At 10:33 PM 5/31/2009, Bill Tippett wrote:
>K5PC:
> > If these snap-ons work, they will make life simpler, and are
> much easier on
>the wallet. I bought six cores from Mouser for about $90.
>
> Either type will work, but the DXE style choke can be made
>using mix 73 binocular cores costing $0.429 each, instead of $15 each:
>
>http://www.newark.com/jsp/search/productdetail.jsp?SKU=02E8908
>
>Wind 3 turns per side, ground one side at the choke and the other
>using the shack ground.
I understand that low-output RX antennas like flags, pennants, and
various loops need more common mode suppression than Beverages. I
wonder if two of those chokes, with a ground in between, 10-15 feet
from the matching transformer, would be a satisfactory design. I am
currently using two 50-bead over RG-59 chokes (unknown or
un-remembered material) in this configuration, but would like to come
up with a more compact and weatherproof alternative. Jack Smith at
Clifton Labs has a design in development that provides roughly 10
times the common-mode inductance of my bead choke (the ON4UN cookbook
design), but his has some bells and whistles (for wider frequency
response) that are probably unnecessary for a topband RX application.
73, Pete N4ZR
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