment on the Tecsun; have not previously encountered them.

B
__________________
Saturn V had 6 million pounds of fuel. It would take thirty thousand strong men to lift it an inch.

Last edited by Bazz4CQJ; 24th Nov 2020 at 5:16 pm.
Bazz4CQJ is offline